An investment casting process for producing castings

摘要

An investment casting process is carried out by the formation of a lost pattern in a lost mold and its ceramic coating once formed. The process comprises the following steps:1) Manufacturing a positive pattern (i.e., with the same shape as the casting to be made) either with hard or elastic material, depending on the cases.2) Manufacturing a temporary mold by pouring a liquid over the positive pattern and cooling it up to its solidification.3) Extracting the positive pattern.4) Forming a temporary pattern by pouring a second liquid into the cavity of the temporary mold and cooling it up to its solidification.5) Melting or solving the temporary mold.6) Coating the temporary pattern with ceramics, forming a solid ceramic shell around the temporary pattern.7) Melting or solving out the temporary pattern and evacuating the resulting liquid from the ceramic shell.8) Filling the shell cavity with molten metal which is allowed to solidify to form the final cast piece.;The process allows the production of all types of top quality cast parts as it makes possible -irrespective of their complexity- forming a lost pattern in a lost mold, thus avoiding the risk of breakage of lost patterns as well as the need of using cores (with high deformation risks). In addition recyclable materials are used in the production of the lost patterns and molds.