- December 01, 2009, By David Argent Contributing Editor
After writing some 41 columns, it is time for me to move on into new business areas. Working with the PFFC staff has been a uniquely enjoyable experience and one I am glad came my way.
From the start, my goal in this column was to look at the converting industry from a process management standpoint and examine the three fundamental parts of the process. These are process inputs, the process itself, and the measurable outputs of the process. Focus was always on defining the output side, since this results in what we hope to sell.
In the latter days of my corporate career, I would frequently tell my peers there are only 12 problems in our industry and that we solve the same ones over and over again. The problems often come back in disguised form. Technical issues and inquiries prompted by the various column topics came from many locations besides the USA, and included Vietnam, Iraq, Iran, Saudi Arabia, India, and Mexico. What was really surprising was the commonality of the issues raised irrespective of geographic location. Apparently the 12 problems are viral! Let's take a generalized look at some of them, in no particular order, and with the view that they may remain areas of opportunity for improvement.
- White Opacity | The issue with opacity is how much is enough to meet the job requirement. In some instances, the stated opacity range is too wide and shipping of product at the high end impacts consumption significantly, whether it is ink or white extrudate. Furthermore, tight controls and measurements of opacity allow converters to decide whether a given opacity level is best achieved by ink or extrudate in their operations.
- Ink Mileage | Accurate job costing includes predicting ink costs based on design coverages. Some printers have good cost estimating models derived from historical data. However, some do not, and ink cost variances result. It is interesting to note that this problem is overcome in digital printing since there is a precise pixel-to-ink-drop correlation.
- Proofing Correlation | To avoid substrate waste and downtime, inks need to be delivered to the press on color. For flexo printing, there are now lab proofers available with interchangeable anilox rollers for precise correlation to the press. Widespread use of these proofers would be expected but are not always in place.
- Solvent Retention | Solvent-based inks for gravure and flexo film printing are here to stay for the foreseeable future, causing residual solvents in the package. There are very few retention standards established by consumer product companies, so in effect, converters have to decide on their own standards, testing methods, testing equipment, and frequency of testing. One response by converters is to use newly developed solvent inks with retention levels as low as water-based products.
- Coefficient of Friction | Out-of-spec COF will cause any number of packaging line and stacking problems. In our current slow economy, new COF problems have occurred due to slow-moving inventory. In one instance, rolls stored for a year were no longer “slick” enough to function due to a slowly dissipating migratory slip package. This level of shelf life probably was not a design parameter but may be in the future. The reformulation would involve a nonmigratory wax to anchor the COF permanently at a functional level.
- Special Causes | In my experience, special cause variation seems to be inevitable, even in the best-run manufacturing operations. A converter consulted me on fade-out of red print on a routinely run package. It turned out to be caused not by light exposure but by a new cleaning protocol for display equipment used by a local supermarket chain. Quick response by the converter and the ink supplier diagnosed this problem and a solution was found.
As mentioned in my December 2008 column, “Special Causes: Enemy or Opportunity,” if the occasional special cause is inevitable, the question becomes: How capable and prepared is your organization for root cause analysis? How quickly can it respond? This scenario is analogous to safety training. You hope never to have to use it, but you had better have your staff prepared and trained to respond when needed.
I have mentioned only six of the 12 repeating problems, but I am sure you have your own list to work on. Good luck and I hope to see and hear from some of you along the way in the converting world. Thank you.
Process improvement expert David Argent has 30+ years of experience in process analysis with particular emphasis on ink and coating design and performance. Contact him at 314-409-4304; firstname.lastname@example.org.