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August 9, 1998

6 Min Read
Micromolding:  Key to market success


In 1980, Precimold designed and built an eight cavity family mold. Each of the eight different parts, designed by Precimold, required a cam actioin to interlock with each other, producing an assembly requiring no screws or other fasteners. The finished product, part of a subway ticket validation system, also was assembled at Precimold.

Precimold Inc. of Candiac, PQ, near Montreal, has pioneered high-precision, high-volume micromolding and micromoldmaking since president Gunter Weiss founded the company in 1966. Its specialties also include two-color, insert, and lead-frame molding. Precimold has molded technical and medical parts as small as .0005g in exotic materials to within ±.0050 mm tolerances with zero defects. The company has built its own unit frame tooling for small parts, not the least of which is an eight-cavity family mold wherein each glass-filled PC part needed a cam action for interlocking with the others. Precimold both designed and assembled these parts for its customer.

Four years ago, IMM took you on a tour of Precimold's shop (see July 1994 IMM). Growing from 25 employees then to nearly 70 now, Precimold has spent approximately $600,000 to add 17,300 sq ft to its plant, bringing the total up to 48,000 sq ft. Curiously enough, even with the interest in small parts molding these days, Precimold's expansion was partly necessitated by its need to serve a customer requiring big parts run on big machines-big for Precimold, that is. Three Engel molding machines were added to the 18 Engels already owned-a 300-ton, a 250-ton, and a 150-ton tiebarless, all part of Precimold's $900,000 investment in new machines.

Precimold now molds parts weighing up to 500g, but Weiss is in no way abandoning small parts molding. He says he has no intention of ever buying machines larger than 300 tons. For example, his new machinery acquisitions also include one of those cute little HM7s-Nissei's horizontal, tabletop, recip-screw, 7-ton hydraulic.

The expansion helps Precimold house its larger machines, but the 17,300 sq ft really were added for another reason-inventory. Precimold ships parts JIT but only after it is satisfied they are ready. The parts it molds are inspected within 4 hours of being molded, some every 1Ú2 hour. They are inspected again after 24 hours and then again after seven days to guarantee all parts ship to spec.

The expansion also has allowed Precimold to open a new design room where it runs Cadkey, I-deas, Artisan, and Smartcam software. During the ice storms this past winter that devastated the Northeast, Precimold operated its entire plant with a truck-sized, rented generator. "For the next time, we will have our own," says Weiss.

Business Advantages
As for molding bigger parts, Weiss believes there are too many business plusses in micromolding to go after the larger part market. Capital investment is more affordable. Generally, you require less real estate for manufacturing, inventory, and everything else. Handling and shipping small lightweight parts also is easier and less costly. "I can put one week's production in a box and overnight it to a customer," he says.

What's more, Weiss questions whether bigger parts yield bigger margins. "I don't see a difference. It's all about selling machine time. You may have a bigger machine, and your hourly rate changes, but are you ending up with more profit just because the machines and the parts are bigger, especially when you consider the higher purchase price of the bigger machine and the higher cost of its energy and floorspace requirements? You also have to buy more material and pay for more storage. If you say your objective is making $20 per hour, that's all that matters. Besides, more people have big machines than small ones today. Why would you want to get into something so competitive?" (See the box opposite for more advice.)

Curiously enough, lack of room was why Weiss decided to specialize in micromolding in the first place. His original "plant" was on the second floor of an office building, which couldn't support big machines. That first manufacturing operation was a lights-out plant running 24-7. After hours, he says, he'd phone the plant, which was directly across the street from his home, and listen carefully to the sound of the two 15-ton Battenfelds he had then. He could tell if there was a problem by the sound of the machines.

Expert advice on micromolding

Gunter Weiss of Precimold shares some of what he thinks it takes to succeed in micromolding:

  • Molding. Process control for profitable micromolding with engineering resins mostly involves injection speed and residence time. Precimold has been successful using standard machines with no accumulators. Weiss doubts whether advanced computers or closed loop controls are absolutely necessary for successful micromolding or even for precision molding in general. "Many people have done some fantastic work before computers came about. We once redesigned two matching CNC-machined metal parts for a micro tape recorder to test deflection on aircraft wings. We recommended a glass-filled polyester, made the mold, and molded the parts with four ball bearing seats of .1250 inch to within .0002 inch. That was 25 years ago . . . on a 15-ton Battenfeld."

  • Tooling. Proper venting at the proper location is as essential to profitable micromolding as it is to profitable general-purpose molding because of the high-speed injection involved. "You don't start venting at the cavity. You must get rid of the air before it gets to the cavity. What you want to do is vent your runner and flash at the end of the runner. Why have air get into the cavity?"

    When it comes to making micromolds: "Everything is EDM." Precimold operates ram EDM machines and goes outside for its wire work. Copper tungsten is used more often than graphite in making electrodes because "copper is cleaner." Copper works better in Weiss's ARD EDM systems from Taiwan while graphite works better with his Eltee Pulsitron EDMs. Precimold uses a CNC milling machine from Dyna Mechtronics for making its electrodes.

  • Product handling. There are many practical solutions to the problem of handling micromolded parts. One that has been successful at Precimold has involved molding the parts onto a carrier strip of Mylar, for example. Another idea is to mold-in a carrier strip made from the same material as the part. Parts can be fed through an automated machine for separation.

    No robots are used on Weiss's smaller machines. On the larger ones, pneumatic Conair sprue pickers with Precimold's own end-of-arm tooling remove and deposit molded parts by their cavity numbers into custom-built containers.

Contact information
Precimold Inc.
Candiac, PQ
Gunter Weiss
Phone: (450) 659-2921
Fax: (450) 659-2923

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