Finite Element Simulation Of Micro Milling Process Of Aluminum Alloy 6061

With the increasing demand for micro parts,Micro milling operations are able to fabricate small parts with complex three-dimensional features,which are widely used in electronics,biotechnology,aerospace and other fields.However,there are several critical issues associated with micro mechanical machining operations which are different with conventional milling.Because of the small diameter cutter,the edge radius of micro milling cutter is comparable in size to the chip thickness,there exists minimum chip thickness when the uncut chip thickness is below the edge radius.Besides,there is also a large amount of issues such as run out,serious tool wear and so on.The micro milling process is not easy to observe,it needs external amplification equipment,and the cost is very expensive.The finite element simulation technology has the advantage of low cost and can obtain the parameters which can’t get from experiment,so it catches the attention of scholars,using the finite element method to study the mechanism of micro milling has become a popular issue.In this paper,the mechanism of micro milling process is studied using the finite element method.The main research contents are as follows:(1)The research background of micro milling both at home and abroad are analyzed.Micro milling as a new form of processing exists many problems,scholars mainly concentrated in four aspects,they are the chip forming and minimum chip thickness,the dynamical modeling of cutting force,the tool wear of micro milling cutter and the finite element simulation of micro milling process.All these factors will affect the final quality of workpiece manufactured by micro milling process.(2)The theory of finite element simulation-rigid plastic finite element method is analyzed.Rigid plastic finite element method is based on the generalized variational principle,in which the admissible velocity field is obtained under the boundary conditions.It is also the minimum value of the functional.Then the physical parameters such as stress and strain can be solved according to the basic mechanics relation.(3)The three-dimensional finite element model of micro milling is established.Detailed description of the modeling process,including the material model,meshing strategy,friction model,separation criteria and the heat transfer parameters are illustrated.Then this paper analyses the influence of the cutting force and chip formation through a series of process about the simulation of the micro milling cutter with different edge radius in the same process.(4)The theoretical cutting force model of micro milling is established.The cutting force coefficient is calculated by neural network fitting.The relationship between cutting force coefficient and edge radius and the uncut chip thickness is obtained.Then the comparison of the calculated micro milling cutting force and 3D finite element simulation results is analyzed,The finite result has a good consistent with calculated value.(5)The influence of different factors on micro milling process is studied by finite element simulation.Firstly,the up micro milling and down micro milling are analyzed by three dimensional simulations.Then,the influence of spindle speed,feed rate and axial depth of cutting on micro milling cutting force is studied by single factor variable method.Finally,experiments are carried out to measure the micro milling cutting force in different cutting conditions,and the cutting force is compared with the simulation results.