Originally Published MPMNMarch 2004

INDUSTRY NEWS

Micromolding Technique PumpsNew Life into Cardiovascular Device 

NorbertSparrow

A polyamide-imide material developed by Solvay Advanced Polymers LLC (Alpharetta, GA; www.solvayadvancedpolymers-us.com)has many desirable properties for device OEMs. Sold under the Torlon name, the polymer combines high strength at temperatures up to 260°C with creep and wear resistance. 

Nevertheless, many manufacturers have shied away from using it to mold parts. "Without the proper equipment and process controls, it can be difficult to work with," explains Scott Herbert, general manager at RapidWerks LLC (Chicago, IL; www.rapidwerks.com).The company has found a way to sidestep potential problems by using a Microsystem 50 molding machine from Battenfeld along with some proprietary processes. (Herbert says that more than $700,000 worth of quality inspection systems support the MS 50.) To illustrate its capabilities, the firm displayed a micromolded part used in a cardiovascular device at the recent MD&M West show in Anaheim, CA.

"Our customers are always asking us to make it smaller, faster, and cheaper," says Herbert. Replacing a machined stainless-steel part with a molded plastic component "would cause materials and labor costs to plummet. But we needed to source a material that could achieve metal-like performance," adds Herbert. Enter Torlon 4203L.

"The component operates at several thousand rpm under a load. So we needed a low-friction material with exceptional strength and wear resistance." In addition, the part is subjected to substantial heat, so the material had to be stable at high temperatures. "Torlon 4203L is the only high-performance plastic we found that met all of these requirements. It allowed us to produce a complex molded part weighing only 4.2 mg that has performance characteristics similar to metal," says Herbert.

Rapidwerks offers medical device OEMs an array of services from parts design and engineering to contract molding and assembly. The company has a Class 10,000 cleanroom. "The Microsystem 50 molding cell is itselfa Class 10 cleanroom," adds Herbert, "so it functions as a cleanroom 
within a cleanroom."

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