Lost wax casting

Lost Wax Casting (also called Investment casting or Precision casting) is one of the most ancient metal working method and its history dates back thousands of years but it came into use as a modern industrial process in the late 19th century.

The molten metal is poured into an expendable ceramic mold. The mold is formed by using a wax pattern (a disposable piece in the shape of the desired part).

The pattern is surrounded, or “invested”, into ceramic slurry that hardens into the mold, and then the wax model is melted and drained away. Lost-wax processes are one-to-one (one pattern creates one part), which increases production time relative to other casting processes. However, since the mold is destroyed during the process, parts with complex geometries and intricate details can be created.

The simplicity of the investment casting manufacturing process allows for high production rates and consistent dimensional accuracy so, it became the solution for many complex parts that are required in large quantities. Furthermore, with the advent of Rapid Prototyping or Free Form Fabrication technologies, investment casting has gained further attention, since expendable RP patterns can be used to produce a single casting within days starting from the digital definition.