Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting materials are usually metals or various time setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. Heavy equipment like machine tool beds, ships' propellers, etc. can be cast easily in the required size, rather than fabricating by joining several small pieces.
Lost wax investment casting can produce a variety of complex and intricate parts with excellent tolerances. Lost wax investment casting is used to produce parts that require tight tolerances with thinner walls and exceptional surface finishes that require very little after process finishing.
Sand casting can be readily produced in nearly any ferrous or non-ferrous alloy. Some other casting processes will melt and pour super-alloys in a vacuum, but that is not typically done as a sand casting. Some materials cannot be “worked”, and must be produced as a casting. The relatively low cost of tooling makes sand casting a process of choice for lower volume needs. Patterns do wear so the material selected for the pattern (typically wood, plastic, or metal) will depend on the expected usage quantity of the part being produced. Though not necessarily cheaper in the short run, the use of machined (or “patternless”) molds may be a cost-effective option for components with expected lower usage over a longer period of time.
Die casting is the foundry production process thanks to which a metal, such as aluminum, is injected at high pressure into a metal mold and finds its permanent shape. The advantages of aluminum die casting are many, some of which are a consequence of the characteristics of the material. The advantages of aluminum are lightness, resistance to corrosion, thermal and electrical conductivity, workability and recyclability, and are added to the die-casting process, which guarantees further qualities. Some advantages of aluminum die casting concern the final product, others the production process.