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Design
We have a large
variety of powder metal presses and computer-controlled
injection molding machines, all built to our specifications.
That gives exceptional range in the types of parts we can
produce. But it's our exclusive, custom-built sintering
furnaces that really set us apart. Sintering is the most
crucial element in both powder metal and MIM production. Our
furnaces feature up to 11 precisely controlled temperature
zones. And we have furnaces especially built to optimize
results for both powder metal and MIM production. Most powder metal and MIM parts producers use belt-fed or
batch furnaces. Belt-fed furnaces limit temperatures and,
therefore, the available performance properties. Batch
furnaces are usually output-limited. Our pusher furnaces
mean we offer you both the superior performance
characteristics of high-temperature sintering and high
production capability.
The MIM process, using multicavity tooling, is well suited
for the production of geometrically complex parts in the
mid- to high-volume range. MIM can reduce cost when compared
with smaller investment castings and discrete machining, and
to some extent, with conventional powder metallurgy when
significant secondary machining or assembly of the P/M part
is required.Metal injection molding typically will not compete directly
with drop-off screw machine components, stampings or die
castings. However, assemblies made by combining a number of
small parts can often be molded as an integral piece by MIM.
The process is capable of forming complex configurations and
has a degree of geometric freedom equivalent to that of
injection molded plastics or castings.
Secondary Operations
Any powder metallurgy process creates some porosity. MIM minimizes total porosity and
typically limits interconnected porosity (that porosity connected to a free surface) to
less than 0.2%, regardless of the product's percent of full density. This means standard
coloring and plating techniques can be used without resin impregnation. Oil impregnation
and copper infiltration are not used with MIM. When heat treated, parts can be case hardened
to closely controlled case depths equivalent to wrought material. Other metalworking
techniques such as drilling, tapping, turning, grinding, and broaching work well with MIM.
All parts are barrel finished unless otherwise specified. These guidelines are not absolute,
and are influenced by a number of factors related to part design.
Surface Finish
Surface finish of MIM parts is approximately 32 RMS (0.80 micrometer), appreciably better
than most investment castings. However, profilometer readings may be affected by residual
porosity and are subject to interpretation. The method of measuring surface finish should
be agreed upon by both the customer and vendor. The surface of MIM parts can be improved by
conventional processes such as grinding, lapping or burnishing.
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