Dear MEMS Researchers,

I am using the MUMPs process to design a push-plunge type mechanism. For
actuation, I am using the Comtois style thermal actuators. Essentailly, I have a
toothed rack that is made to engage with a larger rack, provide actuation to the
larger rack and is then made to disengage. The mechanism works fine but the
teeth tend to interfere now and then. I am using trapezoidal shaped teeth.

One way to overcome the interference (tooth landing on tooth) would be to ensure
that the stroke of the actuators equals the pitch of the teeth. Getting such
perfect control from the actuators over long periods of time is tedious.
Another way would be to design triangular shaped teeth as they would mesh
better. But MUMPs does not allow feature sizes smaller than 2um.

Have any of you faced a similar problem and found a way out of it (so that the
teeth meshin a reliable manner)?

                             ALSO

Has anyone found a neat way of designing a gear-train of desired pitch in MUMPs
while respecting the 2um limitaion of the the process?

Thanks in advance,
Shivalik

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Shivalik Bakshi,
School of Engineering Science,
Simon Fraser University,
Burnaby, BC V5A 1S6
Canada

Email: sbakshi@cs.sfu.ca
Tel: (604) 298-6847