In metalworking, casting is the process of setting molten metallic material in a pre-designed mold. Once the molten metal cools, it becomes a solid metal object in the desired shape. Casting can be achieved with a wide variety of metals, and various materials can be used to form the molds and other equipment. Because casting involves variables, like molten metal materials and mold size, it is important to use the utmost safety precautions during the process and to ensure that trained specialists to operate the molding instruments.

Casting Basics
The basic method of fabricating products by casting is the following ten step process:

1. Pattern development;
2. Mold preparation;
3. Metal melting;
4. Metal pouring;
5. Cooling period;
6. Part removal;
7. Clean up process (removing excess metal from piece, such as risers, etc.);
8. Heat treatment;
9. Optional upgrade treatment;
10. Miscellaneous finalization processes (machining, etc.).

In casting, a mold is used to define the shape desired for the final product. An easy standard example to illustrate this is tin soldiers. Tin soldiers are made with a hollow metal mold that has a mold cavity patterned around the shape of a small soldier. The mold is in two different pieces that, when connected, form the entire pattern. The mold is closed so that the entire pattern is sealed except for a small reservoir area, called a riser, into which molten tin is poured. The mold is set aside for a drying period, and as the tin cools, it solidifies. Once the tin is completely solidified, a fully formed tin soldier is produced. A mold that is filled with molten material is one of the more common casting procedures, but other methods do exist.

There are various types of casting, categorized by the type of mold used. The names used reflect the permanence of the different kinds of molds used: expendable and non-expendable.

Read more: Casting Need to Know Guide