NON-ISOTROPIC SHRINKAGE IN
METAL
INJECTION
MOLDED COMPONENTS
METAL INJECTION MOLDING
ABSTRACT
Metal Injection Molded
(MIM) components, from tooling dimensions to sintered
part dimensions, will shrink 10 to 25%. Typically, MIM
tools are sized by anticipating uniform, or isotropic,
shrinkage in all directions, which should then deliver a
sintered part giving the desired final dimensions. If
the shrinkage is anisotropic, then some aspects of the
part will shrink more or less than others, and the
sintered part dimensions will be smaller or larger than
specified. The can cause expensive tool rework or
secondary operations on production components. In this
study, a production Metal Injection Molded component was measured after
molding, debinding, and sintering for evidence of
anisotropic shrinkage. The orientation of the part in
the process and solids loading of the feedstock were
examined for their effect. The results show that
non-uniform shrinkage can significantly affect final
dimensions, and that the gravity, solids loading and
mold filling of the component play a significant
role.
Metal Injection Molded
(MIM) components, from tooling dimensions to sintered
part dimensions, will shrink 10 to 25%. Typically, MIM
tools are sized by anticipating uniform, or isotropic,
shrinkage in all directions, which should then deliver a
sintered part giving the desired final dimensions. If
the shrinkage is anisotropic, then some aspects of the
part will shrink more or less than others, and the
sintered part dimensions will be smaller or larger than
specified. The can cause expensive tool rework or
secondary operations on production components. In this
study, a production Metal Injection Molded component was measured after
molding, debinding, and sintering for evidence of
anisotropic shrinkage. The orientation of the part in
the process and solids loading of the feedstock were
examined for their effect. The results show that
non-uniform shrinkage can significantly affect final
dimensions, and that the gravity, solids loading and
mold filling of the component play a significant
role.