Manufacturing

Investment casting is an ancient metallurgical art which dates back to Egypt. It was initially used to cast delicate jewelry and idols. Famous sculptors used the process during the Renaissance to create exquisite bronze masterpieces. Investment casting has been used over the last hundred years as a net or near net shape manufacturing process and is now globally recognized as a cost effective and ingenious industrial process which has stood the test of time. The basic process steps are pictorially depicted above and outlined below

Wax Injection

Molten wax is injection molded into a mold cavity to form a pattern or an exact replica of the part. The wax pattern is allowed to solidify in the mold cavity and removed. Each casting requires a pattern. Assembly: Numerous patterns (number varies depending on size and complexity) are attached or welded to a central tree trunk or sprue to form a wax tree.

Shell-Build

The wax assembly is thoroughly cleaned and immersed in a liquid ceramic slurry. This immersion process is repeated several times to form a hard shell or investment. The shell or investment has to be strong to withstand the thermal shock and tensile stresses created during subsequent operations.

De-Wax

The shells are completely dried and the wax completely melted in an autoclave leaving behind a void inside the shell. The void exactly matches the casting. The shells are pre-heated in an oven to prepare them for thermal shock.

Pouring

The appropriate metallic alloy is melted in a furnace and poured into the central sprue using a pour cup. The molten metal flows by gravity down the central sprue and enters the part cavities through portals known as gates.

Knockout

The ceramic shell is broken after the molten metal freezes. The parts are joined to the central sprue and need to be separated into individual pieces.

Cut-Off

The parts are cut off from the central sprue using a cut off saw.

Finished Castings

The parts are sand or grit blasted to improve their surface finish. The parts are occasionally shipped to the customer either in this as cast condition or after secondary operations.