The analysis for the position accuracy of machine tools based on comprehensive errors of the ball screw

The ball screw is regarded as the main transmission part of the NC machine tools and its accuracy is very great influence on the processing error of the machine tools.Analyzing various kinds of errors of the ball screw synthetically,the load error,pitch error,thermal error,manufacture and installation errors are the main errors.They are computed and analyzed by the theory and method of mechanical properties and the influence degrees to the accuracy of ball screw are gained.The homogeneous transfer matrix for position accuracy of machine tools is obtained by synthesizing the all the errors.All parameters of matrix can be measured through the instrument in practice.By inputting the concrete matrix into NC system of semi-closed loop machine tools,the same machining accuracy as closed loop machine tools can be obtained.So,the high accuracy can be obtained with low cost.