The Study On The Influence Of Thermal Factors On Spatial Accuracy And Compensation Technology Of NC Machine Tool

With the development of manufacturing industry,the requirement of CNC machine tools accuracy is getting higher and higher.And the reducing of accuracy caused by thermal error is becoming more and more prominent.Thermal error compensation is an efficient way to solve the problem.In this paper,the XHK715 of 3-axis vertical machining center equipped with HNC-8 is taken as the research platform.Through the measurement and analysis of the error of the machine tool under different temperature,the influence of temperature on the error is studied.The thermal error compensation models are established and some experiments are conducted to verify their compensation effect.The main contents of this paper are as follows:Measuring platform for temperature of CNC machine tool is designed.The method of cluster analysis is combined with the main factor principle to optimize the temperature measuring points.And screw nut seat and bearing seat are selected to be the key temperature measuring points.After that the measuring platform for temperature of CNC machine tool is built by using the plan----HNC-8 + HIO-1075 + PT100.The concept of influence degree is introduced to analyze the influence of temperature on errors of CNC machine tool.And the results show that temperature has the greatest influence on the positioning accuracy of the moving axis,and the influence degree on straightness and angle varies with the moving axis.Furthermore,some thermal error compensation models are built using the multiple liner regression analysis method.At last,by using the error compensation module of HNC-8 system,the thermal error compensation models are verified.The results show that the compensation effect of each model is very significant,in which the positioning error of X/Y axis and the straightness error of X/Z axis are reduced by more than 90%.