In terms of annual dollars spent, Machining is the most important of the manufacturing processes. Machining can be defined as the process of removing material from a workpiece in the form of chips. The term metal cutting is used when the material is metallic. Most Machining has very low set-up cost compared to forming, molding, and casting processes. Machining is necessary where tight tolerances on dimensions and finishes are required. To perform the operation, relative motion is required between the tool and the work. This relative motion is achieved in most machining operation by means of a primary motion, called “cutting speed” and a secondary motion called “feed.” The shape of the tool and its penetration into the work surface, combined with these motions, produce the desired shape of the resulting work surface.
Machining can be categorized in 5 general processes: