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September 20, 1998

7 Min Read
IMM Plant Tour: The guts of a telecommunications molding giant

Try this: Hop on the Internet and then go to twww.lucent.com. When you get there, do a search for "Omaha." Your search results will be amazingly sparse. Now, hop on a plane and fly to Omaha, drive on I-80 due west, and take the I Street exit. That mammoth, sprawling, monumental, behemoth of a building in front of you is understatedly known as the Omaha Works of Lucent Technologies, Bell Labs Innovations. And, inside, a goodly portion of this building's daily activity revolves around injection molding.

But it's not just plain old injection molding. It's the kind of molding that can keep a molding supervisor awake at night, imagining and dreading the variables lurking in the shadows, waiting to wreak polymer havoc. The parts here are small, things like phone jacks, phone jack connectors, network connectors, central office connectors, jumper troughs, and protective housings. The long, thin parts cannot warp and cannot short. The smallest parts are packed with enough grooves, troughs, undercuts, ridges, holes, crevices, and gaps to make a grown molder cry.

This captive molding operation that churns out some 300 million parts a year is surrounded by a gigantic full-blown assembly operation that uses these parts to build Lucent's line of telecommunications cabinets, racks, and connector systems. These products aren't the kind you're likely to see every day. They remain hidden in phone closets in office buildings and in metal telecommunications cabinets standing anonymously on street corners throughout the world. They are the connectors that hold together your computer, phone, and video networks. And as inconspicuous as they are, when disaster strikes in the form of a hurricane, tornado, fire, or flood, the value of these connectors suddenly rises as Baby Bells and businesses attempt to put their communications networks back together. Says Jerry Golmanavich, a member of the technical staff for plastic molding, "We're always busiest when disaster hits."

Training and the Unions

A few years ago the typical problems presented by the small, thin-walled, intricate parts produced in the Omaha plant-shorts, warping, bowing-started Lucent and Golmanavich toward standardization. Although the company has quality and ISO standards to spare, there was no standardization of the competence of employees on the floor. Golmanavich then embarked on a plan to train employees, creating Master Molding Technicians (MMT), quasi-engineers who know the science and process of molding.

Lucent decided to draw from other employees in the plant to build the first class of MMT students. In order to avoid problems with contractual agreements, the union was brought in at the very beginning of the program's formation process. "On most programs, we have a better success rate if we involve the union right away," says Cliff Mindrup, learning and performance senior training specialist. So, for 30 months now the union has been working with management to create and conduct the MMT training program. What the company has built is a series of "gates" through which the students must pass to reach full MMT status. So far, so good. "I think everybody's very pleased with the way the training's going," Mindrup says.

To get into the training program, employees must apply and then pass a simple aptitude test. Then they are given an orientation that teaches the fundamentals of plastics in general, and injection molding in particular. "This exposes them to what the job would entail," says Golmanavich. It also gives them a chance to see what they're getting into, and an opportunity to back out if the topic fails to hold their interest. Finally, a mechanical aptitude test assesses their knowledge of wrenches, screwdrivers, pulleys, and other devices. Students who are still interested are then selected, with union cooperation, based on seniority.

The current class of eight students meets every two weeks for 4 hours, reviewing Paulson CD-ROM training programs, interactive videos, listening to regular lectures, and discussing solutions to current problems they have on the shop floor. When the 21/2-year training period is complete, all students will have 256 hours of classroom training behind them, and they should know everything from how to change out a mold to how to troubleshoot short shots. "My two favorite words in class are 'it depends,'" says Golmanavich. "The class is always looking for a rule of thumb. But there's almost always an exception to every rule."

Divining Data

While competency on the floor was being established, competency in the mold was begun. The chronic reason for most part rejects at Lucent has been underfills, or short shots. Unfortunately, the intricacy of many of the parts does not make a short obvious to the untrained eye. So, often it is the QC department or the customer who discovers such products out of spec-and sends them back. "An 8 cent part could jeopardize a cabinet worth several thousand dollars," says Golmanavich.

To get a better handle on the molding process, Lucent started with RJG's DartNet process control hardware and software, designed to let Lucent process engineers monitor hydraulic pressure, melt pressure, cavity pressure, fill time, pack and hold time, pack and hold pressure, cycle time, and other parameters on every press on the floor. Data from each of the 103 presses is passed to a central monitor in the engineering office where processes can be monitored and troubleshot. It also allows engineers to build start-up parameters for each mold that, once set, make start-up a snap. "It can give you 25 pieces of data in 1 second," Golmanavich says. "On start-up it allows us to get our parameters in place and mold good parts fast."

There are also six mobile DartNet stations on the floor to read data and pressure curves beside the press. Although most of the presses currently transfer on position, injection molding supervisor Ron Yearsley says Lucent is gradually installing transducers in all of its molds for eventual transfer on cavity pressure.

With the DartNet system, Lucent engineers are building a set of pressure and transfer standards for every mold. These standards have dramatically reduced the short shots that have plagued the injection molding process. Learning to read and interpret data and pressure curves presented by the DartNet system is also a major focus of the Lucent training, as are the principles of scientific molding in general.

As to the press itself, many of the Maco IV controllers on the older presses are gradually being replaced with Allen-Bradley controllers that incorporate Wonder Ware screens. The customizable Wonder Ware software lets Lucent build colorful controllers that direct machine and robot processes.

The Importance of Melt Flow

The final indicator of part quality comes from Lucent's very own melt flow lab. "The melt flow is what really tells us the quality of the product," says Golmanavich. Molded parts must meet certain criteria for impact resistance and strength. Lucent also likes to use as much regrind as possible, without jeopardizing that part strength. So every day, members of the quality control department pull sample parts from production and deliver them to the melt flow lab.

There, the parts are ground up, dried, melted, and measured to determine the melt index. Generally, the lower the melt index of the base virgin material, the more regrind that can be incorporated into the mix. With a higher melt flow index (15 to 23), parts become brittle; it's then up to the engineers to determine if the part should be shipped, and if the regrind content should be reduced. Regrind percentage for some parts can run as high as 75 to 100 percent. "As long as the process is under control, it's no problem," says Golmanavich. "We have a standard to go by. If the melt flow index is wrong, the impact resistance is going to be off."

The melt flow index lab measures about 30 machines a day for part quality. Part of the company's focus, says Golmanavich, was ISO 14001. "This is one way we can contribute to continuous improvement," he says, "recycling and ISO 14001 certification." The melt flow index lab also has an x-ray machine to measure pigment content in some Lucent parts, which use specific colors, such as orange, yellow, and black, for different telecommunications applications.

The current class of students in training should graduate in 2000, starting a new generation of Lucent master molders. "All of us have the same objectives," Golmanavich says, "it's to get all eight people through the gate."

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