TIt's not printing. It's not slitting, coating or drying. But it's crucial to all these. It's the day-in, day-out operation of nearly every converting plant—the one that makes operators sweat, supervisors swear and plant managers reach for the bottles stashed in their bottom desk drawers. It's web handling—the seemingly simple unwinding of the web at one end, progress through a series of rollers, and rewinding at the other end—hopefully without bagging, wrinkles or other major flaws that render it unacceptable to the customer.

Why is it still so hard? Why do we still spend so much time and energy, money and brainpower on spotting web-handling problems, fixing them, preventing them? We posed these questions to two of the featured speakers at AWEB 06, a just-concluded seminar sponsored by the Association of Industrial Metallizers, Coaters and Laminators (AIMCAL). David Roisum, Ph.D. is a consultant and technical editor of Converting. Timothy J. Walker is principal of TJWalker+Associates, Inc. and is a frequent contributor to conferences.

Converting: Why is web handling still such a challenge, in spite of the progress in machinery and electronics?

Roisum: While there have been many mechanical developments, most of the progress in machinery is in the areas of computer, drive and PLC controls. Controls do not usually help web handling directly but rather provide the potential for a more intelligent interface to the operator. Whether this potential is realized depends much on whether the programmer understands his customers: the web and the operator. This is not always the case, so the computer can sometimes be more of a barrier than a link. In fact, as I have argued in this magazine and elsewhere, drive performance seems to be degrading as the specialized knowledge required of the programmers is disappearing—so that the advantages of some truly capable drive software are lost.

Another ever-present challenge is that the bar is always being raised. Speeds are increasing. Expectations of quality are increasing. The sophistication of one's competitors is increasing. However, the most significant challenge is new materials, which are often designed with insufficient thought given to web handling and winding. While these new material constructions may perform well for the end-use customer, getting them through the machine and winder without damage is getting much harder.

Walker: Is web handling a challenge? In the majority of converting processes, it is not a challenge. Millions of feet of webs run in printing, papermaking, film coating and similar processes without one iota of thought given to the challenges of web handling. In these operations, web-handling process knowledge is passed down through corporate generations, some actively passed on person-to-person, but much of it is inherent in the product designs, or built into the machinery and controls knowledge base.

Web-handling challenges occur when either this knowledge is lost, or more often, when a new challenge falls outside the experience of product, equipment and human resources. As a local challenge arises, the search for an existing solution begins with calling around inside a company, seeking support from equipment and materials suppliers, browsing for answers in Web search engines, maybe even calling in a web-handling consultant. Everyone hopes they aren't the first to solve a problem, but as long as new products can be imagined, there will be new web-handling challenges to be solved.

Converting: Is there any such thing as a web-handling specialist within the converting or printing discipline any more? And, if so, what is the ideal technical background for such a person?

Roisum: Only a few of the very largest companies have dedicated web-handling specialists. To be a specialist, one would ideally have a background in engineering or science. The ideal degree would be in mechanical engineering, unless one is in corporate research where an engineering mechanics (physics) may be even better. However, anyone with an interest in science and a mechanical sense can serve well, even if lacking the formal education.

On the brighter side, however, the general knowledge of web handling by operators, maintenance people, technical people and even management is getting much, much better. Something approaching 10,000 people have been to a multi-day web school, web-handling conference or are self-taught to similar levels using the wide variety of reference materials on the subject.

Walker: This is somewhat difficult to answer. As a consultant, you tend to work with the companies where the answer is "no." If they had an internal expert, there is a lower likelihood that they would need to bring in an outside consultant. But I know from the attendance at the International Conference on Web Handling (IWEB) that there is an international group of process and controls engineers that consider themselves web-handling specialists. The number of attendees at the IWEB conference goes up and down with the economy, but there is an ongoing base of web-handling specialists. Most of these specialists are with larger companies, where someone can work nearly full-time on web-handling projects.

Web-handling specialists come in at least two flavors: the mechanical/process type and the electrical/controls type. For either type, a BS in engineering is the place to start—though a Master's or Ph.D. degree may prove helpful, the practical knowledge gained from on-the-job experience will solve more problems than advanced mathematics or research acumen. On top of your formal engineering education, the web-handling specialist should seek applied web-handling knowledge wherever possible, from fundamentals classes, from equipment suppliers, from coworkers, and now from the new AWEB Applied Web Handling Conference. Lastly, spend time just standing and watching at as many web processes as possible.

Converting: What one development would most positively impact the state of web handling: better-educated operators and supervisors, better materials or better machines?

Roisum: My observation has been that several very important groups have been seriously left behind: product and process developers, quality-control and customer-service professionals, and the customers themselves. My biggest disappointment, however, has been how few machine designers are seen at web-handling events. Machine builders typically send salesmen to the conferences and shows, and almost no one to schools.

The new economy has made this deficit even worse. My most pleasant surprise has been that (lead) operators outnumber all other job functions combined when it comes to web-handling education. The best operators, who are also formally trained, tend to also be the most literate in web-handling because they already have a better machine sense than anyone behind a desk. We ought to make better use of this resource.

Walker: Without a doubt, the answer is better machines. A good machine contains the applied knowledge of operators, designers and engineers. A good machine is tolerant of web-quality shortcomings. Web handling is all about making a silk purse from a sow's ear, so having a well-designed purse-making machine is your only prayer of magically transforming that pig's ear.

A machine's tension and guiding controls, roller design and alignability, proper use of nip rollers, winder geometry and process control, and other machine features, all add up to versatility and a large process window. Give me a machine with the right mechanical design, good controls, tuning and calibration, recipe-driven setup to retain optimized conditions by product, and you will go a long way—even with turnover in operators and quality variations in materials.