Similar to plastic injection
molding, a molten polymer (called binder) plus ceramic or metal
powder paste is injected into a mold. The part is removed when the
polymer cools. The binder material is removed by either solvent
extraction or controlled heating to above the volatilization temperatures.
The volume (cubic inches) of the part is restricted to small components,
and material properties such as yield strength are lowered.
This process is a recently
developed alternative to conventional compaction methods of powders
in powder metallurgy products.
Injection Molding can
be thought of as a step in a more general powder metallurgy process
consisting of four general steps:
or injection molding