Pattern & Shell Preparation
Wax InjectionThe process begins with production of a heat disposable pattern. This is usually made by injecting wax into a metal die or mould. The final dimensions and tolerances of the casting are affected by variations in the wax pattern, which makes this step critical for accuracy.
Pattern AssemblyThe wax pattern is attached by the gate to a central wax runner system called a sprue. Joining several patterns to one sprue creates a tree that allows many components to be cast at once, and careful handling here improves both quality and yield.
Shell BuildingThe assembly is dipped into a ceramic slurry and then into a bed of extremely fine sand. The cycle is repeated several times to build a shell of the required strength and thermal resistance, which later serves as the mould for the molten metal.
