Machine Controls and Computer Applications in Machining
This article discusses the evolution of computer numerical control and direct numerical control for machine tools. It describes the fundamentals and advantages of numerical control (NC) systems. The article reviews the manual or computer assisted off-line programming methods for programming the tools with the aid of the automatically programmed tool language. It also explains point-to-point and continuous-path or contouring of NC systems and the adaptive systems used for NC.
This article discusses the types of adaptive control (AC) systems for metal cutting according to the AC strategies used. These include adaptive control with optimization (ACO), adaptive control with constraints (ACC), and geometric adaptive control (GAC). The article details the milling and grinding systems based on the ACO strategy. It reviews the fundamentals of ACC systems followed by a description of a particular ACC system for a turning operation. The article also describes the basic characteristics of GAC systems and presents a particular GAC system for the turning of cylindrical parts. It examines the issues in the AC systems such as tool wear/breakage. Trends in the AC systems such as variable-gain ACC systems and integration of adaptive control into CAD/CAM/CIM systems are also discussed.