DNC Method for Flatness Reduction by Machine Tool Error Compensation in Planning Processes

Abstract

Milling is a widely used manufacturing process with the main purpose of generating high precision mechanical components of shapes and sizes given by the numerical control programmed cutting tool trajectory. These mechanical components frequently needs the application of milling operations in order to satisfy the technical specifications that corresponds to their dimensional, geometrical and surface quality requirements. For that reason, the effects of different factors such as cutting tool dynamics, fixturing system design, workpiece material behaviour and applied cutting forces on the desired dimensional precision must be studied, as well as cutting tool and machine tool performance. In this work, the relation between machine tool inaccuracies and geometrical tolerances is analyzed, and a methodology is proposed for improving flatness in planing operations by the correction of imperfections detected in cutting tool displacement according to machine tool axis. These machine tool error correction methodology could be implemented in the current CAD/CAM/CAPP techniques as a means of increasing the milling process performance by identification and correction of CNC milling machine imperfections. The deviations in machine tool displacement during cutting process are identified by metrological analysis, and a modified trajectory for cutting tool is defined by direct numerical control (DNC) from systematic error compensation in machine tool.