Research On Evaluation Of Processing Performance Of Five-Axis CNC Machine Tools And Error Tracing Based On Comprehensive Evaluation Method

Evaluation of machining performance of five-axis CNC machine tools in the manufacturing has been a research hot spot, cutting based on specimen is the common evaluation methods. However, mapping relationship between parts and five-axis CNC machine tools is difficult to determine, after error occurring, how to adjust the parameters of machine tools to improve machine tools precision become difficult. Taking into S specimen designed by AVIC Chengdu Aircraft Industrial according to the actual cutting experience as the object of studying, by analyzing the mapping relationship between the S specimen and five-axis CNC machine tools dynamic factors, combining with the multi-level comprehensive evaluation method, building comprehensive evaluation model of processing performance of five-axis CNC machine tools based on the S specimens. According to model, begin to performance of five-axis CNC machine tools evaluating and the source of error studying. The contents of this article are:(1) By the comprehensive evaluation theory analyzing, proposing method on comprehensive evaluation of machining performance of five-axis CNC machine tools. And according to the method, build comprehensive evaluation model on processing performance of five-axis CNC machine tools.(2) According to application characteristics of comprehensive evaluation, building evaluation index system composed dynamic factors of CNC machine tools and error index of S specimen. In order to avoid the influence of the result due to different dimension of error index, introduce the membership function in fuzzy mathematics, using membership to replace the value of index to make comprehensive evaluating. At the same time, contact the methods of subjective and objective to calculate the weight coefficient, which makes up the shortcoming of the single method. Take the fuzzy operator as aggregation function, combine the membership degree vector and weight vector of the index to participate in the process of comprehensive evaluation. Finally, according to the confidence criterion, determine the level of machining precision of CNC machine tools.(3) Based on simulation platform, calculate the error of dynamic factors of CNC machine tools, such as gain, reverse clearance and acceleration and so on. Through analysis different layer milling of S specimen simulation producing error and the error changed the different parameters, obtaining mapping relationship between contour error and parameters, gotten statistical error influencing area of each index and eventually divided into S specimen chief errors of regional distribution. To the S specimen CNC post instruction of the second layer as a benchmark, the region to coordinate specific. Based on the above results, the three coordinate measuring points of the S specimen were optimized.(4) Based on comprehensive evaluation model, the processing error tracing model of S specimen is established. When the evaluation result of the numerical control machine is poor, the error of the system is traced back to the source of the error. Finally the cutting experiment of S specimen of AB cradle and turntable five-axis CNC machine tool is carried out to verify the accuracy of the comprehensive evaluation model and error tracing model.