Control Systems of a CNC

Point-to-Point System

CNC controls might be either a point-to-point or continuous path system. The point-to-point (PTP) control moves towards the tool to the programmed point, in general in rapid traverse, without engaging the work piece. The PTP system is also called as the positioning system because its exact tool path usually may not be controlled. PTP tool path carry one of the three modes: axial path, 45^o line and linear path. Given figure represents these three modes.

                                                                         Figure (a) : Axial Path

                                                                 Figure (b) : 45^o Line Path

                                                                   Figure (c) Linear Path                                                                                       

The PTP systems are typically utilized in punch presses, drilling machines, and spot welders, which needs positioning in the XY plane in quick traverse mode & executing machining in Z-axis direction. Figure depicts the process.

                                                                                    An Application of a PTP Control System

PTP systems are easy to maintain and less costly.