Research on Total ErrorModel and Error Compensation of CNC Machine Tools

The working accuracy is one of the necessary specifications of CNC machine tools. There are two methods for enhancing the accuracy of machine tools: error avoidance and error compensation. The former method causes seriousrise of the production cost, and the enhancement of accuracy is limited. Whereas using the later method, it is unlimited to the accuracy enhancement. For CNC machine tools, computational real-time error compensationis one of the most economic, effective fundamental methods. Based on the multibody systemtheory, total error model for multi coordinate CNC machine tools, including geometricaland thermal errors is developed. The identification method (22lines, 14 lines and 9 lines method) for the 21 errors of 3-coordinate CNC machine tools, as well as for the 6 errors of rotary coordinate are introduced. By means of software compensation, compensation of geometricaland thermal errors of 3-coordinate and 4-coordinante CNC machine tools are accomplished. Experimentalresults show that the error model is precise and the compensation method is useful.