The Fabrication of Stainless Steel Parts for MEMs
Summary:
A micro-molding process was used to fabricate parts
in the 0.1 to 10 mm size range from a stainless steel
nano-powder. The two types of molds used were both produced
from parts fabricated using the LIGA process so that they
had precise dimensional tolerance and straight sidewalls.
Rigid PMMA molds were made by injection molding and flexible
silicone rubber molds were made by casting. Mold filling
was accomplished by mixing the powder with epoxy to form
a putty-like material that was then pressed into the mold
cavities and allowed to cure.
After pyrolysis of the epoxy, the parts were sintered
in forming gas.
The densification kinetics were measured
in situ using a video system. Full densification was achieved
after 1 hour at 1350°C. The microstructure of the
sintered parts was examined using the SEM. The mechanical
strength, hardness, dimensional tolerance and surface
roughness of the sintered parts were also measured
The two most common techniques for producing parts for
MEMs, silicon surface
micromachining and LIGA, have limitations. Two limitations
of Si micromachining are composition and thickness. The
available materials set includes only Si, SiO2, SiC and
diamond. Part thickness is generally in micron range.
For the LIGA process, the materials set is limited to
materials that can be plated such as pure metal and some
simple alloys. Plating is a slow process and generates
considerable quantities of hazardous waste. Thus an economical
technique that
could produce parts of more complex metals as well as
ceramics and polymeric materials would complement the
existing techniques.
Format:
Pages :6
Size: 2.3 mb
Author :Terry J. Garino, Alfredo Morales, Thomas Buchheit
and Brad Boyce
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