More about Investment Castings

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Investment castings employ a method of casting that is quite often referred to as the “lost wax process.” Casting usually refers to the molding of a liquefied metal, and investment castings are no exception to this practice. The term “investment” may be a bit misleading, but is easily explained when looking at the history this method of casting held. In ancient Egypt this process was utilized to craft the Pharaoh’s precious gold jewelry, and because of the incredible value this jewelry attained, the finished products became known as investment castings.

Investment castings may still be intricate pieces of jewelry, but these days the term also applies to manufactured parts that require special handling and thus cannot be manufactured using other methods. Generally speaking, the complexity of shape and the intricacy of design may determine whether a product needs to be manufactured via this process.

Investment castings are crafted by generating a mold made of wax or any other kind of material that will easily melt away when heated. Once the mold is made, it is coated with a polymer, usually by dipping it into a polymer bath. The polymers used depend on the use of the mold. If high temperature metals are introduced to the mold the polymer used will be different from those molds who will only receive low temperature melts. Depending on the thickness needed, this process may be repeated as many times as necessary. Once the polymer skin over the wax is as thick as desired, the wax is melted away by applying direct heat to the mold. The result is a hollow mold that may be filled with liquefied metal to generate investment castings. The advantage of this method may be found in the intricate shapes that can be made.