Hydraulic Automatic Counting Paper Stacker 1）99% count accuracy. 2）Hydraulic control lifting, more safe and stable. 3）High production efficiency, 1 paperboard can achieve 2 outs, 3outs, 4 outs, 6 outs at one time. 4）Have dozens of patents approved by China’s government.
Machine of this series adopt feeder with automatic lifting device that can achieve automatic feeder feeding and also semi automatic manual feeding. Manual feeding is special available for curved corrugated board and thickness over 6 mm. The machine adopts “wheel into way” of the paper feeding, which makes convenient operation, also can reduce the labor intensity effectively, equipped with multi-group of pressure wheel and wool wheel during the paper running, also equipped with belt to ensure oothly paper feeding. Automatic feeder feeding system is based on ordinary flatbed die cutting machine, to reduce labor intensity, improve manufacturing precision and production effective, can achieve quick and ooth paper feeding by equipped with “4 suction 5 feeding” feeder. Collection unit adopts brush device and blower to ensure paper neatly. The machine could be applied for all kinds of printed paper boxes, 5 and within 5 ply cartons. Have advantage of ooth and accurate feeding of paper, high speed of die cutting also the suitability for variety kinds of works.
The recent release by FEFCO of a new Standard for Converting equipment further emphasises the constant demand by the corrugated industry for consistent print quality, regardless of the press equipment being used. By categorising the key elements of the printing process, such as “Colour variation”, “Ink Consumption”, “Ink system cleanliness after wash-up”, printers, Press OEM and suppliers, can now all work to a common defined standard for converting corrugated paper. This will help to ensure their products are correctly specified and toleranced, in order to meet the specific targets of each of their clients.To document this standard, the FEFCO team, collected and analysed considerable amounts of data, with a fundamental part of the printing section being to understand and quantify the process of Ink transfer through the printing system. In order do this, it is first important to define the term “Ink Transfer”. Within the corrugated converting system, “Ink Transfer” can be defined as “the weight of ink applied to the board, every print repeat”. In relative terms, it can be quantified by measuring how much ink is at the start of the process, specifically, the quantity of ink carried by the anilox roll, in relation to the quantity of ink at the end of the process, essentially, the amount of ink on the surface of the paper board. By defining and measuring the quantity of Ink as an Ink Film Thickness (IFT) in microns (um), it is possible to calculate the relative Ink transfer through the flexo printing process using the simple calculation:Relative Ink Transfer in Flexo =% IFT = IFT on Paper board x 100%IFT on AniloxFEFCO Standard calculation for Ink TransferWhy is understanding Ink transfer important? Taking a look at the causes of common defects in flexo printing, will quickly answer this question, with the majority of defects such as Dot gain, dirty print, skip out, mottling, pin-holing, to name a few, being caused by having too much or too little ink, being transferred through the printing system. This leads to variations in print quality from press to press and from job to job. These are the major hurdles to achieving right-first-time graphics and consistent printed box quality. To eliminate these defects is a constant batttle for convertors, meaning that incorrect Ink transfer can frequently be the direct cause of delays with press set-up, increased downtime, product reject & waste and increased consumable costs. For high quality, cost conscious printers, Ink Transfer matters a lot!Study of Ink Transfer: In a recent project to study Ink Transfer in corrugated printing, one of several sponsored by Pamarco Global Graphics, industry specialist Wilbert Streefland, organised a series of tests on the Bobst Masterflex press, located at a DS Smith plant in Germany. By installation of 2 calibrated Pamarco Eflo anilox rolls into the chambered inking systems, the target was to measure Ink transfer through the converting process and to study the changes in Ink transfer in relation to the common variables of corrugated flexo printing. The key variables tested were 1) Press speed, 2) Paper Board type & quality, 3) Ink density, 4) Water addition to ink 5) Single colour & Wet-on-wet, 6) Full & half tone plates and 7) Anilox specification & cell profile. Weighing the ink loss after each print repeat: One of the unique feature of the trial, was the method used to measure ink transfer. By installation of a precision weigh scale under the ink bucket on each of the print units, and linking with a press sensor to trigger the ink weight measurement with every sheet that passes through the print station, it was possible to accurately measure the ink loss with every sheet of board printed. In a series of 7 different trials, using over 10,000 sheets of board, at print speeds of up to 7000 sheets per hour, the data collected and analysed exceeded 60,000 individual weight measurements.By measuring the exact Ink film thickness of the anilox at the start of the process and by knowing how much ink was deposited on each sheet of board, it was possible to calculate the exact quantity of ink transferred through the process. Hence by monitoring the variations in relative ink transfer with every changing variable, it was possible to determine, which variables had the most significant effect on ink transfer.One unexpected finding of the testing was that the ink loss on one print unit was significantly higher than on other units, to a point where ink transfer had exceeded normal print conditions. This led the team to identify a leaking ink pipe, which was causing ink to be deposited to waste at a rate of several kilograms per hour and a cost of many euros per day. Besides corrupting the data until the problem was fixed, the obvious conclusion of this chance discovery was to consider that the inclusion of an inexpensive weigh scale on each press ink station, could easily identify these types of faults and lead to substantial savings in ink costs on a daily basis. “Press manufacturers take note of potential upgrades!”What are the key factors for good ink transfer in flexo: Several of the conclusions from the trial were expected, such as the addition of water can improve ink transfer, but is offset by a substantial reduction in print density. The trials certainly proved that the addition of uncontrolled quantities of water to the ink is definitely not recommended when trying to maintain controllable levels of colour density. Other results which indicated that wet-on-wet printing gave higher ink transfer than single colour printing were less predictable and would require further testing to quantify the impact on high graphic printing.EFlo anilox: Based on previous tests and industry experiences, it was no surprise to learn that the EFlo anilox had the highest ink transfer in all tests, with the extended cells, proving to give optimum ink transfer under all conditions. However one of the most significant and unexpected findings from the trials was that the relative ink transfer values in all tests, always stayed within the range of 12 to 35%, a surprising low value and certainly one which leads you to ask, what happens to the rest of the ink?Press speed & Ink density: The tests demonstrated that when using high density inks, speed variations between 3500 & 7000 sheets per hour, had very little impact on ink transfer. However when using low density or water diluted inks, which is probably more normal conditions for many board convertors, higher press speed, gave reduced the ink transfer.The substrate is critical: One of the fundamental conclusions of the trial and one which is no surprise to many experienced corrugated printers is that minimum amount if ink that needs to be transferred to the paper substrate is dictated BY THE SUBSTRATE! This means that selection of anilox specification to suit the type of paper board remains the critical decision for printers and press OEM. When printing on un-coated board, you should select an anilox which has sufficient Ink Film Thickness (often referred to as Cell Volume), to provide enough ink for good coverage and print density on that board. This project has shown that changing ink density and press speed will only take you so far; therefore matching anilox specification to paper board remains a fundamental decision for optimising print results.In conclusion, it is believed that these trials are the most comprehensive study of ink transfer through the flexo converting process in a practical and commercial printing environment, but as with many ground breaking projects, in answering some questions, many new questions are also raised. Certainly it is thought provoking that 65-88% of ink remains within the inking system either in the doctor blade chamber & pipework , on the surface of anilox roll. Little wonder that maintaining the cleanliness of anilox remains a major task for printers when trying to produce consistent print results”.
What’s Required to Increase Press Speed?In order to understand what is necessary to improve press speed, it is helpful to step back and remember the big picture. If you look at print growth over the years, the real issue with press speed has simply been a lack of technology. As knowledge and machinery abilities have increased, so has press speed. The machines coming out now are not as gear-driven as the presses that came out in the 60’s, 70’s, and 80’s.The challenge with that growth has been finding ways to get more scientific data with the numbers that involve line screen and volume.Along with the improved ability to harvest this data, the increase in press speeds can also be attributed to the advancement of plate technology, pre-press, and higher quality inks. Press speeds in the past were less than 800 feet, but now they’re close to 3,000 feet. Some CI presses are averaging speeds of 1,200 to 1,400 feet, and still looking to increase, and a few are even running 2,000 feet already.I believe that these increased speeds are a result of five areas in which there has been great improvement over the years:1. Enhanced art work.2. Thinner plates with better ratios of anilox cell to dot-on-plate.3. High line-screens with more volume due to higher-wattage lasers.4. Servo drive machines instead of chain driven – tailor made for the customer.5. Cad cam designs from press to anilox with tighter tolerances.While growth in any of these five areas nearly guarantees improved speed and quality, it is impossible to get repeatability without correct and consistent equipment. Are you using the optimal gear for what you want to print? Do you have the proper anilox roll engravings for the volume you need? Take the time to find out what works for you.The angle of the cells, the carrying capacity of the cell and the number of cells per linear inch. I think banded roll testing is important to increase press speed because it will help you find exactly the right anilox roll for what you want to print. The anilox is known as the “heart of the press” for good reason. Choosing the right roll helps to create a good foundation for a variety of printing challenges. When it comes to increasing press speed and maintaining quality, finding the right anilox is a critical step.
The anilox roll and doctor blades are designed to work together to deliver a precise amount of ink to the plate. It is important to take time during a doctor blade installation in order to ensure print quality. A doctor blade that’s installed correctly will have uniform, balanced contact with the anilox roll and remove ink consistently across its surface. Blade positioning, orientation, angle and pressure will affect the delivery of a precise amount of ink to the plate, and proper installation will give the printer control over consistent, repeatable print quality.Doctor Blade InstallationPositioning and OrientationIt is essential that the metering and containment blades be positioned correctly when they are installed. Depending on the rotation of the anilox roll, the metering blade could be positioned on the top or the bottom of the chamber. Keep in mind that the metering blade is always the last blade to contact the roll before the ink transfers to the plate. The containment blade is installed in the opposite location. If the two blades are installed in reverse, the metering blade will not achieve the appropriate point of contact with the roll and remove the correct amount of ink before transfer. It is important to remember that the bevel tip should point away from the roll or towards the chamber to prevent streaking.AngleThe angle at which the blade comes into contact with the anilox roll is also crucial to proper doctor blade installation and optimum blade performance. Ideally, the contact angle should be 30° tangent to the anilox rollcircumference. In reverse angle and chamber blade applications, the doctor blade angle should be between 28° and 32°. If the blade angle drops below 28°, a larger part of the blade’s edge will come into contact with the roll. When this happens, the contact area is too big to meter effectively and the blade may allow ink to pass underneath or “hydroplane” at high speeds. If the angle exceeds 32°, it will result in faster wear on the blade.PressureWhen a doctor blade chamber is properly aligned, light pressure between the anilox roll and doctor blade is all that’s needed to produce a clean wiping action. The recommended pressure is 25 to 30 lbs. or 1.7 to 2 bars. Anything more than that will lead to a deterioration in print quality, wasted ink and substrate, and accelerated blade and anilox wear.A good way to tell if you’re using the correct amount of doctor blade pressure is to look at the roll once it’s inked. Before increasing pressure, the anilox roll will appear glossy. This is a sign that too much ink is remaining on the surface. Pressure should be increased gradually until a satin finish appears on the surface of the roll. A satin finish is a good indication that the correct amount of pressure has been achieved and the doctor blade is effectively shearing the excess ink from the roll. If pressure is increased beyond this point, the doctor blade edge will bend and hydroplane. The roll will again begin to look glossy because it is flooded with too much ink.The doctor blade plays a key role in the performance of the anilox roll and the printer’s control over print quality. Take the time to double-check blade positioning, orientation, pressure and angle during doctor blade installation to guarantee that the anilox roll delivers the precise volume of ink for which it was designed.
You may think that, once you’ve decided to purchase a flexographic press in principle, that your work is done. However, getting to the point of making a purchase decision – lengthy as this may be – is only part of the process. There are several common errors which can occur, both during and after purchase, that can make your new press more of a challenge to work with than it needs to be. This article will cover four of these commonly-made mistakes.1) Choosing Surplus Features | Not Choosing The Right FunctionsModern flexo presses have many new technological options to choose from. From automation and colours to efficient drive systems and optional add-ons, you will likely be tempted by many features, but do you really need them? You will need to look at your current budget and needs, as well as into your business’s future growth plans for the answer.What kinds of jobs do you currently complete for your customers? Do you expect the types of jobs you do to change, and if so, how? Finally, will those changes require a particular drying system, automation level or one or more optional components? It may be that you have some extra capital to invest in a conveyor system, web cleaner or additional drying system, but if it won’t add value to what you offer or provide you with long-term ROI, it could be money wasted.On the other hand, not having enough of the right features in your press can quickly set you behind the competition. If this is the case, you will need to think about how far this may put you behind, and whether there is a way for you to make the additional investment and obtain those needed elements.The process of choosing the right press can be frustrating. For many businesses, it can lead to choosing a press that has a lot of advanced features, but that won’t be used to its full potential. In order to choose the best press for you, you should match your features with your plans for growth and expansion over the next five years, and choose a press that can grow with you to maximise your production potential.2) Not Choosing A Machine That Works With YouMany businesses will purchase a modern flexo press, and then modify their processes according to the capabilities of that press. This is a common error. The press chosen should be the one that’s most suited to your current process. The way to determine suitability is to test the press before you buy. A top priority when purchasing any flexo press should be to ensure that it can print at the level of quality you require for the substrates you will be printing on.3) Going For A Bargain PressThere’s nothing wrong with wanting to save money, especially on an investment as large as a new printing machine. However, where it comes to buying a flexo press, going solely for the lowest possible cost is not advisable. Whether a machine is cheaper because it is used, was made in the Far East, or doesn’t have many features, not considering the long-term benefits of spending more will be to your detriment. As well, a lower-cost press may also not be as easy to set up, be able to complete jobs as quickly or be as energy efficient as a more expensive machine. You need to think in terms of total cost/benefit over the lifetime of the machine, and not simply about your initial investment.4) Putting It Into Service Too SoonToday’s flexo presses are impressive pieces of machinery, able to produce high-quality at incredibly high speeds and allow for many functions to be carried out automatically. Even so, they do require some time to master. Placing a press into service before your operators have had the chance to fully understand how it works can have many negative results, including inadvertent damage being done to the machine. Enough time must be given to ensure not only that proper training has taken place, but that what was learned was correctly retained.
How to identify the source of a web wrinkling problem and then determine the cure.Web wrinkling during converting can come from a variety of sources--sometimes multiple sources. Thus, pinpointing the exact cause and cure is not always easy. In fact, it is often a process of trial and error.This article addresses seven common causes of web wrinkling along with practical solutions. It should be understood up front that no two webs or web lines run exactly the same. Likewise, no two wrinkling issues are identical. The cure for one may not be the cure for another, no matter how alike.In addition, the causes of web wrinkling can vary greatly. Nonetheless, armed with a better understanding of some of the common causes and cures can help minimize trial and error efforts to get you back on target with your desired productivity and quality goals.Machine misalignment leads to roll misalignment.1. Poor Machine AlignmentMachine alignment is the first thing to check when experiencing web performance problems (see Figure 1). New rollers may be a waste of money if machine stands are not aligned properly. Though most machines are aligned when first installed, misalignment can develop later due to vibration, improper machine or roller maintenance, tension over time, or in colder climates, even freeze-thaw conditions that can shift plant floors.Poor alignment between rollers ultimately can cause a wide variety of web problems, including drift, flutter, and wrinkling. Straightening out the slightest misalignment is critical to achieving a higher quality process.Though alignment services can be tedious or costly, you may save time and money over other remedies that simply do not work. Checking machine alignment is an essential starting point and a good investment.Poor roll geometry can lead to tension differences that cause wrinkling.2. Poor Roller GeometrySometime, a non-cylindrical roller can be the cause (see Figure 2). Imagine a racecar whose tires are larger in diameter on one side of the car than the other, so the car turns naturally inward on the oval track. Likewise, the web will “turn” if the roll is bigger on one side than the other. When the web contacts the following roll at an angle, this roll will try to readjust the web back parallel to the roller’s centerline. This generally results in a wrinkle.Poor roll geometry can come from poor craftsmanship in the design and/or manufacture of the roll, from excessive surface wear or from inadequate roll specifications.3. Poor Web QualityPoor web quality such as gauge variation or poorly wound parent rolls can cause all kinds of problems. Excessive parent roll run-out can translate into vibration and web flutter. Inconsistent or poor quality web material can end up creating wrinkles through the whole process. No roller can totally cure that.Most machine operators can tell when they have a bad parent roll on the stand. Don’t accept inferior parent rolls from your upstream supplier. Once again, do not try to treat the symptom, but attack the problem at the source.Roller deflection from higher web tensions can create tension differences between edges and inside material that can cause sagging centers and/or wrinkles.4. Excessive Roll DeflectionExcessive roll deflection, or bowing of the roll under the force or load of the web, can cause wrinkling (see Figure 3). It may not be the effect of a single roll that causes the problem but the effect of the total system.Like so many other situations, the extent of the problem will depend greatly upon the web characteristics. Small-diameter idlers with long face lengths should raise a red flag for any roller supplier or machine designer. Roller material (steel, aluminum, or carbon composite), roller diameter, wall thickness, face length, web width, shaft sizing, and bearing location all have to take load, or deflection, into consideration.To avoid deflection problems, be sure your rolls are properly specified. When ordering, you should know the amount of web wrap (usually stated in terms such as 10 o’clock to 3 o’clock), web tension (PLI), any nip load (PLI), web width, and maximum expected line speed. A good supplier will walk you through these questions and can even help you troubleshoot much of this over the phone.5. Web ExpansionChanges in web conditions such as increased temperature or moisture content are likely to cause variation in the web material. For example, when a web tries to expand and it is constrained by frictional contact with a roller, wrinkles are likely to occur. In these cases, a strategically located spreader roll—one with a special surface grooving—can accommodate the variation and alleviate the tendency of the web to wrinkle.Unsupported webs are more likely to wrinkle6. The Unsupported WebToo little web support can result in bagging and wrinkling (see Figure 4). Unsupported webs also are susceptible to other environmental factors, such as the drafts from nearby equipment or normal plant ventilation. Even an open door can cause enough draft to result in wrinkling.Idlers typically are used to provide needed web support. The very act of wrapping a web around a roller does increase the web’s lateral rigidity. The strength and weight of the web will have a lot to do with the number and location of idlers needed. An applications engineer can better troubleshoot your problem when provided an elevation side view indicating rollers and location(s) where wrinkling occurs.If wrinkling occurs on a longer web span between rollers, additional idler support may be needed. When evaluating web span, consider the width of the web. A rule of thumb is: short = less than the width of your web; long = 3x the width of your web.7. Improper Web Tension ControlExcessive web tension can wrinkle, stretch, or break the web and cause unwanted roll deflection. Excessive tension can come from too much drag on idler rolls (bearing friction, roll weight, etc.) or from too many idler rolls between drive sections. Stretched edges and slack centers on the web are common with excessive tension.Loose webs also can result in wrinkles. Lack of sufficient tension can come from drive sections being out of sync or a poorly designed or calibrated tension control system.Lighter weight rolls may be the solution for tension problems experienced during line speed changes. These idlers can supply support without excessive drag. If the problem persists once the web is up to speed, an idler designed with special free-running bearings may be needed.If you suspect tension problems are from too many rolls or rolls that are too heavy, try experimenting. Spin individual idlers by hand. Are they hard to turn? Can you selectively remove or replace some rolls and see problems can be reduced?If you are running a light web at light tension, and all your rolls are heavy steel idlers with sealed bearings, you could try lighter-weight idlers with free-running bearings to reduce roll inertia and drag. Lighter materials, such as aluminum or carbon fiber with free-running bearings, can significantly change operating performance.Regardless of the many precautions and cures you might apply to your web converting operation, sometimes wrinkling is just going to happen. In some instances, a special roller will help. In others, it won’t. The problem may be in how the parent roll was wound. It might be in the makeup of the material itself. The cause may be a combination of things, some of which may be out of your control.There is no magic cure for wrinkling. Do your homework and then look to the experience and advice of a qualified roller manufacturer to help work through the options.
THE ISSUES RELATED TO APPLYING UNCONTROLLED INKIn the world of Flexography printing, customers are demanding higher profiled printing while utilizing (4) color process, (7) color HD or expanded color gamut and line work bringing breathtaking life to many packages.Whether it’s the most complicated printing job or the simplest line work, controlling the Ink Film Thickness is very critical when it comes to providing a high quality in a repeatable print job. Commonly known print problems such and dot gain and dirty print contribute to a loss of time and money with customer rejections and reprint costs, short stops for cleaning plates, press downtime for re-mounting plates, and additional job hours and materials to complete the order.As a general rule, the smaller the doctor blade tip thickness in relation to the contact area, the cleaner the wipe resulting in less ink film thickness and a cleaner print.The doctor blade tip must be matched to the specific anilox line screen in order to maintain the correct ink film thickness. Today many companies are spending high dollars on state-of-the-art printing presses, anilox rolls, plate material and inks, often not taking into consideration how much of an impact the doctor blade has and the game changer it provides to improve quality, service and costs.
You spend plenty of time selecting the correct anilox roll for a job. Careful consideration goes into line screen, cell geometry and cell volume in order to guarantee that a precise amount of ink or coating is delivered to the substrate. Aniox roll cleaning is essential to maintain this precision. If you neglect to clean your rolls on a regular basis, you will not get the most out of your anilox investment. Plugged cells will affect print quality and cause you frustration, waste and downtime. An anilox cleaning program consisting of daily, weekly and deep cleaning will preserve the integrity of the anilox engraving and ensure quality, press efficiency and longer anilox life.Benefits of regular anilox roll cleaning:The repeated transfer of a precise volume of ink or coating.Consistent coverage.Reduced labor and less downtime.Fewer job rejections and waste.Longer anilox life and lower re-working costs.Flexo Concepts recommends a 3-step anilox roll cleaning program:1. Daily wiping to prevent ink or coating build-upApplying a liquid cleaning agent by hand and wiping down the roll with a clean, lint-free cloth on a daily basis is the simplest and most effective way to prevent keep ink and coating from drying and building up in the cells. As a basic rule of thumb, the best time to clean a roll is as soon as it is removed from the press. The longer inks, resins, adhesives, etc. have been allowed to sit in the engraving, the harder these materials are to remove. To maximize cleaning performance, choose a cleaner specifically formulated to remove water-based, UV or solvent-based chemistries based on your application.2. Weekly scrubbing with a paste-like cleaner and an anilox cleaning brushManually scrubbing the roll once or twice a week with a brush and a paste or cream chemical cleaner will mechanically loosen and remove any ink or coating residue that remain in cells despite daily cleaning. The cleaner is applied to the roll, vigorously scrubbed in a circular motion with an anilox cleaning brush and flushed with water while the roll remains in the press. It is important to remember that stainless steel brushes are suitable only for ceramic anilox surfaces and brass bristles should be used for chrome surfaces to prevent damage to the engraving. 3. Monthly deep cleaning to remove tough ink or coating depositsOver time a residual amount of ink or coating material is left behind in the cells and the roll requires a deep cleaning to remove these tough deposits. The most common methods of deep cleaning are chemical wash and ultrasonic. The roll is removed from the press and placed into a chemical bath where it soaks in a powerful cleaning solution before being subjected to a high pressure rinse or ultrasonic vibrations to loosen and dissolve the deposits. These methods vary in cleaning effectiveness, risk of damage to the roll, and water and chemical consumption.
A score line in an anilox roll is a groove that has run directly through the engraved surface. The score shows a visible line in the printed or coated product and is irreversible. Once the surface is scored, the roll must be reconditioned or replaced. For these reasons, it is crucial to learn how to prevent scoring whenever possible. Below you will find an explanation on score lines, the different types and how to prevent them from occurring and keeping your print quality as high and consistent as possible. 3 types of score lines:Cosmetic or Preliminary.Lightly Polished.Severe or deeply gouged. What Causes Anilox Scoring?Over ImpressionOver impression can cause premature wear to the doctor blade and roll. Long Blade tip slivers can easily cause score lines: these are formed when the blade bends back causing wear on the side rather than the tip. As the side of the blade wears through, the tip breaks away in the form of a long metal sliver. Normal shavings from blade wear from “kiss impression” will not damage a roll.Doctor Blade Tip Material & SettingsAre you using the same blade for whites or metallic inks as you do for conventional ink? Using incorrect blade tip and material for type of ink can have disastrous results and hardened blades significantly increase the chance of scoring. The same can be said of replacing the blade on every anilox change. A blade “seats” to a specific LPI and is not meant to be used again. Blade forms to anilox and becomes a “Micro” saw. Finally, try resetting the doctor blade chamber after installing new blades. A worn blade is shorter than a new blade and if chamber does not reset, there will be excessive pressure.Try a nickel coated anti-scoring blade. Nickel is softer than steel and ceramic, many converters use this very successfully as it is more forgiving and can cover potential misgivings in the metering process. It will also last longer because of coating; cleaner doctoring because blade is stronger; resist corrosion better because the blade has a barrier coating. And remember, always use higher quality blades. A low quality low cost blade can break down fast.Helpful Hints1. Coated blades are more forgiving than uncoated blades.2. The doctor blades should never extend past the ends of the seals, but should be flush and even with the bevels on the end seal.3. A coated blade will offer more “forgiveness” than an uncoated doctor blade and compensate for error.4. Chattering blades vibrate and this action can act like a jack hammer to the ceramic and break cell walls.5. If too soft, improper end seals will cause leakage and operator might adjust setting to compensate putting more pressure on anilox and stress on the blades. Do not set chamber to stop leaking.6. Correct placement of end seals allowing even contact with anilox and consistent transfer of the ink film to plat.7. Shims break off or can become exposed to the anilox surface and cause scoring.8. Ink resins can glue pigments, blade metal and other debris to the blade.
Consumers in the corrugated industry are demanding a decrease in starch consumption. And not just for the cost savings either. Instead, it is the thinner, weaker paper – with weights as low as 80 grams – that are used for gluing board. This type of paper requires the application of less starch, as little starch as possible in fact. Add the fact that both water and heat are enemies of paper; applying too much water, has a negative effect on the smooth application of starch requiring more or longer drying, with all negative consequences for the quality of the paper. Another trend seen in the industry nowadays, is the fast-growing market for E-flutes and Micro-flutes. The flutes per linear meter for E-flute board are 295 (90 in inches), requiring a consistent application of a low dose of starch onto the board! The application of the level of starch is influenced by two factors:1. The gap between glue and doctor roll;2. The screen/profile on the glue roll;The gap between glue and doctor roll applies for approximately 60% of the glue application and this parameter can only be controlled by using the tightest tolerance in the manufacturing process of both the glue and the doctor roll. This is mainly determined by the materials that are used to manufacture the glue set, and its durability and reliability on the long term. Best results are reported when using a stainless steel glue roll in combination with a ceramic doctor roll. Of course, both have to be according to OEM specifications, even after one or two times reconditioning. In this case, special attention has to be given to the diameter build up of both rolls, preferably with durable materials such as steel or stainless steel. 2nd parameter determining almost 40% of the volume of starch/glue that in the end is transferred onto the Corrugated board, is the screen of the glue set.Theory behind finer screen countsGluing of board can very well be compared to the printing of board. In theory, a finer line count or finer pattern, results in a more detailed print result. The exact same happens with the application of glue: a more even layer of glue is applied onto the board.However, in all honesty, it is also necessary to mention that the finer the line count, in most cases, also the shorter the lifetime of the glue rolls is. In the recent past, very good results were achieved with screen counts of 50 l/cm (130 lpi). Beautiful even layers of glue were applied onto the board, but the minute the glue roll came into contact with the corrugator roll, very easily damage occurred to the fine walls of the cells, creating all sorts of issues like score lines.Together with leading companies in the corrugated industry, glue set manufacturers discovered a compromise that is currently often used while producing board, in the situation of Single-facers as well as Double Backers. A standard engraving of 10 l/cm with volumes of 120 cm3/m2, with an angle of 45° (25 lpi, vol. 78 bcm) and the screen of 15 l/cm with a volume of 60 cm3/m2, also with an angle of 45° (40 lpi, vol. 39 bcm) both deliver very consistent and satisfying results in the application of glue.CONCLUSION:Optimal starch consumption and reduced volumes are only possible with a reduced gap and the absolute tightest tolerances on the doctor roll and glue roll. Furthermore, the application of glue is determined by the screen count, as well as the screen pattern. It may be worth asking your glue- and metering roll manufacturer for the latest developments in this particular field of surface engravings, in order to realize significant cost savings thanks to improved board quality, reduction in paper waste, less starch consumption and less energy consumption (for drying).
Ghosting, a faint image from another part of the design that appears where it shouldn’t, has always haunted the flexo industry. Ghosting is most obvious in areas where large solids are used and always on printed side of substrate in the image area. What causes ghosting?Fortunately, the cause is far from supernatural. While much has been written on the subject, most agree on these six issues as the most likely causes of ghosting.Ink starvation.Ink fluidity is not appropriate.Chambered doctor blade not adapted.Mechanical issue.Anilox roll is not properly cleaned.Premature drying of ink on the anilox roll.What can I do?The next time you have an issue with ghosting, try working through each of these possible solutions.Increase ink level and/or pressure into the chambered doctor blade.Use higher anilox roller volume.Add solvent (retarder) to increase ink fluidity, to flood the cells, and avoid ink drying into cells.Use a specific design of the chambered doctor blade to force ink to flood the cells.Select anilox roller where the circumference is a whole number multiple of the repeat length of the design times the number of plates round the cylinder or change the diameter of the plate cylinder. Increase the speed of the machine.
First of all, let me state the fact: If pressure added by any step in the cardboard processing beyond the range that glue adhesive force or fiber can bear, the cardboard will be crushed. This often causes the inner linerboard fiber damaged or the adhesive force between inner linerboard and linerboard is not effect.This will cause a series of problems, such as equipment congestion, product scrap, poor printing quality, cardboard compression strength reduction. From the point of view of the carton factory, there are four key factors affecting the flat crush, namely laminated cardboard, processing tools, die-cutter status and cardboard feeding.1.Laminated cardboardIn general, corrugated density: the larger the number of flute per inch, the better the printing performance of cardboard, and the stronger the ability to resist flat crush. This is because the flute tip or flute waist is relatively close to the linerboard to provide more support. For example: compared flute B or flute C, flute E has more excellent printing performance and resistance to flat crush, but its edge compression resistance is poor.There are so many factors contributing to the flat crush resistance that it is almost impossible to find a single crushing factor for any given flute type. For example, if flute B crushed under the pressure of 40 pounds per square inch, we can see that the maximum pressure that flute C can withstand will be about 18% lower than that of flute B, that is 33 pounds per square inch, flute A will be about 35% lower than that of flute B. This is then greatly affected by the paper quality, gram weight, moisture content, the amount of glue used in the paperboard processing and the initial pressure applied to the corrugator processing.2.Die-cutting formsAlthough they are respectively used for specific die -cutting process, flatted and rotary steel die-cutting moulding are both used in the three main parts: Steel band( whether used for cutting or scoring ), veneer board, rubber. If any part is not used or improperly set, a flat crush may occur.Most of the flatted die-cutting is processing on the impression device, there is a steel cutting board under the cardboard when doing die-cutting. In the process of die-cutting, corrugated board sandwiched between the cutting board and the steel band, by both of the extrusion, cutting and scoring are both finished at the same time. This requires great pressure and a high degree of accuracy.Because the steel tools are used to cut each other, it is crucial that the distance between the surface of the veneer board and the tip of the steel band, as well as the depth of the impression. If the distance is too all, extra pressure is needed and may cause effluent. In some extreme cases, it drains off the veneer board and crushes the cardboard. If the distance is too large, then the cardboard and paper scraps are difficult to discharge.Even the slightest over impression may cause the steel band over contacting the steel cutting board, causing steel band premature wear. In this way, not only the steel band is not sharp, but may cause short distance above mentioned. In addition, blunt steel band cannot cut off cardboard sharply, and the cardboard may be mashed, which causes the cardboard crushed around the section of cutting line.Most of the rotary die-cutter is cutting on the surface of polyurethane with sawtooth cutting tools. Sawtooth shape and cutting bevel taper putting pressure at different angles in the die-cutting process. Cutting occurs only in the cutting position between the die drum and the anvil pad drum.Therefore, only a all part of the mold is cutting at each moment. Although this process requires much less pressure, the height of the steel band is still an important factor in controlling crush.One of the most unique points of the rotary steel band is the number of saw teeth per inch of the straight-line distance. In general, the less number of saw teeth means less force required to penetrate, however, at the cost of a greater depth of impression. The greater the impression depth, the faster the polyurethane anvil pad wear, resulting in uneven cutting surface, and flat crush.3.RubberThe proper use of exhaust rubber plays an important role in controlling the crush in the die-cutting process. There are various types of exhaust rubber available in the market, each type according to the formula has a specific advantage. Rubber is the least requirements among the die-cutting tools, but it has certain stimulation in controlling the crush.There are three basic types of rubber in die-cutting process, namely, open cell porous rubber, close cell porous rubber and pore rubber. It is worth noting that these rubbers or their use may have a great deal of difference in the rotary or flatted die-cutting process . And among these three types of rubber, hundreds of different specifications and formulas can be divided into different products.●Open cell porous rubber:Appearing in red hue, it is rubber of medium density. The surface is uneven and spongy. Such materials are sensitive to ultraviolet light and can suck dust into exposed cells. Rubber will become brittle and hard over a period of time. There is no doubt that this has changed the characteristics of common rubber, however, excessive impression on this type of rubber has little effect.●Close cell porous rubber:Appearing in grey or black hue, it is widely used in rotary and flatted die-cutting process. Compared with the open-cell rubber, this type maintains longer original physical properties under general factory conditions. However, excessive impression can cause tiny seal cell ruptured. When this happens, the rubber bounces much slower and no longer s properly.●Pore rubber:Pore rubber is the strongest among the three, and is in fact a type of close cell porous rubber. The compact pore structure creates a tremendous amount of rebound force, removing waste from the narrow area. Although this type of rubber can withstand greater pressure, excessive compression can cause the same problem that the same as close cell rubber.Each rubber material is supplied in a number of different height specifications and tolerates considerable error. In addition, over period of time, these rubbers have decreased in height and rebound speed due to recycling use. This is especially common in close cell rubber.Rubber firmness in cardboard crush plays a very important role. At present the industry mainly uses two kinds of hardness test standards: Shore”00” and Shore “A”, which is similar to the Fahrenheit and Celsius scales. Please determine which standard to use for testing rubber.There are two important points worth noting about rubber. First of all, soft materials can usually withstand greater pressure and produce less crush. But it often limits the speed of production. Harder rubber can achieve faster market speed, but more likely to crush carton.Rubber is a porous material, not a solid material. When rubber is compressed, it tends to be solid. The force and energy of the compression is discharged by the rebound force. The tricky part is to decide the degree of how compressible the rubber is and how hard it needs to get waste or product out of the mould. Then we have to find appropriately joint of the two factors, both reduce cardboard crush and extend rubber’s service life.●Veneer boardThere are basically two kinds of thickness of veneer board used to make die - cutting tools:1/2 inch and 5/8 inch. The height of the steel band is always the same regardless of the thickness of the board, but the distance from the tip of the band to the veneer board is variable. To compensate for the distance, a suitable rubber height must be selected .For 5/8 inch veneer board, a thinner rubber is recommended, To 1/2 inch, a thicker rubber is adopted, other than cardboard crush and discharge will happen.4.Die cutter statusIn general, pressing a cardboard on a die cutter will always be more accurate than embedding the anvil pad into the machine. Therefore, in the use of flat die - cutter, irregular cutting surface will not have a great impact. Be careful, however, the adhesive tapes and other materials that is sticky on the pressing plate. These materials may temporarily help cut, but it will also create excess pressure on the board.The condition of the soft anvil pad has a great influence on this part. The alignment between the die drum and anvil pad surface, normal wear of anvil pad and poor rotation can cause excessive pressure, resulting in cardboard crush.5. Cardboard feedingMost of the flatted die cutter feeding cardboard with a gripper bar, which is only contact the front waste. This is an excellent feeding way that will not crush the cardboard.The suction paper feeder with a vacuum device lifted from the top is also excellent and does not crush the board. On the other hand, rotary die cutter with a soft anvil pad usually adopts more than one feeding roller, so that mesh point formed between the polyurethane wheel and the lower steel cylinder. Basically, these die cutter are processing the cardboard in the center position. Liner paper is rough that is easy to wear polyurethane anvil pad, resulting in uneven force, and cardboard crush.Guide wheel of rotary die cutter will also cause cardboard crush. If you use a guide wheel, it is possible to trimming as well as die cutting. If so, remember to minor adjust the mesh point every time you pulling it, so as to better control the cardboard. If not trimming, then moving the paper guide wheel horizontally, at this point, not increase the meshing pressure, to reduce the compressive force.If the compressive force during the cardboard transfer minimized, the corrugated material may be slightly deformed. But this will almost not affect the cardboard strength, simply because the inner linerboard glued by starch glue has good elastic force. If the compressive force is greater than the elastic force, it will damage the fiber material, and this damage is permanent, giving rise to a permanent structural performance problem.
The reason to cleaning a plate is that there is paper ash on the plate. So let's take a look at the top 10 ways of dust removal, which turn out to be absolutely useful!1. Dust removal: tape dedustingTape dedusting refers to wrap a double-sided tape or fiber tape on the paper feeding roller, and dust removed by tape adhesive.The advantage is that the dedusting effect in the early stage is very good, and it is convenient to install, but the disadvantage is that after a period of time, more paper scraps are stuck on the tape to form a hard block. In severe cases, the surface layer will be pressed into a pit, and it is easy to falling off on the cardboard and cause inking paste or printing blank. So after a period, the roller must be cleaned.2.Dust removal : tape on the cardboardWhen the printing plate is stuck by dust, causing the printing blank, we paste the double-sided adhesive tape on the position of printing blank, and then start printing. Double-sided tape can be used to remove the dust from the printing plate, so as to avoid wiping plate, the disadvantage is that it may stick to the printing plate or other positions.3.Dust removal: in- line brush A printing press usually has a row of brushes. If used for too long, the brush will wear out and be covered with dust. This brush must be cleaned and maintained regularly. If the brush is worn, the brush will no longer be able to remove dust. The height of the brush installation should also be checked regularly, if it is a row of brush, it can be changed to a double row of brush, so that dust removal effect could be better.4.Dust removal: roller brushGenerally, a printing unit is added and two brush rollers are installed on it.The speed of the brush is lower than the speed of the printing press, and the brush rotation speed difference is used for dust removal. This cost is relatively large.5.Dust removal: water dedustingInstall a whole piece of plate on the first color printing plate, and then sprinkle with water, remove the dust by spraying water on the plate. The effect is good, and it is suitable for winter. The cardboard won't crack easily. T he disadvantages are easy to deink after watering, and time for cleaning roller is relatively long, besides, the carton pressure will be affected.6.Dust removal: cleaning equipmentBecause it is dusty in the carton workshop, the paper ash is easy to falling in on the top of the printing press and the baffle. If the equipment is not cleaned in time, a lot of dust will be accumulated on the top of the equipment for a long time. When the equipment is opened, vibration will lead to the dust falling off on the cardboard surface or printing plate, resulting in poor printing effect. Equipment cleaning is very important.7.Dust removal: spraying on the groundThe dust on the ground is mainly used in the slotting unit. The paper ash generated in the slotting process is easy to fly in the equipment, so water should be sprayed on the ground. In this way the ash falls to the ground and won’t fly again.This is easy to use.8.Dust removal: suction pipeA row of suction devices are installed on the side of the brush, similar to a vacuum cleaner, except that the suction hole runs through the width of the printing press. Suction pipe can be individually closed, by adjusting the suction to dedusting.9.Dust removal: running the machine to dedustingThe cardboard running through the print press while dedusting. This method is not recommended as relatively time-consuming, and cardboard crushed easily.10.Dust removal: manually brush to dedustingThis method is the simplest yet most time-consuming, and it works relatively well. It means to brush cardboard one after one, then printing. It is quite suitable for all quantity of cardboard , otherwise, it is extremely time - consuming.
Rapid ink cleaning is the way to achieve rapid ink change, while rapid ink change is the way to increase printing efficiency. Ink cleaning for many domestic factories now is a big headache, in particular the environmental protection inspection is getting strict, the longer the ink cleaning time, the greater the amount of sewage, the greater the investment in environmental protection. And the longer the cleaning time, the high the ink consumption, so is the cost. Intelligent ink cleaning is to use chamber doctor blade system, the entire inking system controls ink flow speed by air pressure, the higher the ink flow speed, the better the ink quality. Not only does it reduce the amount of ink, but it also improves the quality of printing.The advantages of the rapid ink cleaning system can be detailed in terms of time and cost.Conventional ink cleaning:10 minutes for each time, a waste of 2 kg ink;Intelligent ink cleaning: Only 2 minutes are needed every time, a total of waste is 0.5 kg ink;Let’s do the math: If 26 workdays a month, 80 min/day of ink cleaning being saved, then the annually ink cleaning time saved: 26 days/month *80 min *12 months = 24,960 minutes/year =416 hours, which improves the efficiency of printing press by 12%.Provided that $3/kg of ink, if using intelligent ink change, the daily cost savings is : 2 kg *$3 *10 times -0.5 kg *$3 *10 times =$45; Annual cost savings: $45 *26 days/month *12 months = $14,000Table1: Comparison of loss and quality between conventional and rapid ink cleaningItems Conventional Ink CleaningIntelligent Ink CleaningCleaning time10m2mInk waste2kg0.5kgWater needed50kg20kgProduction qualityMachine speed change will affect printing color; Scraper pressure is high, the machine speed of production hydraulic lose control Color and scraper always keep the same Maintenance for anilox rollerDamage anilox rollerNot damage anilox rollerTable2: Time and cost difference between conventional and rapid ink cleaningItemsInk cleaning timeInk wasteConventional Ink Cleaning Ink change for10 times a day, 100 minutes in total 2kg*$3*10 times=$60/dayIntelligent Ink CleaningInk change for10 times a day, 20 minutes in total 0.5kg*$3*10times=$15/dayDifference80min can be savedCost savings: $45/day
This paper will enable related operators on FFG and die cutter have a certain understanding of the process and adjustment about flat die cutter by introducing the principles of automatic flat die cutter in production process, in order to achieve the the carton production requirements of high efficiency, fast and high quality, to achieve the purpose of further reducing the production cost of the enterprise.1.Introduction to the s of the automatic die - cutter A complete die-cutting machine is mainly composed of three units, the paper feeding unit, die-cutting unit, paper delivery unit. The feed unit is similar to that of the printing press, which is to feed the paper into the machine, die cutting unit including die cutting and waste clear, it is the main part that cardboard being die-cut. Paper delivery unit is to counting the die-cut cardboard and stacking.1).Lifter There is a lifter before the cardboard is die cutting, the role of the lifter is to adjust the height of the ready die cutting cardboard to the appropriate position, so that operators can easily carry the cardboard. The price of lift is cheap, if there is no automatic paper feeding machine when printing, it is suggested that we can also match a lift, it can greatly reduce the labor intensity of the operator.2).Paper feeding machine The of the feeding machine is to feed the cardboard neatly and orderly into the die cutter, the current feeding machine has two modes, one is the leading edge feeding, one is the sucker feeding. Sucker feeding is suitable for cardboard that the surface is ooth, like color printing, and the leading edge is suitable for ordinary cardboard.The paper feeding unit uses a paper feeder to deliver the stacked cardboard to the rolling section in an orderly manner. There are a lot of wheels on the paper feeding unit. The cardboard is in contact with the paper feeding wheel, and the friction force of the paper feeding wheel is used to feed the cardboard into the machine. During this process, the cardboard is firmly attached to the feed wheel by suction.3).Die-cut mould machine The role of the die-cut mould machine is to roll the cardboard in accordance with the size and shape of the template.4).Stripper After the cardboard rolling, there will be some waste, the waste will be stripped through the waste removal.5).Splicer After the end of the waste, it is a neat cardboard with good quality, these qualified cardboard through the splicer for counting stack.6).Conveyor The conveyor is to transport a certain number of products that has delivered out by splicer to die-cutter, in the back of the conveyor, we can also match a strapper.Above is a complete die-cutting machine production process and the of each part.2.Die - cutter preparation before the operations1).Preparation before the operations The job of conductor●Start the motor of the main engine●Check whether all parts of the machine are normal●Check whether there is any paper residue in the equipment●Check whether there is any foreign body adhesion on the drive shaft and chain.●Check whether the teeth bar on the gripper bar is loose and falling off. First, start the main motor and rotate the start button to the start position.Secondly, check whether the teeth bar is loose, the screw is fastening, etc. The role of the teeth bar is bite paper, during this process, if the teeth bar gets loose or fall off, the gripper is not stable, die cutting will run. At the same time, we should also check the chain, the role of the chain is to drive the cardboard, in die cutting, it often produces some paper powder, paper scraps, if the paper scraps clip in the chain, it will jam the chain, which will inevitably cause the whole equipment in a bad running or mal.The job of paper feeding operators●Clean the chain and drive shaft of the machine, add lubricating oil.●Check the order status of the schedule list, mark the order with materials, and provide the conductor to arrange the orders.The job of paper receiving operators●Adjust the strapper.●Prepare the stripping tape.●Prepare the pallet.●Pad waste paper on the pallet.2).Preparation for production orderIn general, the core adjustment of die - cutter is done by the conductor. There are three main job content: install cutting die, install fill figure, die - cutting pressure adjustment and plate supplementary. For die - cutting, cutting die and filling tool are very important.Install cutting die The cutting die installation is within the range of the operating angle of 120 degrees to 240 degrees, loosen the fixing screw, and then open the locking switch to draw out the die holder. After the die holder is pulled out, open the reverse safety bolt to fix the die holder and then flip the die holder to install the die holder.Two points need to pay attention to the installation of the cutting die: The first is to align the fixed block, the knife needs to be aligned with the fixed block; Only stuck in the fixed block, the whole knife will not run. The second is to align the center line.After the center line is aligned and the position is fixed, the next step is to lock the screw. Generally speaking, first lock the screws on the four corners to fix the template, and then lock 2-3 screws in the center of the template. For places where the cutting die is relatively concentrated, some screws may be added to fix the template.Correction of cutting die After the template is installed, we need to prepare the stitching at the back of the template, that is a process of die correction. When doing the knife die correction, we need to set the breaking point, if not set the breaking point, the whole template will fall down after the cutting the waste cardboard, rather than attached to the whole cardboard, so it's important to have some break points.Break point requirements: as a flute B, the break point width is 1-1.5 mm. The depth is 3 mm.The connection spacing is greater than 15 mm. The break point of flute A: width is 1.5-2.2 mm Double wall: 2mm, depth is 5mm.Special attention should be paid to: Break point can not be set in the residual bridge position, the sponge hardness of the break points should be high than than is not the break point, otherwise it will not be fully rolled. When more than 90 % rolled, it began to fill the knife, that is, after the template is installed, to set and adjust the break point. At the same time, we also need to pay attention to the pressure, adjust to a normal pressure from 70% to 90% , during which there is a process of knife filling.paper scrap installation What the paper feeding unit needs to be adjusted is the front and rear side baffle and suction, if there is a chip unit, then it has the installation of an anti-chip template. Anti-chip template is divided into top template and bottom template.The bottom template is also called themold. Themold has a fixing block which shall be aligned with the bayonet and fixed with the bite bar. Then another bar is moved to the plane section of the mother mold for fixing, so that the mother mold is more secure. After fixing, push the die into the machine. Then push the to template into the machine. The top template is also called the male mold. Attention should be paid when installing the male mold: the bite direction of the male mold is consistent with that of themold. Put the male mold into the slot and push into the machine.
If cardboard scoring is not obvious, its shaping will be not beautiful, and even there will be some size deviation. 1.In general, the reasons why cardboard scoring line is not obvious have the following four aspects: 1).The gap between the upper and lower scoring wheel is too much The upper and lower scoring wheel gap is too big, so the pressure is not enough, which will cause scoring is not obvious.Solution: Adjust the gap between the upper and lower scoring wheel.2).Scoring rubber wheel wornThe rubber anvil wear will cause the whole circumference getting aller, so the scoring line is not obvious.Solution: Replace rubber anvil timely, because it is wear very fast.3).Cardboard strength is high and running speed is fast, resulting in insufficient strength of ??scoring wheel shaft Those scoring cardboard, its flute has a certain degree of hardness, while the scoring wheel is just a stressed wheel. If the cardboard strength is too high, and running speed is too fast, then the pressure time of the wheel on the cardboard surface is short, because the cardboard rebound force is very large, so the scoring line is not deep.Solution:Reduce the running speed or overcome the insufficient strength of scoring shaft4).The shape of scoring wheel does not meet the requirements The reason for improper shape of scoring wheel is that there are some problems with scoring wheel itself, such as variable-ellipse and deformation. In this case, the part where circumference is the allest is definitely scoring very lightly, while the largest is scoring too much.Solution: Replace scoring wheel2.Different widths for slotting position (linerboard and inner linerboard)Slotting position with different upper and lower width means there will have burrs and cracks when the slotting knife cutting the linerboard and inner linerboard.There are three main reasons for this: 1).Slotting knife passivatedPhenomenon: Slotting knife passivation will affect shear force of upper and lower knife, upper knife passivation will make the front cardboard being cut off, yet the back have little force to cut. Therefore, the upper and lower widths are different.Solution:Replace slotting knife2).Use a flat slotting knife Because the flat slotting knife is not easy to penetrate into cardboard, and will be slide due to the friction of cardboard surface. These slip will cause a narrow cut where the linerboard and inner linerboard first being send, and a wide cut where being send afterwards.Solution: Replace the toothed slotting knife.The advantage is that it will directly penetrate into the cardboard, and using the whole cutting edge which will not cause cracks.3).The slotting knife inserted the lower arc knife too deepIf the slotting knifethe lower arc knife too deep, before the cardboard touches the lower anvil, the upper slotting knife has been inserted, and the lower knife cushion has not contacted, it is easy to have cracking at this time.Solution: Adjust the depth of the slotting knife into the lower arc knife so that they are at the same point when contacting, so as to avoid cracking.
Carton production is not merely a good printing, slotting is also a very important part. The slotting depth requirements among all kinds of carton are also different, slotting displacement will affect the effect of carton formation and empty box compression.The specific aspects of slotting displacementThe carton's normal slotting error is plus or minus 2mm. Slotting displacement is mainly reflected in two aspects:1.Slotting depth is the position gap between slot position and cardboard scoring Correct model: Slot depth is in alignment with scoring line, in this way, carton will be well formed.Wrong model: If the slot depth exceeds the scoring line, one corner will be hollowed and the other one will be bulging out when the carton is formed. Molding will be very ugly, and will reduce the carton compression resistance. 2.Slot size position will directly affect the size of the carton. If the size is wrong, the carton will be scrapped. In the conventional production process, the displacement of 2-3 mm may occur, which will lead to poor carton molding, and the flap will be seaming or overlapping, which will further affect the use.10 aspects affecting the slotting accuracy.1.Feeding rubber wheel gap is too looseSolution: Adjust the feeding gap - about -0.3mm of cardboard thickness.2.Improper height adjustment of front baffle in feeding unit.Solution: Adjust the height of the front baffle, about 1.5 times the thickness of the board.3.The gap and position of the clamp wheel are not adjusted well.Solution: Calibrate and adjust the gap and position of the paper clamping wheel.4.Partial abrasion of feeding belt or rubber wheel.Solution: Replace or avoid use.5.There is no fixed-timing correction after replacing the new belt.Solution: Re-correction timely.6.Cardboard is very heavy or the width is large, paper into the cardboard bucket is too much.Solution: Less putting cardboard at the feeding entrance.7.The cardboard is too all.Solution: To add suction black plastic, in order to uniform feeding.8.The cardboard warped.Solution: Separate the warped cardboard with the flat ones, or folding before production, if cardboard is wide enough,reduce the speed.9.Slot gap is not adjusted well, bridge not equipped in the die - cutting unit.Solution: Adjust the slotting gap - about -0.3mm of cardboard thickness.10.Operators setting error parameters.Solution: Reset.Equipment with vacuum slotting In the process of carton production, slotting loss accounts for about 30% of the normal production loss. In addition, poor scoring and slotting will directly reduce the compressive strength of the carton by about 10%, and also reduce the post-production efficiency by about 15%. Some overseas carton factories have introduced a vacuum slotting equipment in order to reduce the loss and improve the quality and efficiency. The reasons for poor carton scoring and slotting is the cardboard in the production process will be jumping, warped cardboard is particularly obvious. This will not only cause great loss, but also reduce the compressive strength of the carton, and reduce the post-production efficiency, or even produce serious fishtail.In conventional production, most of the carton factories will install a strip in the printing press or in the slotting unit to install sponge, this is to prevent the cardboard run off in the slotting process, especially the back knife is most prone to rupture. In general, solving the cardboard jumping can reduce the occurrence of such problems.Then how to effectively solve the problem of cardboard jumping? The following to introduce a device with vacuum slotting .When the cardboard enters into the slotting unit, a set of belts are used to pull the paper. Under the belt is the air suction. When running in the slotting unit, the cardboard is transferring by air suction and the belt. In this way the cardboard is strongly sucked, and effectively avoid the jumping in the whole process of scoring and slotting.Small cardboard made by a way of using a new belt and air suction in the production are more competitive and qualified.Printing press equipped intelligent slotting unit without diantling cutting toolWe are all familiar with the slotting mode of the printing press, which is divided into double knife seat and single knife seat. When the required carton height exceeds the equipment parameters, the knife must be removed, or it will cut into the cardboard. It takes a long time to remove the knife, and there will be safety risks in the process of changing the knife.Here's a new art device that doesn't require to diantle the knife.How it works: 1.Combine the slotting front and back knives in one position.2.Rotate the direction of the slotting cutter to the top, and thenthe upper cutter to stop running.After two steps, the cardboard can be passed through the slotting unit.In the process of cardboard transfer, the difference between this art new device without removing knife and conventional equipment is the former device after the installation of paper feeding wheel in both front and back of slotting knife stand enables the cardboard to stably get through under the slotting knife seat.In the process of production, two paper feeding wheels can transfer the cardboard stably, in the process of slotting, it can reduce the jumping of the cardboard, avoid slotting cracks, ensure the carton slotting more accurate and clean.Two advantages of intelligent slotting units:1.No need to diantling the slotting knife in the production of carton.2.Carton slotting is more accurate, not prone to slot tearing, which is conducive to the improvement of carton production quality and production efficiency.Causes of die - cutting size error and corresponding solutions:Many people are worried about the problem of abnormal die size , in fact, there are five types of abnormal die cutting production, if you can find the cause and their solution, it can be avoided easily.1.Cardboard stability is insufficient.Reason: The length of the cardboard is unstable, the movement range is large, the stability is insufficient. Insufficient stability means when the cardboard in between the rubber pad and the template, if the strength of knife die in each place is not the same, it will cause the rubber pad having different rebound force, resulting in some friction. Large friction, slow cardboard driving, all rebound, fast cardboard moving.Solution: Reduce the rebound force of the rubber pad, raise the die cutting speed. Because of the inertia of the two rollers, the cardboard is sent out quickly, the rebound strength of the rubber pad will be reduced, and the cardboard size will not be a problem.2.The die size of the front and back is not consistentReason: The cardboard is sent out by the paper feeding wheel, when leaving the paper feeding wheel, the paper feeding wheel did not clamp the cardboard, and the cardboard is sent out by inertia, the force is not enough, at this time the upper knife mold in rotation, the rubber pad below is dragging the cardboard, forming a friction force. Cardboard movement is relatively slow, and the knife die rotation is relatively fast, the size of the back will become shorter.Solution: Stick a sponge strip along the circumference on both sides of the cutter, and as much as possible for the long cardboard. In this way, when the roller turns, the cardboard can be brought out through the sponge, to achieve synchronization.3.Rubber wheel The circumference of the old rubber pad is shortened due to wear and tear, but the gear ratio of the cutter mold and the rubber pad is fixed.The circumference becomes aller, in terms of the same angular velocity, the linear velocity of the pad becomes aller. The bottom of the cardboard will have resistance, cardboard will send slowly, and the top of the knife mold is faster than the bottom, which will also shorten the size of the cardboard.Solution: The speed of the anvil is accelerated by a speed difference compensation device4.The transverse part of the die is not easy to cut offWhen making molds, generally the horizontal is 0.2 mm higher than the vertical, but many companies in the adjustment of the mold will knock this height down, which will not be easy to cut off.5.Cardboard leading edge uncertainty displacement.The most important cause of uncertain displacement is the instability of the paper feeding. Cardboard is first from the slotting unit to the die-cutting unit, if not well handled in slotting unit, at the same time the cardboard is very long, and large, the front and back of the paper feed may not be synchronized, which will cause the error size.Solution: Put some tape or sponge on the scoring line to stabilize the feeding speed. That is, let the cardboard uniform delivery, it can solve the feed instability caused by the die - cutting size error.
1. Fixed units and opened units 1) Advantages and disadvantages of fixed unitsThe feature is that each unit is fixed, during order change, preparation can be done without separating the bed. For example, if a bed has 5 colors, when only 3 of them are selected to printing, the fifth color can be used for the preparation before production. The entire production will not be effected. Therefore, it has advantages in shortening the whole preparation and improving production efficiency. Costs are also lower. More importantly, because the unit is fixed, the color accuracy is very high, almost no error.The disadvantages of fixed units are: large space occupation, high price, cleaning and maintenance is difficult.2) Advantages and disadvantages of opened unitsThe unit can be separated and closed. The advantages of opened units are all space occupation, cheap, and clean maintenance is relatively easy.The disadvantage is that it uses gear to moving, color accuracy is not as good as fixed unit. When changing the order, each unit must be separated and then closed, the preparation time is relatively long, and because of separation and close more than one time, it has impact on the accuracy of the gear. When the unit is separating or closing, it is easy to cause danger to operators.2. Direct drive and gear drive printing press At present, the drive system of printing press is divided into direct drive and gear drive.The direct drive is that each color group is driven by a separate servo motor, and the gear drive is that the whole printing unit is driven by one motor, and each color group is driven by the gear.Table 1: Advantages and disadvantages of direct drive and gear drive(as below)Drive modeAdvantagesDisadvantagesGear driveThis is the conventional driver model, and most common way, it’s cheapThe error between gears limits the accuracy of each unit and is not suitable for high-precision products (except for the use of gear equipment from Taiwan).Direct driveEach unit adopts a separate motor direct drive, through the computer control correction synchronization, error is all, suitable for high precision color products, overlap accuracy can be achieved±0.25mm The price is expensive and the maintenance for electronic products is relatively high 3. Upper print and bottom print press 1) Advantages and disadvantages of upper printingUpper printing refers to the printing surface at the upper of cardboard, the roller is rolling the ink on the top of the cardboard. Its advantages are: The printing effect can be seen directly, and easy to check out the printing defects when operating.Of course, the disadvantages: Because the roller is atop, plus the gravity, when there comes the ink viscosity problems, ink is easy to be thrown out, falling on the surface of the cardboard, that is, easy to get ink stain. Another disadvantage is that because the cardboard face up, the dust on it is not easy to fall off, which is easy to form printing blank.2) Advantages and disadvantages of lower printingLower print means the printing surface under the cardboard, the obvious defect is that the presswork can not be directly seen, the printing defects are not easy to find, which has increased the difficulty of inspection. Correspondingly, its advantages is that ink will not fall on the printing surface due to gravity, ink contamination rate is very low. At the same time, the dust will fall down in the process of operation due to gravity, which will not stick to the printing surface of the cardboard, the printing blanks will be less happened.
The anilox roller is the heart of the printing press, If made wrong purchase decision, the production quality will be seriously affected. This article focuses on the following four aspects in terms of buying anilox roller:1. Select the appropriate cell volumeVolume directly determines the size of the anilox roller ink supply, presswork with different degrees of precision requires different ink supply volume, so the choice of anilox roller is to take full account of the roller cell volume.2. Select the right number of screen linesIn general, the amount of ink supply decreased as the number of screen lines increased, the higher the number of screen lines, the aller the amount of ink, relative uniformity is better. For a single cell, because the shape of the cell determines the existence of corner angel inside the cell, and just due to the corner angel, it hinders ink transfer, which is the so- called “corner effect”. The higher the number of screen lines is, the more cells are at per unit length. Meanwhile, considering the existence of a wall between two cells, the higher the number of screen lines, the larger the opening degree of cell, that is, the greater the relative depth, the more serious corner effect, resulting in a reduction in ink supply. Therefore, in the selection of the number of screen lines, ink supply should be fully considered.1) To consider the presswork with different degrees of precisionRelatively speaking, the field, lines, text etc. need large amount of ink, the number of lines should be low, color line patterns need all amount of ink, the number of lines should be high. In addition to the amount of ink, the number of dot lines on the plate should also be considered. The precision degree of presswork depends on the number of dot lines. On the printing plate, as the dot size determined, if a lower line number of anilox roller adopted, the area of each cell will be larger than that of some dots on the printing plate, so when printing, the dot will be immersed in the cell due to the dot without any support of the wall, therefore, not only the surface of the dot is inked, but the side wall is inked, resulting in the dot increased. Practice has proved that in order to obtain superior printing quality, the ratio between the number of anilox lines and the number of dot lines of the printing plate should be kept at about 4:1.2) To consider the printing material and requirementsDifferent printing material has different ink absorbency, so does the ink drying method. That’ why we should fully consider the ink amount among different materials. Generally, if ink absorption is high, we should choose low number of lines, if ink absorption is all, the high number of lines should be considered.3. Select appropriate cell shape1) In line with the form of ink supplyInk supply of flexographic printing is mainly divided into double rollers and scraper type. The scraper type can be divided into positive scraper, reverse scraper, chamber double scraper. Under the condition of the same number of lines, the volume of the four-pyramid cell will be rapidly reduced because of the scraper wear, therefore, the four-pyramid cell in most cases with the form of double-roller ink supply. And four - sided table, six - sided table can be used in scraper type.2)In line with the ink typeOblique cell can improve the performance of ink supply because it can ensure the flow of ink. Therefor, for higher viscosity of ink, or varnish, paint, etc., oblique anilox roller can be used.4. Select the appropriate anilox angleIn most cases, ceramic anilox roller with 60°and regular hexagonal will be considered for ink supply, only in special cases other angles of anilox roller will be used .
In general, when there is poor trapping, you may think that it is due to ink viscosity or PH value, however, you may also ignore that the ink drying is also the main cause of poor color trapping.1.What is poor trapping? What are the disadvantages of poor trapping?Poor trapping refers to two or more colors superimposed together. In many cases, the last color is difficult to cover the previous color, resulting in the former color exposed outside, giving rise to bad pattern printing. Poor trapping will directly affect the appearance of products, causing customer dissatisfaction or complaints, and even return.2.Improper ink fast drying adjustment will also cause poor trappingGenerally speaking, the printing order of trapping is from the light color to the dark color, ink viscosity from low to high, PH value from high to low, however, poor trapping still may occur even though many operators go through the methods above, why? You may ignore that the ink fast drying is also the main cause of poor trapping.As shown in the picture below, it should be the easiest to use black to overprint yellow, but in fact, it fails to do so. Why is that? It can be seen from the photo that, the black ink concentration is relatively high, brightness is also good, ink viscosity and PH ratio is also correct. Ink viscosity and PH ratio of the black color and yellow color trapping: It's not the viscosity, nor the PH, what's the problem? When doing overprint you will consider the ink drying speed, and the faster the ink drying the better the overprint.And the problem of trapping above is just due to the ink fast drying.3.How to adjust ink drying performance to reduce poor trapping?1).Lower ink viscosity does not necessarily show a faster drying speedAlthough yellow viscosity is low, it does not mean that the ink drying is faster than the black, which in the production process is the easiest to deink and scratch, so the ink desiccant added much more. Because of the black ink drying agent added, 14 s ink drying speed can be shortened to 7s, while the yellow is 10 seconds, then the black is significantly faster than the yellow drying speed. Ink drying faster, then the amount of ink transferred to the plate will be reduced, resulting in a fast black ink drying, ink transfer less, resulting in poor trapping.2).The drying speed of the first color should be faster than the latter oneInk drying speed control points: ink drying speed faster, the amount of ink transferred to printing plate will be reduced, inking amount cut down, ink layer becomes thinner, resulting in coverage force decreases. Therefore, in the printing process, the drying speed of the first color should be slower than the latter color.4.Solution of poor trapping should be improved according to the characteristics of productsWhen dealing with poor trapping, we should think before we do, or you will think the theory is useless. The solution of poor trapping should be improved according to the characteristics of the product. It is said that this kind of printing sequence can be black first and then yellow, the effect is very good.
Though doctor is not eye-catching, it has a crucial impact on product quality for high-precision color printing technology. Blade pressure, sharpness, contact position with the plate all having effects on printing quality. According to the actual needs, reasonable adjustment of these factors can solve many printing problems.Good scraper knife can supply quantitative and uniform ink to anilox roller, therefore printing products to meet our expectation. If not, it is easy to cause line marks on print surface, color difference, plug screen and other defects. Therefore, it is very important to understand the working principle of scraper knife and to use it correctly.1. Five important indicators when using a scraperBlade pressure, sharpness, contact position with the plate all having effects on printing quality. According to the actual needs, reasonable adjustment of these factors can solve many printing problems.1) Pressure: The factors affecting the pressure of the scraper knife are the size of the cylinder pressure, the difference between the hardness and softness of blade, the angle of the scraper knife and the printing plate, etc., the greater the gradient, the greater the pressure. Too much pressure will reduce the transfer rate of ink, giving rise to printing plate wear and blade wear, all pressure is prone to dirty the plate or cause scraper line.2) Sharpness of knife: Knife sharpness depends on whether it is a new one, the angle of blade when sharpening, the type of sandpaper (oil paper) used, etc. A proper sharpness of knife should be both effectively scraping, and not produce a scraping mark. Too sharp is often easy to produce scarping mark, and wear the plate.3) Scraper gap: Scraper touches anilox roller, when the blade gap and roller gap is too tight, the amount of anilox roller ink reduced, which will affect the printing ink transfer.4) Flatness of knife: The flatness and warping of the knife mainly depend on the installation method, and of course, it may be related to the foreign matter sticking in the groove of the knife holder or the blade and the liner.When the knife flatness is poor, there will be some water drop-like marks on the edge of the printing surface, or from time to time there will be some intermittent line marks. Some people think that rough ink, bad ink mobility are the reason to cause the above phenomenon, but in fact, poor knife flatness is the reason .5) Doctor movement: A left and/or right movement of a scraper knife plays an very important role in reducing the scraper line, improving the utilization of the scraper, reducing the wear of printing plate. If the doctor movement is abnormal, we should find out solutions to improve.2.Printing line marks may be related to the scraperThe reasons for line marks in printing, one is the damage of plate, the another is scraper not sharp enough. Besides, it’s likely due to a foreign body sticking to the back of the blade. The solution is to move scraper knife back and forth, up and down, so as to shake off the adhesive, if fails to do so, we have to stop the machine, and clean the knife.There is also a problem with the scraper, and many people believe it is caused by ink. The problem refers to sometimes appear irregular dozens of different lengths of line marks, looks like ink accumulation, it is different from the scraper line, which is continuous, but is actually caused by all pressure of the scraper or not sharp blade.3.What to do to solving the specific problemsThe above indicators of the scraper are both different and similar, in solving specific problems, you can use one of them, aw well as comprehensively use to thoroughly solve the problem. For example, when there are some interrupted ink lines, we can both solve by increasing the pressure, and by sharpening the knife. When a more serious dirty plate appeared, it needs a combination methods from several aspects. First to use a sharp blade, second to increase pressure, third to increase the distance between the scraper and the touch side.
1.Inking systemInk system is divided into open and chamber system.Chamber type: To put the whole ink in a enclosed space, that is, the ink chamber. The advantage is that dust is not easy to fall into the ink, and the main components of ink are resin and ammonia, therefore ink is not easy to volatile, and ink viscosity change will be relatively all. The shortcoming is that it's hard to see the amount of ink when you put it in.Open type: The whole ink is stored in the ink container, it is opened, which is easier to observe when you inking. A big drawback is that the dust brought by plate roller or other places is easy to fall in, and ammonia is very easy to volatile due to the open type, affecting the ink viscosity.The inking system is divided into four parts: ink supply, ink wiping, anilox roller and ink reclaiming.1) Ink supplyThere are three types of ink supply: air pump type, peristaltic type, air film type. At present, the air pump ink supply is the common way, peristaltic ink supply is relatively better, because it is the regular peristaltic moving through the compression force. 2) Ink wipingInk doctoring is divided into two kinds, one is by rubber roller, with the gap between rubber roller and anilox roller to adjust the thickness of ink on the anilox roller, the gap adjustment is generally 0~0.5mm. The other is by scraper knife, which has upper blade and lower blade, forming a chamber, after ink doctoring, the ink will be transferred to the anilox roller, the scraper knife angle is adjustable, there are 30°, 45°, 60 ° and other angles. Scraper knife type is a relatively mainstream at present, the scraper knife system includes three parts: a chamber knife on the top, a blade on the bottom, and the ink container.There are two kinds of scraper knife, including plastic blade and steel blade. The advantage of plastic blade: it can better protect anilox roller because it is softer than anilox roller, besides it is easy to install. The disadvantage is that plastic scraper knife is easy to wear, which needs frequent replacement, and the cost is high.The advantage of steel scraper knife is relatively cheap, not easy to wear, but improper maintenance is easy to damage the ceramic roller, such as the scraper installation position is not appropriate, in the case of defects, it is easy to scratch the ceramic roller, so its installation requirements is much higher than plastic scraper knife.Comparative analysis of two scraping systemsModesAdvantagesDisadvantagesRubber Roller1.Simple structure, easy operation 2.Full page printing effect is better 3.Not easy to damage 1.Not suitable for high - screen line printing 2.Ink consumption, more waste Scraper knife 1.Small amount of ink, less waste 2.Suitable for high quality printing 1.The structure is complex, which requires constant maintenance. 2.Improper maintenance is likely to damage the ceramic roller, and the operation is complex. 3.It is necessary to pay attention to the pressure adjustment of the ink supply which is very important, because the stability of the ink supply is controlled by the air pressure Due to the relatively advantages and disadvantages of rubber roller and scraper knife, there is also a compound ink supply system at present. To use rubber roller and chamber doctor for ink doctoring. The ink amount can be adjusted by this form. When to print the field with low printing requirements, use rubber roller to adjust; When printing high screen line with high printing requirements, use a chamber doctor. Its advantage is to combine with the advantages of both, ink thickness adjustment and its adaptability are high. The obvious downside is the complex structure.3) Anilox roller analysis The principle of anilox roller inking is the scraper to rolling the ink to a roller groove, and then rolling the ink to the printing plate.● The structure of the anilox rollerOrdinary anilox roller has a stainless steel roller inside, the surface coated ceramic. At present, the relatively good anilox roller will add a layer of nickel between the two. Because of the strong binding force between the ceramic layer and the nickel layer, the ceramic layer of the anilox roller is not easy to peel off, and hence has good stability and all deformation.● Basic structure of ceramic rollerAnilox roller has roller wall and cells, like a honeycomb, consisting of many holes, which is filled with ink, and ink rolling to the plate from these holes.● The numbers of screen line of anilox rollerThe roller cells have specific requirements, that is, the so-called the number of screen line, which refers to the number of roller cells by length of an inch. For example, 100 roller cells is equivalent to 100 screen lines, 500 roller cells is equivalent to 500 screen lines, at present a roller cell with more than 400 is the high screen line, ordinary printing is in the number of about 250 screen lines.● The arrangement of anilox roller : Mesh The roller cells are also arranged in different angles, with 60°, 30°and 45°, which can be selected according to different printing requirements. What's the difference in this angle? Due to different angles, the width of inking is different, so the roller mesh structure determines the ink supply, imprint and water mark. It can be seen that the ink supply uniform of 60°anilox roller is better, so the 60°roller structure is better.●The amount of inkingIf the width and depth of cell is different, the amount of ink is not the same, the deeper the cell the more ink, but the deeper one will be a big problem, because of the surface tension, the ink accumulation inside is not easy to come out, that is, supplying is not good enough. ●Basic requirements for roller makingYou can ask your supplier to do some tests according to this standard. For example, the full run-out of an anilox roller is 0.01mm, the run-out is 0.01mm, and the dynamic balance is 30g (400 RPM). Problems may be caused if you do not meet this requirement: 1). Ink roller jumping. 2). Damage equipment. 3). Uneven inking. Comparison of advantages and disadvantages of three anilox rollersAnilox roller modesAdvantagesDisadvantagesSteel Roller(Gradually out-of-date)Cheap1.No more than 180 lines 2.low surface hardness, fast wear,highfrequency maintenance 3.Roller cells has bad inking performance, printing effect is badCeramic Roller(Mainstream)1.The surface hardness is high, not easy to wear 2.Roller cells has good inking performance, printing effect is good 3.It can meet high screen line printing, up to 400 mesh 1.High price 2.Not easy to repair, high maintenance requirements High screen line Generally more than 400 mesh, suitable for printing high quality products High cost, and high requirements over the ink, printing plate, cardboard especially the requirements over the ink and printing plate are different from ordinary screen lines.
At present, the biggest advantage of the ink waste water treatment system in the market is that it can shorten the cleaning time by recycling ink in the cleaning process, reducing the output of used water.After configured ink waste water treatment system, using special agents to regularly clean anilox shaft will greatly improve the clarity of printing; Intelligent cleaning with one-button operation, automatic cleaning only for 8 minutes. Production efficiency is dramatically improved, so as to control labor costs, and more than 50% of the cleaning time will be saved. Compared with the traditional cleaning method, the anilox shaft will be cleaned thoroughly, so does mesh; In addition, each group produces about 10 kg waste water, which controls the production of non-fixed waste water and strictly controls the cost of waste water treatment, equipment investment, personnel costs and greatly controlled chemical agents costs. Before ink changing or cleaning on a traditional water-based printing press, the ink residue of each color group between the anilox roller and the rubber roller has about 2 kg. If each water-based printing press changes ink 8 times at one shift, then each shift will waste 16 kg. Let’s take $2/kg ink as example, so $32 is wasted. In total $64/ day, more than $23,000 / year.When purchasing ink automatic cleaning and recycling equipment, the following factors should be considered:1.The removal rate of water-based ink waste water COD, BOD, SS chroma must be high.2.Reduced space on floor.3.High degree of automation.4.Easy to operate, and the effluent treatment effect can reach the national zero discharge standard.
Scoring cracks happened quite often in dry weather, how to solve that? In fact, you can avoid scoring cracks, and improve the production capacity by properly modifying the scoring wheel of printing press, Pre-print wheel modificationCause of scoring cracks: pre-printing wheels of conventional printing press are made of iron on top and bottom and have different radians. If the radian of pre-printing wheel is larger, carton forming easy to form a rounded corner, which would not obtain a good pre-printing effect, and resulting in scoring cracks. Improved method: The upper pre-printing wheel is made of elastic materials such as rubber band or PU rubber. The surface of PU rubber should be a certain radian groove, which playing a buffer role, so that the cardboard is not easy to crack, and the bottom wheel will be used as scoring wheel to do the pre-printing.In this way, it can control the scoring point in advance, which to effectively achieve the straight effect of carton formation.Transformation of scoring wheel Improved method:The top and bottom convex point can be a little wider, radian can be larger relatively, so that the effect of scoring will be more straight which not only can improve the production efficiency of finishing unit, but to avoid cardboard scoring cracks.
1.Printing adaptability of surface tensionIt can be found that the transfer of ink determines the reproduction of color, in this process, many people will often find that the printing press ink transfer is not good. In fact, the most fundamental principle of ink transfer is surface tension, ink transfer relies on increasing the surface tension to set the surface tension value. For example: ink surface tension is less than the surface tension of rubber roller, rubber roller surface tension is less than the surface tension of the anilox roller, anilox roller surface tension is less than the surface tension of the printing plate, the surface tension of the plate is aller than the surface tension of the cardboard. If not in this order, the ink will not transfer up.Liquid is not easy to transfer from high surface tension to low surface tension, which is why when ink mixed with too much water, the color is not easy to print, and the color would be very light. Because the surface tension of water is the maximum, it is between 72 dyne and 72 dyne, and its surface tension will prevent the transfer of ink to these objects, when printing, do not mix water. Also, when you add a little water to the anilox roller, the tension of the anilox roller increases, ink is easy to stick up, so we can properly use water to handle surface tension. 2.Printing adaptability of PH valueLow PH value will cause the ink viscosity increased, resin hydrolysis dry precipitation, finally leading to uneven color, abrasive resistance is poor. While high PH value will cause the ink viscosity decreased, fast liquidity, slow paper and plate drying speed and printing paste ink and other shortcomings.3.Printing adaptability of viscosityIf viscosity is too thin, it will cause insufficient ink coverage on the paper, the ink is light which can be adjusted by thickening agent. If too thick on the other side, it will cause poor ink fluidity, ink consumption too much, slow drying on paper and plate, printing paste ink and other shortcomings. It can be adjusted by diluent. Therefore, when you are doing four-color printing, you should understand the adaptability of printing, understand the relationship between PH and viscosity. The printing order should be from the first color to the fourth color, PH value should be from high to low, viscosity from low to high, we should remember these points.For printing, these are the fundamental principles. If you don't know these principles, you’ll meet a lot of printing problems, but if you can fix the problems according to these principles, it's going to be much easier to print good products.
If cardboard warping, it can be improved through water wiping, steaming, and heavy pressure. However, the result is not satisfied after a variety of methods. So what should we do with this warping cardboard? Discard them directly or reprint? In fact, the loss can be minimized as long as a little improvement being made in the printing process .1. Slotting dislocation is the biggest problem after cardboard is warping After cardboard warped, the annoying problem in the production is slotting dislocated, rather than printing askew. The cartons printed askew at the range of about 3mm are acceptable to many enterprises. But, if slotting dislocated 3 mm, a lot of manufacturers would return all the cartons back. Because the slotting dislocation will directly affect the carton formation and carton physical indicators.2. Special printing process can be used to solve the cardboard warpingIn general, the normal process when printing cardboard is using one machine directly to printing,scoring and slotting. In this case, the process is relatively simple, but it will cause a lot of production losses, especially printing the warping cardboard. Therefore, it is recommended to use a special printing method:Operating procedures: printing press + scoring line (slitter) + slotting (printer or three blades and one angle).Advantages: Lower LossDisadvantages: Complex Procedures3. Specific operation processTake the upward warping cardboard as an example: This warping cardboard, the probability of slotting dislocation is the largest, the following for this kind of warping cardboard is the instructions to improve production.1.First to use the printing press to finish the cardboard printing, do not score and slot. In this way, the printing position is easier to adjust.2. Scoring the cardboard by slitter3.Turn the cardboard upside down to slotting, so that the direction of the cardboard warping has changed, which is conducive to the carton slotting.4.If you have machine equipped “three blades and one angle”, that’s s good. After the warping cardboard printing is completed, and the completion of the scoring, it is directly cut into cartons.If we can follow the above four steps of process improvement, the warping cardboard will be made into a carton oothly. Though there are a few more steps in the process, the production loss is minimized. The profit is rather low in making cartons, production loss must be strictly managed.
1. Paper feeding modeThe conventional paper feeding mode of printing press is: there are three sets of all pull rolls in the front, that transfer the cardboard to the paper feedingrolls, and then the paper feedingrolls transfer the cardboard to the following pull rolls.Because the paper feeding roll is a solid state, the upper and lower has two respectively, when in normal production, the height of feeding rollgap should be about 0.3mm less than the cardboard thickness, the gap can not be large or all, if the gap is too large or too all,the paper feeding precision can not be guaranteed, such as if the gap is too all, clamped too tight, cardboard will be crushed.If it is two sets of paper feeding roll mode, the advantage is of high feed precision, but the disadvantage is easy to crush the cardboard. The easiest thing to happen with two sets of feeding roll is 1).The printing operator adjusts only one set of feeding roll, causing the second set to crush the cardboard.2).Inaccurate display of paper feeding roll gap will lead to misjudgment.2. Paper feeding roll pressure control system Traditional paper feeding mode: The upper roll jumps up and down in the process of paper feeding. During pressure control:1).Pressure control system is inaccurate, resulting in cardboard being crushed.2).High speed paper feeding with a high frequency, but easy to hit the feeding roll, affecting the feeding precision. Improved paper feeding mode: The gap between the upper and lower roll is fixed, so during pressure control:1) The feeding gap can be adjusted according to the thickness of the cardboard when the pressure is controlled.2) The feeding precision is stable.
In carton factory, any intelligence and automation must take carton product quality as the priority, it is not realistic to make high efficiency production without good quality, noris the direction of carton factory transformation upgrade.Therefore, in the use of intelligent equipment, the carton factory must focus on product quality.The following will explain how to improve the chromaticity precision and dot clarity as well as improve the printing qualitythrough intelligence.1.Air- bag scraper is conducive to improve printing quality The traditional chambered doctor blade system adjusts the position of scraping blade and the anilox roller by moving the position of doctor blade on the holder, and adjusts the pressure and controls the ink transfer. There are many human factors in this kind of operation, so the best effect can not be achieved and the service life is short.The advantages of the airbag scraper is: Adjust the thickness of the ink layer according to the product requirements, controlled by air pressure, ink wiping is uniform, that keep the color is consistent, and the service life can extend about 30% than the traditional scraper. 2.Screened printing, dot expansion is conducive to ensure printing qualityThe printing number of screened printing plate is 1 million, while the traditional printing plate is only 700,000 times, the service life of screened printing plate can be extended by about 30%. Besides, dot expansion is conducive to guarantee the printing quality.Compared coated paper printing of the screen printing plate with traditional printing plate,as shown in the figure below. When printing coated paper with the conventional printing plate , the printing surface will be uneven, while the micro mesh printing plate will be relatively uniform. From printing plate perspective, micro mesh printing plate surface is ooth, the regular dots are raised, which appear as the dome, the printing quality is easy to be affected by the changed pressure. ▲ Micro mesh & Dome dotFrom the point of view of dot printing, the conventional printing plate can not be made by 1:1 dot production, so the printing dot deformation is serious, screen dot is made in accordance with 1:1 , so the printing dot not deformed.3. Double anilox roller, one machine with multi-purpose, it is good to ensuring the printing qualityConventional printing press has one fixed anilox roller, which is quite complicated to replace with, as it takes a long time. Double anilox roller structure refers to install two sets of anilox rollers with different lines, and supported inking system in one printing unit. One key switch, then printing with different paper (like coated paper, linerboard) , high dot, large solid area with different amount of ink can be coped easily.The advantage of double anilox rollers is that two anilox rollers can be arranged in one printing unit, which can be adjusted according to product requirements to ensure printing quality. For example, A printing press with the configuration as follows:The first color 250 mesh, the second color 350 mesh, the third color 350 mesh, the fourth color 250 mesh.Such configuration has a strong applicability.However, if there are three colors having large color lump or required high screen line, then the production might be difficult to operate.The details are as follows: 1.When there are three large color lumps, then color lump with 350 mesh is hard to print.2. If three color dot more than 60 lines, then printing of 250 mesh is prone to be dressing.But if you use double anilox roller, configured another two suitable anilox rollers for switching , this problem can be solved quickly.Double anilox roller structure, anilox roller switching can be completed in 3-5 minutes, the operation is very simple. This method can give full play to the performance of the printing press, that is, one machine with multi-purpose, it can print high dot line products, but also the production of ordinary products, it’s two birds with one stone.
When talking about the paper feeding roll , many carton printing operators will think of cardboard crush. It is really upset when the crushing problem cannot be solved. But, do you know that not only printing machines without paper feeding roll exists, but it have been used in many carton factories. Now let's take a look at how printing press without paper feeding roll solves the cardboard crushing problem. There are some differences between the non-paper feeding roll mode and the conventional feeding mode: the leading edge feeder platform has 5 rows of pull rolls, 2 rows more than the conventional of 3 rows. It is directly transferred to the back paper belt by the pull rolls, so there is no need for paper feeding roll to clamp the cardboard for subsequent tranission. Therefore, cardboard crushing problem can be avoided naturally.Feeding mode of the press with no-paper feeding roll in the whole cardboard production: When the cardboard is transferred to the suction belt by the first 5 sets of pull rolls, and then into the printing slotting or die cutting unit, the entire transfer removes the paper feeding roll.Conventional printing press feeding mode has paper feeding roll or suction mode.The equipment of the non-feeding roll is also the suction mode, but different from the conventional suction mode, it adopts the whole belt operation for the transfer, so that the cardboard can run more oothly in the overall transfer operation, which is conducive to the color register. In the production of cardboard, air absorption should be adjusted according to the size of the cardboard and flute, so as to ensure the paper feeding accuracy. Scope of application: This type of non-feeding roll mode is suitable for printing cardboard with downward warp, rather not upward warp, especially for high-quality material cardboard. Without the feeding roll unit, the cardboard will not be crushed, thus improving the capacity of the crush resistance of empty box.The key point of the non-feeding roll printing press is the maintenance of the pull roll and the control of air suction, second is the tightness and deviation correction of air suction belt , these two factors will affect the printing accuracy. Table:Comparison of paper feeding roll and non-paper feeding rollItemsAccuracyThicknessGap AdjustmentPaper feeding rollGoodLoss 0.3mmHaveNoe-paper feeding rollGoodNo lossHaving notDifferencesLittleNot damage cardboardLower labor intensity
In the process of printing, deinking often occurs. Once deinking, it will affect the production speed, and cause color separation and cardboard pollution.There are many reasons to cause printing deinking, generally it first comes to you is that the ink viscosity is too high or ink foam, but printing deinking is not necessarily the problem of ink, may be the printing plate is not installed tightly.Printing plate loosening is easy to cause deinking and burr of printing patternsWhen the operator installs the plate, the lock is not tight or the lock system of the printing press is loose. If the printing plate becomes loose during production, it will cause deblurring. The reason for this is due to the loosening printing plate, the plate base in the process of transission will be stained with ink, of course, printing ink transfer force is uneven in the process of production because of loose printing plate lock, this would cause ink dragging, resulting in deinking and blurry. Because the print plate is not locked, the plate base is easy to bulge out. It is stained with ink during operation and then transferred to the cardboard. The extra transferred ink is printed on the cardboard, but the printing plate if not locked, is prone to pulling, resulting in the printing deinking. Solution: lock up the print plate, check and clean regularlyIf printing plate not locked well, it will appear printing burr, color register inaccuracy. So in the production process, printing plate must be locked well, and regularly check and clean printing plate lock system, to ensure the normal operation of the locking system.
Carton formation should go through a series of processes like printing, slotting, stitching or gluing, strapping.With the improvement of equipment automation, these processes have evolved into one process. Such as printing, stitching(gluing) unit production line.No matter single machine production or inline production, every process in carton formation will have an impact on the cost. In other words, the more processes that go through, the higher the cost. The larger the batch size, the lower the production cost of the equipment with higher degree of automation and vice versa. However, in the case of more orders yet less quantity per order, the production cost of using a single machine is low, and vice versa. Important processes for reducing the carton formation process cost :Printing: High ink viscosity means high layer thickness, resulting in ink costs increased. This not only affects the printing speed but the printing quality, so the ink must be a high concentration while low viscosity.Slotting: In general, the slotting process has little impact on the cost. Cutting carton tongue and trimming, as well as slot width will affect the cost. It depends on the precision of the equipment. For high precision equipment, tongue of double wall carton can be reduced to 87.5px, and tongue of single wall carton can be reduced to 70px. In this way, the length of the cardboard can be saved by 12.5px. For example, if there are 1 million cartons every year, the loss of 5000 meters will be reduced. If the carton is $0.57per meter, it is in total $2,857. That's pretty impressive. If you produce more, you save more. So the carton process improvement is very important for production cost control. Not only various occasions accordingly, but to understand the final needs of customers, in this way , a win-win approach could be achieved through process improvement.
1. The basic structure of scoring and slotting unitThe purpose of slotting is to cut a certain width and depth on the flap of a cardboard. When making the carton, the knife must be diantled when the height of the carton exceeds the maximum distance between two slotting knives, and the position must be adjusted accurately, otherwise it will cause the equipment and tools damaged, also reduce production efficiency and increase production costs. The scoring and slotting unit is composed of slotting unit, scoring unit, angel cutting unit and trimming unit. The slotting unit consists of an upper slotting knife, a lower slotting knife and a scrap knife. Of those, the lower slotting knife has four round steel plates, and the distance among them is exactly the thickness of the upper slotting knife. The scrap knife is used to remove the paper scraps left in the lower slotting knife to avoid shut down due to paper jam. Generally the scrap knife is made of copper.Some slotters have two scored shafts, while others have one. Similarly, some slotting machines have two slotting shafts, while others have one. Two scored shafts are used for initial and secondary scoring, or pre-creasing and scoring, respectively.There is a row of scoring rollers on the scored shaft. These steel scoring rollers have different shapes according to different purpose. When processing heavy gram cardboard, high pressure scoring roller should be used , so the scoring accuracy can be ensured. When the flute height increased, the width of the scoring should also be increased, so as to avoid the inner layer cracks .The scoring can be flat or have a 0.5mm to 0.4mm raised.2.Introduction of each part’s Scoring unit: The is to scoring several lines out of the cardboard to facilitate formation.Angel cutting unit: Mainly divided into knife holder, blade and anvil. The is to remove the excess pieces of paper at both ends of the tongue joint.Trimming unit: It is mainly divided into two semi-circular steel trimming knives respectively, whose is to cut off the excess paper edges. Basically not use any more.Double shaft knife holder: Mainly used to narrow the width of slotting.Pre-creaser: Also called crushing roller, it is to install a pair of metal scoring rollers directly in front of the slotting knife. Its main is to make pre-creasing adjustment for scroing, in order to facilitate the formation of the carton, and prevent score cracking. If pre-creaser with power, it can better achieve a certain degree of pre-pressure and line speed.3.Process details in production Anti-cracking crushing roller: The gap should be less than the half of the thickness of the cardboard, and the standard is not to crush the cardboard.Scoring roller: The gap is about the half of crushing roller, the standard is not to crush the cardboard.Slotting knife: The gap of upper knife embedded the lower knife is about 3mm, the gap of clamping is about 5mm, and the upper holder or lower holder should be taped with sponge to anti-skid.Trimming knife: The upper knife should touch the lower one for more than 6-10mm, and should be sealed vertically.4.Factors to notice in order to ensure the scoring and slotting effectIt is very crucial for carton’s logistics performance and formation that whether the scoring and slotting is good . When the scoring is skew, carton formation will not be square enough.If the slotting edge is too deep, it will break the surface layer, the compressive resistance of empty carton will be reduced. Poor scoring or slotting will affect the production efficiency of the post-process, so the scoring must be straight and deep. The slotting edge should be ooth, not rough.In order to achieve good slotting and scoring effect, we must pay attention to the following factors:●Slotting knife wear Slotting knives are consumables among the printing components. The major problems may occur including slotting knife is rough and wear, and failing to cutting off the paper scrap. The main reason is the slotting knife wear. After the slotting knife used for a period of time, the blade wear and tear, getting thinner, and there will be a large gap between the upper and lower knives, resulting in the paper is no longer being cut but tore. Then the edge of the paper is easy to break and become rough. So we need to check the slotting knife regularly, and screw must be fastening on a regular basis.●Slotting depth Slotting knife is divided into upper knife and lower knife, the depth of upper and lower knife is different, so is the cutting effect. Conventional production of single wall cardboard and double wall cardboard has a certain standard cutting depth, single wall is shallow, while double wall is deep.In addition to paying attention to the depth of the slotting, the scrap plate of slotting knife holder should also be noted. When the scrap plate is worn, the paper is easy to get stuck in the slotting knife, resulting in the expansion of the lower knife holder, which leads to a larger gap between the upper and lower knife, resulting in rough slotting edge and rupture.●Scoring roller gap and scoring depth Scoring is divided into pre-creasing and scoring. Crushing roller is mainly to destroy the flute, that is, after the flute crushed, it is conducive to scoring. Generally, the gap of crushing roller is half of the thickness of cardboard, that is to say, if the thickness of cardboard is 6mm, the gap of crushing roller is 3mm, so as to make it more matching. Scoring depth in general should not crush the cardboard. The depth can be adjusted according to the thickness of the paper and the crushing roller.●Slotting paper guide shaft The paper guide shaft of the slotting knife holder plays a transfer role in the slotting process, if the height difference between the paper guide shaft and the lower slotting knife is too large, the cardboard can not be supported in the slotting process, which exacerbate the run-out. Paper guide shaft is to ensure the cardboard oothly transferred to the stacking unit, so the role of the paper guide shaft is also very critical.5.How to solve the score cracking by adjusting scoring ? ●Improved plans of scoring equipmentPre-creaser improvement: Some of the all factories do not have pre-creaser, it is highly to consider converting a pull paper roller into pre-creaser. And this can be also applied to those whom having pre-creaser, in this way, the probability of score cracking will be greatly reduced after two pre-creasing.Scoring roller improvement: The width and depth of the scoring should be reasonably calculated. You can also make the scoring roller larger, so that the run out of the scoring roller will be reduced, that will be conducive to scoring.1) If two pre-creasing are selected, pre-creasing gap must be gradually reduced, and put them in order from large to all, and check if the pre-creasing position is correct.2) The scoring roller pressure should be gradually increased, in principle of not cracking the cardboard.3)To regularly check the scoring depth, and to correct the roundness and balance of the scoring roller.
Cracking refers to paper score crackings when the product in the die-cutting or folding. This is a common problem in die cutting, especially in dry weather. It should be analyzed according to the specific situation.Paper crisp, low moisture content, especially paper after high temperature polished, it is easy to crack in die cutting. In this case, wet the paper before die-cutting, water machine could be used to water the back of the paper, to increase moisture content, make it slightly pliable, and then put the paper into die cutter. After die - cutting, if the cardboard cracks when laminating, you can spray some water on the crease, in order to alleviate the cracking. 2.The surface of the presswork has a large field of blue or black and other dark color, which is very easy to cracking after die-cutting. Not or less adding ink additives in the dark ink during the printing, to enhance the adhesion of ink on paper, reduce cracking.3.When cardboard thickness is too large, cracking comes out. At this time, the height selection of die cutting steel line should be reasonable.4.Putting tympan paper under the steel plate is easy to cause cracking. At this time, to reduce the thickness of the tympan paper.5.Die cutter with high pressure is the reason to cause cracking, pressure should be reduced, so that paper trim would be well separated.6.Crease matrix or bottom die paper is too thick, scoring is narrow, resulting in cracking. Appropriate thickness of crease matrix should be selected with a moderate scoring width .7.The paper powder falling off from the cutter collected in the slot will cause cracking. Operators should promptly remove paper powder, foreign bodies, etc..
Try This! And Many Common Printing Problems in Debugging Can be Avoided It has skills to debugging printing press, not just by feeling. If you pay attention to the following points, many common carton printing problems can be avoided.1.Make sure adjust the plate pressure to zero : Hanging the plate (preferably full-page), and slowly reduce the gap between the anilox rollers, 90% of the inking area is the zero of plate pressure.Note: The front end of the printing pattern is not neat if the plate pressure is too large. Also, this gap needs to be calibrated monthly.2.Zero adjustment of printing pressure: Take double wall of flute B as an example, slowly reduce the plate gap, ensure 90% of the full-page printing area is inking. At this point, the electronic control value minus the thickness of the cardboard is the zero of the printing pressure. During normal operation, the printing pressure is about 0.2-0.5 mm lower than the cardboard. The back side of the printing surface will be irregular if the pressure too much.Note: This gap needs to be calibrated monthly. 3.The principle of printing feeding roller adjustment ?is the same as printing pressure.4.In principle, the thickness of cardboard should not be reduced by more than 5% during the production, otherwise the carton compression will be seriously affected.5.During the process of production, when the printing press was accelerating, if the cardboard is overall running dislocation, the pressure of the pull rolls should be increased, and the printing pressure should be increased from the back to the front, otherwise the printing blanks will be occurred.6.In the production process, the cardboard without downward warping often appears slotting run-off, the main reason is the transition from the last color of cardboard to slotter entrance is not good, so that the cardboard will hit the lower slotting knife. Problem can be solved by adding transition plate.
Inconsistent of printing color is the problem that many factories will encounter. Mostly, when large orders in the production, the color difference will always be occured. Besides, the color in each batch is different. Why is that? How to prevent?1.Reason analysis: In the production of large orders, when the printing press continuous in the production for about an hour, the ink viscosity will rise, and the printing color is getting dark. The common practice for operators in this case is to add water to continue printing. When printing for another hour or so, the color of the ink changes again. Due to adding the water in the early stage, the ink concentration decreased, so the color will be different from the one at the beginning. Generally, new ink will be added to the press. However, this will not only waste ink but the color cannot be kept in the same.2.Preventive measures: 1).Inking: In the production of large orders, when inking to the machine, it’s recommended only half a barrel of ink used, rather than the whole barrel. When the color is getting light during the production, then add the other half bucket, so as to ensure the viscosity of the ink and color concentration remain consistent, and the printing color is consistent, so the amount of ink would be reduced.2).Inspection: Samples must be reserved every 3000 sheets for comparative inspection to prevent printing color difference. 3).Color sample: Color card must be made. Color card can be divided into standard color, upper limit color and lower line color, so that color can be well controlled.
During the plum rain season, printing is easy to deinking and blurring. The humidity of corrugated cardboard is high, due to the humidity weather, resulting in the cardboard become soft, the press must increase the pressure. When the ink transferred to the paper, due to the humidity, it is easy to form font expansion, giving rise to printing paste. In addition, corrugated board humidity will also cause the printing surface deinking. So how to control that?1. Pressure of printing press In rainy days paper feeding gap must be well controlled, it should be within -0.4 mm of cardboard thickness. Because the cardboard itself is relatively soft, if the paper feeding gap pressure is too tight, it will crush the cardboard, subsequent pressure has to be increased as well, which is easy to cause paste and deinking. Reduce the feeding pressure to ensure hardness of the cardboard. In this way the printing pressure can be reduced to ensure the clarity of printing.2. Ink High ink viscosity is also one of the important reasons for printing blurring and deinking. Therefore, in plum rain season, ink viscosity must be lower, and ink concentration must be high, so that the ink drying speed will be fast, printing paste and deinking can be avoided .
In the process of using a printing plate, the plate will be worn out, when wear to a certain extent, it must be scrapped and replaced with a new one. But one thing that often happens is that there is only a all hole in the plate, which is most likely to appear on a full page or color ribbon. Once these plates are replaced, the cost is quite high, so whether they can be repaired to continuously use?During the printing process, why does plate appear all holes? Generally, due to hard objects are stuck on the printing plate. During the printing process, a hard object dropped causes a all hole in the plate. The presswork will have some printing blank after a all hole has been made.When this happens, you can remedy it by doing the following:Common ways: Put a tape or hard objects on the back of the printing plate. If flat wire is used, cut it short and knock it flat, and place it under the all hole and then fixed with tape, and then to printing. In the printing process, because there is wire under the hole, the hole will be put on top, the pressure will be increased, and printing blank will be avoided.Less common methods: Dissolve the unexposed resin, dripping the solution into the hole, and make it flat, in this way, the printing plate can continue to use. Because the resin is sticky after it dissolves, the resin will be incorporated into the resin plate.Printing plate remedial with these two methods are widely used in the industry, the profit of making cartons is all, so we can only save cost by saving the production of materials.
There are many quality problems in the production process, such as printing paste, deinking, printing blank and so on. Among them, the printing blank is a common one.This article will focus on how the operator quickly find the type of printing blank and fix it.Printing blank is the most common and difficult quality problem in the production of corrugated cartons. Printing blank seriously affects the printing effect, which will lead to the unaesthetic printing on the surface of cartons, and even a large area of printing blank will be regarded as unqualified products, resulting in a waste of production.There are many reasons cause printing blank, such as paper water absorbency , ink viscosity, printing pressure, paper scraps, dust etc.. Of course, the reasons for printing blank are different, so are the methods. As an operator, how to quickly find the solution to the problem?The following highlights three of the most common printing blank and solutions:1.Printing blank caused by improper pressure adjustment1).Plate pressure is not enough (that is, printing cylinder and anilox roller pressure) : there are scoring mark on the cardboard, which is bump. Printing blank caused by insufficient plate pressure is mainly reflected on the printing surface that is not complete, printing patterns on the edge is not smooth, and printing patterns on the cardboard has scoring mark. As long as you touch the printing blank, you can find that there is a concave and convex , once this happens, it shows that the plate pressure is insufficient.If the printing unit is separated, check the printing plate, the lack amount of ink on the plate is also the lack of pressure on the printing plate, that’s why printing blank was caused. Generally, the printing blank area is relatively large.2).Printing blank caused by insufficient printing pressure (pressure roller and printing cylinder) : plate with enough ink, no bump There are similarities between printing blank caused by insufficient printing pressure and by insufficient plate pressure, but there is a very obvious difference, that is, the printing pattern on the cardboard has no bump, there is enough ink on the printing plate.Improvement : The best solution for these two types of printing blank is to adjust the respective pressure to the appropriate position, then you can directly improve the printing blank.2.Printing blank caused by low ink viscosity: ink of printing pattern is light, appearing pinhole. Printing blank caused by low ink viscosity, the most obvious is the printing pattern of ink color light, and appearing pinhole, printing pattern looks very virtual.Improvement :The emergence of such printing blank is to first check the ink viscosity, you can increase the ink viscosity or add some new ink, then such printing blank would be solved.3.Printing blank caused by paper: Printing pattern deinking Printing blank caused by paper is mainly reflected in the printing pattern deinking, if it is the color lump printing blank, it is mainly reflected in the middle of the paper, because the ink absorption of the paper is very poor, ink can not penetrate into the paper, ink floating on the surface of the paper, as long as rubbing the paper,the ink would fall off.Improvement : Do not try to add printing pressure and plate pressure, be sure to working on the ink, add resin content and penetrant into ink, which is more effective than others.Conclusion: There are more than these aspects to cause printing blank and more ways to solve the problems. The above four are the most common phenomenon in the production process. Of course, such as the soft and hard of printing plate and cardboard etc. will also cause printing blank .
How to improve production efficiency is a concern of each and every company.This article introduces a solution to increase the production efficiency of printing press by 50%, from how to reasonably arrange the preparation work to on-site debugging, personnel division, etc., we hope it will be helpful for the people in the corrugated industry.1.Improving the starting- up time is the keyReducing the setup time is one of the most effective ways to improve the efficiency.If we make 20 orders per printing press per day and each order change takes 20 minutes, each printer will be stopped for up to 400 minutes per day. If it only takes 10 minutes to change the order, it will save 200 minutes and increase the efficiency by 50%.In order to achieve this, we need to reasonably arrange a series of work from preparation to on-site debugging, division of labor and so on. The goal of increasing efficiency by 50% can only be achieved by increasing the equipment's start up time. So,how to achieve that?2.Do a good job in preparation, then you’ll get twice the result with half the effort Let's talk about the details of the pre-press preparation. What do we need to do for pre-press preparation? How do you ensure everything is right?1).Prepare the necessary ink for the printing press Check whether the ink PH, viscosity, hue is up to standard. Because PH controls printing adsorption on the paper, especially the dot overprint is the most prominent. If you set the PH value to 9 for the first red color, and the second overprint blue color is 8, so the effect of overprint is that the blue color can not cover the red color, overprint effect will be very poor. Similarly, viscosity is one of the most critical factors to control the quality of printing, viscosity too high will appear unclear printing, deinking and other phenomena, so it must be tested. If inking without checking the hue until it gets wrong , and then clean the ink, it will waste 2 kg ink and spend at least 15 minutes to stop to changing the ink. After checking the printing production schedule, arrange the staff to get the inks needed on the day and place them in the workshop. Before operating the printer, stir the inks first, and then ink to the circulation of production.2) .Prepare the printing plate required by the printing press In the printing process, it is often found that the printing plate is wrong after start printing or it can not be printed due to wear and tear , resulting in stop for changing order. Each time it will cause 30 minutes of downtime waste and each cleaning ink waste at least 2-4 kg. So how to overcome this?●According to the production schedule, the staff will take printing plate and send it to the printing press.● The operator first to do the basic detection of the plate, such as whether the text is correct.●Check whether the surface has stains or wear, and then send it to the machine and check if the printing plate number is correct.3).Prepare the cardboard In the printing process, after the printing plate, ink are ready for the press, we found that the cardboard did not come out, resulting in the machine to change order and wash ink, this kind of things often happen. The following suggestions are for your reference and can be used to prevent similar problems.●First to check if the cardboard has been prepared already, to avoid the printing plate being placed but no cardboard to printing.●Scheduling the cardboard order according to production scheduleConclusion: if the above three aspects can be achieved, our on-site downtime will be reduced by 20%. Only when the details are well controlled, can the efficiency of the printing press be gradually improved.3.Synchronously manage internal and external tasks to improve printing efficiency by 50% Enterprises want to improve the printing efficiency, the best way is to record all the adjustments and divide them into internal and external tasks. Turn the internal tasks into external tasks whenever possible and reduce the time required for external tasks. 1). Internal tasksInternal tasks are activities that must be performed while the device is locked, such as changing the printing plate, adjusting the position of the scoring roll etc., which the machine must be stopped. So how to finish the internal task in advance? Usually a set of equipment equipped four people, number 1 is the captain, the rest is the deputy.●We often find that when the former order finished, the staffs have no idea what to do, but just wait for the captain's order. Therefore, we need to reduce the connection time between opening the machine and the downtime of the former order, so as to achieve the effect of shortening the preparation time.●After the former order finished, the equipment stops. Our operators often look for tools , take tools and make repeated actions. We have to reduce the amount of time that people have to hold the tool repeatedly after the machine is turned on, and reduce the repetition of actions, so the time is reduced.●In normal operation, usually after the former printing done, we should clean the ink for the former order, and then to find another plate, this will waste 1-2 minutes.The correct approach is to prepare in advance the replaced plate, pad and ink, and place them in the needed printing unit. This could save two minutes.●It is very important to adjust the process parameters of the next work order, which should be adjusted according to the data record on the process card, so as to prevent the adjustment after the machine starts printing.●The tasks of operating printing press is a team work. When one of team members fails to complete internal tasks, others should actively help and focus on the internal tasks.Summary: According to the above operation, 4-5 minutes can be saved, that is, 20 orders a day, 100 minutes would be saved, improve the efficiency of 20%.2).External tasksThe external task is the activity that can be performed during the carton production: preparing printing plates, inks or inking and other working items, so how to shorten the external time?●After the former order finished, we should quickly clean the paper feeding section and start to adjust, take away the presswork , adjust the stacker to prepare the pallet.●We need to make the best use of operator no. 4 to complete external events. Only by properly arranging the operator’ work flow can the waiting time be reduced.Conclusion: In order to increase the printing efficiency by 50%, we need to achieve the actual demand through on-site operation and verification. One method can be used for reference is to actually shoot the scene with a camera, and then discuss and improve. After 2-3 times of discussion and improvement, it will be definitely saving a plenty of time.
We all know that once the paper feeding gap adjustment is not appropriate, it will lead to a variety of quality problems, too much pressure will crush cardboard, too all will cause printing askew. So how to accurately adjust the printing gap? Why the paper feeding roll fail to feed paper after the feeding gap is adjusted to the minimum?1. Here is a case: the scale value is 0 but the paper can't be transferredThere is a corrugated manufacturer, who is specialized in producing flute B cardboard. Once, when flute E corrugated box was made, the operator had adjusted the feeding gap to the standard position of 1.5 mm, but the paper was still unable to feeding. Later, considering lack pressure, the operator adjusted the feeding gap scale, but until the value shown 0, the paper was still unable to transfer, why was that?After that, the engineer opened the equipment, surprisingly found that the paper feeding roll bearing had accumulated a lot of paper dust, paper scraps, though the scale displayed 0, the feeding roll did not mesh properly.2.One misunderstanding: the data shown in the scale = feeding gapMany people rely heavily on the scale data when making printing gap adjustments. It is considered that the data shown in the scale is the printing pressure. However, in actual production, the gap value shown on the scale is not necessarily the actual value of the feeding gap. Why is that? When the paper feeding roll bearing is stuck by paper scraps, oil, etc., it will cause the eccentric wheel to slip, thus resulting in the failure of adjustment of paper feeding gap.1).The standard operation in adjusting the feeding gap is divided into two steps● To test the thickness of the cardboard, the vernier caliper is generally used●To determine the feeding gap adjustment value according to the thickness of the cardboard, and cardboard thickness with different flute is not the same, cardboard thickness -0.3 mm= feeding gap2).Read scale The feeding gap adjustment roll is from 0-13, that is, the feeding gap is 0-13 mm. The larger the gap value is, the lower the pressure will be. When the value is displayed 0, it means that the feeding roll is in the mesh state with the maximum pressure.3.Three steps to ensure the accuracy of gap adjustment1).Regularly tighten the screw of feeding gap adjustment scale, ensure the scale adjustment accuracy. 2).Regularly correct feeding gap to ensure feeding accuracy. Feeler gauge is generally used, Feeler gauge thickness = gap thicknessSpecific adjustment method: first,the feeler gauge into two feeding rolls, and adjust it until the feeding rolls completely clamp the feeler gauge, and check whether the scale data is consistent with the thickness of the feeler gauge. If not, further adjustment is required. 3).Clean and maintain the equipment regularly to avoid oil stains and paper scraps sticking to the feeding roll bearing.
1. Stable ink quality Stable ink quality is the key factor to control chromatic difference. Now many customers will compound spot color inking order to promote the uniqueness of their products and increase security features.Spot color ink ratio must be accurate, so as to ensure a stable ink hue, and the brightness, saturation can meet the requirements.If ink quality changes, it will lead to a large discrepancy.The technical content of ink mixing is relatively high, so the requirements for experience are also very high. If enterprises without owning ink mixing specialist can request ink manufacturers sending technicians to offer door-to-door service. In short, the quality of ink affects the overall effect, it must be carefully selected and used.In the process of using ink, there exists a series of problems including viscosity increase, ink distribution, hue change etc. after volatilizing. These need to be timely adjusted according to specific situation. In the printing operation, front-line staff, especially the captain, will find out many effective methods and all innovations in practice. All proven effective methods should be actively summarized and promoted.2. The inking performance of plate material The inking performance of plate material, especially the one wore out after being used for a long time. The progress of plate technology has greatly improved the quality of printing, to a certain extent to reduce the chromatic difference of the presswork, but whether it is rubber plate, resin plate or flexo, long-term wear will greatly reduce its inking performance. Therefore, it will frequently cause problems such as shallow imprinting, unsaturated ink layer. If in this case just add the printing pressure, rather fundamentally solve the problem, it will only lead to plate material further damage and chromatic difference, and carton compression resistance will be greatly reduced.3.Pressure balance, uniform printing The speed and stability of printing can both lead to color changes. As the printing speed increases, the ink volume increases rapidly, the ink layer thickens and the color increases. On the contrary, when the printing speed decreases, the amount of ink is reduced, the ink layer becomes thinner, the ink is lighter, and the amount of ink is difficult to reach saturation. Therefore, in order to maintain a stable color, it is necessary to maintain a stable printing speed.The same goes for pressure control in printing. Too much pressure, the amount of ink is all, the printing is breezing. Too all pressure on the upper roller, the gap of roller larger, the amount of ink is too much, not only resulting in thick ink layer,hue change, but dot printing will cause paste, and solid field printing will cause creeping.4.Control paper material color, gluing amount, oothness and other indicators Paper whiteness is included in spectrodensitometer measurement, so measurement and analysis of the chromatic difference among products have to remove the impact of paper color, because the customer will never forgive the chromatic difference caused by the paper factor. Therefore, control paper chromatic difference also become an important job. Especially in the current carton packaging market, the white paper is not used commonly, coloured kraft paper, board paper accounted for a larger proportion. Printing on colored paper will produce the effect of “sunglasses”, which should be prevented in the prepress design.Paper oothness, gluing amount will also cause carton printing chromatic difference. Paper with high oothness will be plane reflection, color will appear bright and light. On the contrary, rough paper will have ink layer diffuse reflection, hue will appear heavy. The gluing amount of the paper will affect ink adhesion, and the thickness of the ink layer directly affects the chromatic difference.5.Strict management system on standard color sample In general, the customer will deliver a standard color sample, if it is a newly developed product, the customer will also confirm a standard color sample before mass printing. Therefore, the customer's color is the standard, color management must be based on the sample color.1).Respect the customer's original standard, do not change without permissionNo matter how many times the plate material is changed, the technical parameters can not be changed, if possible, color density, chromatic difference and other standard items should be recorded into the spectrometer.2). Properly keep to prevent loss, damage or discolorationImproper storage of samples is easy to cause discoloration, once color changed, it will lose the significance of being standard. If used for guiding production, the consequences are unimaginable. Therefore, it is necessary to establish a strict management system to provide a good light-proof and moisture-proof environment.6. Record management Records not only enable product traceability, process records can also enable operations to be traced. According to the requirements of ISO quality management system, there are many kinds of records, which should be done according to document requirements one by one. The projects that really guide production operations and quality control are largely fixed. After each batch of cartons are finished, the ink ratio, viscosity index, printing number, machine speed, operation notes, product inspection and measurement data, even customer comments should be recorded in details. These are truly assets that are conducive to quality improvement and quality improvement.The printing process is variable, and these measures above can not totally ensure there is no chromatic difference. In order to do a good job in color management, and reduce the corrugated box printing chromatic difference, it also requires our crew operators, inspection personnel, management personnel to be careful in observation and adjustment, diligent summary and improvement innovation. In short, color management can achieve the goal of optimizing the carton printing quality.
1.Printing crush formsIn the printing production , the cardboard is often crushed, giving rise to the problems such as unprinted patches and printing paste, reduction of the carton pressure resistance, which is a serious problem threatening the production quality. The cardboard crushing is divided into all-crushed, strip crushed and part crushed, we need to make a detailed distinction to the reasons.1).All crushed If the carton is found to be completely crushed, please check whether it is full-page printing on the surface. If not, the crush probably caused by paper feeding roller. If it is full-page printing, first we should release the printing pressure and then feed the paper. If the cardboard is not crushed, it demonstrates that the pressure of printing plate is too much,that’s why to crush the cardboard.2).Strip crushed This is one case of the part crushing, generally the pressure of pull rolls is too large, resulting in cardboard being crushed. At this time the crushed cardboard is in a strip state, and the width is the same with the pull rolls,, this kind is easy to distinguish.3).Part crushed The cardboard crushing area is where the printing pattern is, indicating that the reason for part crushed is the high printing pressure, the crushed size is the same with the printing pattern.Of course, too much die-cutting pressure will also cause cardboard crushed. And the cardboard crushed in terms of the press is probably the too much printing pressure. We should analyze according to actual situation.The impacts of printing crush: 1. When cardboard crushed, it will directly lead to the expansion of printing dot, reducing the printing fineness.2. The crushing will result in the reduction of the carton compression value, generally giving rise to a 10% drop in the carton physical index.3. Printing crush is a production accident, in order to meet customer requirements with demand products, the carton factory will have to rework, which definitely increase the paper costs .
In carton enterprises, to make high-quality cartons and achieve good printing effect, both printing captain and operation staffs should establish correct operating concepts and develop standard operation process, and constantly think the improvement of operation according to the problems occurred in the operation process.1.The first operating concept is “gently”The quality of presswork depends on whether the equipment is in good condition, which the key is being “gentle”, including plate pressure, double rollers, scraper pressure, printing pressure, paper pressure, die cutting pressure etc., which are theoretically the lighter the better. First, it is not easy to damage the intensity of cardboard. Second, it’s easy to find problems, for example, when in the printing process, some part of the cardboard can not be printed, in this case, the traditional approach is to continually add pressure, which is the wrong way. The reasons why some part of the cardboard can not be printed are various, such as the plate not in flatness, the mal of the equipment, etc., if blindly adding pressure, cardboard will get crushed.So in the printing process, we should pay attention to the concept of “gently”. If this is not taken seriously, then the service life of the printing press will be short and the quality of the presswork will become worse. The following is a breakdown caused by excessive pressure of the scraper, resulting in an uneven scratch on the presswork.2.The second operating concept is “standardized operations”Usually all the printing parameters should be wrote down, and even some conditions during the operation process should be recorded to form a process standard. For example, plate pressure gap, tranission gap, scraper pressure, printing pressure, paper roller gap, scoring line, ink, PH value, ink viscosity, etc. As process standards, these are the most important factors, we should establish a standard operation, and well record. 3.The third operating concept is “labor division” Printing press is different from production line, which the coordination is achieved by unified command through computer automation, and the entire assembly line. While the printing press is totally another thing. It is usually two or three people to operate a press, especially now the cost of workers, technical staffs is very high, under the condition of technical personnel scarce, some printing press only has two people to operate. In this case, the division of labor is very important, otherwise the efficiency will be affected. The core of printing press operation is the preparation, which takes a long time. In this process, the concept of coordination is the most important part of the printing unit. 1). The coordination of operating process (4-color plate with mold) The traditional printing press is usually operated by three people so as to make high efficiency. First, captain A, he would set the parameters, then take the mold, and install the mold. Second, the deputy B, he would take the plate, put the plate in the press, and get the ink, fill the ink. Third, the deputy C, he would pull the cardboard, and set the stacker behind the printing press at the same time, and then prepare the pallet.After all this steps, the captain begins to adjust the press and the production will be beginning.2).The coordination when operating process is done(4-color plate with mold)When operating is done, they should cooperate with each other. For example, captain A should write reports, clean up defective products and analyze the reasons. Deputy B should remove the mold and printing plate, and deputy C should be responsible for recycling ink. Then make preparation for the next order.
Notes for conventional paper feeding roll system1.Cardboard crushed to a large extent due to improper human adjustment.2.The abrasion of the feeding roller will reduce the feeding precision.Feeding roller abrasion also affects the feeding precision. If feeding roller abrasion heavily, roundness decreased as result, to put it simply, the speed of rotation becomes slowly to form the speed difference, speed difference between all feeding wheel and feeding roller produced , so feeding accuracy will naturally produce errors.3.The hardening of the feeding roll will reduce the feeding accuracy.Both the feeding wheel and feeding roll are made of rubber. Once the rubber hardens, the friction of the paper feeding will be reduced and the feeding effect has to be achieved by increasing the pressure.4.The feeding roll tends to slip on the scoring line.5.There are safety hazards with paper feeding roll.Feeding roll gap setting parameters:According to the flute to set the feeding roll gapA flute 4.5±0.3mmB flute 2.5±0.3mmC flute 3±0.3mmE flute 1.2~0.8mmCB flute 6±0.3mmAB flute 7±0.3mmCE flute 4.2±0.3mmAE flute 5.5±0.3mmThe methods that operators adjust the feeding roll gap:1. Use calipers to measure cardboard thickness for data verification. The standard operation for adjusting feeding gap is divided into two steps:1).Test the thickness of cardboard, the vernier caliper is generally used for measurement.2).According to the cardboard thickness to determine the feeding gap adjustment value, different flute with different feeding gap. Generally speaking, cardboard thickness -0.3 mm= feeding gap2.Set the standard position for the gap scale of the printing press.3.Do not blindly increase the feeding gap. Daily maintenance for feeding roll1.In order to ensure the accuracy of paper feeding, the gap of paper feeding roll should be adjusted regularly. Generally, it is corrected with a feeler gauge, feeler gauge thickness = gap thicknessSpecific method: Firstly,the feeler gauge between two feeding rollers, and adjust it until the feeding roll completely clamp the feeler gauge to check whether the scale is consistent with the thickness of the feeler gauge. If not, further adjustment is required. 2.Paper feeding roller should be cleaned regularly to avoid oil stains and paper scraps getting stuck paper feeding roll bearing.3.Feeding roll screws should be tightened regularly.
At present, most printing presses adopt the leading edge paper feeding. An indispensable part of the leading edge paper feeding is the paper feeding rubber roll. The advantage of paper feeding roller is that it can transfer the paper smoothly to the carrying roll, the main of paper feeding roll is to transfer.Friction will be produced in the process of feeding paper, if you do not pay attention to the maintenance during the process, the paper feeding roll will need to be replaced, not only to cause cost waste, but also some other production loss.1.Abrasion is the “biggest killer” of paper feeding rollNow there are more and more manufacturers produce paper feeding roll, the service life of each and every is not the same, feeding roll loss is mainly caused by wear and tear, because paper feeding will produce friction, the circumference of rubber roll after a long time use will be changed, and it needs to be replaced after a certain period of time. 2.Paper feeding roll abrasion will cause mass production wasteLet's do a math: take the configuration of model 1200 as example, if one paper feeding roll is $11, 64 rolls in total for the paper feeding unit, so the total cost is : $11*64pcs = $704, if the maintenance is not well, paper feeding roll will be replaced in half a year, then the spending in one year on the paper feeding roll will be$1,408.But this is not the most important, if the paper feeding roll wear, it will cause slotting shift, color process inaccuracy, printing askew and a series of production losses, not only resulting in production waste, but human cost waste. 3.How to maintain and use the paper feeding roller1) One of the main reasons for paper feeding roll wear is that the paper scraps get stuck between the roll and the supporter, so the position where paper scraps stuck will be immediately worn out when running at high speed. So when foreign matter is found in the front of paper feeding roll, it must be promptly cleaned.2) After a period of time, switch the paper feeding roll, that is to switch the roll at both sides to the middle, be sure to make it on the same level, only in a flat surface, can reduce paper feeding roll wear.3) Paper feeding roll should be regularly cleaned and maintained, alcohol can be used. Do not use toluene for cleaning. After cleaning the paper feeding roll, it can work well, and friction of the paper feeding roll will be increased as well.4) Paper feeding roll rotation with an uneven speed is also a main reason for wear, so we must repair and maintain paper feeding roll when they are rotating slowly.Special reminder: The operator of the printing press should often pay attention to the cleanliness of the paper feeding roll, because the damage of the paper feeding roll directly affects the precision of printing transmission, and sometimes feeding askew may be caused by a damaged paper feeding roll .
The quality of printing plate has a direct impact on carton printing quality. Paying attention to the quality of the relevant links can improve the printing quality, extend the plate service life, reduce plate loss, reduce production costs.1. Reasonably use plate materials Rubber Plate Flexo resin plateIn the corrugated carton printing and production process, the commonly used printing plate mainly have rubber plate and flexo resin plate. Compared to resin plate, rubber plate is featured low cost, large quantity of printing, but poor printing accuracy, low efficiency. Complex patterns, fine text (such as bar codes, web text and all fonts) and large areas of full-page field printing require resin plate to complete. High screen line printing with a large amount of printing, laser flat screen printing plate is much durable, because flat screen printing, dot angle vertical, so the number of printing has increased.2. The quality of flexo resin plate Because corrugated board has the deficiencies including surface not smooth, rough, warping, dusting, picking, paper sandwiched with sand etc., in the printing process, these problems are easy to cause pasting plate, crush, and even wear or damage flexo resin plate, resulting in short service life of the printing plate.The general thickness for flexible resin plate is 3.94 mm, Shore hardness is 33-36. The printing plate must be wear-resisting, strong impact resistance, moderate hardness, good resilience after pressure, ink uniform, consistent thickness.Other materials (double-sided adhesive paper, water-free tape) : when paste double-sided adhesive paper and water-free tape resin plate to polyester film, if the viscosity is not strong, the plate should not be used, to avoid the resin plate rebounding due to the strong pressure and impact during printing, in the case of not gluing, giving rise to damage or lost the printing plate.It is recommended to use silicon defoaming agent instead of hydrocarbon defoaming agent . Because hydrocarbon defoaming agent will cause flexo resin plate swelling ( n-butanol is used to wash the plate after flexo resin plate exposure) making printing plate cracking, accelerating the damage of printing plate.3. Process quality control ●Production of flexo resin platePlate-making exposure control is the key, different exposure time makes the hardness, corrosion depth and elasticity of flexible resin plate greatly different.Exposure time too long and/or over exposure will cause graphic loss or wash out, and printing plate also become deformation, hardening and brittle.Exposure time too short, that is, underexposure will make plate’s surface sensitive layer being washed away.●Layout methodsCarton printing generally have more overlap plate, when imposing, better not to cut the plate too fragmented, it is better to make each same color of the printing plate into a whole.We should better care those loose and all plate when pasting, which is prone to be damaged or lost in the printing process due to the poor adhesive.Besides, do not pull during the process of pasting, maintenance, replacement of all pieces of plate, or plate with fine patterns, text, to prevent damage and tear the printing plate.●Pasting the plateTo ensure pasting flat, the edge of the printing plate must be sealed with water-free adhesive paper. If the printing plate and printing roller surface not contact tightly, the printing plate will warp upward. And the warped part is easily to rebound after permeating into the ink, resulting in the plate being damaged or lost in the printing process.
In carton factory, the corrugated carton printing problems caused by unreasonable graphic design and flexographic production often appear, which seriously affect the pattern and printing effect of the carton. Now we will look at the problems in graphic design and flexographic production.1. Avoid full-page printing When designing corrugated carton, we should first avoid full-page printing in water borne flexographic printing press. When designing corrugated carton with full page, because pressing roller touches corrugated board, pressure between the plate and pressure roller will cause huge damage to the compressive strength of corrugated cardboard, and the infiltration to paper by a large area of ink will also reduce the compressive strength of the cartons. The physical performance of corrugated carton after the full-page printing will lower about 30%. Therefore, designing graphics and text should be as simple as possible, and try to avoid printing graphics and text everywhere on the corrugated carton, not to mention full page printing. If some cartons need full page printing, color group can not be too much, and the printing pressure in the premise of ensuring the printing effect should be as all as possible. Large quantities of cartons should choose other printing process. The application of corrugated carton pre-printing technology in domestic corrugated carton industry is an ideal solution to full-page printing, and it can achieve multi-color accurate overlap.2. Reduce the number of overlap The more the number of overlap, the more decreased the carton compressive strength, so the overlap should be reduced as much as possible. In particular, all patterns of accurate overlap, because the water borne ink on the surface of the corrugated carton will seriously affect the effect of overlap edge, especially when the offset carton products for water borne flexible printing, overlap color should be changed according to water borne flexible printing process. The pursuit of green packaging and saving packaging is actively advocated by many international enterprises. Simple, lively and creative pattern design can not only express the information of packaging products, but also save packaging resources and reduce production costs. Therefore, in many corrugated carton packaging, reducing the number of overlap is conducive to improve physical performance of corrugated carton packaging. On the other hand, too much overlap will lead a poor color reduction effect on corrugated carton, the cost for overlap is also very high.3. Avoid all font printing Flexible resin plate for all text is no problem, but corrugated carton from the effect of publicity should try to avoid all characters. For example, the text below 50px can hardly be seen at a distance of more than 5 meters, thus losing the significance of promoting the products. Printing times of the Plate with all font will be greatly reduced, printing operation is difficult to deal with. Printing pressure is light, text is shallow, if increase the printing pressure, on the one hand, it will lead to dot deformation, text and lines appear obvious "edge effect", on the other hand, corrugated structure will be damaged to reduce the strength of the carton. Therefore, all font printing should be avoided for carton graphic design .4. Avoid ribbon printing (i.e. the same with mechanical direction of corrugated board)There are horizontal gradient lines on the patterns of some cartons. When printing, carton in this area is very easy to break because the stress is concentrated. The printing pressure will crush the flute, so the ribbon printing should be avoided. 5. Use ink with strong saturation and coloring For some carton samples with bright colors, the ink color should be eye-catching. Because the color of corrugated board itself is quite dark, we should try to choose color saturation, strong coloring ink (such as bright red), otherwise, printed color and expected color will have a big difference. It is not realistic to assume that the color on the proofs will be the same as what you see on the monitor, or as the samples printed by the inkjet machine.6. Relax pressure of flexo on corrugated cardboard A design with a all gradient dot pattern should consider a high printing plate screen lines . In the flexo dot design, the factors of printing press precision should be considered, the pressure range of flexo on corrugated board should be relaxed, and the ratio between the screen lines of printing plate and the lines of anilox roller should be reasonably selected. 7. Reasonable design of opening type The position of the hand hole on the carton should be designed in the middle as far as possible, and reasonable opening shape should be considered in the design.8. Avoid large differences in printing patterns on the same pageCarton layout design should avoid large areas of the field and dot printing on the same layout.9. To consider elastic deformation of flexible plate Because the flexible plate is elastic, after installed on the plate roller, the plate will be bending along the circumference of the roller, yet almost not bending along the roller axis. This deformation will cause the size of the printed text to change. For those high-end printings, you must take measures to compensate, the best way is to change the size of print film. If there is a round pattern on the manuscript, it can be photographed by using a deformed mirror with the calculated compensation factor. The compensation factor is the reduction factor of the print film, that is, the percentage of the size of the print film should be reduced in the direction of printing.10.Make sure the sample is consistentThe sample should be kept the same in graphic and text design output, to avoid the output difference of different printers, which makes it difficult to test and judge.
One must-have for a printing press is the printing plate.Producing a good quality plate not only improves the productivity and quality of the printing press, but also facilitates the management of the plate. This paper mainly introduces the preparation method of solid photosensitive resin plate.1. Exposure The exposure steps can produce the concave and convex parts of the plate, after the material changed along with the chemicals.1) Back-side exposureBack exposure is the first step in the plate making process, which must be carried out by the back of the plate. This may form a uniform thickness or form a basis that may support the entire layout.2) Front-side exposureFront exposure is the main exposure step. The transparent part of negative film is hardened by ultraviolet light and is connected to the exposed part on the back. 2.Washing plateAfter exposure, the plate will form two different chemical structures, but on the surface it looks the same (before being washed). The process of plate washing will show the concave and convex layout.Using brush and chemical solvents can remove solution of the unexposed part on the plate,(refers to the part that is not exposed to ultraviolet light). This method does not dissolve the hardened part and leave it on the plate.Once the plate contacts the solution, the protective layer on the plate also began to dissolve.3.Dryness and StabilityAfter the plate washing process, followed by drying stabilization process. After the plate washing, the plate absorbed some solvents (about 10% of the plate thickness).In order to maintain the thickness of the original plate, the absorbed solvent must be removed.Use hot air (60℃) to dry for a period of time (1-4 hours depending on the thickness of the plate and the amount of solvent absorbed). The drying process will remove most of the solvent and the residue will evaporate during an 8-hour standing time (stability process).4. Final ExposureThe final exposure is the final step in making plate.1) CL final exposure(Ultraviolet chemical lamp) A short exposure with an ultraviolet beam (the same light source used in the exposure procedure).This will fix the plate's chemical structure, increase the strength and printing resistance. This is technically ready for printing, but may be affected by the stickiness of its own surface.2) GL anti-viscosity treatment (UV sterilization lamp)In order to prevent possible problems in printing, viscosity must be removed, it is necessary to apply anti-viscosity treatment. The most commonly used method is to use ultraviolet sterilization lamps to remove stickiness. This step is the same as the post-exposure, only with a different light source (GL light source).The exposure tolerance for this process is very all, so be careful to verify its correctness.The lack of such GL exposure procedure may still cause problem of sticky plate . However, overuse GL exposure will lead to "plate crack", and affect the printing resistance.Note: 1. Anti-viscosity treatment can also be done by chemical treatment (bromination, chlorination) or powder treatment. 2. Sterilization lamp is very destructive to eyesight, never to use the naked eyes to look directly.
1. Check the Process Sheet and Process InstructionAfter having the operation concept, we should check whether the preparation before printing is sufficient. First, to check whether the content of process sheet is complete, such as the notes on process sheet, generally include: printing model, specification, plate number, printing status, numbers etc., Second, to check whether the process instruction is complete. Printing process instruction is a very important process reference for processing before printing. Therefore, we must carefully review before printing.2. Check Sample CartonBecause the colors of carton are various, even the carton, the color can be varied from its nature color to other colors. That’s why even the same color that printed in the different kind of paper would appear differently. In this case, it is vital to check the cartons before printing.3.Check Parameters of EquipmentThe most important thing before printing is to check if the initial parameters of the equipment are correct. The initial parameters refers to whether the gap is reasonable when the equipment is to print the cardboard. We can have a better understanding about whether the gap in the following parts is adjusted properly, including front baffle, side baffle, paper feeding roller, inking roller, printing roller, slotting crush roller, scoring roller, we need to make sure these initial parameters are adjusted to zero before printing.4 . Check the Ink 1) Hue Check● Use a scraper blade or color wheel to scrape a ribbon on the color paper, then compare with the sample color to determine whether the color is correct. Hue directly affects whether the color of the printed product is correct, which is the first important item of ink quality inspection.● The most objective method is to use the colorimeter. We scan the standard color with the colorimeter , and then scan the color scraped by a scraper, this two colors will form a density difference. But a lot of factories do not have colorimeter, therefore they can only observe with naked eyes, in this way, there is one thing in particular, due to the illuminant difference, inspection result can be greatly different, therefore the illuminance of fluorescent lamp is very important. Make sure to use fluorescent lamps. Some factories use xenon lamps, which will cause problems , especially on night shifts.2) Viscosity CheckIn flexo ink viscosity detection, we usually use Tushi cup and stopwatch, this is the simplest method, its advantages are easy operation and carrying, durable and low price. Of course, there is also a complex method, that is to the use torque viscometer, it is more scientific, being used for experimental calibration, but the actual operation is not very applicable.Requirements of Viscosity Test a).Before the test, the ink must be mixed evenly;b).Make sure the measuring tool is correct;c). Try not to have foam on the measuring cup;d).Try to control the ink viscosity in 10~30 seconds (No. 4 cup). Generally, the general viscosity is about 24 seconds. 3) PH Value TestPH value is used to test the ink PH, which has a certain impact on the ink viscosity, and ink trapping. Generally, PH value tester is used for detection. PH value detection requirements: the probe should be cleaned, the calibrated button should be pressed before detection, and timely cleaning should be carried out after inspection. This kind of detection is very accurate.Some companies use PH test paper, this method comes with a problem,that is, some color can not be tested, because the PH test paper is detected by discoloration, once other ink sticks on the test paper, it will cause errors.4) Surface Tension TestThe surface tension test is conducted only when there are a lot of hard-to-interpret problems come out. This is not a regular way. Surface tension is measured by a surface tensiometer.5. Check the Plate The printing plate has three layers, the surface is a printing plate, the middle layer is a pad, the back layer is double-sided adhesive tape, the pad and the printing plate will both affect the quality of printing.1) The Hardness of the PlateThe key to check plate is to check the hardness, the surface hardness of 3-7mm resin plate is generally in 30-40 Shore hardness.2) Whether the base of test plate is roughGenerally rough base is caused by the following reasons:underexposure on the back, brush-out pressure and time are not enough, the time of using brush-out potions is too long, exposure is not uniform.Having burrs when the base is rough for printing.3) The surface of the printing plate is crackedThe reason is because the front exposure light distribution is not uniform, curly storage, printing plate is not stored in the dark room, printing plate is oxidized in the air. In the case of plate cracks, cracks will be stained with ink, bring bad effects on the presswork.4) Obvious cracks on the base The main reason is because the exposure time is too long, the base surface hardness is too high, it is easy to crack under a certain tension, so that affects the transfer of ink.5) Check the flatness of the plateBefore make-ready, we should pay great attention on flatness, a lot of people would add more pressure when the printing effect is bad, this is wrong idea. In this condition, we should first check whether the printing plate is flat.6. Check Anilox RollerAnilox roller inspection does not need to carry out very frequently, but must do on regular basis. A high-precision test usually takes two aspects: the amount of ink, and to use a luminous magnifying glass to take a picture.1) Use a professional camera, placed on the anilox roller to film, then it can show the proportion of mesh blocking.2) You can use 60-100 times of luminous magnifying glass, the magnifying glass is placed on the roller, the focal length is adjusted, and the digital camera is placed on the magnifying glass to shoot, it also can obtain the real image of mesh . Once a month or twice a month is acceptable.3) Load the obtained mesh image into the computer, compare the blocking ratio, and judge whether to clean the pattern roller according to the blocking situation.The new images will be shiny, 10% of the mesh blocking will be blurry, 20% will be dark.4) Scraper inking, if 10% blocked, it should be cleaned immediately, glue roller inking, if 20% blocked, it should be cleaned immediately. It is recommended that you do a simple cleaning in every shift, as cleaning becomes more complicated when the blockage reaches 10% or 20%.Simple cleaning is to use a brush and washing powder, if done every day, then the monthly photo can be completely neglected. The quality of presswork will be very good. There is one thing to remind,that is, different roller with different brush. If ceramic roller, steel brush should be used, if steel roller, then we choose a copper brush, otherwise the roller will be damaged.7. Cardboard InspectionHere are six things to watch out in cardboard inspection: flatness, temperature, humidity, paper PH, ink absorption, paper surface tension. Cardboard ConditionInfluenceFlatness 1.The precise of printing color register. 2. The control of printing pressure. 3. The ooth of paper feedingTemperature 1.Ink drying speed. 2.The service life of plateHumidity1.Ink transfer. 2.When humidity is high,the feeding roller will destroy the hardness of the cardboard. 3.The increase of the printing pressure will lead to the compression resistance reduced, 4. Too dry will affect the ink leveling.Paper PH The change of paper PH will directly affect the control of ink PH value.Ink Absorption1.The strength of ink absorption affects the transfer of ink. 2.The ink absorption of coated paper is the worst, special ink is needed.Paper Surface TensionPlate and ink surface tension will be affected by the surface tension of the paper surface, ink with less surface tension is needed.
When printing in full page, most of the enterprises use die-cutting production, to ensure the quality of printing, it needs to increase a certain area (such as increase 20 mm) around the circle of original carton, in order to ensure the carton will not have printing blank. The increase of 20 mm is the full page trimming loss, which will increase the area of the cardboard. For example, if 100,000 cartons are being made, the length of the carton is 100,000 * 0.002 m =20 m, and the width is 20 m. Then if to make 100,000 cartons, then the extra 20 m *20 m =4000㎡ is used, The calculation is based on $0.43 /㎡, so $1,715 will be wasted. It wasn’t a deal!The reason to use die-cutting production, simply because there is no way to ensure the edge printing of cardboard will not appear unprinted patches. In terms of production,the process and personnel input increased, but efficiency reduced, the cost of die-cutting board production and die-cutting trimming size increased, the overall cost is higher than 5%. But in fact, if we use a different way, that is, to increase inking amount, then the die cutting production will be passed, it is twice the result with half the effort! How to ensure the printing without printing blank, here are the following simple analysis:1. About cardboardTo ensure the edge of corrugated board is smooth, the edge should not be warping, if warping, it is to consider the direction of the paper, reverse printing is not allowed, otherwise,the edge of the cardboard will appear printing blank.2. About inkThe color concentration of red ink must keep high, that is, high concentration, low viscosity. If the concentration is not high, the probability of printing blank is very big, to avoid this, you must increase the printing pressure, but increasing printing pressure will lead to cardboard crushing. So we must ensure the quality of ink, this is a key point.3. About printing platePrinting plate needs to be improved. First, printing plate hardness should be controlled at 34 degrees, if the plate hardness is too high, the printing plate transfer ink ability will be weakened, which is necessarily caused printing blank. Secondly, tape on the edge of the upper and lower flap of cartons which is in the back of the plate, increase the pressure of cardboard edge printing.4. About pressureMeasure the thickness of cardboard before production, and adjust the gap between paper feeding roll and front baffle according to the actual thickness of cardboard. Paper feeding roll gap is very critical, it must not be too heavy, if the pressure is too much, the cardboard will be crushed, any subsequent pressure will have to be increased. At the same time, the edge of cardboard is also easy to turn up, resulting in printing blank, so it is important to adjust the feeding gap.Although not all full page printing can be done without trimming, die cutting, some products can be improved through the production process to achieve production without trimming, so as to reduce production losses, and improve the production capacity.
People who operate a printing press know that they would often encounter a series of problems like color process inaccuracy and printing skew. New hires don’t know how to hang plate, even many time being told, the plate often hung upside down.How to accurately hang the plate and enhance plate hanging efficiency?First to analyze the steps of plate hanging:● Confirm which color to hang.● Confirm the direction of the plate hanging.● Lock after the plate being hung, and confirm whether it is skew.These three steps look simple, but some people still make mistakes out of it. Generally new hires don't know how to hang up. Why? This is because there is no standardized labeling for this type of problem. So how do you avoid that?A green tape will be pasted on the operation side. The color of the tape can be marked according to the production time: For example, red tape for 2013, green for 2014, and purple for 2015. Even if you have thousands of plates, you can instantly tell at a glance when this plate was used. For the plate management, it is simple.Label the operation side of the printing plate with the plate number, color and color group. The printing of this color group is showing which color to use, that is, when the operator looks at the marked value, he can accurately find the printing unit of hanging plate, so as to avoid waiting for the captain to tell you where to hang up.Put a red arrow in the middle of the center line of the printing plate to indicate the direction of hanging plate. There is a mark on the operation side and a mark on the center line, so as long as you tell or demonstrate to any new employee, I believe he will know how to hang the plate immediately, and how to confirm the direction and position.Only the above three actions, things become simplified.Plate hanging is operated by staffs, to hanging a standard printing plate, we must following the below: 1.Ensure the paralleli of film base and lath.2.Ensure that the starting position of the printing is parallel.3.The box drawing must be correct.4.Install the printed plate with the strip.If you do can the follow above four steps, you can improve your accuracy on the plate hanging by more than 50%.
It is not common for domestic enterprises equipped automatic paper feeder, the common practice is manually paper feeding, or if better, semi-automatic paper feeder is used. Automatic paper feeder is a necessary production equipment in Europe, which can greatly reduce the number of paper feeding operators.Automatic paper feeder is divided into top printer paper feeder and bottom printer paper feeder. If an upper printer with push feeder, the front piling cardboard must be turned upside down before it can be used, because the cardboard coming out of corrugator is in the condition of inner layer upward and face layer downward, which is not suitable for the top printer. The top printer paper feeder is suitable for impose feeding mode for transmission. Features of automatic paper feeder: The paper can be evenly arranged into the paper feeding unit, which can meet the demand of high-speed production and greatly reduce the labor cost and labor intensity of the operator.The paper jam in the feeding section of the automatic paper feeder and the printing press is the most common problem in the production process . The reasons for this problem include:1. The width of the side baffle is quite narrow.2. The upper arch of the side baffle is too all.3. The height of the front baffle is too short.4. The speed of squaring board is too slow.5. Insufficient air pressure of the squaring board.
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