Category: Doctor Blades

Versioning and Variable Data in Flexible Packaging

According to Smithers Pira in its “Future of Global Flexible Packaging to 2020” report, “Flexible packaging has been one of the fastest growing packaging sectors over the past 10 years, thanks to increased consumer focus on convenience and sustainability, and this rapid development will continue to accelerate.” This growth, however, will depend on the industry’s ability to cope with market trends driving shorter run lengths.

Versioning and Variable Data Printing

Two of these trends driving shorter run lengths are versioning and variable data. Versioning is used to produce packages for different variations of a product (such as a line of flavors) while maintaining brand continuity. For the printer, a large print job is segmented into smaller lots that are customized based on each “version” of the product.

Variable data printing is mainly used in flexible packaging applications for product authentication and logistics in the distribution chain. Companies can add a unique identifying code to each package, allowing individual products to be “tracked and traced” through the supply chain. Bar codes and RFID codes are used to facilitate inventory and prevent counterfeiting.

Both versioning and variable data lend themselves well to digital printing, a process that can easily and cost-effectively produce small lots. In flexible packaging, however, long runs are required to achieve the economies necessary to be profitable. How can a flexible packaging printer be competitive?

1. Take Advantage of New Wide Web Technologies

As run lengths become shorter, changeover speeds become more critical than press speeds. The wide web industry has responded with equipment technologies that make faster set-ups possible such as gearless presses, anilox sleeves and automatic impression settings. Some printers are converting to fixed ink sets, such as extended gamut, to minimize the number of wash-ups, or eliminating manual cleaning altogether with automatic wash cycles.

2. Add Mid-Web Equipment

A number of large format printers are adopting mid-web press technology for economical production of medium-length jobs. By comparison, these presses not only cost less but are built for faster changeovers, lower tooling costs, and less consumption of ink, plates and other consumables. They require fewer operators to run and deliver easier reproduction of high-quality graphics.

3. Incorporate Digital

Finally, for some work, digital just makes more sense. Digital printing’s sweet spot is its ability to produce short runs economically. By adding this complementary technology, printers can take advantage of the flexibility offered by having both capabilities under one roof. Like narrow web, using digital for short run work also frees up wide-web presses for big jobs.

The flexible packaging industry is experiencing a reduction in run lengths driven by shifts in the way brand owners do business. Printers have to find ways to adapt to such changes as versioning and variable information printing by creating new technology and processes. By improving equipment to shorten changeover times and adopting additional printing capabilities, wide web printers will be able to claim its share of future growth in the package printing market.
New Polymer Doctor Blades with MicroTip Are Best for Applying Special Effects Coating

Anyone who uses doctor blades for printing knows the range of options available today. From the thickness of the material to the tip configuration, a doctor blade’s design has a direct impact on the job it will do. While traditional tip options have ranged from straight to rounded to lamella, the new kid on the block, “MicroTip,” offers printers a smart choice when applying special effects coating.

Special effects coatings are challenging

More and more, packaging companies are using specialty coatings to differentiate their brands and create a tactile and visual experience for consumers. However, special coatings such as glitter, grit, soft-touch, metallics and pearlescents present particular challenges for the printer. These coatings have high viscosities and contain larger particles which make it difficult to accurately control the amount of coating

being applied. (UV chemistries, common in specialty coating applications, have a viscosity of 5-7 times that of water and solvent-based formulas.) This higher viscosity applies extra pressure to the metering blade, resulting in hydroplaning or “spitting” (especially at high line speeds), and increases coating consumption and waste. In these cases, a customized blade solution is often necessary to control the lay-down of coating.

New Polymer Doctor Blades with MicroTips can help

Doctor blade manufacturers have found a way to make new polymer doctor blade materials that can overcome the limitations of steel in specialty coating applications. By engineering a modified lamella tip, known as a “MicroTip”, on these materials, they have introduced a doctor blade product that offers the best of traditional plastic and steel.

Why do they work?

When used to apply special effects coating, steel blades are subject to accelerated blade wear from the coarse anilox engravings and corrosion from the harsh coating chemistries. Today’s new polymer materials are compatible with all coating formulas and do what plastic blades are known to do best: last longer.

The blades can be engineered to a full range of size and profile combinations to optimize metering performance with the higher viscosity and large particulate formulas. They range in thickness from .027”/.7mm to .050”/1.25mm to offer varying degrees of stiffness, rigidity and deflection. These properties combined with the new MicroTip edge allow the blades to achieve a fine contact area with the anilox roll and deliver a fluid transfer of coating to the blanket with no spitting or slinging, even at high press speeds. Add to this a range of MicroTips, (M10, M15 and M25) and these blades can be customized for a “perfect fit.”

Doctor blade optimization for special effects coating

The choice of blade thickness and tip will be determined by the anilox configuration, which is driven by the viscosity and solid load of the coating. Typically, higher line screens and lower cell volumes will require a smaller MicroTip (an M10 or M15 for dull/satin/gloss coatings for example), but as line screens decline and volumes increase, a MicroTip providing a larger contact area (M15 or M25) will perform better. By optimizing their next generation polymer doctor blades with the appropriate MicroTip, printers are able to achieve longer blade life in these applications than with steel.

If you’re a printer struggling with special effects coating, consider switching to a next generation polymer doctor blade with a MicroTip. A magical combination of advanced material and tip might be just what you need to achieve a perfect lay-down of coating with longer blade life to boot.

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Consultative Selling: What It Is and Why It Works

Today, successful sellers act as trusted advisers to their buyers to help them find the best solutions. By adopting a consultative selling strategy, salespeople create value in the selling process and benefit from better sales results, stronger customer bases and referrals.

What is consultative selling?

Consultative selling is defined as “personal selling in which a salesperson plays the role of a consultant” by www.businessdictionary.com. It’s a sales method where the salesperson gains a solid understanding of the buyer’s challenges before recommending a solution. An important distinction from other methods is that the main objective is helping the prospect find the right solution, not just getting him to “sign on the dotted line.” The key elements of consultative selling fall into four categories: research, relationship, resolution and reward.

Research

Today’s customer is much savvier than in the past and is doing his homework before buying. The explosion of digital media has made it easy for people to access information online and share experiences with each other. The buyer has already explored solutions, competitors, and prices and is well educated by the time a vendor comes calling. The salesperson has to do his research, too, and can take advantage of “lead intelligence” to learn about his prospects and home in on the most qualified leads.

Relationship

The consultative salesperson is an industry expert who “gets it” and wants to help. He continues to learn more about his prospect’s challenges and obstacles by asking open-ended questions to uncover his real motivation for buying. He builds trust by sharing his knowledge without asking for anything in return.

Resolution

If the seller’s products are determined to be a good fit for the buyer, the salesperson presents the customer-specific benefits of his products, figures out the next steps in the purchasing process and establishes a timeline for closing the sale. If it is clear that he can’t meet the buyer’s needs, it is completely acceptable for him to recommend an alternative solution, even if it’s a competitor!

Reward

No matter the outcome, consultative selling results in a valuable experience for both sides. The buyer is able to get advice from an industry expert who helps him understand his obstacles and navigate a solution. By investing time to provide tailored, customized solutions, salespeople will enjoy better closing rates, higher value sales, increased customer retention and referrals.

In the end, consultative selling is about helping prospects find solutions. Salespeople who take the time to fully understand their buyers’ needs and challenges are in the best position to recommend the right solutions. They will be rewarded with satisfied, loyal supporters.
Kanban 101
In today’s competitive marketplace, manufacturers are looking for ways to improve efficiency and wring costs out of the production process. By adopting lean manufacturing concepts, companies can eliminate waste and operate more efficiently. One way to do this is to implement kanban, a Japanese inventory scheduling system that promotes just-in-time production by delivering parts on an as-needed basis.

In a kanban system, the production process is seen as a “chain,” where each “process” becomes the supplier for the next (“downstream”) process in the sequence and a customer to the previous (“upstream”) process. This approach extends all the way to a company’s external suppliers and customers. It optimizes production flow and minimizes inventory levels by directing the supply of parts and components to workers exactly when and where they need them.

The advantages of using a kanban system include:
- Lower inventory costs
- Quicker response to changes in demand
- Increased productivity and efficiency
- Reduced waste
Kanban Origins

Kanban originated in Japan in the mid-20^th century by Toyota looking to increase the efficiency of its factories. Its engineers were inspired by the inventory replenishment process used by supermarkets. They observed that customers purchase only the items and quantities they need, and store employees restock their shelves with only as much product as they expect to sell. This began an important distinction between a “push” system of manufacturing and a demand-based or “pull” system.

Push vs. Pull Inventory Control Systems

With traditional push manufacturing systems, companies produce what they think their customers will order and make items to stock in batches. While there are economies of scale, the downside is that inventory costs are high and companies can end up overproducing if sales forecasts are incorrect. Excess inventory ties up working capital, increases storage costs and exposes the company to the risk of parts becoming obsolete.

A pull strategy, on the other hand, ties production directly to actual customer demand so there is little risk of overproduction and little excess inventory. Tasks in the production process are completed when requested by the next process down the line so parts or components are “pulled” into production only when needed. With a pull system of inventory management, a company may find itself slow to respond to a sudden increase in demand but very little capital is tied up in excess parts and storage.

Kanban Cards

In order to facilitate its just-in-time manufacturing system, Toyota instituted a method using cards in its factories called “kanban” (a Japanese word combining “kan” for card and “ban” for signal). The cards, called “kanbans,” contain information about how to replenish each component used in production. By moving a kanban, an employee can signal when more parts are needed by an upstream process, prompting the production or purchase of these additional parts. Each kanban conveys all information required to replace the item such as the part name, number and description as well as the quantity to be produced and any other information about how the replenishment should take place. When delivering a kanban, the employee will write the date the order is initiated or “dropped” and when the parts are needed. The card is placed in a kanban rack to be retrieved along with the container by the appropriate person in the upstream process. Once replenished, the bin containing the new parts and kanban card are returned to their original location.

Six Elements of Kanban

The following principles are fundamental to a kanban system:
1. Downstream processes always pull from upstream processes
2. Upstream processes produce only when instructed
3. Defects are never passed on to the next station
4. Kanban cards are attached to part containers and no item is moved without a kanban
5. Production is leveled throughout the system to prevent bottlenecks
6. There is continuous fine-tuning of the kanbans in the production process
The success of kanban as an inventory control system depends on its execution. Adopting this system requires well-defined, documented procedures and training so employees are clear about every step, because a disruption in the process may lead to out-of-stocks and delays in filling customer orders. If executed properly, this is an excellent tool used to facilitate just-in-time manufacturing by eliminating waste and inefficiency from the production process.
What the Automakers Have Taught Us About Manufacturing Efficiency
We’ve learned a lot from the automakers when it comes to manufacturing efficiency. Our car-making forefathers took a long look at their production methods and figured out ways to increase value by making improvements in their processes. Today, printers, along with countless other industries, are realizing the benefits of implementing these concepts to improve their bottom lines.

It started with Henry Ford. He revolutionized the production process by using interchangeable parts, standardization, and what he’s best known for, the assembly line. By streamlining production, he was able to mass produce the Model T and make cars available to middle class families across America for the first time in 1908. By 1927, Ford had shipped 15 million cars, and the Model T came to symbolize a new method of manufacturing.

In the mid-21^st century, Toyota engineers expanded on Ford’s ideas to become more market-focused. Their inspiration came from a supermarket model of inventory management where stores restock their shelves as products are purchased by shoppers. Applied to manufacturing, the concept of just-in-time inventory replenishment recognizes that more efficient inventory management results when customers “pull” products through the supply chain.

According to Toyota’s website, the objective of its “Toyota Production System,” or TPS, is to serve its customers and employees while aligning with the company’s business goals. Central to the TPS are the principles of “Kaizen,” “Just in Time Manufacturing” and “Jidoka.” These values attempt to maximize efficiency and quality by using methods that simplify production flow and speed up response times. Production is driven by customer demand, and the way resources are allocated within the plant is known as “kanban.” All employees throughout the organization strive for continuous improvement in every aspect of the process.

Modern lean manufacturing is derived from the TPS and strives to eliminate all excess from a manufacturing system by focusing only on the things that add value. By removing the causes of “muri”,” or overburdening of people or equipment, and “mura,” or unevenness, the overall “muda,” or waste in the manufacturing process is reduced. (These terms were originally used in Japanese martial arts to protect the fighter by eliminating unnecessary movements!) In relation to manufacturing, seven deadly wastes (or mudas) have been identified:
1. Transportation
2. Inventory
3. Motion
4. Waiting
5. Over-processing
6. Over-production
7. Defects
These activities take up time, resources and space and add no value in the eyes of the customer. The more these wastes can be minimized, the more dollars a manufacturer can wring out of the production process.

For several years, press builder Gallus has seen lean manufacturing concepts in the print industry “as a means of ensuring perfect job processing without sacrificing profit margins.” Through its “Smart Production Concept” program, Gallus helps its customers evaluate their print quality, production sequences and production environment to find opportunities to improve pressroom efficiency. The press manufacturer compares lean manufacturing to Formula 1 racing, where “a single second more or less at a pit stop can make the difference between winning and losing.”

We can learn a lot from our predecessors when it comes to many things, and manufacturing methods are no exception. Through the years, companies have continued to improve upon the basic concepts of production efficiency introduced by Henry Ford and Toyota. Today, printers and businesses across many industry sectors strive to adopt the principles of lean manufacturing in order to achieve the ultimate goal of maximizing value to customers and optimizing profits.
Polymer Doctor Blades are Safe Substitutes for Steel in Flexible Packaging

If you are using steel doctor blades, you are probably well aware of the risk of serious cuts from handling the blades. Pressroom injuries can be expensive in terms of morale and accident-related expenses. Today’s next generation polymer blades combine the best of traditional plastic and steel blades and provide safe substitutes for steel in flexible packaging applications.

As steel doctor blades wear, their tips become honed through contact with the anilox roll, leaving razor-sharp edges. Press operators need to be extremely careful and wear protective gloves when removing the worn blades from the press to avoid injuries.

Until recently, steel was the only material capable of producing the high quality print required in flexible packaging applications so printers had no choice but to accept these risks. While plastic blades were safer, they were not able to achieve a fine enough contact area with the high line screen rolls.

Today’s next generation polymer blades act as a hybrid between steel and plastic and offer a safe alternative to steel. The combination of an advanced polymer material and an innovative “MicroTip®” design allows these blades to perform in highly demanding applications where previously steel was the only option. Due to their material composition, the new polymer blades are safe to handle even when worn. Converting to these blades will reduce lost-time accidents and can save a printer a lot of money in terms of workman’s compensation insurance rates, medical bills, labor replacement expenses and press downtime.

When it comes to the pressroom, safety is everyone’s concern. Flexible packaging printers no longer have to accept the danger that comes with using steel blades to get the print quality their customers demand. To greatly reduce the risk of injury and associated costs, try substituting next generation polymer blades for steel.

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Anilox Roll Cleaning is Essential to Effective Ink Delivery
You spend a lot 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 roll 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.

When a newly engraved anilox roll arrives from the manufacturer, volume is even across and around the surface of the roll. As the roll is used, however, a residual amount of ink or coating material is left behind in the cells after the transfer has taken place. The residue dries and creates build-up in the cells. Over time, these deposits decrease the capacity of the cells and reduce their ability to carry and release the volume of liquid for which they were designed. This residue also raises the surface tension, or dyne level, of the roll and increases the tendency of the coating to “cling” to the surface. When this occurs, the roll will not release the proper volume or ink or coating to the plate.

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-up

Applying 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 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 brush

Manually 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 deposits

Over 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. With these methods, 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.

There are also particle-blasting methods of mechanically removing the dried cell contents. These methods are especially effective for removing chemistries that may be resistant to chemical cleaners. Soda blasting technology uses small granules of sodium carbonate to go in and “pick out” the ink or coating. The roll is then rinsed with water and wiped to remove any remaining soda residue. A more eco-friendly method to deep cleaning anilox rolls that uses no water or chemicals is the MicroClean™ System: an off-press, completely dry media cleaning machine that uses recyclable plastic media pellets. The system gently but thoroughly removes all types of dried inks and coatings, virtually restoring cell volume to full capacity with each cleaning.

Laser cleaning is another anilox deep-cleaning method that’s growing in popularity and effective at removing chemical-resistant ink and coating deposits. The technology uses a pulsed laser beam to heat and evaporate the tough residue in the anilox cells. This method requires no consumable and produces no waste stream, although the capital investment is high.

Like on other parts of the press, a maintenance program for anilox rolls keeps the ink delivery system running at its peak. Regular anilox roll cleaning will prevent anilox cells from plugging with residue and stop build-up before it dries. Maintaining anilox rolls through a regular cleaning program can pay off tremendously in terms of maximizing print quality, press efficiency and cost control. Click here for more information on our anilox roll cleaning brushes
5 Reasons to Switch to Polyester Containment Blades

Switching to polyester containment blades from steel can offer several benefits for printers. Here are the top 5 reasons to make the switch:

1. Elimination of Back Doctoring:

Some printers encounter back-doctoring issues at higher press speeds when using steel containment blades. Steel blades are too rigid to allow back-doctored ink to flow back into the chamber, leading to ink buildup and negatively affecting press uptime. Polyester blades, while effectively containing ink, are flexible enough to enable back-doctored ink to return into the chamber, preventing back-doctoring and maintaining print quality.

2. Cost Savings:

Polyester containment blades are significantly more cost-effective than steel blades. The price per inch for polyester blades is typically one-third to one-half that of steel, making them a cost-efficient choice for printers.

3. Enhanced Safety:

Replacing the steel containment blade in a chamber with polyester reduces the risk of doctor blade injuries by 50%. Polyester blades are safer to handle, as they don’t pose the same cutting hazard as steel blades during installation and removal from the press.

4. Prevention of Anilox Damage:

Polyester containment blades are gentle on anilox rolls. They won’t score or damage the rolls, and the material contains no sharp fragments that could break off and harm the engraving on the roll. This non-abrasive quality helps extend the life of anilox rolls, saving on the expense of re-engraving or replacement.

5. Reduced Environmental Impact:

Polyester containment blades emit a smaller amount of carbon dioxide during production compared to steel blades. Using polyester blades can help printers meet environmental requirements for reducing their carbon footprint, contributing to an eco-friendly printing process. Switching to polyester containment blades reduces downtime and provides a lower per-unit cost while delivering safety benefits, reducing back-doctoring, and lowering the environmental impact of the printing process. It’s a small change that can make a significant difference in efficiency and overall performance in the pressroom.

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New Doctor Blade Technology Is Worth a Look

As a consumables manufacturer introducing new doctor blade technology to a mature industry, we’re constantly hearing, “But I’ve done it this way forever.” Press men are busy and don’t’ have time to waste trying new products when their current ones are working fine. But changing times call for an ongoing evaluation of your print process to find ways to improve. Today’s printers are smart to run controlled tests of new products to make sure they are maximizing efficiency and profitability and “keeping up with the times.”

Anilox Roll Evolution

Chrome anilox rolls

Let’s use anilox rolls as an analogy. When chrome-plated anilox rolls came on the market almost 80 years ago, they were an improvement over the previous (and crude) methods of ink transfer. Steel rolls were covered with a chrome layer and mechanically engraved using a knurling tool. The dimples or “cells” filled with a precise volume of ink and carried them to the plate. This gave the printer more control over the ink application process and better print quality.

As the industry continued to evolve, however, the limitations of chrome-plated rolls became apparent. The chrome surfaces wore down quickly from the friction between the roll and the doctor blade. Due to their shape, the cells quickly lost volume capacity and print densities declined. Also, the maximum line screens that could be achieved with the knurling tool were 500 lpi which was only enough for basic and moderate graphics reproduction. As demands for higher quality printing increased, and there were advancements in presses, plates and inks, so did the need for better anilox roll technology.

Ceramic-coated rolls

To keep pace with the industry, anilox roll manufacturers began applying a ceramic coating to their rolls using a plasma spray device. These new surfaces had hardness of over 1400 Vickers compared to 850-900 Vickers for the chrome-plated surfaces. As the hardness of the roll determines its strength and durability, the new surfaces had better resistance to wear from the doctor blade. These rolls were too hard to engrave mechanically and lasers started being used to etch the rolls. The lasers produced a consistent engraving with cleaner cells and more distinct cell walls. Higher line screens could be achieved to expand a printer’s graphics capabilities. The ceramic surfaces not only lasted longer but the cells were also less sensitive to volume changes from wear. Printers gained more control over print quality and were now able to achieve target ink densities with thinner ink films.

New doctor blade technology

Like presses and other press components, doctor blades have evolved to adapt to the market. Blade manufacturers are continually experimenting with new materials and edge designs and introducing new doctor blade technology to keep up with their customers’ needs.

Steel

Today’s steel blade users have a choice of carbon, stainless, long life, coated and ceramic blades to fit their precise applications. Until now, steel was considered the only material capable of achieving a fine contact area with the roll and producing an effective wipe on high line screen engravings. Printers had to accept the downside of frequent blade changes, injuries and anilox roll scoring because there were no alternatives.

Plastics

Plastics, on the other hand, have always been known for their blade life and safety. The material has to be thicker to provide rigidity and these blades were suitable only for producing low-moderate graphics. The upside is that they don’t have to be changed as often, and the long and steady wear period allows for consistent ink film thickness for the duration of the print job. The material is also safer to handle and won’t score anilox rolls. Plastic doctor blade choices include a variety of acetals, UHMWs, and polyesters.

Next generation doctor blades

Flexo Concepts® recently introduced a new blade that acts as a hybrid between steel and plastic. A combination of an advanced polymer material and an innovative tip design called “MicroTip™” allows the blade to perform in high line screen applications where previous non-metallic materials were not an option. Printers using these advanced polymer products get blades that can produce the graphics quality of steel while remaining safe to operators and anilox rolls. The blade is now successfully being used in a range of narrow web and wide web applications.

As with anilox rolls and other press components, new doctor blade technology has gone hand in hand with the evolution of the flexo printing industry. The new polymer MicroTip blade is an example of a product that, once again, improves upon “what you were using before.” Why not try it?

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The Right End Seals Will Prevent Leaks in Your Doctor Blade Chamber System
In an enclosed doctor blade chamber system, the job of the end seals is to keep the coating or ink from leaking out of the ends of the chamber. Selecting the right end seals for your application is critical to achieve proper doctor blade seating and prevent leaks. If used correctly, these inexpensive consumables will ensure graphic quality and save a printer thousands of dollars in waste, downtime and replacement of other press parts due to premature wear.

Problems That Result from Failed End Seals
- Chamber leaks and mess
- Poor graphic quality and ink/coating waste
- Excessive doctor blade wear
- Premature anilox roller wear and scoring
- Press downtime
Why Chamber Leaks Occur

While there are other causes of chamber leaks, failed end seals are responsible for the lion’s share. It is important to use an end seal material that is compatible with the type of ink or coating being used, the length of the run and the press speed. Good seal design for a proper fit is also critical to ensure that end seals contain the liquid within the confines of the chamber. Incorrect end seal size and shape will leave gaps for fluid to leak out of the ends. If the seals aren’t sufficiently lubricated, the increased friction against the anilox roller will cause buildup and leaking. Enlist the help of your end seal supplier to work through these issues and make sure that you are using the correct end seals for your application.

When a chamber is leaking, a press operator will often try to fix the problem by increasing the load pressure instead of looking for the cause of the leak. End seal leaks should never be resolved by increasing chamber pressure. The additional pressure increases friction between the doctor blade and the anilox roll and causes both to wear prematurely. Paying a little extra attention when installing doctor blades and end seals can prevent many leaks from occurring in the first place. After installing new end seals, a press operator should evaluate the chamber and confirm that there is a snug end seal fit with no gaps or distortion. The doctor blade should have some upward pressure to form an adequate seal, but not so much that it requires extra loading pressure to make contact with the anilox roller in the middle of the blade.

End Seal Materials for Chamber Systems

There are various end seal materials which range in abrasion resistance, durability and solvent resistance. Again, your end seal supplier is a good resource to help you determine the best material for your application:
1. 1. Foam seals are the most common and the least expensive type of end seals. This material generally does not perform as well as other materials and may not be a good choice for long runs, higher press speeds and certain fluid chemistries. There can also be a lot of variation in the density of the material which can range from super firm to more malleable.
1. 1. Neoprene or rubber seals offer longer life compared to foam seals. They are compatible with aqueous and UV coatings & inks so they don’t have to be changed out between jobs. However, these seals do not seat well due to the coefficient of friction between the material and the anilox roller surface.
1. Pre-soaked felt end seals are a superior solution for resolving leaks. These end seals are oversized for a snug fit and pre-soaked in petroleum to reduce friction and prevent buildup. Felt end seals are compatible with all ink and coating types, provide a tighter seal and typically last longer than rubber and foam seals. Keeping felt seals lubricated with seal grease is key to their superior performance and longer life. Felt end seals tend to dry out after the anilox system is flushed with detergents and water. Applying seal grease to the radius portion of the seals after flushing the system will ensure a tight fit and extend the life of the seals by reducing friction.
Choosing the right seal material and design for your application and replacing end seals when necessary will help ensure that they do their job of keeping inks and coatings from leaking out of the chamber. Better yet, the right seals will allow for proper doctor blade seating and a predictable and even transfer of fluid from the anilox roller to the blanket. Despite their small cost, end seals have the power to save thousands of dollars in waste and downtime.
Corrugated Ink Delivery Systems: Two-Roll or Doctor Blade?
The flexographic ink delivery process has come a long way since the days when “Fragile – Do Not Drop” and “This End Up” were the only requirements of box printers. New press designs are able to achieve the quality of work that has traditionally been done by litho lamination, and corrugated printers have to produce a consistently high level of quality to compete. The evolution of the ink delivery process from a two-roll ink metering system to the enclosed doctor blade chamber has made this possible.

There are currently three types of ink metering systems used in corrugated printing applications: the two-roll system, the single blade system and the enclosed doctor blade chamber system. All three systems rely on an anilox roll to transfer ink to the plate. The difference lies in how the ink is applied to the anilox roll.

Two roll corrugated inking system

The Two-Roll Ink Delivery System

In the original two-roll ink metering system, a fountain roll rotates partially submerged in an open ink pan, picking up ink and applying it to the anilox roll. The anilox roll transfers the ink to the plate cylinder which then lays it down on the sheet. Though still widely used in the industry, there is a lot of variability in the two-roll system which results in a lack of control over the amount of ink transferred to the plate:

Imprecise wipe of the anilox roll leads to inconsistent volume of ink delivered to the sheet.

Color strength fluctuation and ink slinging can occur at higher press speeds due to the hydraulic force between the rubber roll and the anilox roll.

Transfer characteristics vary according to the hardness or “durometer” of the rubber roll.

Ink viscosity is subject to evaporation, dust and surface skimming due to the open tray design.

Single blade corrugated inking system

Single Doctor Blade Ink Delivery System

The addition of a reverse angle doctor blade added precision to the ink metering process. In the single blade ink metering system, a doctor blade made from steel, plastic or a composite material is used to replace the rubber roll. The blade is installed just beyond the ink metering nip to shear ink from the anilox roll surface. Doctor blade ink metering systems give the printer better control over the volume of ink being delivered to the plate. Where a rubber roll often leaves an additional ink film on the surface, a doctor blade shears ink cleanly from the roll. The inks perform better on press and a printer can achieve a more consistent ink film thickness. Ink consumption is reduced, and color application is consistent across the sheet even at higher press speeds.

Chamber doctor blade corrugated ink delivery system

Enclosed Chamber Doctor Blade System

The most recent development in the flexographic inking process is the enclosed chamber doctor blade system. In this system, two doctor blades are used along with an enclosed chamber to dispense the ink to the anilox roll. The reverse angle blade acts as the metering blade and wipes excess ink from the anilox roll. The trailing blade acts as a capture or containment blade and holds the ink within the chamber. Foam, rubber or felt gaskets seal both ends of the chamber and keep ink from leaking out. The ink is delivered through a closed loop from the ink pump to the doctor blade system and then back to the pump.

With this method, a printer can maintain ink viscosity because the enclosed design provides protection from evaporation of solvents or amines from the ink, depending on whether the ink is solvent or water-based. Also, dust, slinging and skimming are minimized. Better control over ink usage means lower ink consumption by as much as 15% per year. The system holds less ink than open pans, so there is not as much leftover ink at the end of a press run and ink can be removed and stored for future use.

Due to a more efficient cleaning process, a smaller amount of cleaning solution is needed to clean up a chamber so cleaning solution waste and disposal costs are also reduced. Color changes are quick, speeding up changeover and setup time on a run. The enclosed chamber system is more eco-friendly because of reduced ink consumption and disposal of waste ink as well as a lower volume of cleaning solution and water required to wash-up the station for a color change.

After years of being relegated to jobs with low graphics requirements, flexography now rivals other printing methods for quality. Today’s corrugated printers are able to produce products that are highly attractive and eye-catching to the consumer due to advances in the ink delivery process. Whether they opt for a single doctor blade system or see the benefits in investing in a dual blade enclosed chamber, printers gain clear advantages by using doctor blades in terms of controlling ink film thickness and maintaining color consistency.

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Optimizing Your Doctor Blade Trialing Process

Testing a new doctor blade in your printing operation should be a collaboration with your suppler that boosts performance while avoiding costly guesswork. Instead of randomly ordering samples, follow a systematic, data-driven approach.

Collaborate
Start by sharing key details about your press—dimensions, machine model, blade holder type, ink specifics, and any pain points you are experiencing. This information lets your supplier recommend tailored doctor blades rather than generic samples. There are a lot of options in terms of material type, thickness, and edge configuration.

Run Your Trial
Your supplier will likely send you one or more blades based on your provided data. Appreciate what these are and take care when testing them. They’re designed for your specific needs and should be used in a controlled production run.

Crawl, Walk, Run

Install and test the blades under normal operating conditions. Consider starting on a single print/coating station if the blade is new to you. Contact your supplier with any questions related to setup or installation and alignment. Clean the blade holder or chamber, using minimal blade pressure.

Provide Feedback

Complete any surveys your supplier has seeking feedback on the sample performance. Record important details and observations made during the testing related to blade longevity, metering quality, and any anomalies. Feedback is especially important if the blade fails as this can help your supplier make alternative recommendations by changing blade material, thickness, or edge configuration.

The Takeaway
An iterative, collaborative testing process is more efficient than random sampling. By working closely with your supplier—starting with detailed information, running controlled trials, carefully documenting results, and refining based on feedback—you achieve optimal performance and a long-term printing solution. Embrace this method to streamline your doctor blade selection and keep your press running at peak efficiency.

Trial a TruPoint Doctor Blade
Three Reasons Why Sheetfed Offset Printers Should Replace Their Steel Doctor Blades with Plastic

The goal of a sheetfed offset printer, like every printer, is to produce printed pieces efficiently and economically. In sheetfed offset coating applications, selecting the right doctor blade will help keep presses running and minimize costs while maintaining a safe pressroom environment. By replacing steel with non-metallic doctor blades, a printer can reduce pressroom injuries, eliminate anilox roller scoring and extend blade life.

Three reasons to replace your steel blades with non-metallic doctor blades:

1. Pressroom Safety

Steel doctor blades are responsible for a large number of pressroom injuries each year. As the blades wear, their edges become honed through contact with the anilox roller. This leaves razor-sharp tips that can cause serious cuts. Press operators need to be extremely careful and wear protective gloves when removing the worn blades from the press to avoid injuries. Due to their material composition, non-metallic doctor blades are safer to handle even when worn. Switching to non-metallic doctor blades will reduce lost-time accidents and can save a printer a lot of money in terms of workman’s compensation insurance rates, medical bills, labor replacement expenses and press downtime.

2. Anilox Roll Scoring

Steel blades are also to blame for many cases of anilox roll scoring. Incorrect blade installation or too much blade pressure can cause small fragments of metal to break away, become trapped against the roller and destroy rows of anilox cells as the roller turns. The score line appears as a thick band which runs around the circumference of the roller and affects the corresponding area of coating coverage. The printer wastes substrate and coating and has to have the roller resurfaced or replaced at a significant cost. In addition to scoring, steel blades accelerate wear on the surface of the anilox roller. The friction between the blade and roller erodes the anilox cell walls. As a result, the cell volume is reduced and the anilox roller can no longer carry the precise volume of coating that it was designed to deliver. Non-metallic blades are non-abrasive and will neither score rollers nor cause accelerated wear on the anilox roller.

3. Blade Life

Steel blades wear quickly and need to be replaced frequently. Non-metallic blades, on the other hand, have a long, slow wear period and deliver a consistent application of coating for the duration of the print job. They have a low coefficient of friction which means they need to be changed out less often. By switching from steel blades, a printer can minimize press disruptions and keep presses running longer.

For sheetfed offset printers using in-line tower coating units, there is a non-metallic blade available for every application. Tresu and Harris & Bruno chamber users can opt for the TruPoint Orange® blade with MicroTip® edge – a blade capable of effective metering with the added advantages of improved safety, reduced anilox roller scoring and longer blade life.

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Take Care of Your Doctor Blade Chamber and It Will Take Care of You!

Carbon fiber chamber system by Celmacch

The job of a doctor blade chamber is to help deliver a precise, consistent ink film thickness to the substrate.  Like other parts of the press, the doctor blade chamber needs to be maintained and inspected on a regular basis to ensure its peak performance. Taking the time to do this is a smart way to maximize press uptime and minimize costs.

What Can Go Wrong

1. The chamber needs cleaning – The doctor blade chamber requires regular cleaning to make sure it functions properly. Dried ink and coating particles can interfere with doctor blade seating in the blade holder and cause the chamber to go out of alignment.

2. The doctor blade chamber is not aligned properly – The doctor blade and anilox roll work best together when there is light, consistent contact between the two. If the blade does not have even contact with the roll due to chamber misalignment, it will not shear the ink cleanly and consistently from the anilox roll surface.

Doctor blade chamber corrosion

3. There is corrosion or pitting in the chamber components – Over time, regular exposure to harsh cleaning chemicals can cause corrosion and pitting in parts of the chamber. This can create recesses in the metal that prevent the blade from lying flat in the holder. Pitting also makes cleaning difficult, and particles from a corroded chamber can dislodge, settle into the ink and score anilox rolls.

4. The chamber is bowed or warped – Due to the length of the doctor blade chamber, it can bow and become warped from being mishandled. When bowing or warping occur, the blade will not lay flat along the full surface of the blade holder and contact the anilox roll uniformly when engaged.

Oftentimes, the press operator may try to correct some of these issues by increasing pressure to force contact between the anilox roll and doctor blade. While this may fix the problem temporarily, it often makes it worse. The added friction from excessive blade-anilox contact can cause chamber leaks and accelerated wear on the blade and roll.

What To Do

1. Clean the chamber – A cleaning routine involves wiping down the chamber with a cloth and flushing with approved cleaning solutions every day to remove ink deposits and particles from the doctor blade and blade clamp.  (This can take place when the press is shut down to clean the anilox roll which is also recommended on a daily basis.)

2. Verify chamber alignment – Operators should take the time to make sure the system is properly aligned and parallel on a regular basis. This will prevent early and excessive doctor blade and anilox wear and ink leaks.  If aligned properly, the system will remain stable even at increasing press speeds.

3. Inspect the chamber for defects – Chamber bodies should be flat and straight. This should be confirmed periodically (such as when other scheduled maintenance is taking place). To check, take a long straight edge and lay it along the full length of the doctor blade. Look for gaps which indicate that the chamber is bowed or warped. Also, examine the blade mounting surface and holder for corrosion and pitting. The chamber should be replaced if any of these conditions are evident.

4. Replace consumable parts – It is important to replace doctor blades and end seals when needed. Skimping on these inexpensive consumables is penny-wise and pound-foolish! Using new blades and seals to ensure a good contact area with the anilox roll and a tight chamber seal will prevent chamber leaks and anilox roll damage.

5. Standardize a cleaning and maintenance routine – Establish a recommended schedule of cleaning and maintenance for the doctor blade chamber. Make sure that procedures are documented and press operators are properly trained and evaluated.

Tresu’s carbon fiber E-Line chamber

6. Convert to a carbon fiber chamber system – In addition to other benefits, carbon fiber chamber constructions, such as the ones pictured here by Celmacch and Tresu, offer superior resistance to corrosion and pitting.

The doctor blade chamber is a precision tool that plays a vital role in producing a consistent product, and a regular routine of cleaning and maintenance will ensure its peak performance. A small investment here will go a long way to guarantee that this press component does its part in keeping your bottom line healthy and your customers happy!
New Polymers Meter Like Steel Doctor Blades

Steel doctor blades used to be a printer’s only option to produce high-end graphics. It wasn’t because he didn’t want longer blade life and the safety benefits that came with using plastic, steel was simply the only material that could sufficiently meter a high line screen roll. Not anymore! Today’s next generation polymers and advanced tip engineering have at last resulted in a non-metallic doctor blade with the metering quality of steel. This blade can replace steel doctor blades in a full range of flexo printing applications from solids and lines, to reverses and fine print, to screens and process work. Here’s why.

Steel Doctor Blades vs. Traditional Plastic

Due to its thinness and stiffness, steel has been the only blade material that could achieve a fine point of contact sufficient to execute a clean wipe on a high line screen anilox roll. By comparison, the characteristics of traditional plastic doctor blades require them to be thicker to provide the same rigidity. While they have other benefits in terms of safety and blade life, their thickness prevents them from maintaining a fine contact area with the anilox. As they wear and their contact area with the anilox roll grows, plastic blades produce changes in tonal value and dot gain when metering high line screens. For this reason, they have historically been limited to jobs with low to modest graphics requirements.

Next Generation Polymers

Now, specially formulated polymer doctor blades can compete with steel in the most demanding graphics applications. Unlike traditional plastic, the stiffness of the next generation material with a precisely engineered MicroTip™ edge allows the TruPoint Orange doctor blade to achieve and maintain a fine contact area with the anilox roll. Orange can deliver effective metering on line screens up to 2,000 lpi (785 L/cm) and produce graphics of the highest quality. The following diagrams compare the contact areas of traditional plastic, steel and next generation polymer blades:

Doctor Blade Contact Area Comparison

As shown, the contact area of a worn traditional plastic blade grows to .060″ (1.52mm) compared to a contact area of .016″ (.40mm), for a worn steel blade. The next generation polymer is able to maintain a contact area of .012″ (.305mm), equal to or smaller than that of most steel doctor blades, throughout the life of the blade due to the edge design. The engineered tip wears slowly and evenly and delivers consistent ink film thickness for the duration of the print job.

Today’s innovations in polymer doctor blades offer printers a viable alternative to steel. A combination of advanced materials and new tip technology has yielded a blade that meters as well as steel on the highest line screens yet retains the benefits of traditional plastic. Printers no longer have to compromise on anilox scoring, blade life, and safety to fulfill the most demanding graphics requirements!

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Cut-to-Length Doctor Blades Can Reduce Ink Chamber Leaks
Doctor blade chamber leaks are costly in terms of downtime and waste. While failed end seals are responsible for a large number of chamber leaks, ill-fitting doctor blades can also contribute to leaks. Ordering cut-to-length doctor blades from your supplier is a smart way to reduce leaks, maximize doctor blade and end seal performance and save a printer thousands of dollars every year.

Problems arising from Chamber Leaks:

Ink waste

Substrate waste

Excessive solvent consumption for clean-ups

Downtime for change-overs

Reduced doctor blade life

Scored anilox rolls

Increased end seal consumption

Chamber leaks are a nuisance in the pressroom that cause frustration and reduce press efficiency. When faced with a leaking chamber, a press operator has to stop the press and clean up the mess. Often, he will try to fix the problem by increasing the load pressure instead of looking for the basic cause of the leak. While this may work as a temporary solution, it can lead to other problems such as accelerated doctor blade and anilox wear. The increased pressure may also force ink out of the ends of the chamber, making the situation worse. Paying a little extra attention when installing doctor blades and ends seals can prevent many leaks from occurring in the first place.

Causes of Chamber Leaks:

Improper seal material

Bad seal design

Lack of proper seal lubrication

No dead bands on anilox rolls

Anilox roll chips

Incorrect doctor blade length

Failed end seals account for many chamber leaks. Using an end seal material that is not compatible with the type of ink being used, the length of the run or the press speed will allow ink to escape from the ends of the chamber.  Ink build-ups can result from not using the appropriate lubrication to reduce friction between the anilox roll and end seal. If the seals are not a proper fit, they will not do their job at containing ink within the confines of the chamber. Working with your end seal supplier is a good way to work through these issues and ensure that you are using the correct end seals for your application. (View End Seal Brochure)

The condition of the anilox roll can also play a role in chamber leaks. If the roll lacks a dead band (an unengraved area) at each end, ink will build up there and cause the seals to fail. Chips on the ends of the anilox rolls can also create ink buildup and compromise the integrity of the end seals.

Incorrect Doctor Blade Length can cause Chamber Leaks

In addition to failed end seals and defects in the anilox roll, doctor blades that are too short or too long

Doctor blade is the correct length for the chamber

can be another source of leaks.  When changing a doctor blade, it’s important to make sure that the new blade is the right size for the chamber and installed correctly. If it’s not a perfect fit, the doctor blade provides a gap through which ink can leak out of the chamber.

When properly installed, the doctor blade should have some upward pressure from the end seals to ensure a sufficient seal. A very slight rise in the blade is okay, however, extra loading pressure should not be necessary to get the blade to wipe the center of the anilox roll.

When a blade is too short or too long for the chamber, it prevents the end seals from doing their job. The blade should come to about halfway across the tops of the end seals when placed in the chamber. If the blade does not reach the seals, then the seals can actually prevent contact between the doctor blade and the anilox roll.

Doctor blades are too long for the chamber

On the other hand, if the blade extends beyond the outer edge of the end seal, it may create a small opening between the underside of the blade and the end seal which creates a path for ink to flow out of the chamber. If it’s too long, the blade may also become wavy and not lie flush with the roll, causing uneven metering and leaking.

Installing doctor blades that are a perfect fit for the chamber will eliminate this source of leaks. When ordering doctor blade material by the roll, it is important to confirm the proper blade specifications with your chamber OEM to make sure that press operators are cutting blades to the correct length.  An easier way to ensure the proper size is to order cut-to-length doctor blades from your supplier that are ready to install right out of the box.

Cut-to-length Doctor Blades can Reduce Chamber Leaks

Doctor blades that are the incorrect size for the chamber can be a frustrating source of chamber leaks, downtime and waste. Installing blades correctly and making sure that they are the precise length according to OEM specifications is one way to prevent this problem. Ordering cut-to-length doctor blades from your supplier will not only speed up blade changes but also ensure a perfect fit to maximize blade performance and minimize leaks.

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