Machining is a material removal process (like cutting, grinding, etc.) that uses some sort of cutting tools to produce the desired size and shape in an object. The object is typically cut from a larger piece of stock, which is available in a variety of standard shapes.
Casting is a mechanical engineering process in which materials in a molten form are poured into a prototype called a cast or a mould. Once the liquid solidifies, it takes form of the desired shape. Casting is therefore used as a mass manufacturing process with minimal wastage (as compared to machined components) while achieving uniform properties. Casting allows mass manufacturing of complex parts economically and efficiently. The materials used for casting vary according to the need of the mechanical element to be manufactured. Casting is one of the important procedures to manufacture mechanical elements; the other procedure being machined components. There are various casting processes in use today, including ductile iron casting, sand casting, die casting, etc.
Castings are used to manufacture numerous engineering components like windmill hubs, gear cases, industrial valves and valve bodies, rotors, flanges of different types, pump housings, etc. The list of machine castings is almost never ending.
Machined castings involves many aspects of engineering – starting with a proper drawing of the machine to be cast, the selection of the material and of course choosing the right casting process. With advances in technology, especially FEA (Finite Element Analysis), CAD and CAM, optimizing the design of the machine has never been easier. However, selection of the proper metal / alloy for the machine casting is a matter of engineering skill and experience. Here are a few criteria for selection of the casting process:
- The number of castings
- Material used for casting
- Manufacturing cost
- Tolerance (dimensional accuracy) desired
- Surface finish required
All the casting processes have their pros and cons.
India is one of the leading casting manufacturers in the world. With more than 50 years of experience, the machine casting industry in India has the resources, skills and the experience to make it a global player in this field.