| Computer Numerical Control machine (CNC machine) often regarded as "original engine", which has a direct impact on the development of the manufacturing industry. Five-axis CNC machining represents the most advanced productivity level of the country. The accuracy is the only professional evaluation standard of CNC machine tool, so each CNC machine tool manufacturer has been making endeavor to reduce errors and to improve accuracy. Based on the above reasons, the type of errors and causes analysis, reasonable error modeling methods, the effective test and compensation, all of them have the most important significance to the accuracy of the CNC machine.There are 2 major salient error sources of CNC machines. One is caused by manufacturing defects and assembly shift, called geometric error. The other is kind of thermal error, which is caused by thermal deformation. This article mainly studied about methods to improve the accuracy of the CNC machine, by means of making integrated modeling analysis which adopts error modeling methods based on multi-body dynamic. With further measuring the numerical of error modeling by using metrology equipments such as dual-frequency laser interferometer and ball bar, we finally sort test data for error compensation to achieve our ultimate aim, improving the machine working accuracy.In order to further validate the effectiveness of the error modeling, measurement and the compensation method, this article takes the HTM40100h horizontal car milling composite processing center as experimental subject, and uses the X, Y, Z axis three straight spools and B,C axis, two rotors to build comprehensive error model and data measurement. Then make offline compensation with the data result via 840D numerical control system, and optimize the CNC machining contour error with the online control of the feed speed. From the final control rendering, the method controls the comprehensive error of CNC machine optimally, and the machining precision is significantly improved. |
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