Web handling

The Science of Web Handling

Web handling "the physical mechanics related to the transport of continuous flexible materials (webs) through processes and machines" has gained recognition as an engineering discipline - largely through the efforts of the Web Handling Research Center at Oklahoma State University, (WHRC). Work at the Center is creating a growing arsenal of knowledge that can be used to solve web process problems. Many problems that once required expensive online experimenting can now be solved quickly by applying basic engineering principles.

Imagine investigating a crime committed by invisible perpetrators. Even witnesses would be unable to identify the culprits. Your case would have to be based on what could be seen at the crime scene and on circumstantial evidence. Troubleshooting web handling problems is like that. The most important web handling variables are stress and strain, and even with today's technology, there are no practical methods for observing them in a production environment. The only evidence of them, with the exception of gross averages, such as MD stress, is in consequences such as wrinkles or misregistration. Good web handling troubleshooters have to learn to look at a web and visualize the invisible details of stress and strain to diagnose the problems.

So, how does one learn the art of seeing the invisible?

Like anything else that has invisible causes, it's easy to make up plausible, but completely wrong, theories (myths) about how stress and strain produce problems. For example, before 1960 lots of web processors were completely confused about how misaligned rollers caused webs to shift laterally (and often wrinkle). One of the favorite myths was that "the web tracks to the tight side". In the middle of the twentieth century this and other mysteries began to get sorted out by small groups of researchers working in many different places.

For decades much of the best work stayed in desk drawers at the companies where the work was done. But, in the 1980s some enlightened engineers (friends of mine - Dr. John Shelton, and Bruce Feiertag) recognized the need to coax this knowledge out into the open, where it could be organized and extended to create a recognized branch of process technology. This was something whose time had come, because by 1986, working with Dr. Karl Reid at Oklahoma State University, they had found enough like-minded people at major corporations to meet the corporate sponsorship requirements for a federal program to create the Web Handling Research Center (WHRC) at OSU. Beginning in 1991, the Center began sponsoring bi-annual IWEB conferences where serious researchers meet, present papers and discuss their latest work. The university has also graduated a number of students who earned their PhDs with web handling research projects conducted in the center's well-equipped lab.

The WHRC has been an outstanding success. In its nine volumes of conference proceedings you will find most of what we presently know about how to "see the invisible" correctly. In fact, long-term participation in the WHRC's work (plus deep familiarity with the contents of those nine volumes of proceedings) has become the de facto credential for web handling expertise - a qualification possessed by all of the leading web handling consultants.

The success of the WHRC is demonstrated by the fact that, the Association of Metallizers, Coaters and Laminators (AIMCAL) has begun offering application-oriented conferences and training programs based on its work. Four of the leading web handling consultants are now actively involved in its programs.