Workpiece Fixture Planning Method for Continuous Multi-Axis Machining with Consideration of Motion on Translational Axis

Abstract

This study deals with a new method to plan fixture conditions of a workpiece on a trunnion table in a continuous multi-axis-controlled machine tool. The motion of the translational axes on the machine tool is usually greatly affected by machine tool structure, tool posture change, and the fixture conditions of the workpiece. However, in a conventional CAM scheme, the fixture conditions are designed to be determined separately. Furthermore, a method of planning these conditions to reduce total machining time has not been proposed. Therefore, this paper proposes a new planning method for workpiece position and posture on a trunnion table. The proposed method consists of two different steps. In the first step, a large number of fixture condition candidates are assumed automatically. In the second step, geometric calculations are executed to estimate the distribution of features in terms of motion on the translation axes. The second step is equivalent to the repetition of coordinate transformations in the conventional post process software. In the developed prototype system, parallel processing technology known as GPGPU is introduced to drastically reduce calculation time. The developed system can visualize differences in total travel distance, maximum velocity, and total machining time for each candidate. These results can assist a CAM operator in selecting the optimal fixture conditions in a short time.