Milling Deformation Analysis And Error Control Of Machining On Automobile Engine Cylinder Block Surfaces

Automobile engine has the features of thin wall and multi-hole and its structure is complicated.In order to solve the problem of milling deformation of the automobile engine,the paper use the method of simulation and experiment to analyze the clamping deformation and milling deformation of automobile engine cylinder during the top surface machining and the profile error control measures of milling deformation are put forward.The main contents of this research include the following three aspects.Firstly,the deformation caused by clamping in engine block milling is analyzed.Based on the structural features of the N12-type cylinder block and the characteristics of the 5-axis CNC milling process system,this paper analyzes the fixture layout from the aspect of location mode and clamping device.The value of clamping force of the engine cylinder block is determined through the analysis of hydraulic clamping system.The finite element model of clamping deformation is established by softwares of Pro/Engineer and HyperMesh.And the model is solved by the software of ANSYS.The deformation of the top surface of the cylinder block based on different clamping force,different clamping position and different support position is simulated by finite element.The simulation results show: the clamping force,clamping position and support position have different effects on the deformation.Compared with the effect of changing the support position,the influence of changing the clamping position is greater.Compared with the effect of changing the clamping force,the influence of changing the support position is greater.Secondly,the deformation caused by cutting force in engine block milling is analyzed,and the relationship between the deformation of the top surface of the cylinder block and the profile is established.Through the orthogonal experiment,the cutting force model of milling cylinder block is established and provides the required milling force values for the simulation of the top surface deformation of the cylinder block.The deformation rule of cylinder block top surface is analyzed by deformation simulation of milling cylinder block,and the relationship between the milling deformation and the profile is established.Finally,the corresponding strategy of error control is put forward from the point of view of machining optimization and compensation,aiming at the error control of the profile of the top surface of the cylinder block.Experiments show that the deformation error control strategies of cylinder block milling can effectively reduce the profile error of cylinder block.