Investment Casting

Wax Injection

The process begins with production of a heat disposable pattern. This pattern is usually made by injecting molten wax into a metal die or mold. 

Pattern Assembly

The wax patterns are attached by the gate to a central wax runner system. The runner system is called a sprue. Patterns, runners, and pouring cup compromise the cluster or tree. 

Shell Building

The shell building technique involves dipping the assembly into a ceramic slurry and then into a bed of extremely fine sand. After drying, the process is repeated. Up to 7 layers may be applied in this manner.

Dewax Operation

The completed shell is placed in a steam autoclave where the pattern melts and runs out through the gates and pouring cup. 

Firing the Shell Mold: Preheat

The ceramic shell molds must be fired to burn out the last traces of pattern material and to preheat the mold in preparation for casting, usually in the range of 2000 degrees Fahrenheit (1100˚C).

Casting

The preheated shell is filled with molten metal by gravity pouring. As the metal cools, the parts, gates, sprue, and pouring cup become one solid casting. 

Shell Removal: Knockout

After the metal solidifies and cools, the ceramic shell is then removed by vibratory methods.

Casting Removal: Cut Off

Individual casting are removed from the cluster by friction sawing or by means of a cut off wheel. 

Finishing Operation: Gate Grinding

Remaining gate protrusions are removed by belt grinding.

Completed Casting: Finished Casting

The final part is now ready for heat treating and shipping to customer