Troubleshooting Part 2: Coating/Laminating

Troubleshooting: Coating & LaminatingBy Tom Kerchiss, RK Print Coat Instruments Ltd

Co-operation and shared goal setting has become increasingly prevalent in label and package printing and converting as all supply chain providers and operatives strive to meet benchmark standards while endeavoring to make a profit. Regardless of whether the process step that you are engaged in is printing at the start of a run or it’s a converting process at the end of a run it is in every one’s interest that process variables and what causes them are understood and that inconsistencies are bought under control in the shortest possible time, with minimum inconvenience and with as little waste generated as possible.

It goes without saying that process quality is only as strong as its weakest link. For example, if print is of the highest quality this will count for nothing if a subsequent coating process, slitting or rewinding goes awry. Apart from product throwaway the printer will have wasted time, energy and material turning out a product with value only to see it scrapped.

When it comes to print processes such as flexography there are devices now such as the FlexiProof for identifying, resolving and controlling ink variables; for colour matching and determining printability: gloss, durability, rub resistance, etc. Other devices, such as the hand held portable trouble shooting device, the EsiProof were covered earlier in an editorial entitled Part 1 of Troubleshooting.

Coating and laminating are process areas that are theoretically straight forward but are becoming more complex as time goes on. Coating and laminating has its own set of challenges, some of which the coating technologist seemingly has little control over.

Coating

The substrate onto which the coating is applied is often responsible for a range of defects inclduing: poor adhesion, poor planarity and lay-flat. Substrate associated issues of note include winding irregularities as well as the defects that arise as a result of airborne and other forms of contamination. These defects can occur during substrate manufacture, product shipment and storage and during on machine processing including, when the product is being fed through the machine or on being unwound and rewound. In many instances the problem is exacebated by the presence and generation of electrostatic forces. Even the operator may introduce contaminants such as skin, hair and fibre from apparel.

An inability to coat a substrate uniformily or to wet the substrate effectively warrants mention. In order to deposit a fast flowing fluid coating onto a given substrate with no voids or inconsistencies its necessary that the surface tension of the coating solution and the substrate surface interface optimally.

To achieve the best of surface conditions it may be necessary for the surface to undergo modification via flame/electrical discharge or plasma treatment. Another approach is one taken by the manufacturing chemist whereby surface tension characteristics are measured and the formulae is manipulated within specific parameters.

As with many of the problems that arise during processing, regardless of whether its flexo printing, slitting, coating or laminating there is rarely a clear cut solution, its often a case of eliminating possible causes one by one. Coating uniformity or lack of it can sometimes be due to substrate manufacturing variability or an innapropriate choice of coating applicator. For instance, variation in the thickness in a non-transverse direction can, particularly if knife coating is the selected applicator method affect coat uniformity. The reason that knife coating technology is susceptible to substrate variation is that the blade is set at a fixed height and therefore substrate/coat contact interface is critical.

Staying with knife coating for the moment its worth noting that the way in which an air knife coating is applied can produce some unexpected results. When a coating is deposited on a web at high speed the flow of fluid is subject to an alternating flow regime. All laminar flows on a moving web have a parabolic velocity profile with the fluid at the surface of the web moving at the speed of the web. The fluid at the air interface however, behaves differently and is just a bit slower than the speed of the actual web. In effect the volume flow up exceeds the volume flow down.

With regard to air knife coating the thicker flow builds up just below the air impingement zone or meniscus. Once the air knife allows the thinner coating flow to pass, any excess liquid collects below the meniscus and will not flow on until the lower layer builds up and becomes thick enough to balance the upward shear force that derives from the web. This ebbing and flowing produces tiny fluctuations in the flow of coating just above the air knife which can result in the coating looking flawed. Sometimes the coating fluid smooths down and has a desirable varnish or enamel looking finish. Sometimes it does not smooth down and the coating shows signs of chatter or streaking. If this occurs the coating operative has little choice but to experiment, find an appropriate suficant, one that will promote post coat smoothing without jeapordising wetting or adhesion properties.

Laminating

Laminating throws up its own share of problems. Sometimes when a two ply dry bonded laminate comes off the machine it has a hazy appearance. This often perplexes everyone, especially when the job has been run previously without any problems using the same substrate and adhesive. In reality the clue to what’s causing the problem is in the hazy appearance. If too little adhesive is applied to the primary substrate high and low spots willl allow air bubbles to develop and with it the hazy appearance. If the adhesive coat weight is increased the haziness should disappear.

As with most processing functions attention to detail pays off. For example coatings and primers must be dried properly. Lets consider an out of line heat seal coating application as an example.

This heat seal coating is applied to foil for the purpose of providing adhesion to polyester. The heat seal coating is deposited on one side of the foil. This coated foil travels through an oven and the dried coated foil is wound up in rolls. The rolls are then stored until they are needed. The roll is unwound and combined with the polyester by passing the two substrates through a heated nip to effect the bond. The material is then rewound with the foil/heat seal coating/polyester ready for shipment to the customer.

Any coating or primer must be dried completely. If not the material could become tacky and when wound up in on itself the material will adhere to the backside making subsequent unwinding impossible

Good housekeeping is a must. The flow rate to roll coating pans should be monitored and adjusted; solution and applicator temperatures must also be watched and the gap between applicator and coating roll measured with substrate in place. Consideration must be given to the correct coating applicator. A slot die applicator may well give good results when used with a closed surface substrate such as polyethylene as the fluid will not penetrate and will be uniform. However the same applicator if used on a substrate with an open porous surface would produce a less uniform result as some of the fluid will penetrate into the pores. In this instance a knife coater would be the best option because as the blade is fixed at a set height from the web there will be uniformity of coating fluid and the pores or cells of the substrate will be filled.

Coating viability depends to a large extent on selecting the most appropriate coating method for a product to be processed – not always easy. The coating operative must take into account product function, desired coating weight, quality level needed, raw materials required, and of course the material onto which the coating is to be applied needs to be considered. There is a wide range of pre and post metered coating technologies that can be used. But which one will give the best reproducible quality? Sometimes its trial and error to determine which technology to use and this is especially true when it comes to developing new products.

The Rotary Koater

The Rotary Koater, a pilot printing, coating and laminating system designed and developed by RK Print Coat Instruments is an ideal system for those faced with daily coating/laminating challenges. As a research and development tool it enables the manufacturer, the printer, the converter and others, to undertake R & D on an economical scale and under precisely controlled conditions. It can be used to test different formulations, substrates and processes. It is also highly effective as production machine for the small-scale production of specialized materials.

On the other hand there are those organizations that for one reason or another need specialized machines; a standard machine simply won’t suffice. The VCM or Versatile Converting Machine meets the needs of this niche market.

Each VCM is purpose built and unique to each customer. A precision system, each is built under conditions of close commercial security. Customers are able to select from best available technology including 15 different printing/coating technologies.

rkprint

RK Print Coat Instruments Ltd
Litlington, Royston, Hertfordshire SG8 0QZ
www.rkprint.com sales@rkprint.com

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Troubleshooting: Colour Consistency

Troubleshooting: Colour Consistency

By Tom Kerchiss, RK Print Coat Instruments Ltd

Because colour has such a powerful influence and plays an important role in building a winning brand – everyone from brand owner to marketer to the printer and converter are seeking colour harmonization across all packaging shapes and formats, regardless of whether the substrate is flexible film or carton.

Achieving Colour Consistency

Achieving consistency in colour on press is sometimes easier said than done.  Colour in itself can be a slippery customer, colour may agree with set numerical values but when its visually being reviewed and approved for a particular job its not unknown for the customer to voice colour accuracy concerns, the reason being that the way we each interpret colour differs. 

But that’s not all, problems that arise when colour is being evaluated can include geometric metamerism, a phenomenon exhibited by colours that appear to be a match at one angle of illumination and viewing but when the angle of illumination is changed they no longer match. Geometric metamerism can normally be traced to issues surrounding gloss and/or substrate surface texture.

Certain colours when used on specific substrates can produce results that can be unexpected. For example, in situations such as flexo printing on transparent films for bread wrapping, the scattering characteristics of an opaque white ink layer greatly affects the appearance and colour of the finished product.

Printing and package converting can sometimes seem to be a constant struggle to combat process variables. Colour inconsistency is a major cause of production bottlenecks, delays, waste (energy, materials, labour & time) and missed deadlines.  Colour variations are of course far from being the only variable that the flexographic package printer has to contend with there are many others that can occur some of which the root cause of the problem may at first be difficult to pin point. Sometimes it’s more about eliminating what the problem isn’t. In other words methodically working against a checklist eliminating the obvious until what remains is the solution. Think carefully before panicking has something changed? Defects such as dirty prints, where clumps of ink larger than the half tone image are transferred to the moving web may be caused by increased press speeds and using inks that are not optimized for that purpose and/or the necessary changes have not been made to the dryer, e.g., slower drying speeds.

UV curable inks can present several challenges such as spitting and dive-in. The latter can generally be resolved by adjusting the speed of the press in relation to the curing lamp wattage. Spitting can be controlled by lowering the viscosity of the ink, though that is not always possible and by adjustment/replacement of a suitably optimized doctor blade. 

Colour may sometimes appear more intense than it should be. In this instance it’s often down to one of two causes: too much ink is being carried by the metering roll/doctor blade; alternatively the problem is related to the colour of the ink being too concentrated during mixing. Adding an extender in controlled amounts will enable an ink kitchen operative to resolve this problem. If the problem has been identified as one of too much ink, the volume can be reduced by adjustment of the metering system or by adding thinners.

While colour may appear too intense when a proof is made the reverse can occur as well: colour can look washed out or paler than expected. If this occurs it can be due to the ink being too thin, insufficient ink is being picked up which may be due to a clogged up anilox. The flexo printer to resolve this problem can increase the viscosity of the ink with fresh and un-thinned ink; clean the anilox or increase press speed or a combination thereof Good housekeeping, which includes cleanliness and routine maintenance checks are important.  It is also worthwhile having troubleshooting and other devices that help to identify and resolve potential problems in place. This is especially important when the printer is working against the clock and the customer is awaiting delivery of an order. One such troubleshooting device is the hand-held ‘take anywhere’ EsiProof colour-matching tool from RK Print Coat Instruments, which can be taken from machine to machine.  This device helps to reduce downtime and on-press waste and offers a return on initial capital outlay of a few weeks.

The Esiproof is a compact precision unit into which an anilox roller, EPDM stereo roller and doctor blade are fitted to enable the user to obtain realistic, high quality flexographic proofs, up to one metre in length. The use of a doctor blade enables the proofing of all flexo inks including high viscosity UV curable inks. The unit enables colour proofing for both customer approval and spectrophotometer readings.

The Esiproof has been modified to make the already competitively priced device, even cheaper, but without compromising on performance. For instance the micrometers used for adjustment have been replaced with springs. Highly adaptable, the Esiproof can be supplied with ceramic laser engraved rollers from 140 to 800 cells per linear inch or with mechanically engraved steel (QCH type screen) and chrome plated anilox rolls. Both ceramic and steel anilox rollers are interchangeable.

The Esiproof is an ideal tool for pressroom managers enabling them for example to quickly produce proofs from multiple machines on the fly. It facilitates the proofing of fine tones, and higher viscosity inks such as UV curing inks.

Another device, one that can be used by producers and users of flexographic inks as well as by substrate and other manufacturers and suppliers is the  FlexiProof. This device saves time spent adjusting inks on press and contributes to consistent product quality. In addition to colour matching, determining printability and resolving issues surrounding ink and substrate: the FlexiProof, which is a scaled down but component critical exact version of a flexographic press can be used for pilot runs and the trialing of unfamiliar materials.

It is ideal for standard test procedures such as evaluating gloss, scuff, chemical resistance and durability.  This compact device is available in a number of variants, including the FlexiProof UV for the inline curing and proofing of UV inks and the FlexiProof LED UV for heat sensitive substrates.

rkprint

RK Print Coat Instruments Ltd
Litlington, Royston, Hertfordshire SG8 0QZ 
www.rkprint.com sales@rkprint.com

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Top Causes of Anilox Scoring and How to Prevent Them

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by Doug Jones

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

Anliox Scoring - Score lines

Anliox Scoring - Samples of score lines on different substrates

Samples of score lines on different substrates

What Causes Score Lines?

Over Impression

Over 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 & Settings

Are 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.

Anliox Scoring - Score Line Check List

Helpful Hints

  1. 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

Get the flexo solutions guide now!

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Imaging the Possibilities

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by Catherine Green, All Printing Resources

Exploring Today’s Plate Imaging Options
A common fear among those still using film imagesetters to produce photopolymer plates is that their device is on its last days–barely hanging on to operational status. Replacement parts are few and far between, leaving little choice but to scour the Internet for parts and redundant equipment to keep the imagesetter operational. In a recent survey, some imagesetter users reported expenses of up to $9,000 annually for parts and services. It also represents taking the risk that the imagesetter can be repaired in a timely fashion (or at all) to avoid costly downtime. The purpose of this article is to present options available to satisfy nearly every budget and quality requirement.

Choosing an imaging system that fits your needs is critical to a successful return on investment. Not only should the current requirements be considered, but perhaps more importantly future needs and objectives.

  • What are the objectives of your company in the next five years?
  • What level of quality will your customers demand, and what will your competitors have to offer?
  • How many finished plates per hour or shift need to be completed?
  • What are your typical and maximum finished plate sizes?

Before selecting an imaging device, knowing the answers to these questions will ensure that this important asset will fit your needs for many years to come.

Eliminating Film: A Streamlined Platemaking Workflow
For those seeking a way to eliminate film from the platemaking process, there are several options. Direct engraving, laser ablation, and inkjet CtP are all filmless plate imaging options. While all three methods yield an imaged flexo plate, there are considerations for each method that can make or break these technologies as a fit for your business.

Laser Ablation
By far the most popular digital platemaking option, laser ablation devices use a YAG fiber or diode laser to ablate image areas on digital flexo plates (plates with a black carbon LAMS layer). Ablation refers to the process of the laser beam(s) vaporizing the black carbon layer, exposing the plate material beneath. This allows the ablated areas of the plate to be exposed to UVA light and cure, forming the printing image. Specially engineered ablative films can also be imaged by this type of device to produce positives or negatives for applications requiring film. Laser ablation devices are the current industry standard for digital platemaking for a number of reasons including high quality output, wide selection of compatible plate materials, and overall efficiency.

Laser Ablation Pros:

  • Efficient throughput of plates.
  • High resolution imaging capabilities and specialty screening options.
  • Small overall footprint with minimal auxiliary equipment.
  • Excellent reliability and ease of use.
  • Seamless imaging capability (with Esko CDI Cantilever and ITR plate sleeves).

Laser Ablation Cons:

  • Initial cost of equipment can be a large expense.

The largest and leading supplier of laser ablation devices is Esko. Esko is a global supplier of integrated solutions for the packaging and labels, sign and display, commercial printing and publishing industries. Esko has been developing software and hardware innovations for packaging and printing for decades. The company invented digital flexo in 1995 and has been leading the development ever since. Esko’s flexographic solutions are used in about 90% of high quality flexo production. Today, Esko is synonymous with excellent quality and consistency in all flexo printing applications.

Another global supplier of laser ablation plate imaging devices is Xeikon. Formerly known as FlexoLaser, Xeikon’s ThermoFlexX devices also utilize a YAG laser for ablating plates. In December 2015, Flint Group acquired Xeikon to expand their reach into the digital printing market, forming a new division called Flint Group Digital Printing Solutions.

Inkjet Computer-to-Plate
As a newer technology in the plate imaging market, Inkjet CtP eliminates film from the platemaking process by utilizing inkjet technology to print a mask layer onto analog sheet photopolymer. The process is simple, fast, and the equipment is the least expensive of the digital plate imaging options. While overall image quality is not on par with laser ablation, this option would be suitable for narrow web printers who can work with the small plate size requirement and are not planning to implement high resolution/high LPI printing techniques.
DigiFlex is the exclusive manufacturer of the FlexoJet 1725 Inkjet CtP device for flexographic plates. Their unique bi-component ink and laminated primer system make this device compatible with nearly any analog plate on the market. Uniquely, the Aquaflex Optima plate does not require the laminated primer to be applied, resulting in a streamlined workflow and consumable savings.

Inkjet CtP Pros:

  • Small device footprint.
  • Quiet operation, even suitable for office environments.
  • Can utilize same analog material through transition to digital imaging.
  • Flat top dot is produced when primer is applied.

Inkjet CtP Cons:

  • Imaging resolution is lower than laser ablation.
  • Periodic manual cleaning is required.
  • Ink and laminate consumables required for operation.
  • Printed mask must be removed with water before solvent processing.
  • Limitation on the size of the plate that can be produced.

Figure A – Comparing Laser Ablation to Inkjet CtP Plate Imaging

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Direct Engraving

Direct engraving machines image plate materials using a high-powered engraving laser. The laser destroys the non-image areas of the plate to create relief. These machines eliminate film as well as traditional plate processing equipment, and can provide nearly unlimited dot profiles (shoulder angles and tip shapes). While these machines can provide some unique capabilities, they can be quite expensive. Here are some key factors to take into consideration:

Direct Engraving Pros:

  • Two step platemaking process (engraving, cleaning).
  • Nearly unlimited control of dot shape and shoulder profiles.
  • Seamless imaging capability.

Direct Engraving Cons:

  • A limited number of materials can be engraved using this process.
  • The engraving laser can only produce one sheet/sleeve at a time, so throughput is considerably less than other platemaking processes.
  • These machines are typically large and can require filter and suction equipment to be installed in a separate, specially-designed room.

Direct engraving devices are available from SPGprints, Hell Gravure, Luscher, and Kodak.

Negatives Without the Negativity

If the analog platemaking process better suits your company’s needs, or if you are using liquid photopolymer, continuing with film may be the best option for you. Thermal film imagesetters provide durable, high quality film negatives (or positives) with the convenience of a thermal desktop printer. These devices utilize a precise thermal imaging head paired with a special thermally-sensitive film to create finished film in one step. No chemical processing, no additional equipment, no hassle. All Printing Resources carries the EXILE line of thermal imagesetters, which offers a variety of sizes for nearly any application.

Thermal Imagesetter Pros:

  • Excellent density, crisp edges – suitable for many applications.
  • Durable film can be stored for 20+ years without degrading.
  • Fast, chemical free film output. No processing or darkroom required.
  • 1200 x 1200 dpi resolution is suitable for fine line work and screen rulings up to 120 LPI.
  • Small device footprint, no extra equipment.

Thermal Imagesetter Cons:

  • Not suitable for screen rulings over 120 LPI.
  • Thermal print head is a consumable, but replacement can be covered with film purchase agreement.

Inkjet film printers are also available, but image quality is compromised as compared to thermal film or traditional imagesetter film The images in Figure B show the difference in edge definition and image formation between these two technologies.

Figure B – Comparing Thermal and Inkjet Film Imaging Quality

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EXILE Technologies (formerly OYO Instruments) is a leading manufacturer of professional-quality thermal imaging equipment, film products, and direct-to-screen devices. EXILE Technologies is proud to manufacture all equipment in the United States.

If you are new to digital platemaking, or simply looking to upgrade your current equipment, All Printing Resources can help. We offer the equipment options, on-site training, and flexographic printing know-how to ensure your plate making process is completely optimized and performing to it’s full potential.

Quick Reference Chart – Plate Imaging Options
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Plugged Cells?

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Cell plugging is a common issue associated with anilox rolls. It is a costly problem that can be controlled or eliminated from your process through the use of recent technological advancements and a preventative maintenance program. Instead of listing the many problems that cell plugging creates, I’ll get right to the real focus of this article: how to maintain consistent anilox volume control. We all know that there are an enormous amount of variables in the Flexo process. In order to stabilize those variables and maximize your investments, it is up to you to control the issues that are within your power. This article is intended to give you the tools to do just that.

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The Anilox Roll

The anilox roll is the mechanical heartbeat of every Flexo process. With each beat of that anilox heart, there is either a sellable or a non-sellable product being created. Managing the variables of the anilox process is where the preventative maintenance program really comes into play. Controlling, tracking and performing scheduled preventative maintenance are the keys to ensuring the making of a consistently sellable product.

Press operators and their support team are the human heartbeat of preventative maintenance. Their cooperation and proper training will maximize your anilox investments and facilitate the production of consistently sellable product off the press. The process is as follows: the volume of each anilox correlates directly to the ink film thickness consistently being transferred to the plate; the ink that is being metered by the anilox must be maintained at optimum and recommended pH/viscosity levels to ensure precise and uniform ink release, as well as a decrease in plugging issues. Common practice by press operators is to add base to ink on press to compensate for inadequate printed ink density and this is costly. A individual anilox rolls unanticipated volume loss, creates the need to make ink adjustments or change anilox rolls. Due to the intricacy and importance of the anilox roll, operators need to; care for them, get to know them, and subsequently trust each roll in their mix to maintain the highest levels of productivity.

Technologically speaking, recent advancements have given rise to improved cell geometry and greater consistency of engravings. Pamarco’s EFlo engraving is a prime example of an advancement in anilox cell geometry. This new technology  provides the ability to improve both productivity and metering consistency.

EFlo engraving

The EFlo engraving is an extended cell that allows for 15% more ink release, while having the shallowest, flattest-bottomed cells. The shallow shape of the cells means longer running press times without the need for stopping to clean up. Longer press times means increased productivity. Cell-plugging issues are also reduced through the use of the shallow cell geometry, making it easier to thoroughly clean and maintain consistent ink films. These translate to an increased line screen of your anilox roll when converting from conventional → EFlo, due to the improved control of ink release.

Cell Plugging & Effective Anilox Care

Information compiled by Pamarco through anilox evaluations points to many converters struggling with both cell plugging and effective anilox care. Cell volume is one of the keys to understanding these problems. The cell volume is measured in Billion Cubic Microns or “BCM.” This is the volumetric capacity of ink or coating that an individual engraved anilox cell can carry. Maintaining uniform volumetric capacity throughout all of the engraved cells on an anilox roll is critical in effectively producing consistent, quality products. It only takes a 10 to 15% reduction in cell volume because of plugging to create consistency issues on press. Pamarco’s Cell Restore has been proven to be a solution to this difficulty throughout the industry, and was formulated specifically for breaking down cross-linked, water-based resins.

Cell plugging is caused by a build-up of dry ink or coating in the cell bottoms. Cell Restore was engineered with a focus on breaking down and swelling the dry ink, and that’s exactly what it does. It is a neutral pH, spray-on solution that fractures cross-linked resins on a micro emulsion layer, without jeopardizing the life span of the ceramic coating. It is also very user friendly. After applying the Cell Restore and letting it work for 5 minutes, a micro-fiber pad is used to remove the swelled and suspended resins from the cells. It is recommended to incorporate this cleaning solution into your regular Preventive Maintenance schedule to prolong the time period between major cleanings (I.E. Soda Blasting Units from Eaglewood Technologies Sanilox System).

In conclusion, incorporating a comprehensive program focused on maintaining the integrity of your anilox roll inventory will add value to your investment.  Your process will see a reduction in hidden costs, improved quality and greater consistency. The print nip for each unit of a Flexographic press should be looked at as a body, surrounding its mechanical heart (the anilox roll). It works to the favor of both the printers and the converters to collaborate with and draw upon the expertise of their vendors. When properly utilized, the relationship that you have with your anilox roll vendor can greatly benefit your business.

About Pamarco:

Committed to the market since 1946. From offering the most extensive portfolio of products on the market, to offering the best consultative advice, to delivering an overall superior customer service; all underpinned by their passionate corporate culture, Pamarco has been able to build enduring and meaningful relationships with converters and OEM suppliers all around the world. To find out what Pamarco can do for you, visit www.pamarco.com.

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3 Tips to Prevent UV Ink Spitting

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by Doug Jones, Apex International

UV inks are considered by many to be the most popular in the narrow-web space.  And for good reason.  Print results with UV inks are consistently better than those using water or solvent-based inks.  But the use of UV inks is not without its challenges.  Chief among those challenges is the issue of spitting.

There are several theories as to why spitting occurs with UV inks and not with water or solvent inks.  Generally, these revolve around the higher viscosity of UV inks comparied to water or solvent and the impact it has on the doctor blade.  Specifically, the higher viscosity can move the blade just enough to allow more ink than is intended to slip through.  Other theories suggest that anilox cell type, viscosity, press speed and doctor blade specifications all play a role.  Regardless, the results can be a disaster, particularly at high speeds.

Ink_Spitting_1

While exactly why spitting occurs is a subject for debate, what is not in dispute is that the relationship between doctor blade and anilox is at the core.  If spitting is creating a challenge in your shop, try these tips for better print results:

1. A stiffer doctor blade may prevent excess ink from getting under and transfering to the plate and substrate.

Testing shows a thicker blade will minimize UV spitting because they resists hydroplaning and do not allow texcess ink to transfer to the anilox.

2. Try a 30° anilox cell with openings

The ink can move through the openings in the anilox cell walls preventing ink from being built up onto the back of the doctor blade.  (Situation 1a).

Ink_Spitting_2

A word of caution: This solution is only temporary. Because the roll will wear over time, the openings will become smaller and eventually disappear. So over time you will get the same situation as with the regular anilox roll. Ink will built up at the back of the doctor blade (situation 1b).

3. Try GTT Channel engravings.  

There is no pressure built up at the doctor blade because the ink can move through the GTT channels. Therefore no ink builds up onto the back of the doctor blade and no ink drops from the doctor blade onto the flexographic plate or substrate.

Ink_Spitting_3

Get the flexo solutions guide now!

 

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Color Evaluation Pitfalls in Flexo Applications

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by Tim Mouw, Applications Engineering & Technical Support Manager, X-Rite Pantone

Lighting plays a huge role in how you perceive color, making a light booth a crucial part of any flexographic visual evaluation program. It can help you verify whether the color of your product is acceptable, plus ensure colors will remain accurate in every lighting condition at point of sale and after purchase.

Visual evaluation is especially important for packaging applications, which require consistent color across different substrates, inks and printing processes. You can spend hours getting brand colors right, but if packaging doesn’t match on the store shelf, the product will be seen as inadequate.

Always view your prints under lighting conditions that conform to ISO standards. In addition to D50 (daylight), you may need to view production samples under other lights that simulate store or household lighting to assure that different parts of the package, such as the label and the box, will continue to match on display shelves or in the consumer’s home.

X-Rite’s Spectralight QC

 X-Rite’s Spectralight QC is a holistic visual color assessment system with state-of-the-art light sources capable of meeting practically any brand owner specification.

However, just using a light booth isn’t enough. Today we’ll share a few common pitfalls our customers encounter when visually evaluating color.

  1. Light booths are painted Munsell gray, a neutral shade that does not distract your eyes from the colors you are evaluating. It’s important to keep everything else around you neutral, too. Wearing brightly colored clothes or storing objects in your light booth will distract your vision.
  1. Make sure your light booth is the only source of light in the room. If you set it up it in the print shop under bright fluorescent lighting, or place it near a window with sunlight pouring through, these light sources will interact with the standard source you have selected in your booth and skew your results.

X-Rite’sLight Booth

  1. Do you wear glasses or contacts? Make sure the lenses aren’t tinted, because even a little color can make a difference when you’re judging slight variations in color.
  1. When looking for color difference between two samples, they should be touching. Leaving even a little blank space between them can trick your eye into missing a slight shift in color.

Judge QC

With five light sources, X-Rite’s Judge QC will help you evaluate standard to samples and batch-to-batch color variation.

  1. Staring at a color for longer than a few seconds doesn’t improve your decision-making ability. In fact, our delicate eyes require frequent rest during critical color evaluation. Once they start to get tired, they’ll send incorrect information to your brain, so only look at a sample for a few seconds, then close your eyes and let them rest before looking again.

Want to learn more? Check out The Science Behind Visual Evaluation on X-Rite’s blog for a more technical explanation for making your visual evaluation program the best it can be.

Mouw_TimAbout the Author:

Tim Mouw is the manager of the Applications Engineering and Technical Support Team for X-Rite in the Americas. In his role, Tim oversees a team of 20 technical support specialists that help customers improve color quality control processes. Over the past two decades, Tim has tough over 300 courses on color science across North & South America, Europe, Asia, and Australia.

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Filed under Color Management, Printing

Cut Print Production Cost & Improve Quality and Consistency

Apex-logo-300

From the time Printing has been accepted as a means of communication, the effort has been to transfer ink from the tray to the substrate. There have been consistent developments and the target has been to improve the quality of fixed palette or expanded gamut print, for short or long run.

apex-print-quality

Different printing processes also developed to suit the printing of various substrates. All the printing processes have some common factors. These are:

  1. Transfer ink from a tray(container) to the substrate.
  2. Use the correct shade of ink to get the correct shade in print.
  3. Use the correct volume to get the correct depth.
  4. Distribute the ink uniformly to get even colour across the substrate and to get the correct tonal gradation.
  5. To use the best resolution possible on the press. This is not always true. As there are presses that can print higher resolution, but even than lower resolution is used:
    1. To suit the substrate being used
    2. To be safe with a lower resolution
  6. For multicolour printing to use CMYK + pantone inks of the correct hue and density for correct colour reproduction.

To achieve the above objective every effort has been directed towards improving the depth of the colour and range in print. In the process a higher volume of ink is being used that produces a thicker layer on the substrate and requires more energy to dry.

One look at the recent development that have taken place in the Flexo industry will show that all the photo polymer plate manufactures have tried to:

  • Target improved ink transfer in the solid areas to improve the ink transfer(increase the ink volume) to get a higher solid colour depth.
  • Trying hard to hold a finer dot(of 1% and below) of a finer screen ruling on plate, at a higher plate and equipment cost that add to the cost of processing the plates
  • This capability is limited to the use of special plates and software meant for use with these equipment.

All these require higher investments and add to the cost of production.

Almost all anilox roll manufacturers have tried to create a higher cell volume with finer screen rulings so as to provide the required depth of colour in the solids when using the finer screen on plate.

The time has come to look at the possibility of changing this by:

  1. Using standard lower density inks for most jobs, improving the printing of the highlights.
  2. Using a more uniform and thinner layer of ink, without losing the required print densities
  3. Improve press speed and production capacity
  4. Improve the colour gamut in print while eliminating the need to use pantone shade inks
  5. Black ink uses carbon as the main ingredient. The reduction or elimination of black ink in print makes printing more environment friendly and provides you with carbon credits. It makes packaging of food more healthy and less toxic.

That helps reduce the cost of printing, while producing a greater depth in colour, improving the print range and reducing the energy to dry the thinner layer of ink. When you do this change you:

  1. You eliminate the inventory of Pantone inks
  2. The make ready time required to match the colour in print, on the press. It also reduces the cost of wasted /unused Pantone shade inks in stock at the end of the year, every year.
  3. Reduce the anilox inventory and use the same anilox rolls for almost all jobs.
  4. Reduce the overhead costs, with reduced press down time, as you use the same anilox rolls for the same colour on the same station.

One notices that Gravure printing is able to achieve the highest print densities even though they use liquid inks, while in Offset printing the ink densities are the lowest. This is because the ink layer laid on the substrate, in offset, is the thinnest.

If we are to reduce the density of the inks we use in printing than the cost of the inks would come down. By reducing the ink density we are reducing the density of the highlight areas. This will reduce the effect of dot gain in the highlights, which is a major problem in flexo printing. This small change will enable us to print the fine highlight details easily and cleanly. It will also allow us to print the vignettes smoothly even when we use coarse screen with coarser screen anilox rolls. Even though the coarser screen anilox rolls use a higher cell volume and will provide a thicker layer of ink, the lower density in the highlights will reduce the effect of the dot gain to the eye and provide the required softness to the image.

Get the Flexo Solutions Guide Now!

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Filed under Anilox Rolls, Printing

Making the Best of a Necessary Good: Marking, Identification & COOL

Matthews_Marking_MAS_Spot

By Liz Churchill, Vice President for Sales & Marketing, and Lyndsey Farrow, Marketing Communications Specialist, Matthews Marking Systems

It’s easy to think of variable marking, coding and identification requirements as a necessary evil, but the truth is they’re a necessary good. Look at all the ways packaging codes and markings can benefit consumers, producers, retailers and the brand itself.

Documenting Origin and Freshness

Every smart shopper looks at the “best by” or “use by” code to make sure they’re getting a fresh product – and to judge whether items that have migrated to the back of the fridge need to be thrown out.

Country of origin labeling (COOL) for meats, fish, shellfish, nuts, fruits and vegetables can also benefit consumers by providing information to guide purchase decisions, and by helping packers, processors and retailers ensure the integrity and traceability of the food supply. COOL can be controversial, and the World Trade Organization recently ruled that mandatory COOL legislation in the U.S. for muscle-cut meats presents an unfair barrier to international trade.

However, companies and legislators who believe in the benefits are still pursuing options such as voluntary COOL – and mandatory COOL still applies to a wide range of consumable products. Most important, surveys have repeatedly shown that shoppers prefer to know where their foods come from, and the USDA has concluded that COOL benefits the consumer.

Shoppers usually get their way in the marketplace, and, whether mandatory or voluntary, labels identifying country of origin are likely to play a greater role in the decisions they make at the meat case and produce aisle.

Ensuring Authenticity and Safety

Far less controversial than COOL, but even more important to product safety, are the bar codes and other serialized markings used to identify individual lots, shipments and packages of drugs, cosmetics and other products for purposes of authentication and traceability.

Serialization codes are essential for supply-chain management and assurance. They provide the ability to track products from source to consumer, and to recall products quickly in the event of a problem. They support compliance with local regulations, such as varying tax codes or disclosure requirements in different jurisdictions. They can help ensure the supply chain is efficient and accountable. And they can help give consumers confidence that the products they consume are genuine and safe.

Delivering a Better Experience

Increasingly, variable marking is also being used to understand and respond to the preferences of individual shoppers. Serialized codes can be printed on loyalty cards, on promotional flyers and coupons, inside bottle caps, on product packages and more.

Variable codes and personalized graphics can engage shoppers and encourage them to take action – by participating in a contest, claiming a discount, earning a perk. And the data behind the markings can be used to help manage promotional programs and gain insight into each shopper’s behavior.

Serialization can also provide the data you need to determine whether goods are being purchased in-store or online, at which particular retailers, and even whether specific types of promotions are meeting their targets. Codes can even be used to help prevent a program from going viral and blowing through your promotional budget.

Strengthening and Protecting Brands

In the final analysis, all types of identification codes are about brand trust. The information printed on the package isn’t just data. It’s a story about where the item has been and how fresh it is. Reassurance that it’s safe to consume. Motivation to make the brand a part of the consumer’s everyday life.

That’s why most manufacturers will include codes such as “best by” dates even though there’s no regulatory requirement to do so. If the code isn’t present and trustworthy, shoppers won’t just abandon the purchase. They may abandon the brand.

Conversely, markings that are legible, helpful and reliable benefit everyone who touches the brand – from supply chain managers, to marketers, to retailers, to the shoppers who ultimately determine brand success.

Better Processes and Technologies for Better Marking, Coding and Identification

With all the good that variable marking and coding can do, why do brand owners, packaging engineers and production line managers regard it as a necessary evil? There are many reasons package and label markings can be costly, difficult to manage and error-prone. Here are the top three issues, and what you can do to address them.

  1. Print Quality. Poorly printed markings bring consequences. A juice bottle may be left on the shelf because the freshness date is illegible. A shopper may lose confidence in brand quality or authenticity if the label doesn’t “look right.” A recall may balloon to disastrous proportions if a defective bar code makes a bad lot of product untraceable.

A smudged “best by” date used to be regarded as acceptable, but that’s old thinking. There’s no reason today to accept anything less than the best possible print quality appropriate to the application. Labels and packages should be designed from the beginning to optimize marking requirements – from leaving a discrete space where state tax codes can be printed on a wine bottle label, all the way to printing logos and promotional information directly on the package in the same step as the variable code.

Brands that care about quality should also invest in the best available print technology. Big advancements in inkjet, thermal and laser printing have been made in just the past five years. In fact, the print quality, speed and control offered by today’s most advanced systems can rival the capabilities of traditional printing technologies – so variable markings can be designed as a seamless part of the preprinted package or label.

  1. Data Management. Regulations change. Different jurisdictions have different information and format requirements, even though the product in the package may be the same. Consider, for example, the sweeping changes to food labeling regulations that have come to the EU – or the new FDA regulations that will soon be changing the look and content of labels in the U.S.

To all that, add the complexity of managing multiple printing systems on multiple production lines – not only for primary packaging, but secondary and tertiary packaging as well. Brands need to centralize packaging design and printing control in order to respond quickly to content and format changes across all packaging types and minimize the risk of incorrectly coded packages.

An advanced, centralized print controller can be configured to draw product and supply chain information from official sources – such as product information databases, ERP systems and brand asset repositories. Based on this data, markings can be designed to meet the requirements of each regulation, label design and package type, with any changes propagated automatically to all printers of every type, anywhere.

3.Cost Control. Printing codes can affect production costs in several ways, especially when applying adhesive labels. For example, there’s the capital and maintenance costs for labeling equipment. There’s the cost of buying consumables such as print ribbons and adhesive labels, and of managing the waste they leave behind. There’s the cost of lost production and scrap when consumables need to be changed or when labeling creates a bottleneck on the production line. And there’s the cost of separately managing and storing preprinted boxes and labels.

While traditional preprinting and labeling methods will remain the preferred choice for many brands and marking applications, the speed, simplicity and quality of today’s direct-print systems can offer a cost-effective alternative in the right circumstances. Direct printing can help brands gain market flexibility while saving preprinting, warehousing and labeling costs. Depending on the package design, secondary and even primary packaging can be printed in a single step right on the production line – not just variable markings but also the brand logo, messaging, nutrition facts, promotions and more.

Turn a Necessary Good into an Opportunity

There are many other potential issues and strategies for addressing them. But the core takeaway is that variable marking and coding isn’t a necessary evil – it’s a positive good that benefits the consumer and the brand. More than that, it can be an opportunity to improve production processes while helping your brand stand apart in the marketplace.

With over 160 years of experience – leading up to today’s most advanced technologies – Matthews Marking Systems understands your marking and coding challenges, and how these challenges can be re-envisioned as opportunities for your brand. Visit our website for guidance on specific applications and a complete library of coding and marking resources.

Matthews Marking Systems is part of Matthews International Corporation, the parent company of SGK. http://www.matthewsmarking.com http://www.sgkinc.com

Liz Churchill_Matthews_headshotLiz Churchill, VP Sales and Marketing, Matthews Marking Systems has 30 years’ experience in the product identification area, identifying products through bar codes, text and graphics in industrial, CPG, pharmaceutical and medical device markets. With an Industrial and Systems Engineering degree from The Ohio State University, Liz has been issued two application patents for a track and trace system in the global wine market. Presently, Liz focuses on global sales and marketing, working with sister companies to provide winning solutions from primary packaging through distribution of products. http://www.matthewsmarking.com http://www.sgkinc.com

Lyndsey Farrow_Matthews_headshotLyndsey Farrow, Marketing Communications Specialist, is an expert in marking and coding requirements for a variety of industries with Matthews Marking Systems, a Division of Matthews International Corporation. http://www.matthewsmarking.com http://www.sgkinc.com

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Filed under Labels, Printing

Back Doctoring – Causes and Solutions

daetwyler-600

If you’ve ever experienced the hard deposits left by dripping inks and back doctoring, you know it can impact print quality, damage equipment, and cause cleaning and maintenance headaches… but wouldn’t you also like to know why it keeps happening?

back-doctoring

It starts seemingly simple enough – with visible ink leakage dripping in the catch pan under the doctor blade chamber. Yet, when seals and calibration settings are checked there doesn’t seem to be anything wrong. But the proof is right there in the pan and on your equipment.

Your problem could be due to back doctoring.

When excess ink remains on the anilox roller, it can cause drips and icicle-like build up that impacts the overall performance of your press. This is particularly common on Central Impression Presses where back-side decks rotate against the containment blade and leave residue.

Is it back doctoring? Here is how to check:

  • Are there any tell-tale icicles forming on the backside of equipment and bottom of the blade holder?
  • Does the problem persist even after adjusting pressure settings?
  • Are your end seals in proper working order?
  • Does the problem persist even after ensuring all chambers and anilox rolls are parallel with one another?

If you answered yes to one or more of these items, you can reduce and prevent back doctoring with the right kind of doctor blades installed on your equipment.

Download the full Back Doctoring White Paper for more information. 

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