Geometric Error Measurement for CNC Lathe Based on Profile of Machined Workpiece

This study proposes a measurement and improvement system for the consistency of machined diameter by a CNC lathe with referring the external shape of a machined workpiece. Under the assumption that the external shape of the workpiece is axial symmetrical, the axis of symmetry equivalent to the axial line between the spindle nose and the tailstock can be regarded as the compensatory reference for the straight line motion in turning. This axis in ZX plane can be represented as the successive change of center position of the both external profiles with use of a laser scan sensor traversing in the lathe. For the compensatory machining, the CL data is modified and applied by taking account of the magnitude of machining error from the compensatory reference. As the results of the compensatory machining, the accuracy of finishing has been highly improved as precise as the positioning accuracy of the lathe