Research On Dynamic Error Of Five-axis CNC Machine Based On S-shaped Test Piece Machining Tool Envelope

In recent years,CNC machine tools have developed rapidly towards high speed and high precision,and dynamic error has been paid more and more attention.Five-axis CNC machine tools are widely used.During processing,dynamic errors affect the processing accuracy.The analysis of dynamic error is beneficial to improve the machining accuracy of five-axis CNC machine tools.For the error detection of five-axis CNC machine tools,at present,the test piece is mainly detected by trial cutting,and the size of the error is obtained by measuring it,which is used as the basis for judging the machining accuracy of the machine tool.However,in the actual processing inspection,the principle error and other errors will be introduced,resulting in that the measurement results of the test piece cannot accurately reflect the accuracy of the machine tool.Although a variety of technical means can be adopted to reduce the error of CNC machine tool processing,the influence of the principle error cannot be ruled out.Therefore,this paper studies the calculation method of the contour error of the S-shaped test piece based on the tool envelope surface,aiming to eliminate the influence of the principle error on the final result.According to the S-shaped test piece model,the method calculates the contour error of the S-shaped test piece by collecting the actual positions of each axis of the five-axis CNC machine tool during the machining process.Firstly,the S-shaped test piece is modeled and analyzed,and the theoretical model of the S-shaped test piece is constructed;the kinematics analysis of the five-axis CNC machine tool with double turntable is carried out,the kinematic model of the CNC machine tool is established,and the theoretical motion transformation is obtained.Secondly,the geometric model and analytical expression of the side milling tool are established,and the calculation process of the tool sweep envelope surface is deduced through the side milling machining envelope conditions;for the cylindrical milling cutter used for machining the S-shaped test piece,the tool position file is used to obtain the calculation process.Move the axis surface,and then obtain the envelope surface of cylindrical milling cutter side milling.Then,for the five-axis CNC machine tool in the experiment,when running according to the given finishing code,the data monitoring client is used to collect the movement positions of each axis of the machine tool;the side profile of the test specimen is obtained through the tool position,and the side profile is Compared with the theoretical processing side,the deviation between the actual collected side and the theoretical processing side is obtained,and then the S-shaped test piece is measured by a three-coordinate measuring machine to obtain the contour error.Finally,using the method in this paper,the dynamic error calculation of the Sshaped test piece is carried out in the experiment,and the visual representation of the tool sweep contour under no-load and loaded conditions is obtained,and the corresponding contour error map is calculated.Through the research of this paper,the principle error of the S-shaped test piece during side milling is eliminated,and the dynamic error of the CNC machine tool is more accurate.