ABSTRACT
The automation of machines tools by computer numerical control (CNC) has revolutionized today’s industrial world. This chapter first introduces readers to CNC machining system, its advantages, and limitations; and then covers the role of computer-aided design (CAD) in CNC machining followed by discussions on CNC machining working system, zero systems, positioning systems, open-loop and closed-loop control CNC systems, and the like. Work-part programming is explained by listing/tabulating G-codes and M-codes and by writing syntax statements as well as a real-life part program. The roles of machine control unit (MCU) and processing equipment, in a CNC system, are illustrated with the aid of diagrams clearly indicating a coordinate system. A distinction between the open-loop control and the closed-loop control CNC systems is made with the aid of sketches. Mathematical models for motion control for both open-loop and closed-loop systems are presented. This chapter contains 15 mathematical models, 10 diagrams (including a photograph of CNC machine), 13 worked examples/calculations, and 4 MCQs with answers.
