BROOKHAVEN, MISS.-Every morning at 6 a.m. a tractor trailer pulls away loaded with the past 24 hours' production at Delphi Packard Electric Systems' Brookhaven plant. That's 864,000 injection molded connectors that go out as parts in automotive wiring harnesses assembled at the plant or as components for items that will be assembled at one of Delphi Packard Electric's other plants.
``We promise the customer that we will ship in 24 hours,'' said Arnold Senger, plant superintendent. ``We don't miss that deadline.
``We may have one tool with GM's entire requirement on one machine,'' he said. ``When they say they need 7,000 pieces, we have to ship 7,000 pieces.''
The Brookhaven plant was the first to implement Delphi Packard Electric's modular system for molding precision parts, dubbed PreMo, when it started a 60-machine molding plant in 1988. A second 60-machine plant under the same roof but separated by a wall was started in 1990, and Brookhaven officials hope to get a third 60-machine cell approved. There are three more presses in the laboratory.
The plants compete with each other - as well as all of Delphi Packard Electric's other molding operations - for every job.
Quality standards are high. The plant suffered only two external returns of its products during 1994 - both because of mislabeling.
Brookhaven employs 66 workers in the molding operation and 485 in wiring harness manufacturing. About 40,000 square feet of the 203,000-square-foot plant is used for molding.
Unionized press operators tend 12 presses each and the five on duty during a shift tend to congregate in central control areas. They watch the machines via a series of color-coded status lights. The self-managed crews are responsible for nearly everything: machine and tool setup, delivering resin in gaylords, parts inspection, final pack out, some machine maintenance and even plant maintenance. Workers in the two plants decide their own schedules and currently the two plants works different schedules.
``I think 60 machines is a manageable social structure,'' said Charlie Sims, precision molding supervisor at Brookhaven. ``Five operators can make decisions.
``There is no supervisor after 4:30 p.m., so in the evening and on weekends the workers do their own scheduling, quality control checks, everything,'' Sims said. ``Three process technicians and I have beepers, but we hardly ever get called.''
Battenfeld presses in Brook-haven include 95 with 17 tons of clamping force, and 25 with 38 tons. Molds are single-cavity, shot size is about 1 ounce and cycle times are eight to 12 seconds. Machines are calibrated the same and molds are designed to work on any machine. About 15 mold changes are made in the plant each day.
Presses mold an average of 7,200 parts each day, holding tolerances to 0.002 or 0.003. Wall thicknesses are generally 0.015-0.02 inch.
The plant currently uses 240 molds and 47 different resins, including some that are as much as 30 percent glass-filled. Most of the resin comes from Delphi Packard Electric's compounding plant in Rootstown, Ohio.
Because of the high number of different parts molded at the plant, production runs of 400-600 are common, but are occasionally as low as 10 parts. The daily shipment keeps product inventory to less than 24 hours.
Machine uptime is about 99 percent. Productivity has increased each year, Senger said.
``When we first went to single-cavity molds, everyone said we couldn't compete,'' Sims said. ``But we have a one-time investment, low overhead, and good maintenance, so the machines just run, run, run.''
PreMo operations now use single-cavity molds, but Senger said future versions probably will use two- and four-cavity models.
``Conventional molding is becoming much more sophisticated,'' Senger said.