ABSTRACT
The difference between machining and the other two primary forming processes is that materials are removed from a general bulk shape to obtain the desired three-dimensional shape. The material is generally removed in the form of "chips," but it may also be removed as fine particles or powder (in grinding or polishing operations), or by dissolving or vaporizing (in processes such as electrochemical machining and electrical discharge machining). The removed material, chips, powders, etc., is difficult to recycle and can become expensive waste materials because of environmental problems. Shearing is a cutting operation that is generally classified as a sheet metal forming operation, because sheet metal parts must be cut out before they are formed, but it is actually a machining operation.
