Size optimization for CNC gantry milling machine of high speed railway turnout
                 ZHANG Yu1，LI Shenhua1，LI Wei1，XI Xinghua1，ZHANG Chaojie1，GUAN Yingjun1，LV Qingtao2

(1.School of Mechatronic Engineering，Changchun University of Technology，Changchun 130012，China; 2.Shanghai Tianming Information Technology Co.,Ltd.,Shanghai 201499,China)

Abstract: Aiming at the problem that the base frequency of CNC planer milling machine of high speed railway turnout is low, taking the machine tool as the research object, the dynamic characteristics of its main structure were studied, and a dimension optimization method based on sensitivity analysis was proposed. Through modal analysis and harmonious response analysis of the main structure of the machine tool, the first ten order natural frequency, vibration mode and amplitudefrequency response curve of the machine tool were obtained, and the weak links of the machine tool structure were found. Then the sensitivity analysis of the machine tool was carried out. According to the sensitivity degree of each parameter to the quality and natural frequency in the analysis result, the key size of the machine tool structure was selected, and then the key size of the machine tool was optimized. The results indicate that after optimization, the natural frequency of the machine tool is improved, and the resonance frequency is avoided successfully, which meets the design requirements of the machine tool.

Key words: high speed railway turnout; CNC gantry milling machine; modal analysis;harmonic response analysis; sensitivity analysis; size optimization