A test casting known to be dimensionally sensitive to process variations was selected for foundry process capability studies. Ferrous and nonferrous castings were produced in foundries using green sand, no-bake, and lost foam (EPC) processes and the resulting castings analyzed for surface finish and dimensional precision. All conventional casting processes had difficulty with the 0.5 degree taper on the pattern. After much difficulty drawing the pattern from conventional sand molds, the cope and drag pattern taper was increased to 1 degree in order to produce castings. None of the conventional sand casting processes could produce cast-in holes. EP castings had cast-in holes, almost zero taper, close dimensional tolerances and a superior surface finish compared to conventional sand castings.
| Number of Pages : | 28 |
| Published : | 06/01/1990 |
