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 pressrun—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 press time. I am happy to say that Plastic Packaging Technologies LLC—where the “FIRST in Motion” printrun took place—was not one of those places.
“For our fingerprint and characterization trials and the pressrun itself, the only variable was the substitution of a different plate technology into the existing workflow.”
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.
About the Author: Sean Teufler is 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 Harper since 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’s Award for Leadership Excellence in 2012. Sean is steadfast in his support for all that flexography entails.