PEEK for thin wallsPEEK for thin walls
August 23, 2008
LCP, PPS, and epoxy thermosets used to be the only high-end engineering plastics capable of being molded in wall thicknesses of less than .2 mm (.008 inch). A recent product debut from Victrex (called Victrex 90) changes the landscape by boosting flow rate to double that of standard-flow PEEK. Moreover, while Victrex 90-based products have a lower molecular weight, they offer mechanical, thermal, chemical, and electrical properties equivalent to standard PEEK grades, according to Victrex.
The new resins are available unfilled (as powder or pellets) or reinforced with glass or carbon fibers. Fiber loadings of up to 60% are reportedly possible without sacrificing ease of processing, surface finish, or cycle time. The higher loadings are said to produce substantial improvements in modulus, toughness, and coefficient of thermal expansion.
Andrew Ragan, product manager at Victrex USA, says, ?These products are designed for injection molding thin-walled, intricate components and highly filled compounds without sacrificing ease of processing. They are engineered to replace thermosets, ceramics, and metals in consumer electronic, surface-mount, and micro-fluid handling applications.?
A target application for Victrex 90-based products are devices that use the lead-free soldering process at 260Â°C (500Â°F), common in the electronics industry. Explains Ragan, ?Traditional polymeric materials such as PBT, nylon, and PPS fail because they distort or melt under lead-free solder conditions. In contrast, the new products readily meet the demands.
Additionally, the polymer?s high-flow characteristics are ideally suited for the complex shapes required by the electronics industry to make devices smaller and more lightweight.?
A recent application using Victrex 90, a 50-mm radial blower disk for a respirator (pictured), was molded with a wall thickness of just .3 mm.?MM
Victrex USA, Greenville, SC
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