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Designing a Complex Aerospace Pump Housing With Investment Casting

Jiten Shah

As a near-net-shaped casting process, investment casting offers tight dimensional and profile tolerances with no or minimal draft and excellent as-cast surface finish. Since the disposable wax-like pattern is typically assembled using multiple pieces, the process allows design engineers the freedom of consolidating complex features and sub-assemblies into a one-piece casting configuration. 

In the case of a new pump housing for a commercial aircraft engine, casting provider O’Fallon Casting (O’Fallon, Missouri) combined a multiple-part assembly into a single component with interconnected core passages. The resulting design was lighter yet stronger, eliminated failure points, and held tighter tolerances with precision compared to a fabricated version. Plus, 13 weld plug openings were reduced to four. Overall, the one-piece design had a lower per-piece cost, grade B metallurgical quality and pressure tightness performance improvements.

Click here to view the rest of the column in the November/December 2021 Casting Source digital edition.