Reasearch On Measurement,Modeling And Identification Of Volumetric Thermal Errors Of Horizontal Machining Center

As the development of precision and high precision machining technology,the proportion of thermal error caused by the heat source inside and outside in total error of the machine tool is becoming higher and higher.In order to reduce effect of the thermal error in the machine tool,this paper does research on the thermal error detection,simulation and modeling for finding the relationship and law between the thermal deformation of the large-scale structural functional parts and the volumetric thermal distortion and providing reliable data support for the thermal error compensation.A mathematical model of the thermal deformation of the guide rails and the individual thermal error of each axis is proposed through the rigid body kinematics theory.Then this paper establishes linkages between the single thermal error and the end space error mapping based on the theory of vector.This modeling method is applied to JIG630 precision horizontal machining center,the thermal deformation data of each main functional part is analyzed and the thermal deformation of the guide is changed by the multiple linearity.The distribution of thermal volumetric error in the machine tool is obtained after bringing the result into the model.In order to solve the problem of dissatisfaction with the rank of thermal error identification equations,the individual position error and angle error of each axis are identified step by step.Firstly,the nine-line method is used to identify the positioning error and the straightness in each axis,then the thermal error hypersteady equations with the angular error polynomial coefficients as the variables are established through combining with the spatial thermal error measurement data,Finally,the angle error of each axis can be calculated by solving the thermoacoustic uncertainty equations.On the other hand,the thermal stability coupling analysis of the whole machine is carried out based on using DOE module of Workbench to changing the position of each parts in Creo,then the simulation results of the spatial thermal error are obtained.Thus the individual error of each axis in JIG630 precision horizontal machining center can be identificatedIn order to accurately grasp the distribution of thermal error in the working space,this paper designs the 3-D space thermal error detection device based on the R-test,and optimizes the parameters of the measuring angle and the size of the measuring plate.In addition,in order to further improve the accuracy of the device,the measurement error is compensated by means of experimental calibration.Finally,this paper examines the thermal performance of JIG630 through the independent research and development thermal error detection device,deformation detection system and other instruments which include the thermal sensitivity of the machine temperature,thermal deformation and space terminal thermal error.Thus the individual thermal error can be identificated based on the experimental results which can provide reliable data support for the thermal error compensation.