Fabrication

The overall shape of the component is unique for PM main bearing caps. The sculpted shape required for weight reduction also required a step change in the manufacturing process. The powder transfer required to form a defect-free part requires the near perfect choreographing of upper and lower tooling. Both product and process technology advances were necessary to produce a robust product.

The component required the use of multiple upper and lower levels consisting of 5 punches on both upper and lower as well as core rods and significant powder transfer. Requirements for engine weight reduction drove the designers to an “upside down” sculpted version to realize weight savings and required substantial powder transfer to form the crankshaft bore.

Results

The novel design delivers a part that is 23% lighter than previous versions and offers a 10% better fatigue strength.
The unique shape has exceeded customer strength requirements; however, it’s important to note that the early relationship between end user and fabricator was pivotal for successfully developing this component. The early design was intended for a traditional bore down compaction process, but through discussion between the end user and fabricator, a more innovative approach was taken that resulted in component benefits.