Rapid casting using alternative approach of pattern and mould making

Abstract

Evaporative pattern casting (EPC) process facilitates the production of parts with complicated geometries. Two major problems associated with EPC are the fabrication of the metal tooling and complicated mould preparation. To overcome these limitations, a novel rapid foam casting (RFC) process is proposed. The complicated pattern geometries as selected on the basis of shape complexity are produced by the author's developed rapid prototyping machine namely 'segmented object manufacturing'. Patterns are then converted into metallic castings by adopting two alternative moulding processes for EPC, i.e., no-bake and green sand moulding. Taguchi's orthogonal array is used for the design of experiments to investigate the effect of the part geometry, pattern density and moulding method on surface finish and dimensional accuracy of the casting. Analysis of variance (ANOVA) is also performed to find out the individual participation of each factor on the surface finish and dimensional accuracy of the casting. No-bake sand moulding process gives tighter dimensional tolerances and better surface finish in comparison to green sand mould. The study also proves that even if several designs are being produced with the same complexity, it will yield the same quality. [Submitted 9 April 2020; Accepted 14 August 2020]