As geometry of machined parts becomes complex the demands for more precise and faster machining using advanced computerized numerical control (CNC) are increased. Especially, recently improved computing power of CNC enables the implementation of the complicated control algorithms. Consequently a variety of intelligent control algorithms have been studied and implemented in CNC. This paper reviews the recent progress of control technologies for precision machining using CNC in the area of interpolation, contour control and compensation. In terms of interpolation several corner blending methods and parametric curves are introduced and the characteristics of each method are discussed. Regarding contour control algorithms recently developed multi-axis contour control methods are reviewed. Latest research efforts in compensation algorithms for geometric, thermal and friction induced errors in CNC machining are introduced.

CFRP (Carbon Fiber Reinforced Plastic) and CFRP-metal stacks have recently been widely used in the aerospace and automobile industries. When CFRP is machined by a brittle fracture mechanism, defect generation behaviors are different from those associated with metal cutting. The machining quality is strongly dependent on the properties of CFRP materials. Therefore, process control for CFRP machining is necessary to minimize the defects of differently manufactured CFRPs. In this study, defects in drilling of CFRP substrates with a variety of fiber directions and resin types are compared with respect to thrust force. An experimental study on material interface detection is carried out to investigate its benefits in process control.