Though they have been refined through the ages, significant differences exist between the two methods used to make metal parts.
Sand casting and investment casting are methods of creating metal parts by pouring molten metal into three-dimensional molds. Although methods are thousands of years old, both have been refined over the years to minimize the amount of metal used and reduce any extensive machining and finishing required. But significant differences exist between these two methods of making metal parts. First let’s take a look at the basics behind each.
In sand casting, molten metal, usually iron, steel, bronze, brass, aluminum, magnesium, and other non-ferrous alloys, is poured into a two-piece mold. The molds are created by compacting sand—most often mixed with clay as a bonding agent and moistened with water—around a pattern or model of the final product. The mold is split apart and the pattern removed. The two halves of the mold are put back together and the void is filled with molten metal. Once the metal cools sufficiently, the mold is opened, the sand removed, and the part taken out.
Several of the same parts can be cast at the same time, or a range of different parts can share a mold. Molds are destroyed in the process, but new ones are easy to make. The sand is often reclaimed and reused multiple times.