Microinjection Molder Can Produce Tiny Thermoplastic Parts

Originally Published MPMN November 2001

INDUSTRY NEWS

Microinjection Molder Can Produce Tiny Thermoplastic Parts

A new micromolding machine is capable of producing thermoplastic or silicone rubber parts measuring 0.05 to 20 mm³. The Sesame machine supplied by Murray Inc. (Buffalo Grove, IL; www.nanomolding.com) can mold 20 sesame seed–sized parts, each measuring 2 mm³ and weighing 0.0022 g, from a single plastic pellet. The machine is designed to provide fast throughput, controlled injection, and brief material residence time. Total injection time can be as short as 0.02 seconds for the full 40-mm stroke. Molded component wall sections can be as thin as 0.001 in. at pressures up to 50,000 psi. A pneumatically driven vertical plunger prevents material degradation during the plasticizing process. In addition, a plunger operated by a linear servo-driven motor performs injection of the material. A high- pressure valve separates these operations, and a nozzle shutoff valve prevents excess dripping from the nozzle. The Sesame offers a color touch screen PC interface for control of process variables and data collection. The pneumatically actuated machine is lubrication-free and is powered by 120 V ac to allow incorporation into cleanrooms.

Katherine Sweeny

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