The Featured Part is an Aluminum Die Casting (note: gloss surface is after milling, grey surface is after lapping)
Aluminum Die Casting has evolved to meet many manufacturing needs. In a basic sense, molten Aluminum alloy is “forced” into a cavity under pressure to replicate a part geometry. With carefully designed tools, parts can be made with undercuts by using mechanical slides. The porosity is minimized by the design of the runner system and overflows. The surface of the tool can texture parts. After the parts are cast, the runners and overflows are removed, allowing the part to be stress relieved, machined, and coated.
The Featured Part is cast using a vacuum assist process. The molten material is forced into the cavity under pressure while the cavity is under vacuum assist. This increases the cycle time but reduces porosity. The part is then machined and lapped, holding parallel and perpendicular tolerances to ten thousandths of an inch. Finally, two bimetallic bearings are pressed into the casting, providing the customer with a part that does not need additional processing before assembly.