Investment casting is a method of producing castings in the lost-wax process. The resulting parts stand out for their high level of detail, dimensional accuracy and surface quality. In many cases, the technology can eliminate the need for machining.
The process is used for castings with a typical mass of 30 g to 200 kg. Higher part weights are possible. The technology is suitable for the casting of virtually any steel and alloys based on iron, aluminum, nickel, cobalt, titanium, copper, magnesium or zirconium.
The castings are normally ready for assembly or require only very little machining. As a rule of thumb for efficiency, investment casting is particularly attractive for components of complex geometry and/or eliminating the need for complicated machining. Further benefits can be derived by integrating fixtures into the part for subsequent manufacturing steps. Investment casting is an especially profitable process for larger volumes.
For each component, a wax model is made by injection molding.
Several wax models and the sprue, also made of wax, are combined to a casting cluster.
The mold is created by dipping the model into ceramic slurry, followed by sanding and drying. These steps are repeated several times until the desired strength of the shell is achieved.
The wax is melted out of the models, and the ceramic molds are fired.
The desired alloy is poured into the preheated molds.
Once the alloy has solidified, the ceramic mold is removed and the sprue is separated from the castings.
The parts can then be heat treated and reworked, if required.
The parts are checked for compliance with drawing specifications and material properties.
Almost any metal material can be processed by investment casting. The technology is particularly suitable for alloys difficult to machine.