details DESIGN


As-cast cored holes eliminate drilling.


• Careful design of the tooling and cores allows the use of as-cast cored holes with high precision tolerance and reproducibility. As-cast holes in iron castings reduce mass and provide better properties around the cored hole, as op- posed to holes drilled afterward. Some cores can be oriented perpendicular to the parting plane with careful core design by casting engineers.


• T e minimum cored hole diameter is driven by section thickness and molding process. Typically for green sand casting, the minimum diameter is 0.5 in., with the section thickness not in excess of 1 in.


Smooth transitions at cross-sections eliminate risk of dimensional defects.


• Abrupt changes in the cross-section may induce the residual stresses inherent to the casting process and lead to tearing and/or distortion and warpage. Smooth transitions at the junctions eliminate such risks and pro- vide higher casting quality with consistency.


Jiten Shah is president of Product Development & Analysis (PDA) LLC, Naperville, Ill., and a 25-year casting design and manufacturing veteran.


Mar/Apr 2012 | METAL CASTING DESIGN & PURCHASING | 23


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