Research On Geometric Error Measurement And Modeling For Multi-Axis NC Machine Tools

To improve the manufacturing accuracy, this paper takes TH5656five-axis high speed machining center of table-tilting as the studying object to build the geometric error modeling, measure error and identificate the NC machine tool,then the test piece. With the measurement of the geometric error and the precision modeling of the multi-axis NC machine tools is built, and then their errors transferability rules from the part to the machined workpieces are analyzed. Based on the work done before, the error compensating software is compiled successfully, and to verify the accuracy of the geometric error model, two test-pieces are processed based on the software error compensating. The main works are as follows:1. Transformation matrixes is used to describe the relative position and gestures between any two body in MBS. After that, the paper established the geometric error modeling for TH5656five-axis NC machine tool.2. The scheme of detecting and distinguishing the geometric error is designed, and laser interferometer and photoelectric auto-collimator is used to detecte and distinguish the geometric21geometric errors of translational axis. And the paper calculated the linear positioning error and repetitive positioning error.3. This paper gives the idea of software error compensating and written the error compensation software, and predicted machining accuracy and compensating error. The software is off-line compensated by modifying the G code to realize the compensation target.4. Verification process is carried out by experiment. Respectively the original G code and the compensated G code is used in the test-piece surface finish machining, then the points data of the test-piece surface is collected by a coordinate measuring machine. Finally, this paper analyze the surface differences, verify the correctness of the proposed method and work.