Investment casting process（2）
Create the main pattern: the mold maker made the original pattern with wax, clay, wood, plastic or other material. In recent years, the production of patterns using 3D printing has become widespread.
Create a mold: A mold called the main mold is made to fit the main model. If the main pattern is made of steel, the master mold can be cast directly from the pattern using a metal with a lower melting point.
Production of wax molds: Although called wax molds, the sheet material may also include plastic and chilled mercury. Wax patterns can be produced in one of two ways. In one process, the wax is poured into the mold and turned until a generally uniform coating of about 3 millimeters (0.12 inches) thick covers the inner surface of the mold. Repeat this step until the desired pattern thickness is reached. Another method is to fill the entire mold with molten wax and allow it to cool to a solid object.
There are two core options: Soluble wax or ceramic. The soluble wax core is designed to melt the investment coating with the remaining wax pattern and the ceramic core is removed after the product is cured.
Combine Wax Patterns: You can create multiple wax patterns and assemble them into one large pattern, pouring in one batch. In this case, the pattern is attached to the wax gate to create a pattern cluster, or tree. To attach the pattern, use a heating tool to slightly melt the specified wax surface, then press it against one another and allow it to cool and harden. Up to hundreds of patterns can be assembled into a tree that looks like the finished piece.http://www.pump-casting.com