Investment Casting 101
Thousands of years ago duplicate metal structures were cast from an original sculpture by the lost-wax casting process. Investment casting is one of the oldest metal-forming techniques based on this lost-wax casting process. A beeswax pattern is coated with refractory ceramic material, which then hardens and takes the shape of the casting. The ceramic mold is then heated to melt the wax and remove it. Molten metal is then poured into the cavity. The metal solidifies and the ceramic mold is broken. This casting method allows the production of components with accuracy, repeatability, versatility, and integrity in a variety of metals and high-performance alloys.
Aluminum alloys, bronze alloys, magnesium alloys, cast iron, stainless steel, and tool steel are the most common metals used in investment casting. For casting metals with high melting temperatures which cannot be molded in plaster or metal, this method is useful. Parts with complex geometry such as turbine blades or firearm components are generally made using investment casting. High temperature applications are also common, which include parts for automotive, aircraft, and military industries.
The biggest benefit of investment casting is that it can produce complicated parts with very fine detail and excellent surface finish that would otherwise have been difficult with a die casting method.
The manufacturing process
There are two ways for making casts: using the wax model itself in the direct method, or creating a wax copy of a model that necessarily not be of wax, with the indirect method. The following are the steps for the indirect process which can take two days to one week to complete:
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