ABSTRACT
In manually operated machine tools, the process starts from the part drawing. Then the operator determines the manufacturing strategy, sets up the machine, selects the proper tooling, chooses the working conditions, and manipulates the machine controls to make the part (Figure 18.1). It is accordingly clear that using the manual machines involves a considerable number of decisions that in¨uences the quality of the nal product. The level of quality obtained depends on the skill and the concentration of the operator. When batches of identical parts are required, it is preferable to use methods that do not depend on the operator skill. In this regard, automatic machines are mechanically controlled by cams and mechanisms. These machines are preferable for producing large batches; however, they are expensive and time-consuming to reset. Using numerically controlled (NC) machine tools, the control of the machine is not performed either by the operator or by cams and mechanisms. NC machines use a series of binary coded numbers that are interpreted by an electronic system. By using the NC technology, each component is an exact replica of the data contained in the NC part program, and high levels of accuracy, repeatability, and uniformity are achieved.
