Thermal Error Analysis And Compensation Of Direct Drive Type A/C Axis Numerical Contral Milling Head

The five-axis linkage machining equipment is the key one of the important industrialsectors which includes aviation, aerospace, mining equipment, power equipment. It isapplied to the processing of complex surfaces in high-precision, high-speed, complex,intelligent machining. Direct drive A/C-axis numerical control milling head is the corecomponent of medium-sized or large-sized five-axis numerical control linkage machiningcenter. The A and C two rotary axes uses direct drive torque motor. And it omits everylinks between the motor and the working components so that the length of the transmissionchain is reduced to zero. Therefore, it has the advantages of compact structure, highaccuracy and low failure rate. In this paper, it studies direct drive A/C-axis numericalcontrol milling head, especially focus on analyzing milling head thermal error, finiteelement thermal analysis, the compensation system established. The main contents are asfollows:(1)According to the A/C-axis milling head actual working conditions, determining theheat source(such as bearings, torque motors, meshing tooth plate, electric) of the A/C axismilling head, analyzing the cooling conditions of the milling head, analyzing the millinghead thermal error. It uses homogeneous coordinate transformation method to establish thedecoupling matrix among direct drive A/C-axis numerical control milling head motionpairs’ the coordinate system, and then establishes a mathematical model of thermal errorcompensation.(2)According to the basic theory of heat transfer, it could determine the correlationcoefficient of the milling head thermal analysis. Milling head model is established byPro/E, and it has a series of simplified which is based on the actual calculation. The modelis imported into the ANSYS finite element analysis software. It uses steady-state analysisand thermal-structural coupling analysis to study the direct drive A/C-axis numericalcontrol milling head, determining the maximum temperature rise’s position and thermal deformation when the milling head reach thermal balance in the work.(3)According to Siemens840D numerical control system, it builds a thermal errorcompensation system. Using temperature sensors to collect and process errors, importingthe thermal error model to thermal error compensation system. And then it will achievedirect drive A/C-axis numerical control milling head thermal error compensation.Above all, the method of the direct drive A/C axis numerical control milling headthermal error analysis and compensation can provide research ideas and methods ofthermal analysis and compensation. It is of important significances to increasing controltechnology equipment manufacturing capacity for independent innovation.