Different Processing Methods of Precision Casting I

Date:24-11-2016

Precision Casting is a process in which liquefied material, such as molten metal, is poured into the cavity of a specially designed mold and allowed to harden. After solidification, the workpiece is removed from the die to undergo various finishing treatments or for use as a final product. Precision casting is typically used to create intricate solid shapes, and cast products are found in a wide range of applications, including automotive components, aerospace parts, electronics, mechanical devices, and construction supplies.

Although precision casting is one of the oldest known manufacturing techniques, modern advances in casting technology have led to a broad array of specialized casting methods. Hot forming processes, such as die casting, investment casting, plaster casting, and sand casting, each provide their own unique fabrication benefits. Comparing both the advantages and disadvantages of the common types of casting processes can help in selecting the method best-suited for a given production run.

1. Sand casting: Sand casting typically relies on silica-based materials, such as synthetic or naturally-bonded sand. Casting sand generally consists of finely ground, spherical grains that can be tightly packed together into a smooth molding surface. The casting is designed to reduce the potential for tearing, cracking, or other flaws by allowing a moderate degree of flexibility and shrinkage during the cooling phase of the process. The sand can also be strengthened with the addition of clay, which helps the particles bond more closely.

Many automotive products, such as engine blocks and housings, are manufactured through sand casting. Its main advantages as a casting process include relatively inexpensive production costs especially in low-volume runs, the ability to fabricate large components, a capacity for casting both ferrous and non-ferrous materials, and a low cost for post-casting tooling.

Despite its benefits, sand casting yields a lower degree of accuracy than do alternate methods and it can be difficult to sand cast components with predetermined size and weight specifications. Furthermore, this process has a tendency to yield products with a comparatively rough surface finish.