Our Metal Casting Methods

There are many different metal casting methods. At Precise Cast we have chosen two methods that are especially well suited to low-volume production (1-1,000) of aluminum, magnesium, and zinc castings - a plaster casting method and a sand casting method.

For help in choosing a process Click Here
For help in choosing an alloy Click Here
See our Machined Parts page for information regarding the machining process.

Plaster Casting (Rubber Plaster Mold)

Plaster Casting is the process of making cast metal parts using plaster molds as the "die".

A machined pattern is used to make a silicone “tool”. The tools are usually made in two halves. (A tool to produce a core is also sometimes required.)
Plaster is poured into the tool halves (and the core, if required) and allowed to harden
The hardened plaster halves (and the core) are dried and assembled (or assembled and dried) to form a plaster mold
Molten metal is poured into the assembled plaster mold
After it cools, the plaster is broken away from the metal and the casting (with rigging) remains

Benefits:

Tooling timing is much faster than die cast tooling timing (1-2 weeks vs. 10-20 weeks)
Tooling cost much less than die casting
High detail, fine features, and very thin walls are possible
Parts can be cast with zero draft
Quality finish

Sand Casting

Sand Casting is the process of making cast metal parts using sand molds.

Basic Sand Casting process (for more information, see our Sand Casting Process page):

Sand is molded around a pattern or packed over a “match plate” to create two mold halves
Molten metal is poured into the cavity created between the two mold halves
After the metal cools, the sand is broken away from the metal and the casting (with rigging) remains

Benefits:

Very short tooling lead time
Tooling is less expensive than plaster casting and much less than die casting
Excellent mechanical properties