Study Of Thermal Characteristics On Key Components Of Boring-milling Machining Center

Following the development of machining for higher degrees of automation and higher precision,the demand of the accuracy of machinery are becoming higher.But the machining accuracy is restricted by technological system error,and force deformation and thermal deformation are the major error source of them all.In the article,the key components of boring-milling machine center including the feed system and the boring system are taken as research subjects,and the temperature distribution and deformation law are achieved by thermal-structural coupling analysis.Then rational optimized measures are put forward based on the analysis results,and the boring accuracy has been improved.The specific content is as follows:1.Based on heat transfer theory and the research of machine structure,the heat transfer mechanism and heat source of machine center are analyzed,and the heat generation and convective heat-transfer coefficient of feed system and boring system in boring processing are calculated.2.The temperature field and deformation law of feed system can be carried out by thermal-structural coupling analysis.Then we can get the main heat source and the influence of the deformation in three directions on the machining accuracy.According to the analysis results,using hollow screw–pass the water-cooled to decrease the deformation is proposed.Moreover,the flow rate of coolant is determined by theoretical analysis and finite element simulation.3.By contrasting the results obtained from static analysis and coupling analysis,the main factors affecting the deformation of boring system in three direction can be got.And the curves between the deformation in every direction and stroke distance of ram is obtained by coupling analysis of the boring system when the ram in different strokes.4.A new compensation method that hydraulic pull rods is put forward to solve the problem of boring error caused by the deformation of system and the compensation device is designed.What is more,the functional relations and curve between pull rods compensation forces and stroke is achieved by theoretical calculations?finite element analysis and polynomial least squares method.Verification by finite element analysis shows that boring accuracy after the compensation satisfies the requirement of machine tools.