Metal Injection Molding (MIM) has historically suffered from part defects, both visible and beneath the surface. Given all that has to go right, from a materials and processing standpoint as a part goes from molding to debinding to sintering, each step introduces the potential for part defects that can range from cosmetic to catastrophic.
A successful approach to tackling defect problems is by applying advanced process analysis and optimization techniques. Sink marks, which are rampant in MIM, represent a case in point. On two of the earliest of our MIM parts, sink marks were reduced by 99.9%. To achieve such a reduction, our engineers conducted experiments that evaluated every process factor that could affect sink, including gating, venting, temperatures, debinding, and sintering conditions. Thermal imaging cameras monitored the tool and the solidifying part. The work revealed, at least for these two components, that venting and gate thickness optimization would all but eliminate sink.
For more information on MIM defects and solutions, please visit http://www.mimwork.com/resources/Common-defects-in-MIM.html