Research On Comprehensive Evaluation System Of Processing Properties For Five-axis CNC Machine Tool Based On The “S”-Shaped Test Piece

Five-axis CNC machine tools plays an irreplaceable role in the processing of aerospace thin-walled parts. The method of cut standard parts is general used for detecting the precision of CNC machine. Several standard parts are widely used such as NAS979, which is proposed by NASA, and NCG2004 proposed by Germany, but there are still some problems to evaluate the processing precision of five-axis CNC machine. A new standard part called “S”-shaped Test Piece, which is proposed by Chengdu Aircraft Industrial(Group) Co., Ltd., has been widely received because its’ good performance in the detection of five-axis CNC machine.Taking “S”-shaped test piece as research object, the mapping between contour errors of “S”-shaped test piece and parameters of motion axes is researched in this thesis. The evaluation index is extracted and the evaluation model of processing precision of five-axis CNC machine is established, an evaluation system is also developed based on this model. The main contents are shown as below:1. Several parameters that have great impact on the processing properties of CNC machine are selected. Simulation platform is used to determine the mapping between the parameters and the error-sensitive areas on “S”-shaped test piece’s surface. The comprehensive evaluation index is extracted in error-sensitive areas, and the layered evaluation index system is established based on the affiliation.2. According to the characteristics of the evaluation index system, the index weights are calculated according to Rank Correlation Analysis in every index layer, the actual value of indicators is fuzzed with membership functions, and an appropriate fuzzy operator is selected for fuzzy synthesis. Finally, a model of comprehensive evaluation of processing properties for five-axis CNC machine tool based on the “S”-shaped test piece is established, and Matlab software is used to program the comprehensive evaluation algorithm.3. Taking the model as foundation, the client of system of comprehensive evaluation of processing properties for five-axis CNC machine tool based on the “S”-shaped test piece is developed by Matlab-C# combined programming. ASP.NET language is used to program the website of comprehensive evaluation system and SQL Server is chosen to be the system database. The comprehensive evaluation system not only could assess the processing properties of CNC machine, but also could analyze and extract the most important parameters during the processing using the contour data on “S”-shaped test piece’s surface given by CMM. The evaluation results provide a basis for the adjustments and maintenance of five-axis CNC machine.