Cast Parts

Numco USA provides offshore as well as domestic services for custom metal castings. We offer strategic sourcing for sand casting, precision casting, and die casting. No matter what casting method your project requires, our partners consistently deliver high-quality cast metal products that meet or exceed expectations.

Die Casting

Die casting can be used to produce parts from zinc and aluminum, and is ideal for smaller pieces and more intricate part designs. Molds for die casting are created from hardened tool steel which is machined into the desired shape. Like those used in sand casting, die casting molds are built in two halves, which are separated after casting to remove the resulting part(s).

Molten metal is forced into the mold cavities under high pressure (up to 25,000 psi or greater), and this pressure is maintained until the casting cools and solidifies. High pressure is necessary to fill the mold quickly, before any part of the casting solidifies. This process yields smooth part surfaces and can produce parts with thinner walls than other casting methods allow.

Sand Casting

Sand casting can be used to create parts from steel, stainless steel, gray iron, malleable iron, and ductile iron. Also known as sand molded casting, this process uses sand—usually mixed with clay or another bonding agent—as the mold material. Roughly 70 percent of all metal castings are created using this method.

Mold cavities for sand casting are created by compacting the sand mixture around an existing part, model, or pattern inside a multi-part molding box, called a casting flask; cavities can also be carved directly into the sand. The top and bottom halves of the casting flask are assembled and the sand is dried. Molten metal is then poured into the mold and left to cool. The casting flask is removed and the sand cleared away, leaving the completed part.

Sand casting can be used to produce a wide range of custom components, including large, heavy, and/or complex parts.

Precision Casting

In precision casting, parts can be cast from steel and stainless steel. Often referred to as investment casting or lost wax casting, this process uses specialized wax materials to create molds. The wax is then encased in a ceramic shell that creates an exact—and far more durable—replica of the wax mold. The wax is melted and removed, and the ceramic mold is used to produce the cast parts.

Investment casting allows for more intricate and complex shapes than other casting methods, and can be used to produce parts that would be difficult or impossible to create through other processes (machining, fabrication, etc.). It tends to yield parts and components with very good surface finishes, which can reduce or eliminate the need for additional finishing work.

Precision casting is generally used to produce smaller parts, but large and/or heavy products can be accurately cast using this process, as well.