In the Investment Casting industry, soluble waxes are used to create precise intricate cavities. The soluble wax is injected or extruded into a die. When the part has solidified, it is then placed on a pattern die so the pattern wax can be injected around the soluble core. Finally, the injected pattern is introduced into a bath containing a mild acid and the soluble core is left to leach out until the pattern wax piece is free of the soluble component. Soluble waxes have had a poor reputation amongst the foundry men because of the many problems associated with their use such as; lack of fluidity after melting, abrasive behavior during handling and injection, inferior surface finish after injection and potential health & safety issues during the leaching process. Therefore, investment casting wax manufacturers have placed a greater interest in their study and improvement.
It is the intent of this paper to provide the investment casting foundry man with a broader understanding of soluble cores from a functionality stand point by reviewing their chemistry and analyzing their physical/chemical behavior in the foundry. In addition, guidelines will be provided to enhance surface finish, dimensional consistency and dissolution characteristics that in turn could help produce a better pattern wax thus a better final casting.