DOWNLOADING WISDOM FROM EXTRUSION SAGES: WITT'S SOFTWARE AIDS TRAINING, TROUBLESHOOTING

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Witt Plastics Inc. has parlayed 60 years of extrusion experience from two industry veterans into a knowledge-based software system used for on-the-job training and process troubleshooting.

The 110-employee Greenville, Ohio, custom sheet extruder specializes in thin-gauge, rigid thermoplastic sheet products in cut-to-size sheet and roll forms. Like most manufacturers, Witt relies on the experience of veteran operators — such as Bob Patton and Terry Longfellow — to keep processes running smoothly. But the company, which reported 1996 sales of $25.1 million from its two plants, has invested in a high-tech solution to help it retain this experience long after its experienced workers retire.

The company has spent nearly four years developing and customizing the software system, dubbed the Witt Advisor, to train machine operators and solve extrusion problems on the production floor. In a paper presented at the ANTEC '94 conference in San Francisco, the firm spelled out the principles behind the project, but much has evolved since then.

John L. Witt, 63-year-old chairman and chief executive officer at Witt Plastics, said the Witt Advisor is still a work-in-progress — and probably will remain so for several years—because the knowledge base is updated continually.

The plastics processing industry — which Witt estimates is many years behind the military and some other industries in its use of artificial intelligence — ``is very thin on using this approach to problem-solving, so I think this is a whole new era on how people are trained,'' Witt said in a recent telephone interview. ``Our training is always imparted in the same way, so we are providing a consistent basis to learn.''

The software programming associates certain processing characteristics with defects. If, for example, a defect is identified in quality control or on the production floor, the operator pulls up a menu that lists defects, describes the flaw, and the software guides the operator through process variables that contribute to the defect and its corrective steps.

The Witt Advisor identifies 19 types of product defects: brittleness, color, opacity, dimensions, edge buildup, gauge, voids, contamination, surface blemishes, orientation, flatness, dog leg, telescoping, dyne, angel hair, blocking, bead roll, pock marks, and edge dust. In addition, the software addresses concerns over equipment damage due to overtightening or misadjustment of the restrictor bar and die lip.

The associative relationship between defect and process is critical to the software's knowledge base because it mimics the actions of an expert extruder. Veteran operators adjust processes and produce a quality product in a timely fashion because they understand the closely coupled operating steps and interrelated process parameters.

An adjustment to a single component in the extruder line causes complex interactions that can disrupt the process and damage equipment. Better extruder controls with some diagnostic capabilities have improved the operator/extruder line interaction, but successful line operation usually still hinges on the operator's personal experience.

That is one reason John Witt believes that what his firm has developed is not directly transferrable to another company.

``The majority of extruders would look at this and say, `This isn't the way we do things here.''' But he added, ``We will help anyone who wants to develop this technology.''

``If someone wanted to do the same type of program, they would need to have a programmer or access to one through a consulting firm.''

Still, Witt hopes publicity about the software program might stimulate other companies, including those outside of sheet extrusion, to pursue similar objectives, and that communication among such firms could further the overall process.

``I am hoping to bring the industry forward,'' he said, ``like moving from a pencil to a computer for writing.''

Jan Gish, Witt's artificial-intelligence specialist and training coordinator, said the software reduces long-term reliance on extruder experts and provides their knowledge and experience 24 hours a day.

Its added benefit has been in training, formalizing training as part of the problem-solving process and letting operators explore the Advisor before the fact to create what-if scenarios so they are prepared when a problem occurs.

The training program involves a skill matrix, because not everyone learns at the same level, given the experience that they come in with, said Gish, whom Witt hired specifically to develop the Advisor program.

Another company expert involved with the Witt Advisor participated recently in the core group helping to draft extrusion-related guidelines for the Society of the Plastics Industry Inc.'s worker certification program, and Gish expects the Advisor to meet certification criteria once the Washington-based association finalizes its guidelines.

``What we have found in the course of developing this, is that [the Advisor] is actually a thinking tool. We found little nuggets of knowledge that are useful in other areas and it shows how people actually solve problems. It is an iterative process,'' Gish said.

Because custom extrusion typically is characterized by frequent product and polymer changes in short runs, there is a high demand for operator decisions that involve complex decision-making skills in order to respond to any failure-diagnostic information.

This is a particularly beneficial tool for training in small companies because the costs are minimal, operators learn at their own rate, and it does not constantly require capital investment for upgrades.

Process improvements are added to an existing base of knowledge so learning tools are updated constantly.

The Witt Advisor is PC-based, so it is located on the production floor and in the company's training facilities. The mouse-driven system uses a 386, 486, or Pentium processor and is programmed using expert system and object-oriented technology as development tools. It requires at least 8 megabytes of RAM, a 200-MB hard disk, a mouse and VGA monitor.

``Training usually gets cut when things are cut back and it is really a short-sighted approach,'' Gish said.

``Small companies don't have the resources to upgrade all the time, so we have learned how to build our own and access it easily.''

Gish is a panel member for the NPE conference session ``Training — What Works and What Doesn't,'' scheduled for 1:30-5 p.m. Tuesday, June 17.