Investment Casting Process

Abstract

A process for the production of a shell mould, comprising the sequential steps of: (i) dipping a preformed expendable pattern into a slurry of refractory particles and colloidal liquid binder whereby to form a coating layer on the pattern, (ii) depositing particles of refractory material onto the coating, and (iii) drying, steps (i) to (iii) being repeated as often as required to produce a shell mould having the required number of coating layers, characterised in that during at least one performance of step (ii) the particles of refractory material have been pre-mixed with a gel-forming material whereby to coat at least a portion of the refractory particles with the gel forming material such that after contact with the coating layer moisture is absorbed by the gel-forming material thereby causing gellation of the colloidal binder so reducing the time required for drying in step (iii).

Dependencies are inferred from the claim text.