WAX PATTERN DEFECTS

Abstract

It is common knowledge that the investment casting process or “lost wax process” starts with a wax pattern. It is created by injecting wax into a mould cavity, where the pattern is an exact copy of the cast part with strict dimensional tolerances. It also has to allow for shrinkage of the material to be cast. This pattern is then dipped into a silica slurry bath. For a good surface finish, finer slurry and zircon sand is often used. The shell is then heated to dewax the mould, followed by firing and preheating before the molten metal is poured into the dewaxed cavity. A good understanding of the wax injection process is essential for good quality parts to be created.

Key words : investment casting, modeling methodology, cost reduction, concurrent engineering