Improve Performance Reliability While Reducing Waste

First published in FLEXO Magazine, January 2019 issue.

Written by Harper Technical Solutions team member, Richard Hernandez

When I was first learning how to run a press, one of the biggest things I could remember thinking was, “How am I supposed to know how these different anilox rollers print?” I would watch all the veteran operators switching out anilox rollers, and they knew exactly which one to drop into press for each job. How did they learn it?

They learned from trial and error. For the development of my understanding, it was much the same. As time went on, I figured out how to use the anilox volumes to my advantage and knew that some jobs would take this anilox, and others would run better with that one. It was all part of “learning the trade.” There had to be a better way to know which one to use, and a better understanding of what it took to obtain reliable performance.

I would like to take the opportunity to discuss how to get reliable performance and a basic understanding of the anilox, while giving an in-depth look at how to get your shop’s ink department and presses correlated, anilox rollers identified, and how to keep things organized and maintained to help you reach the full potential of your anilox rollers. In turn, this will help keep your waste down, help to promote color consistency, and keep production time up.

LINESCREEN, VOLUME & GEOMETRY

Linescreen

Understanding linescreen, volume and geometry, and how they work together is the beginning step to consistent, quality printing.

You may have certain artwork or a certain account whose print dynamics always seem to be a problem when running on press. The simplest solution could be that you are running a plate, anilox, and ink combination that is not made up of the optimum materials for that application. Locking down your anilox selection is where to start.

How does line screen play a role in the anilox? The line screen provides the cell opening on the surface of the anilox (see Figure 1). The line screen is defined by how many cells are present per linear inch on the roll (LPI). A properly selected line screen does two things: It allows for distribution of volume without compromising cell quality, and it supports the printed dot. When running artwork like 4-color process, a high line screen is used to help support the low dot percentages, also known as highlight screens.

Figure 1: The line screen is defined by how many cells are present per linear inch on the roll (lpi).

Volume

Historically, because the inks are formulated to hit color with thin ink films, your volume will not need to be high. Pairing more open
cells (lowering line count) with a set volume provides a greater deposit efficiency and puts more ink on the plate. The wider opening can be useful in specialty applications like particle transfers. Particle size would then dictate required volume.

Another way the LPI helps is by supporting the printed dot. Knowing the line screen of your artwork and what look you are going to achieve is how you will determine the LPI of your anilox. If you have a high line of artwork, you do not want a low line screen anilox because your dots on the plate will over-ink or under-ink instead of having ink evenly distributed to the plate dots. This will cause the bridging of dots and dirty print since too much ink is distributed. One thing to keep in mind is that the LPI of an anilox does not change with wear. It is always consistent. The only time the line screen will change is when you send it in to be remanufactured and request a different LPI.

How is volume a factor in anilox selection? Volume is the amount of ink contained in the cells of a defined area (see Figure 2). This is
measured in BCM. A frame of reference will help you scale the concept of the micron: Take one human hair and look at a cross-section and divide from one side to the other into 100 equal width pieces.

Figure 2: Volume is the amount of ink contained in the cells of a defined area.

Each equal width is one micron. A cell volume of 0.5-2.0 BCM is used along with a high line screen. With a high line screen, not too much ink is needed because you are typically printing fine screens without solids. A volume of 5.0-10.0 BCM is a deep cell, which will hold a lot of ink that will be distributed to the plate. These are typically used for varnishes, coatings, and whites.

You would use these volumes with a 300 LPI to 150 LPI anilox where full solids and complete coverage are needed. In many cases, the volume will be dictated by the ink supplier because formulations are dialed in to specific volume expectations. Always consult with the ink supplier to better understand the needed volumes and why. Volume can change because the BCM will be affected by wear and the cleanliness of cells. As an anilox wears down, the cell will get shallower and not carry as much ink as it did when it was new. Plugged cells immediately lower volume and can only be remedied by a thorough cleaning.

As you can see, the LPI and BCM of an anilox are major factors in how much ink will be distributed to the plate. Both play off each other and cannot work independently. But there is one more factor in your anilox identity—the geometry of your anilox.

We know how the LPI and BCM of an anilox play a role in print. But what is the best way to be assured that the ink is distributed from the cells? The geometry of the anilox is the answer.

Geometry

There are so many ink systems in the industry now to help catch the eye of the customer that converters need to be sure they have the tools that can create the expected look. Some coatings are designed to be thin in consistency and others very viscous; there are different geometries that release ink in different ways to accommodate the viscosity. Hexagons, channels, elongated cells, trihelical designs, and 45-degree quads are just a few engravings that are offered to help with converter applications (see Figure 3). Some geometries are universal in application, like the 60-degree hexagonal. Others have niche applications but are more effective. Typically, thin viscosities perform better with enclosed cells and higher viscosities perform better in channel arrangements.

For coatings and inks that have never seen a flexographic press, these often need to be tested with a banded roll to dial in the right engravings. There certainly are exceptions to every rule, so speak with your anilox supplier’s regional technical support about engravings they offer and how they can help.

Figure 3: Hexagons, channels, elongated cells, trihelical designs, and 45-degree quads are just a few engravings that offer help with converter applications.

You will also want to know the needs of your plate material, ink, and artwork, and include their representatives in selecting the correct anilox rollers.

Anilox Audits

The first thing that needs to be asked is, “What is the current state of your anilox inventory?” If you were to walk your shop floor, chances are operators will have their own go-to anilox rollers. They will have a good gauge on their anilox performance, but this understanding must be taken to a higher level to meet pressroom needs. This could potentially be the originator of any color inconsistencies you might be experiencing during a color match. But how do we find out the condition of our anilox rollers? Two words—anilox audit!

Anilox audits are a great tool that will help you identify the three main components we have discussed as well as the anilox condition, so you can understand better what you have and the role each anilox can best play in your production environment.
An audit will also help in identifying which anilox rollers are damaged. A damaged anilox will have many signs, and with the help of your anilox supplier, you can identify the sources of damage and eliminate them. Chipped edges, score lines, worn cell walls, broken cell walls—these are just a few that can be brought to light by an audit. There is nothing more frustrating for printers than to have an otherwise perfectly good engraving get needlessly damaged and render it useless.

• Chipped edges are usually caused by handling. Bringing an anilox in and out of the press and hitting the press frame is a good example. Another way to get chipped edges is when moving a roller into storage, sliding the sleeve or roll to the back or bottom of a rack, and making forceful contact. A doctor blade unit, sling guard or chamber not properly attached or inserted could also be a culprit. Additionally, corrosion can also loosen the bond between the ceramic and the base and allow the ceramic to flake away
• Score lines are a tricky defect because they may or may not show in print, and finding the source can be difficult without assistance. Sometimes they are not deep enough to see in the print but are readily identified visually. Sometimes they fall right in the print area and cause an undesired print quality. Identifying the sources of contamination that get in the ink and between the blade and anilox, causing the scoring, is a task with which your anilox supplier can help
• Worn cell walls will cause an ink color to print lighter than what came out of the ink department and should be taken out of rotation. Wear can come naturally from use, but you would also have to consider blade pressure, blade holding equipment, and abrasive inks (see Figure 4). One of the most important functions of the anilox audit is to identify worn rolls and get them out of circulation without resorting to press trial and error
• Broken cell walls will cause the ink to print dark spots. If you have a 700 LPI anilox that has broken cell walls, those cells go from 700 to potentially 500 in those areas, meaning lost dot support and unwanted increases in volume where those spots are located. An operator could be chasing an issue for which he or she will not find an easy solution

Another way an audit will help is by identifying the line screen and volume of those few anilox rollers that are not marked. We all have seen anilox rollers that are older and have had their identifying marks worn down and made illegible. This will also be helpful in identifying where the proofer roll in your ink department is printing.

Figure 5: After an anilox audit, you will have an echotopography digital volume (EDV) value and 3D image of every anilox to review.

When the audit is graded and returned to you, you will have an EDV value (echotopography digital volume) and a 3D image of every anilox that you can then review and determine which should be cleaned and returned to inventory, monitored in future use, and which ones should be removed and replaced (see Figure 5). EDV is the measured volume of BCM.

If you own anilox rollers that are scored, have chipped edges, or are dinged, you may want to consider replacing those as well. These are factors that can cause print defects. If the doctor blade gets pulled back due to a chipped edge, it may look like a gear mark. A scoreline or ding can cause a void on a full reverse print on an anilox that otherwise matches the color perfectly. Those are just a few problems that could come about from damage that is visible. An anilox audit helps identify both issues that are visible or not visible to the naked eye.

When the anilox base condition is salvageable, you have the option of remanufacturing those engravings as well.

Achieving the full potential of your anilox inventory starts with understanding the linescreen, volume and geometry, then partnering that knowledge with proper inventory management and the useful tools the anilox audit provides. Who would have thought that all this information could have come from an anilox audit?

Knowing the components of an anilox, and how they play a role in your application, will help your workflow move smoothly out your shipping doors.

About the Author: Richard Hernandez is a sales/technical service representative – Western Region for Harper Corporation of America.

He brings more than 24 years of extensive experience in the printing industry with six years in offset printing and 18-plus years in flexography. Within that time, he has gained extensive knowledge of Webtron, Nilpeter, Comco, and Mark Andy Inc presses, as well as A.B. Dick and Heidelberg, offset presses. Richard began his flexographic career at Los Angeles Label, which led to production lead and supervisory experience at The Label Co, and Paradigm Label in California. Prior to arriving at Harper, he was the print manager at Precision Label, which helped him excel in his color matching, team member training and mentoring, and troubleshooting skills. While there, he also assisted with the R&D and product development that helped drive the company into industry-leading trends.

To view the original FLEXO Magazine article click HERE.

The Steps Taken to Optimize Crucial Parts of the Project & the Relevant Sections of FIRST to Follow

First published in FLEXO Magazine, October 2018 issue.

Written by Harper Technical Director, Sean Teufler

The “FIRST in Motion” project culminated in a presentation during the session of the same name at Forum 2018 in Indianapolis, IN. Previous FLEXO Magazine articles chronicling the project (published in the August 2018 and September 2018 issues) dealt with objectives, details, and a look into initial processes.

The purpose of the project, from my perspective, was to demonstrate the adaptability of a FIRST-oriented printer in the utilization of a “new-to-its process” plate technology. This is not an easy challenge for a printer that does not possess the diligence and background I will describe in this article.

The real secret to success with optimization is no secret at all when you see it in action: It is the execution of a well-written plan where everyone knows each person’s role and responsibilities.

The other purpose of this article is to outline the importance of ink and press optimization and reasoning behind them, as specified by FIRST. FIRST, of course, is an acronym for Flexographic Image Reproduction Specifications & Tolerances. It comprises a collection of industry knowledge and serves as the ultimate guideline for the flexographic workflow. It is important to distinguish the meaning of the term “guideline.” In our sense, it serves to tell us that the document provides a means to achieve the most from your capability, having created such a capability that allows you to maintain process control and achieve repeatability. A printer must create that capability, and we found this project was a clear demonstration of that from the ink and press optimization.

OPTIMIZATION & THE PRESSROOM

Let us consider the larger context before we look into the steps of optimization. The guideline I just mentioned helps build the foundation for the print dynamic. That foundation also consists of practice and repetition to maintain the print dynamic. This means when the day of the trial comes, you are able to perform all the functions of measurement, preparation, and selection.

Always look to eliminate sources of contamination, like the residues on the ink lids shown here. All photos courtesy of Sean Teufler

The only things you should learn during a fingerprint or characterization are the presses’ capabilities, not whether you can measure, clean or print consistently. If you find yourself doctoring inks, changing aniloxes or switching decks, then you have not optimized the press or its components. Worse, you may find there is an issue with its condition and preparation. Waiting until the day of the trial to practice how to use your measuring equipment, prepare chambers and aniloxes, manage viscosity and maximize printability is akin to waiting to study for an exam until the day of the test. In both scenarios, you will quickly discover that you should have been much better prepared.

What is optimization, in the terms of the pressroom? Optimization finds its initial roots in FIRST Section 1.3.1, Press Optimization. This section is a must-read, as it speaks to the fundamentals we strongly expressed in our “FIRST in Motion” presentations regarding control and measurement within the confines of normal, everyday practices. Keep in mind, these must be good practices for legitimacy, rooted in FIRST.

Aclean, well-balancedchamber creates the opportunity for even ink transfer

For our fingerprint and characterization trials, and the press run itself, the only variable was the substitution of a different plate technology into the existing workflow. The optimization was based on these everyday practices. This put the burden of impartial testing firmly on the shoulders of the press department. The essential parameters for the test conditions included viscosity range, ink temperature, contamination-free equipment and clean aniloxes that have been verified at the required volumes. Although it is briefly mentioned in the section as even delivery, the chamber system is another variable that must be accounted for during an optimization and day-to-day operations. It is not enough to have optimization without the organizational background, discussion and conveying of understanding. FIRST Section 1.4.2.3, Communication is where we learn that we must have press operators, inkroom personnel, and production management teams working toward the same goal and to effectively express what is going right or wrong, and why. These goals must be established and agreed upon, and preparations must take place before any trials. Those participating must understand the goals and their role in meeting each of them. The optimization question then becomes how to actively evaluate. Think of it in this context: Can we sustain a stable print condition? This evaluation is done only through the work of measurement.

ON-PRESS INK CONTROL

FIRST Section 20.2.6, On-Press Ink Control discusses the measurement of temperature and viscosity. Viscosity is temperature dependent for more than just measurement. It is also a prime indicator of the condition of the ink. What does temperature mean to a printer? It means to always be aware of operating temperatures for your inks and surrounding systems, such as pumps and dryers. Operating at temperatures in excess of the accepted range can adversely affect solvent- and water-based ink performance. Solvent inks will flash off solvent quicker and at different evaporation rates, affecting balance and dry rate through the anilox-plate-substrate transfer process. For the printer, this means a constantly changing print dynamic of dot gain, color and chance for defects. Water-based inks may lose their pH balance and begin to kick out at higher temperatures. This quickly affects color strength and clean transfer.

When it comes to your own setup, you want to become proficient in your temperature and viscosity measurements. Infrared temperature measurement is very useful as an external verification. You will also want to provide training in the proper use, care and selection of the viscosity cup. Many viscosity measurements are fooled by dirty or damaged cups. Selecting a viscosity cup would seem simple enough, but for accurate measurement you need to be using the exact same brand—not just the same number—as they may not perform the same. In other trials we have experienced measurement differences of seven seconds or more in cups that were supposed to measure exactly the same, so be sure to test them to a calibrated standard before issuing for use. We also often find damaged and dirty cups being used, and these create considerable print defects as inks are misadjusted to a false viscosity. Understanding how to use a cup, how to hold it, how to accurately gauge the break, and when to start and stop the time measurement are all important functions of a proper manual viscosity check.

It is essential to properly calibrate the inline viscosity settings with accurate cup measurements.

Once your viscosity cups and your ability to use them correctly are validated, they become a powerful tool in ink stability and provide a foundation. You can then build redundancy through the use of calibrated inline systems for viscosity and temperature measurement. These systems are ideal for monitoring and maintenance control of both temperature and viscosity. They are set through hand measurements mentioned in the prior passage. Being able to accurately and independently verify confirms your automated measurements are within expected tolerances. Sometimes indications of instability in the print are just an indication viscosity control is either not happening or not being calibrated properly.

Contamination can also affect color control, so any press components that come in contact with the wet ink must also be contamination-free. Doing otherwise risks unmitigated color shifts without another cleanup and a replacement of the ink. This would mean the sump, pump, internal piping, anilox, chamber or blade system, and any viscosity cups used must all be contamination-free.

20.4.2, ANILOX SELECTION

In terms of anilox selection, we worked with the existing inventory of high-line, low-volume aniloxes on the “FIRST in Motion” print project. The anilox specifications had been optimized for the existing process workflow. The requirements for our trial were the volumes needed to support color achievement at a printable viscosity

Once established, the maintenance of the anilox cell condition becomes paramount to any future success. You can easily fall in the trap with solvent inks where you achieve color but cannot sustain it due to an imbalance of pigment load, vehicle and solvent. Don’t let dirty cells contribute to changes when the condition can be so easily rectified with cleaning. Aniloxes always need to be cleaned and verified along with the sequence of ink and anilox placement, known as the anilox deck sequencing. This is to ensure consecutive setups follow the exact same anilox placement and condition. Why would that be important? You are wanting to minimize any potential variation and any conditions in individual stations can be spotted much more easily and traced to the source of the variation when you are not mixing and matching components.

20.4, INK METERING SYSTEM

The ink metering system is a vital macrostructure within optimization. Macrostructure refers to the machine-tolerance precision with which a metering system must operate. Changes in blade angle, sweep, and tip consistency can adversely affect ink film transfer by allowing too much ink to pass through. More importantly, the inconsistency as the blade re-seats—changes angle to compensate for excess pressure—adds to a constantly changing print dynamic that runs entirely counter to the whole purpose of optimization. The condition of components, including any doctoring assemblies and especially chambers, is critical. An ideal and attainable setup would have the following features:

• Low pressure on the blades

• No leaking around the seals and blade areas

• A kiss impression

• Chambers and pumps free of contamination

When we speak of FIRST, we must begin with press optimization. Everything defined afterward—the fingerprint, characterization and every subsequent press run—relies on the achievement and sustainment of the press optimization. I have been to many trials where there was more discovery than actionable use of the presstime. I am happy to say that Plastic PackagingTechnologiesLLC—where the “FIRSTin Motion” print run took place—was not one of those places.

I always remain a skeptic when analyzing because when you stop being skeptical, you start making assumptions that make you overlook key points. The first thing you should check is how well the trial parameters are communicated. I met with the staff and discovered all the aniloxes were clean, ordered and mounted in the racking, where they were identified and organized. All the inks were properly set to viscosity and maintained throughout the trial. The racking of decks was done with precision and care. The chambers were built properly and were free of contamination—precisely the type of setup you would expect from a sustained optimization—and the delivery was spot on.

Everything came together right on time and the only small delay was laying out the measurement plan for the trial itself. You could not have asked for more from the press crew, ink team or pressroom management that day. The real secret to success with optimization is no secret at all when you see it in action: It is the execution of a well-written plan where everyone knows each person’s role and responsibilities.

When dealing with FIRST, you must embrace what the words tell you and make them come alive in your pressroom. FIRST comes to fruition in many specific flexographic processes but none are as universally important as optimization. What does FIRST tell us? It tells us to communicate among teams and to pay attention to individual steps taken. It then tells us to evaluate steps by measurement and finally and most importantly, to keep the process within stable, acceptable parameters.

A look at the entire web—CMYK on the left, expanded gamut (EG) on the right—from the project at the center of “FIRST in Motion.” Concept and design by Bob Coomes of Plastic Packaging Technologies LLC, and Patrick King & Charlie O’Shields of VENN49 Creative Lab. Prepress and color management by Mike Jeroutek & Kerry Thonen of The ALC Group

About the Author: Sean Teufler is a Technical Director for Harper Corporation of America and holds FIRST Implementation Specialist Certification.

Sean has been in the industry since 1991 when he started out as an ink technician. He has held technical and sales positions with Harpersince 2003. He is a seven time tech of the year award winner for Harper. Sean co-chaired FTA’s Fall Conference 2012 and 2016. He became chair of FTA’s Supplier Leadership Council in 2017 and has spoken at numerous Fall Conferences and Forum events, participated in the judging for FTA’s Excellence in Flexography Awards Competition, and led two Flexo Quality Consortium (FQC) projects, one of which garnered him a President’sAward for Leadership Excellence in 2012.

To view the original FLEXO Magazine article click HERE.

First published in FLEXO Magazine, June 2018 issue.

Written by Harper Western Regional Sales & Technical Manager, Greg Horney

Widely respected management consultant Peter Drucker is often quoted as saying, “You can’t manage what you don’t measure.” You can use whatever version of this you like, such as, “You can’t improve what you don’t measure.” The idea is ensuring you are measuring the elements that impact your bottom line. These are your key performance indicators or KPIs.

Monitoring your KPIs is an essential part of production management and continuous improvement. These KPIs should have a direct tie to the bottom line if they are going to mean anything. Often, these KPIs are individually monitored, and include categories such as waste, run time, downtime or makeready. Improvements in any of these categories can be presented with false savings or “funny money” because of the effect on other categories. Each KPI should include one or more consequential metric to ensure that if one shows improvement, it does not adversely affect another.

Taking a hypothetical example, we have a 17-in. press and we are monitoring the makeready times on jobs of similar length for all 8-color presses over the period of a month (depicted in Chart 1). The team launches a project for makeready reduction with a goal of 20 percent. After the month passes, the team reports makereadies have improved by 25 percent.

On its own merits, it looks like a great improvement. However, if team members would have measured a consequential metric, they would have spotted that downtime was increased when the solutions used for faster makeready times were applied. The team would have realized the need to go back and find other means to reduce makeready without adversely affecting downtime.

OEE, from a continuous improvement “ point, helps managers set goals that target three main measurements: availability, performance and quality.

ORGANIZING DATA

Overall equipment effectiveness (OEE) is a tool used to evaluate how well a manufacturing process is functioning. The idea of OEE is not a new one—it came about back in the 1960s, pioneered by Seiichi Nakajima. Seiichi based OEE off of Harrington Emerson’s idealisms on labor efficiency.

OEE calculates in a manner that allows you to see how a particular machine, shift or shop performed while keeping consequential criteria in the data. OEE, from a continuous improvement point, helps managers set goals that target three main measurements: availability, performance and quality.

Chart 1 All data courtesy of Harper Corporation of America

Chart 2

The intention of OEE is not to replace your current KPIs, but more to organize the data that is already being collected. When a drop in OEE is recognized, getting to the root cause is, in most cases, easily traceable through which multiplier dropped. Each of these measurements utilizes two indicators that can be broken down into smaller buckets for analysis.

As we go through OEE here, understand this is a 10,000-ft. view. There is a lot here that can go much deeper. There are versions of OEE that break down to OEE1, OEE2 and even OEE3; this discussion will only skim the surface.

Monitoring your key performance “ indicators is an essential part of production management and continuous improvement.

Just like any KPI, both the data collected and how it is measured is completely yours and your interpretation of what should or shouldn’t be measured, but it must include the six key losses of planned and unplanned stops, minor stops and slow takt time, and production and startup waste. One prime example is in the availability set, where one company may measure as availability accounting for 24 hours/day and 365 days/year, where another may feel availability only accounts for scheduled machine time which may include breaks and lunches if the press is not staffed during those periods.

The important thing, once you have determined how to measure the data, is to stay consistent.

OEE is derived from the following equation: OEE = Availability x Production x Quality. To break down OEE to its core, let’s look at each element

AVAILABILITY

Your availability is simply your run time divided by your planned production time, where your run time equals your planned production time minus your stop time. Within your availability multiplier, you have both planned and unplanned downtime.

Planned downtime includes things like makeready, matrix changes, roll changes, etc. Unplanned downtime, commonly attributed to machine failure, includes things like maintenance downtime (mechanical, electrical, etc.), unscheduled breaks or meetings, ink spills, color matching, and web breaks.

Each shift needs to record any downtime and makeready time. Unless the press is running every minute of the shift non-stop, those times will be recorded and identified as to why. This will include roll changes, ink adjustments and so forth. Stops that include web breaks, ink overflow/blowout, color matching, alarm stops and the like are counted as unplanned downtime. These examples should all be tracked as smaller buckets for deeper dives into their root causes or for continuous improvements.

Let’s look at an example of a shift:

Planned downtime = 120 minutes

• 3 roll changes/hour @ 5 minutes each = 15 minutes x 8 hours = 120 minutes

Unplanned downtime = 32 minutes

• 1 ink blowout @ 20-minute clean-up

• 1 web break @ 12 minutes

Chart 3

480 minutes/shift – 152 minutes total downtime ÷ 480 minutes/shift = 68.3 percent Availability for the shift

DEFINING DOWNTIME

It is critical to understand what downtime is. Downtime can be considered as anything that doesn’t make a physical change to the product. Using the letters in “downtime” as an acronym—as described by Taiichi Ohno, the father of the Toyota Production System—it is easy to sort downtimes. There are essentially eight types of waste:

• Defects include product that does not meet or exceed customer expectations, to include makeready and production waste

• Overproduction is the overrunning of a job that is not billable. Sometimes we overrun jobs because we know waste is high or to put into inventory. But you have to be careful, as both high waste and inventory are forms of waste if we do not have purchase orders (POs) or inventory agreements in place. It’s a calculated risk

• Waiting is poor takt time where one process is faster or slower than the next; where one process has to stop to wait to perform the next task

• Not utilizing employee skill or talent is not having the right people in the right place. This can show up in the form of poor training or not fully utilizing the talent of your staff

• Transport is the moving of materials from place to place. If you are having to move your material all the way across the plant to perform the next step in converting, you may want to look at improving your workflow

• Inventory can be both raw materials or finished goods. If we don’t have POs or agreements to purchase, carrying an inventory is a calculated risk, as graphics change and can render printed materials useless. Overpurchasing raw materials without solid forecasts is also a calculated risk. A customer may have always purchased a 1.5 mil white poly label, but now wants semi-gloss to reduce costs. If you loaded up on 1.5 white poly, you may be stuck with it for a while

• Motion is the waste of movement. If you have to walk all the way to the end of your press multiple times a day to get a flathead screwdriver, think about where you need that flathead all the time and put it where it is needed the most. Doing a good spaghetti diagram identifies motion waste pretty quickly

• Excess processing is usually caused by a lack of standards, excessive reports and human error. This can be the result of an overthought or poor process reacting to a previous defect

These wastes, like the OEE here, is covered at a very high level and can be broken down to finer detail.

Teams would track planned and unplanned downtime caused for continuous improvement projects to improve availability. Activities such as ink proofing using anilox correlation, 5S, lean manufacturing practices and robust maintenance programs will improve the availability element of OEE.

PERFORMANCE

The performance measurement in OEE looks at your “running to standard” by considering both idle and small stops as well as slow takt time as the key indicators for this multiplier. Taken from the German word for the baton an orchestra conductor uses to keep the time or the beat, takt time is just that—the measurable beat or pace of production.

Essentially, takt time is the manufacturing rate for a finished product to get to the customer. This can be both internal and external customers. For internal customers, it is the time it takes to finish a task to completion for the next process that physically changes the product. Transportation from one process to the next, sorting and waiting— these are not measured as takt time, but rather as a form of waste. For external customers, slow takt time results in late deliveries or long lead times.

Instances such as web breaks, blade changes and ink adjustment all count toward idle and small stops. Items like having to run slow due to ink or substrate performance, or registration issues, would account to run standard.

Typically, run standard is measured against the machine rate of the press, rewinder, laminator, etc. If a press machine rate is 700 fpm on the nameplate, that would be the standard of your OEE metric. There are ideal run rates or theoretical run rates that can be used as the standard. However, this would be a standard that company stakeholders would have to agree on, based on a long history or established machine burden rates, especially when those burden rates are based on ROI or asset value of that equipment.

Machine rate is the metric that frustrates machine operators the most, especially in narrow web operations. The leading reason is that machine rates are based on the mechanical capability of the press while not taking into account the many different types of converting done inline, such as die cutting, de-lam/re-lam or cold/hot foil. Machine rates should not be changed to reflect downstream converting unless the downstream operation has an identified mechanical capability associated with it. Then you can take the lesser of the two. An example would be a turret rewinder with a slower speed than the press. If the operation is not used all the time, take the higher of the capabilities. By not doing so, you can introduce bad information to the dataset. Taking the higher capability number will yield a lower OEE number; however, these are your baselines. The rule of “it is what it is” applies.

With any equipment, we all understand that breakdowns, such as web breaks, wrap-ups and ink spills happen along the way. Wouldn’t it be a perfect world if we could all run at the 100 percent rated speed of the press regardless of the job? These anomalies will be identified by using the results of OEE. Equipment, strategies and processes to reduce anomalies and enhance performance could include the following: 5S, press optimization, standardization, inline color management, vision systems, auto-register and maximizing roll length to reduce roll changes.

QUALITY

Simply put, quality is your yield, defined as good product divided by total product ran (see Chart 2). Almost every plant I’ve been in looks at waste and/or yield as a KPI measurement. If you are tracking good product, the difference in total product ran is your waste and if you’re tracking waste, your total product ran minus your waste is your good product. Essentially, it’s what went in versus what good came out.

Quality is a metric where the potential for “creative math” may come into play on production floors, with methods such as understating waste, shorting total product ran or claiming roll footage deviation. Utilizing OEE, you avoid any “fudging” of the numbers to improve without skewing the availability and performance elements to make the math work. Of course, you must always validate your numbers because at the end of the month during inventory, it all gets hashed out and that creative math gets caught.

With quality comes consistency and repeatability. Ways to improve quality metrics include adopting Flexographic Image Reproduction Specifications & Tolerances (FIRST), inline vision systems, auto-register systems and establishing standard operating procedures (SOPs).

When we look at our OEE numbers from a high level (as in Chart 3), we can see our three measurements of availability, performance and quality, along with our final OEE number. It’s easy to see areas that need improvement or may have shown dips that affect your OEE percentage. Often, we know what may have happened, be it bad film, ink, dirty anilox or any other combination of issues that happen in manufacturing. The idea is to understand and see those issues and make efforts to reduce those occurrences to drive the OEE trend upward.

When establishing OEE baselines, often operators, managers and business stakeholders are taken aback initially by the numbers. Especially in the flexo industry, OEE is often a low percentage and a large pill to swallow as stakeholders come to grips with the issues that have arisen. We know that if these issues are left to grow unchecked, they become the bogeys of performance improvement efforts.

Once you understand that the numbers are not a personal judgment, but rather a baseline from which to improve processes, OEE becomes a much more effective tool. It’s really understanding numbers that go into the calculations and why they are what they are.

Overall equipment effectiveness is a way to evaluate how well a manufacturing process is utilized. The three major categories of availability, measuring both planned and unplanned downtime, production measuring both idling/small stops and slow takt time, and quality measuring both production rejects and makeready/startup waste, all make up your six big losses and goal for measuring OEE. OEE gives the opportunity to address the little things that plague us daily and make the manufacturing process as productive as possible. It also allows you to prioritize improvement efforts by evaluating what is happening on the production floor, like downtime wastes, run speeds or capacity

About the Author: Greg Horney has more than 30 years of experience in flexographic and offset printing. He has a BS in applied arts and sciences from Rochester Institute of Technology. Greg has worked from the ground up in the printing industry where his experience ranges from gopher and pressman to graphics and prepress, quality, continuous improvement/project management, print management and production management.

Greg is a Lean Six Sigma Black Belt and is also FIRST Implementation Specialist Certified. He both chaired and co-chaired sessions at FTA events, most recently chairing the “Pressroom Pressures” session at Forum 2017 and speaking on a panel at Fall Conference 2016. Greg has participated as a judge in the Excellence in Flexography Awards on three occasions and has published articles in FLEXO Magazine. Greg is now applying his years of industry experience to helping Harper Corporation of America and the Harper Graphic Solution Group’s customers as a technical service representative in the Central Plains and Southwest regions.

To view the original FLEXO Magazine article click HERE.

How to Clean Anilox Rolls & Understanding the Chemicals Involved

First published in FLEXO Magazine, December 2017 issue.

Written by Harper Vice President of Sales, Alan Rogers

It’s time to clean your anilox roll as you prepare for your next job. You go to your work station and see several bottles of cleaners. You try one and you do not see good results. You reach for another and, this time, you spray an abundant amount of cleaner on the roll. The results are better, but not to your satisfaction, so you grab another bottle. After several minutes of scrubbing, you finally have a clean roll.

But to what extent? And to what expense?

There are thousands of different cleaners on the market, each with different formulas and ingredients. Some manufacturers formulate for specific applications, such as anilox rolls or printing plates. Many chemical companies market cleaners that are great for dissolving ink, grime, grease and removing stains. Other companies manufacture multi-purpose cleaners, advertising their products are great for any and all applications.

If your job is to clean anilox rolls, how do you know which cleaner is the correct one, specifically to clean while not damaging?

Prevent plugged cells (seen on the left) by keeping your aniloxes clean. When in press, keep ink circulating to prevent it from drying in the cells. Photos courtesy of Harper Corporation of America.

KNOW YOUR MAKE

Before you apply any chemical to your anilox roll, it is important to understand its makeup and to review any chemical’s Safety Data Sheets. As a printer, you are always taught to protect the ceramic coating of your anilox roll and to prevent chips, dings and scratches. However, it is just as important to protect the base or core. Many anilox rolls are made of steel bases, which can be quite heavy. To combat the weight issue, anilox companies are making lighter bases by substituting aluminum. If you are using anilox sleeves, these products are made from various composites encased by an aluminum cladding.

It is very important to know the “ material from which your anilox is made, as different cleaners can cause damage or corrosion to the base. That’s true of mild steel or aluminum, the composites or the cladding.

More importantly, you should know what chemicals in different cleaners can cause damage to your anilox rolls, especially those made from aluminum. Look for cleaners that state “aluminum safe.”

When it comes to cleaning with a brush, stainless steel should be used on ceramic anilox rolls. Don’t use brass brushes on ceramic and always brush in a circular motion.

Anilox rolls are made by spraying a ceramic coating to the base and then laser engraving to form cells. This coating, although hard and durable, has a certain amount of porosity by nature that allows for liquids to eventually penetrate to the core. The higher the porosity in a ceramic coating, the faster this penetration occurs. Therefore, it is extremely important to rinse immediately after cleaning a roll and not allow cleaners to soak on the ceramic over a long period of time. This helps prevent the liquid penetration from attacking your base.

SODIUM HYDROXIDE

Sodium hydroxide is used in many industries, mostly as a strong chemical base in the manufacture of soaps and detergents. Sodium hydroxide is very alkaline (high pH) and is soluble in water, ethanol and methanol. For these reasons, it is a very common ingredient found in many cleaners in the printing industry. The high pH dissolves water-based inks, cleans dirt and grime, and is very aggressive.

However, it can also attack aluminum and cause corrosion to your anilox roll. Sodium hydroxide reacts with aluminum and water to release hydrogen gas. In this reaction, sodium hydroxide acts as an agent to make the solution alkaline, in which aluminum can dissolve. If you are using a cleaner with sodium hydroxide to dissolve your dried inks, you may also be dissolving your anilox base or core, especially in sleeves. These types of cleaners should be handled with extreme care and rinsed immediately. If you have ever experienced a “blistered” anilox roll, chances are you may have used a sodium hydroxide-based cleaner and did not rinse properly. This bears repeating: When using chemicals with sodium hydroxide, you must rinse thoroughly!

Sodium hydroxide is the chemical name; however, it may be listed under a different name on the label of your cleaner. The most common synonyms are: aetznatron, ascarite, caustic soda, collo-tapetta, fuers rohr, hydroxide de sodium, natrium causticum, collo-grillrein, natriumhydroxid, natriumhydroxyde, plung, rohrpitz, rohrreiniger rofix, sodium hydrate, (Na2 (OH)2 ), white caustic and (Na(OH)).

POTASSIUM HYDROXIDE 

Potassium hydroxide is another chemical you may want to verify as an ingredient in your cleaner. Potassium hydroxide is an inorganic compound and is commonly called caustic potash. Along with sodium hydroxide, this colorless solid is a prototypical strong base. It has many industrial applications, most of which exploit its corrosive nature and its reactivity toward acids.

Successful chemical cleaning should be considered a science rather than “ just a maintenance procedure.”

Potassium hydroxide solutions with concentrations of 0.05 percent to 2.0 percent are irritating when coming into contact with the skin, while concentrations greater than 2 percent are corrosive. For these reasons, safety glasses and gloves should always be worn when using press-side cleaners. In addition, a thorough rinse of the anilox roll should always be standard practice when using these types of cleaners.

Be sure to use an anilox cleaner whose contents you know and understand, and use proper safety precautions when doing so

Five steps to a good cleaning are as follows:

• Clean thoroughly with a recommended cleaner

• Rinse

• Rinse

• Rinse

• Dry thoroughly

Synonyms for potassium hydroxide include caustic potash, lye, potassium hydrate and (K(OH)).

These are just examples of chemicals all printers should be aware of prior to cleaning their anilox rolls. There are many aluminum-safe options in the marketplace that do an excellent job of cleaning rolls while protecting the integrity of your engravings, your base and your skin. Look for “aluminum safe” on the label to ensure you are using one of these safe cleaners.

10 TIPS FOR ANILOX ROLL CARE & MAINTENANCE

The use of safe cleaners is just one aspect of maintaining your anilox inventory. Every printer should implement a care and maintenance program geared toward the cleaning, protection, storage and handling practices of their anilox inventory.

These 10 tips are recommended to protect your anilox roll investment:

• Incoming inspection: Inspect the box/crate to ensure no damage has occurred during transit. Should damage be visible, notify the carrier immediately to establish liability

• Handle carefully: Remove the roll from the box/crate, and unwrap and inspect it. Handle with care. Any ding, dent or scratch could destroy the engraved cells and affect your print quality

• Protect your investment: Always lift the anilox roll with both hands or use a hoist. Do not drag the anilox roll off or across the table or floor, as you risk damaging the engraved cells. When not in use, use a protective cover to avoid damage

• Keep circulating: When in press, ink should always be circulating and the anilox rotating when not in use. This prevents ink from drying in the cells

• Doctor blade applications: Disengage the doctor blade from the anilox roll during color changes to make sure there is no ink buildup. Always use filters and magnets if you are using doctor blades—These will help prevent scoring

• Keep clean: In a perfect world, the anilox should be cleaned at the end of every job. This should be the daily routine of every press operator. A stainless-steel brush should be used on ceramic anilox rolls. Do not use brass brushes on ceramic. Always brush in a circular motion with a safe cleaner

• Watch the pH: Do not use any cleaner on your anilox that is highly caustic or acidic. Blistering or delamination of the ceramic may result. The acceptable pH range of a cleaner is 6.5-11.8

• Know what you are using: Aluminum-base cores are more susceptible to corrosion and should be cleaned with a mild chemical or mechanical cleaning procedure

• Anilox sleeves: Use “aluminum safe” cleaners on all anilox sleeves. Keep the insides (bores) and ends of sleeves clean. No dried ink. Keep sling guards clean and free of dried ink to prevent grinding and damage to the ends. Do not allow chemicals or cleaners to contact the internal composites. This can also lead to delamination of the ceramic. Use caution and protective end caps when cleaning in chemical bath tanks. Do not allow the temperature above 120 degrees Fahrenheit when using chemical bath tanks

• Post-cleaning practices: Always thoroughly rinse and dry the anilox surface and ends of the ceramic. Flash off any residual chemicals or water with an alcohol wipe or “anilox surface cleaner.” When using compressed air to dry, be sure the line is oil-free

These are great tips to follow when setting up your anilox roll care and maintenance program. It is also recommended to train your staff on the proper cleaning and handling techniques. This is important so everyone has a full understanding of the effects of improper chemicals and not only how they may cause harm to the anilox roll, but also for personal safety.

It bears repeating that safety glasses and gloves should always be used when handling chemicals and cleaners. The health and safety of your employees should be your first and foremost concern. EPA and OSHA issues must be addressed and Safety Data Sheets should be reviewed with all personnel handling these cleaners. Successful chemical cleaning should be considered a science rather than just a maintenance procedure.

About the Author: Alan Rogers was the vice president of sales for Harper Corporation of America, overseeing anilox sales for the U.S., Canada and Europe.

Alan has more than 20 years’ experience in the printing industry, in both inks and anilox rolls. Prior to Harper, Alan was the national sales manager for Arcar Graphics, Waterbase Inks and Coatings, out of West Chicago, IL. Alan graduated with a degree in industrial management from Georgia Tech, where he also played college football. Alan began his career with Harper in 2004 as the technical account manager for the Southeast for wide web printers and converters.

First published in L&L Yearbook, 2016 issue.

Written by Harper product development engineer, Tony Donato

Plenty of articles and predictions in recent years are telling us that the age of intelligent packaging and printed electronics (PE) is just around the corner. I will not say what is coming, but I will relate what I have learned working with multiple universities, material and equipment suppliers and my own experimentation to see what is possible. This article is coming from the perspective of a generalist with a machinery maintenance and manufacturing background that has been working with the printing industry for over 25 years.

“Printed electronics is not simply putting conductive ink in a print station. There is a lot to consider”

Just to clarify, printed electronics is not new and has been around for decades; over 40 years ago I was taught how to chemically etch a circuit board. Membrane switches, used in common appliances such as microwave oven panels, are commonly printed on modern printing presses. Today, of the print processes, screen printing is used the most. Graphic printing processes are being viewed as tools to move electronics into flexible, wearable and lower cost applications. The majority of conferences I have attended are all discussing, exploring and wanting to move products into a roll to roll application (R2R) for various reasons, including cost reduction, market expansion and new product development.

To start off, it is important to understand the differences and similarities between graphics and functional printing using the flexographic process. Flexography has developed into a printing process that uses the precision placement and size of dots of different colors of ink to convince the human brain it is looking at a graphic printing that conveys an image that resembles reality. Graphic printing is literally in the eye of the beholder. In a few seconds a package’s graphics must catch the eye and win over a potential customer to buy the product. Once the purpose of the print job changes to a functional nature, the printed product has to respond and react not just to a consumer but also the laws of electrical physics.

In a simplified view of electrical functional printing, the printed image has to provide a conductive pathway where the electrical current can flow uninterrupted and with the functional properties needed. In many cases the functional properties will terminate at a voltage source (i.e. battery) and provide high amperage or it may be a dielectric insulation or some combination with multiple layers. In short, we are printing wires that need to allow the uninterrupted flow of electrical current or insulation to make a device function. The important point to understand is current – the flow of electrons – can only happen if the printed trace line is continuous with no pinholes or breaks, since electrons do not jump

When printing a conductor, the trace line width and thickness of a particular deposited conductive material (silver, carbon, graphene, conductive polymer etc) will determine the amount of current that can flow. All conductive inks are not the same. The base material itself determines the overall effectiveness and the ink film thickness needed to achieve minimum resistance. Very simply, silver ink is more conductive than a carbon-based inks (graphite, graphene etc), therefore more carbon ink needs to be deposited to provide the comparable electron flow or conductivity as metal-based inks. Translated into flexo terms, the BCM’s of the anilox roll required for silver ink (2 to 5bcm) is much less than the BCM’s need for carbon based ink (10 to 30bcm). The exact volume is be application dependent.

Printing with flexo 

In printing conductors with flexo, instead of a graphic artist being concerned with eye appeal, the circuit designer is concerned with functionality and will calculate the required current load or needed properties for the device. That calculation will determine the criteria for what size printed trace line (cross sectional area) is needed. To complicate production planning, material costs are also considered in determining how to print. With silver at the higher end of ink costs, even though the amount carbon ink needed may be two or three times more, carbon ink may be the preferred choice and require using different anilox rolls than initially specified.

Think of extension cords. They come in different wire gage sizes and number of strands; the combination determines how much current can flow without damaging (melting) the cord. If the wire size is not sufficient for the required current flow, heat will be created. As many have learned the hard way, an extension cord sized to light a lamp is not the proper conductor for an air compressor, even if both rated for the same voltage. The good thing about R2R printed electronics is that circuits or devices typically are designed for low DC voltages and current (except in Electroluminescent (EL), where an AC electric field is required).

5 mil PET 4 layers for EL. Silver, Dielectric, Phosphor and Transparent conductor Toaster oven: Left 250F 10 minutes. Right 285F 10 minutes.

From the printer perspective all materials used must fit together and function in the daily environment required for the device. Inks and substrates must be compatible. Even the moisture content of a paper substrate needs to be considered because it could affect the performance of a printed device. Also with many inks, elevated drying temperatures may be needed to sinter (sintering can be thought of as a curing method for the ink) the metal particles of the ink into a continuous trace line. These elevated temperatures can damage conventional PET substrates and other plastics. I have curled and wrapped paper and ruffled PET trying to sinter the ink.

Not all functional printing entails conductive inks. For example, biomedical applications can be achieved with printing too. For example, sensors may be printed that absorb sweat so a chemical reaction may take place to detect a predictable physical outcome. These sensors can be used for monitoring a health factor.

In summary, the mindset needed to print PE or other functional devices needs to grasp all aspects of the printed job, not merely its appearance. The materials used will need to have functional properties. The functional properties will need to be tested using a multifunction electrical meter or test fixture and not a spectrodensitometer. To fully cure the ink and not damage the substrate sintering methods will have to be investigated that are not on the average flexo press. PE is not simply putting conductive ink in a print station. There is a lot to consider.

“Only around 1 to 2 percent of flexo printers doing a form of functional printing today, but those numbers will keep expanding as flexible and wearable device applications gain in popularity”

From the contacts I have met over the years in exploring PE, I landed on an electronic geek website, Sparkfun, which has a Bare Conductive ‘Touch Board’ to ‘turn touch into sound’. So a project was started to use the ‘Touch Board’ to create a hybrid device that used a flexo printed component combined with conventional microcontroller development platform. Hybrid devices are a realistic approach using conventional electronics that cannot be Flexo printed as the brains of the device. Flexo print can be used to build the traces as well as print the capacitive sensing ‘touch pad’. The ‘Touch Board’ can accept 12 inputs, so a conductive keyboard was laid out mathematically to match the locations of the inputs on the board and match the repeat of the plate cylinder of the Harper QD Flat Bed flexo print. Then a fixture had to be designed to couple the ‘Touch Board’ to the printed sensor touch pad.

The ‘Touch Board’ has 12 sound outputs that are MP3 formatted so different sounds can be loaded such that when the printed sensor is touched the preloaded sound is produced. One other neat feature of the board is the sensitivity of the capacitive sensor can be changed to make the board be a proximity sensor (1”) instead of merely a touch sensor.

The following picture shows all the components.

The QD Flatbed Flexo Printer was used to print conductive carbon inks for testing of trace line conductivity for touch sensor patterns. Testing different plate images and anilox engravings (120/15 XLT, 75/29 XOS and a 200/14.0 XOS) is easily done to find the best combination to work with a Touch Board combined w/ a print mounting fixture to demonstrate direct contact and proximity contact in a hybrid device w/ MP3 added sounds and a printed sensor pad.

In the picture, you can see an amber LED light illuminates (top of photo) when a key is touched and on the right picture the proximity of a hand activates the board. We made a video that shows the printing of the project and the project in action: https://www.youtube.com/watch?v=a8bgXCTBdIo.

If I had to guess, only around 1 to 2 percent of flexo printers are doing a form of functional printing today, but those numbers will keep expanding as flexible and wearable device applications gain popularity. Perhaps you will be one of the leaders in functional printing.

I need to thank Novacentrix, Sun Chemical and MacDermid for their help with the Touch Sensor project and Cal Poly, Clemson and Western Michigan for technical guidance.

To view the original L&L Yearbook article click HERE.