Investment Casting

GPI offers metal casting prototype services in a variety of materials including magnesium, aluminum, zinc, and bronze, which are created with a plaster, sand, investment or permanent molding process.

The Process

1. A master model is created
2. "Master Molds" are made from the master model
3. The "Master Molds" are used to generate plaster molds
4. Drying of mold (typically 3-5 days)
5. Metal is poured into the plaster mold
6. Cleaning and prepped for shipping or machining

Wax is injected into an aluminum die to produce a pattern that is an exact replica of the part to be produced.  For every casting, a wax pattern must be manufactured.  The patterns are clustered around a coated sprue and repeatedly dipped into an agitated vat of ceramic and allowed to dry.  After a shell thickness of approximately 3/16" has been built; the molds are dewaxed by either flash firing at high heat (1400 F.) or autoclaving (pressure and steam).  The hollow shells are then preheated to 800-2000 F. depending on the alloy to be poured and the molten metal cast immediately into the hot shell.  After cooling, the ceramic is vibrated and blasted off the metal parts and discarded.  The balance of the cleaning operations (cut off, grind, heat treat, straightening, blast) are straight forward and quite similar to the other casting processes.

NEW MATERIAL: B403 Mg Alloy