Adopting a Process Model

Published: August 01, 2006, By By David Argent Contributing Editor

The most important part of a converting operation is printing, because it governs both product appearance and production efficiency.

At one time each job was seen as a new experience, and this approach was associated with very high waste levels. About 15 years ago, industry experts in the rapidly expanding field of flexo printing realized that many innovations in inks, anilox rollers, plates, and press controls had eliminated much of the variation. However, these improvements were applied sequentially, and the interactions of improvements were not quantified.

This led to the formation of the Flexo Quality Consortium (FQC) — a group of inquisitive and motivated suppliers to the converting industry. The tradition to this point was for suppliers to bring their new products to the converter in isolation. Unfortunately, this still happens in many cases today, and it can lead to longer improvement cycles. For example, a lower-volume anilox roller could be tested, and the inks would print up weak.

The first task of the FQC was to adopt a process model, the simpler the better. The input-transform-output (I-T-O) model was selected (see diagram).

Probably the most important finding was that output measures were linked to process inputs by predictive equations. In other words, if you change a variable on the input side, the result is predictable and quantifiable as an output measure of quality.

This model allows us to think through improvement strategies in a logical way.

One way of seeking improvements is simply to change an input variable and see what happens. A better way is to look at output measures and decide which has the most impact from a business standpoint.

With run lengths diminishing, waste can be the difference between profit and loss, so changes in the printing process are geared more and more to cutting waste. Thus the impact of all printing process variables, or system inputs, can be assessed for their impact on waste.

My experience has been that converters measure so many things, there is no time left to analyze the data at the end of the month, and many times the items being measured are simply not actionable.

In summary, it is good practice to define the criteria that are important to the business and select performance measures that quantify these criteria accurately.

There are only five areas that matter: product quality, yield or waste, throughput, uptime, and unit cost. Improvements can be made in any of these areas by changing the press inputs appropriately and having actionable tracking measures in place. If you can measure it, you can manage it.

Editors' Note: PFFC welcomes David Argent to our pages as a monthly columnist, addressing issues of process management.

David Argent has 30+ years of experience in the converting industry. He specializes in process analysis and improvement with particular emphasis on ink and coating design and performance. Contact him at 636/391-8180; This email address is being protected from spambots. You need JavaScript enabled to view it.