About Castings…

Castings are integral to the engineering industry, and have been in use for the last 6000 years. Casting is a mass production process that involves pouring of a liquid into a mold of desired shape, which is then allowed to cool. They are used to make complex shapes which are not very easy to attain otherwise.

There are two broad categories of castings: expendable and non-expendable casting.

As the name implies, expendable castings are those where the mold is temporary. These types of castings include sand casting- ( ductile iron casting / Grey Iron Castings ), investment casting, plastic casting, etc. It should be understood that expendable molds do not necessarily mean inexpensive materials, however; the process refers more to molds that have to be broken to remove the materials cast rather than the single-use molds. There are many materials that can be used for expendable casting molds including concrete, resins, plaster, polystyrene foam and of course, wax (investment casting or lost wax casting).

Non expendable castings involves the use of long-lasting (more or less permanent) molds which do not need to be broken in order to remove the cast material once it has set or cooled. Die casting is probably the most well-known non-expendable casting process known, in which molten metal under high pressure is forced into cavities of steel mold called ‘dies.’ Die casting is suitable for small to medium sized applications.

One of the major advantages of die casting is the ability to use the die repeatedly. However, the die eventually deteriorates due to the high-pressure and high-speed injection of molten material.