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PPI 'Cells' Thermoformed Parts New Jersey-based Productive Plastics Inc. uses a cell approach to manufacture and fabricate pressure- and vacuum-formed parts. Sidebars: BY KAREN M. KOENIG Productive Plastics Inc. is not your typical custom molder. In addition to utilizing both pressure- and vacuum-forming methods, the Mount Laurel, NJ-based company relies on dedicated work cells composed of thermoformers and CNC routers to manufacture a variety of components. "With the seven cells, we can have up to 15 jobs running at any given time," said John Zerillo, vice president. Jobs run the gamut from machine guards and medical diagnostic equipment to seat backs for rail cars and electronic components. A ranking of PPI's markets lists industrial as the number one industry, followed by medical diagnostics, mass transit, electronics/computers and point-of-purchase/retail displays. "The POP market was number two for us approximately four years ago (for vacuum forming)," Zerillo said. "We're looking at it again in '98 as a market for pressure forming." Pressure forming currently accounts for 60 percent of PPI's work. (See sidebar, "Thermoforming: Pull vs. Pressure.") The ability to create greater detail and undercuts with pressure forming has helped PPI gain new accounts, including manufacturing cab interiors, headliners and door panels from ABS for a major truck company, Zerillo said. "We're very excited. This is the first time pressure forming has been introduced into the heavy truck market." Pressure forming has also enabled PPI to break into markets traditionally served by the metalworking industry. "A lot of our business is in the conversion of sheet metal products to our business," Zerillo said. For example, PPI recently completed a prototype for a 48-inch by 40-inch by 14-inch rear tractor cover for a forklift. "The cover was pressure formed on a textured mold. The aesthetic benefits are that it's non-rusting, non-scratching, it will not dent, and by being plastic, it increases the life of the product over time," he said. PPI is also working with a customer to convert printing press controllers from metal to plastic. "By converting to plastic, we can take 30 to 35 percent of the cost out of the part," Zerillo added. The majority of plastic products produced at PPI are formed from Royalite ABS, PVC and PVC blends, acrylics and polycarbonates. Manufacturing in a Cell Here's how it works: One operator is responsible for the forming, trimming and deburring of a complete job order. While a part is forming, the operator is simultaneously positioning a cooled part onto a Thermwood CNC router for machining. Once positioned, the router automatically begins the trimming process, leaving the operator free to deburr. "We have invested approximately $750,000 in capital equipment -- specifically on multi-axis routers -- because we wanted this cell approach," Zerillo said. "By having the former and trimmer dedicated to a cell manufacturing process, we reduce setup costs and time. We're also able to better utilize our employees," Zerillo said. PPI has seven manufacturing cells. Of the seven thermoformers in the cells, two are Maacs (a new pressure former and a vacuum former), three are AAAs (two pressure and a vacuum former), one is a Drybol vacuum former and one a Zamac vacuum former. The company also has an older rotary AAA former. All of the CNC routers are Thermwoods, which are downloaded from a CAM workcenter using a MasterCAM software package. Carbide tooling purchased from Onsrud Cutter and Velepec is used on the routers. "We don't resharpen the tooling because it can affect the dimensional stability. So we go through thousands of cutters per year," Zerillo said. Project Development PPI uses CAD design and solid modeling to render the project prior to mold making. "We're a bit unique in that we very rarely use wood molds. Because there is an inordinate amount of involvement between staffs, we're confident that once we get approval of the design, we can go ahead with a regular cast-aluminum mold," Zerillo said. Jobs typically range from 250 to 3,000 parts. The majority of projects are regional."We're regionally driven because of the nature of our business. There are not too many pure custom formers that are national in business," Zerillo said, citing shipping costs as one of the reasons for this occurrence. To increase its customer base, PPI is exploring market diversification and application development. Under the direction of marketing coordinator Allison Cenedella, the company is working to identify new markets through research, mailings, "and a lot of inside cold calls for lead qualification. We try to match our skills to an industry and then do a search," she said. One market under scrutiny is the transportation industry, where PPI is looking for additional ways in which pressure-formed plastic can be used in place of metal components. Another way to attract clients is by offering value-added services. In addition to its forming and machining capabilities, PPI offers the following value-added services: photo etching on molds, silk screening, hot stamping, embossing and finishing. The company also offers seminars on designing pressure-formed parts. Quality Control "We applied for ISO certification because we're beginning to see customers desiring it. Hal Gilham (PPI president) and I also saw the benefits to the company as far as the control procedures," Zerillo said. "Many customers require some type of certification of compliance with each order," said Monroe Danbury, quality assurance manager. PPI has two systems of internal quality assurance checking, Danbury said. Each operator is responsible for submitting a minimum of two components of a single order per shift, to a quality control inspector. "The inspector verifies if the part is good. We check the tolerance, thickness and any criteria deemed significant by the customer. If the part is good, it gets a green sticker," Danbury said. Since each operator is responsible for quality control on a component, a single job is likely to be inspected not just as a finished product, but also during the thermoforming/machining process as well as finishing. Backing up the first method of quality control, "We also have random surveillances by the inspectors," Danbury added. In addition to Danbury, PPI employs three additional quality control inspectors, two working the first shift during peak production hours, and one for the second shift.
Thermoforming: Pull vs. Pressure Thermoforming is defined as the process of combining heat and pressure or vacuum to form the sheet to the mold. Both methods can be used to produce large parts that exceed 200 square inches, in moderate quantities, typically ranging from 250 to 3,000 parts per job order. In vacuum forming, vacuum is pulled, causing the sheet to form to the mold; negative pressure draws the plastic onto the mold. In pressure forming, compressed air is used to push the back of the plastic sheet up against the mold., creating greater detail and undercuts than vacuum forming. Pressure forming accounts for 60 percent of PPI's forming; the remaining 40 percent is done with vacuum, said John Zerillo, vice president of Productive Plastics Inc. There are considerations for using pressure forming versus vacuum forming. "Both use relatively the same amount of pressure. However, pressure forming often uses heavier gauges of material, for longer cycle times," said Zerillo. Insert molding techniques, ribs and undercuts, can also be utilized with pressure forming, he added. Design considerations
To receive a copy of Productive Plastics Inc.'s guide, contact Allison Cenedella, marketing coordinator, at 14 Roland Ave., Mount Laurel, NJ 08054; (609) 778-4300 FAX: (609) 234-3310. From Patterns to Pressure Forming Founded in 1955 by Jim Gilham, Productive Plastics Inc. began the transition from making wood patterns for foundries to plastics during the plastics heyday of the '70s. "Hal Gilham (Jim's son) directed the company into plastics because he saw that the pattern industry was dying and that plastics were booming in mid-70s," said John Zerillo, vice president. "It was a logical transition because they had the in-house tooling and expertise. So along with (engineering manager) Lou Carrera, they kicked off the thermoforming effort," Zerillo said. Today, the Mount Laurel, NJ-based company has two facilities totalling 46,000 square feet; one facility is dedicated to fabricating, with a materials and tooling storage facility located nearby. The company works two shifts, six days a week, manufacturing a wide range of components for a variety of industries.
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