Because of pattern costs, this method is best suited to higher volume production. Rapid production rate. Good dimensional casting detail and accuracy. Shell molds are lightweight and may be stored almost indefinitely. Since the tooling requires heat to cure the mold, pattern costs and pattern wear can be higher.
Energy costs are higher.
Material costs are higher than those for green sand molding. Permanent Mold Permanent molds consist of mold cavities machined into metal die blocks and designed for repetitive use. Currently, molds are usually made of cast iron or steel, although graphite, copper and aluminum have been used. Permanent mold castings can be produced from all of the metals including iron and copper alloys, but are usually light metals such as zinc-base, magnesium and aluminum. Normally, gravity molding is used because it is more accurate than shell molding.