Method of geometric error compensation for
large CNC milling machine
XIONG Ping
（Technology Department，CSR Zhuzhou Electric Locomotive Co.，Ltd.，Zhuzhou 412001，China）
Abstract：Aiming at geometric error of CNC milling machine，the modeling of milling machine's geometric error was established. Thegeometric error sources of the milling machine were analyzed. With the high accuracy and large scale measurement and data processingcapability of the API（T3）laser tracker，the identification algorithm of the three axis's displacement error，angular displacement error andperpendicularity error were put forward，geometric errors of CNC milling machine were accurately identified by laser measurement andcalculation. Milling space geometric error mathematical models of CNC milling machine was established. Based on the milling machine'sgeometric error compensation model，the geometric error compensation software was developed by using object oriented programmingmethod. The results indicate that the plane machining accuracy is improved 50.77%，which can verify the effectiveness and accuracy ofcompensation method.
Key words：CNC machine tool；error identification；laser tracker；error compensation