Fabrication
Material composition was relatively straightforward, utilizing MPIF FC-0208-50 to mimic AISI 4140 cold-rolled steel. Physical load on the component was determined to be relatively low, with no significant requirements placed on elongation or tensile strength. Tolerances needed to be maintained on the post feature due to bushing size requirements. The diameter of the post is qualified by machining, where the snap ring groove is also created. The rectangular tab is milled from stock intentionally left at the end of the post during the compaction process.
The 700 g part is manufactured near-net shape utilizing hydraulic compaction with fill compensation and selective ejection. Secondary machining is required on the 15.957 mm post for bushing tight-sliding fit, snap ring retention feature, and for the tab on the face of the post. The final operation is zinc electroplate with clear chromate conversion for corrosion protection.
Preventing cracks at ejection was the largest hurdle to overcome, but with the selective motion provided by the hydraulic press, balancing fill and ejection deflections were possible. For machining, a custom counterbalanced jaw setup was required for part work holding due to the central axis being significantly offset from the center of gravity of the balance of the part.