Application Description
Engineered for precision positioning tasks where lubricants cannot be tolerated, a linear actuator uses a Vespel® polyimide part for its rotor shaft. Applications include food processing, electronics, etc.
The shaft is bonded with epoxy adhesive within the rotor of a bi-directional d.c. stepping motor. It is hollow and has internal threads to mate with a threaded steel rod of 1/4 in. (6 mm) diameter. As the rotor turns in 1.8° steps, the rod moves linearly in increments of 0.0003 in. (8 microns).
Benefits Gained
Reliable unlubricated service. The manufacturer reports that a rotor shaft functioned well after 1.3 million cycles raising and lowering a 16 lb. (7.3 kg) load.
Repeat accuracy. The Vespel® shaft resists deformation well above the actuator’s maximum operating temperature of 260°F (126°C), thus assuring precise, repeatable positioning.
Simple assembly. Because Vespel® can be bonded with selected adhesives, actuator assembly is quite simple.
Materials Selected and Why
Vespel® parts provide the combination of lubricity, wear resistance, strength, dimensional stability and bondability required for long-term unlubricated service.
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