Plaster Mold Investment Casting Process
This is the best process to simulate aluminum or zinc die cast parts in both properties and appearance. Aluminum or zinc parts can be shipped in as little as 2-5 weeks from receipt of 3D CAD part geometry, depending on size and quantity.
The rubber plaster mold process offers an alternative to ceramic investment casting, steel casting ,precision casting and prototype die casting. This process is both suitable for short run production quantities of aluminum and zinc parts.
Castings from plaster molds simulate die cast parts for appearance and properties. Tooling is low cost and easily accommodates geometry modifications and design enhancements. The rubber plaster molding process also serves as a short run (<2,000 /year) production process for programs that cannot justify the cost of hard tooling.
Castings from the rubber plaster mold process feature excellent surface finishes, complex geometry (including undercuts and complex coring).
Investment casters who use the plaster mold process do not require a wax patterns. Instead, the plaster mold process begins by using a pattern master. Today the pattern master is produced using rapid prototype (RP) technologies. Typically an SLA (stereolithography) model is made of the actual part using “as cast” CAD geometry. This master is used to produce a temporary rubber negative which, in turn is used to produce a final rubber positive. Plaster slurry is then poured over the rubber positive to produce the plaster mold. The foundry then pours the metal into the plaster mold. Once the metal solidifies the casting is removed from the mold by breaking the plaster away from around the part and consequently destroying the mold. As with all metal castings machining stock is added to areas requiring close tolerances not achievable in the “as cast” form.