Just-in-time specialist World Class Plastics implements new equipment and technology with forethought and consideration. As a result, the benefits of these investments are quickly realized.
That's the conclusion World Class Plastics Inc. (WCPI) reached when it set out to add optical gauging, automatic degating, and a sophisticated SPC system to its 32,500-sq-ft plant in Russells Point, OH. WCPI is a privately held custom molding operation that has grown in seven years from one press and one customer to a $10 million-plus molder producing 10 million close-tolerance parts/month.Â
This plant specializes in JIT production for customers in the automotive, medical, appliance, and industrial markets (see "JIT on Steroids," July 2000 IMM, p. 14). Many products go directly from floor to truck in this scenario, so the need for automation, tracking, and accuracy is obvious. Yet, before implementing any new technology, WCPI first explored the benefits it wanted to achieve and then looked for the best solution and implementation method to support those goals.Â
WCPI molds several parts for the PT Cruiser. One such part, an instrument cluster bezel, is automatically trimmed and degated using a servo degating robot.
"We strive to minimize variation in the process," says David Wisniewski, engineering and R&D manager. This is why the company decided to install CNC degating systems (Aeroboy SK-250 from SAS Automation). WCPI has 25 Sumitomo presses ranging from 18 to 350 tons, each of which is serviced by Yushin servo robots and sprue pickers. The degating systems were placed on the end of the servo robot traverse beam.Â
"Using CNC degating instead of doing it manually produces more consistent results, and the quality goes up," explains Wisniewski. In addition, the system helps molding technicians, each of whom is generally responsible for running five to six machines, to manage the process and consistently get good parts.Â
To help ease the installation of the systems, WCPI purchased a modular system. "The quick-change end-of-arm-tooling (EOAT) systems slide in and clamp rather than screw down," explains Wisniewski. "As a custom molder, we are always changing jobs. We have two dedicated presses, but the rest can run jobs from two to three days down to 6 hours. So we needed a flexible system."Â
A recent visit to the plant illustrated this concept. In a workcell with a 160-ton press, instrument cluster bezels for the PT Cruiser were automatically degated and trimmed. The tool that WCPI inherited wasn't designed for ease of manufacture, according to Wisniewski. It should have been hot-edge gated; instead, there were two small subrunners coming off the hot manifold. "We have to nip the subrunners and flush trim the gates. One runner is situated behind a rib, so we needed a reach-around cutter." JDV Products built a custom nipper blade from WCPI specifications.Â
An optical comparator, the OGP Avant 600, provides automated measuring capabilities for parts with tolerances as low as Â±30 Âµm.
Another component of the WCPI strategy involves having each workcell take responsibility for its production and quality goals. To that end, the company purchased a 32-bit SPC software package called Synergy 2000 (Zontec), so named because it consists of three parts that work together.Â
One part is used by production technicians for real-time data collection and input. Data inputs automatically into the system through calipers, micrometers, and height gauges. Another capability helps quality managers and engineers establish control and spec limits and to analyze data. A third component lets managers monitor the processes in real time from a single screen and create reports.Â
Brett Johnson, director of quality, explains how this new technology was introduced. "Rather than forcing this system on our employees, I went to a trainer's workshop first, and then shared what I learned with representatives from all three shifts. Over a weekend, we completed associate training and went into production on a Monday. The process was seamless."Â
In the near future, the system will allow selected customers the ability to review actual data through a secure Internet connection. This eliminates an additional QC check normally performed when the parts are received.Â
The new system was also flexible enough to incorporate a suggestion from molding technician Greg Postle. He noticed that manually entering part numbers introduced unacceptable levels of human error. He asked if parts could be assigned bar codes for keyless entry. "We produce about 400,000 part and shipping labels per year," says Johnson, "so the idea was immediately investigated."Â
A bar code containing the part number is now printed on each job card. Technicians scan the code with a pen, which then prompts the system to enter that part number. In another version of the job card, scanning the code produces a bar code label for shipping. Both systems have reduced error throughout the plant.Â
Tight-tolerance, visually critical parts are the order of the day at this facility. WCPI produces, for example, several tiny components found within every GE refrigerator around the world. These parts have tolerances of Â±30 Âµm.Â
To ensure that parts meet dimensional tolerance requirements, WCPI added a video measuring system (Avant Zip 600 from OGP) for quality checks. Target dimensions are first input into the system along with a part number. The automated probe then does the measuring.Â
"We needed something that could inspect anything we mold, and after extensive research, we knew that this was the system," says Johnson. Cost savings on inspection alone are estimated at $100,000 annually.Â
World Class Plastics Inc.
Russells Point, OH
Optical Gaging Products Inc.
(716) 544-0400, ext. 391
(513) 648-0088, ext. 204
SAS Automation Ltd.