Milling Deformation Theory And Prediction Methodologies Research Of Aluminum Alloy Flexible Deformed Component

Aluminum alloy flexible deformed component is widely used in many industrial fields,such as vehicles,aerospace,weapons and so on,for it has advantages of light weight,corrosion resistant,heat resistant,high specific strength etc.However,these components are usually parts with thin wall thickness,weak stiffness,large appearance size and complex structure,on the other hand,in order to reduce the weight of these parts and improve the structural strength and usability of the system,these parts are gradually developing to the direction of lightweight,miniaturization and high accuracy.Therefore,in actual machining process,these flexible deformed components are easy to deform,which is difficult to guarantee the machining precision and machining quality of the product.Based on the theory of metal cutting,methods of theoretical analysis,finite element simulation and experimental study have been used in this thesis to conduct systematic research,which is mainly focusing on machining process simulation and deformation prediction of Aluminum alloy flexible deformed component.The main research work and innovative achievements includes the following aspects:1.Machining deformation theory under coupling effects of fixture system,cutting force and cutting heat is established.Based on Hertz theory,contact models between workpiece and fixtures are established.Based on the principle of minimum total complementary energy and Lagrange energy method,The workpiece-fixture system static model and dynamic model are established.Based on heat source theory,the milling unsteady state heat conduction is analyzed,and the milling heat transfer theory simplified model is established.Based on the flexible multi-body dynamic finite element analysis method,machining deformation prediction model of flexible deformed component is established.Effect of clamping,milling force and milling heat on machining deformation is considered in the prediction model.It provides theory basis for milling deformation simulation prediction model of flexible deformed component.2.The dynamic milling deformation of flexible component and experimental verification is established.The contact model between the workpiece and fixtures is modeled by spring-damping elements.The material removal process of the workpiece is model by the model change function of FEA software.The milling process is simplified.The deformation due to clamping and milling is calculated respectively.The influence of the damping on milling deformation is studied.Milling experiments are carried out.Eddy current sensor is used to measure the milling deformation of the observation points on the workpiece online.The measuring results and the predicting results have good consistency.The effect of layout of fixtures on the machining deformation is revealed.The results illustrate that the closer the triangle formed by the three locators in the primary datum is to an equilateral triangle,the smaller machined surface errors will be.3.The milling temperature-deformation field coupling problems of simplified model for flexible deformed component are simulating calculated.Based on the fully coupled finite element method,the heat source during milling process is treated as surface heat.The thermal load is applied on the simulation model,and the milling temperature field cloud picture and temperature rising curve of monitoring points are obtained.It can be seen from the calculation results that the cutting temperature is mainly concentrated in machining area.Compared to the results of simulation model without thermal load,the internal stress increases markedly.The curve tendency of same location on z axis is consistent.Due to thermal expansion effect,the thinner thickness of workpiece is,the machining deformation induced by thermal stress is greater.But,when the thickness of workpiece gets a certain value,the machining deformation induced by thermal stress is decreasing instead.The temperature change of a point on machined surface of aluminium alloy 6061 flexible deformed component during milling process is real-time monitoring by using the platinum thermometer sensor.The test results and the finite element simulation results have good consistency,thus verifying the correctness of the finite element model.4.Machining deformation simulation prediction key techniques of aluminium alloy flexible deformed component are developed.As a case study,the finish-milling deformation of fitting surface of camshaft frame is predicted.By using the Python language,secondary development of ABAQUS is conducted through scripting interface.By integrating the advantages of ABAQUS/ CAE,INP file and Python language,simulation prediction key technologies of aluminium alloy flexible deformed component are developed.By using the ray method of computer graphics,it is determined whether the cutter tooth is in contact with the workpiece.The face milling force is predicted and applied to the nodes of finite element.The face milling experiment of simplified aluminium alloy 6061 camshaft frame is conducted.It has a good agreement between the measured values and predicted values,so the simulation key technologies are reliable.Therefore,it is realized that the finite element modeling and post processing can be completed rapidly by using the modularly established finite element prediction technologies of flexible deformed component.