Method of Five-axis Tool Radius Compensation Based on Post-processor

Abstract

In order to solve the problem of tool radius compensation in five-axis machining for the CNC systems without the function of five-axis tool radius compensation, a method of five-axis tool radius compensation based on post-processor is proposed. First, the basic principle of five-axis tool radius compensation is investigated. For three types of cutters(i.e. ball-end cutter, flat-end cutter, and torus cutter), tool radius compensation direction and vector equation of compensated cutter location(CL) point are derived, respectively. Second, a five-axis CNC machine tool with rotary head and table is used as an example. In terms of the relation equation between CL data and machine control data and vector equation of compensated CL point, a relation equation between compensated CL data and machine control data will be obtained. Then, a post-processing software with the function of five-axis tool radius compensation is developed using Visual C++ 6.0. And the post-processing software not only generates the compensated CNC program directly, but also generates the CNC program with macro variables of tool radius compensation. Finally, an aero blade surface is machined, and the machining process is simulated by using VERICUT software. Simulated results verify the correctness and effectiveness of the proposed method. Accordingly, the proposed method can easily implement the function of tool radius compensation for the CNC systems without the function of five-axis tool radius compensation, and avoid the complicated process that when the cutter radius changes, the programmer must return to CAM system to generate new tool paths and post-process CL data again. Further, the proposed method can shorten the total machining time of parts and enhance the reusability of CNC program, and will be widely applied in practice.