Study On Micro Milling Force And Process Of7075-T6Aluminum Alloy

Today,with the intelligent products used widely,the demands ofmicro-precision parts are becoming more and more diversified in all fields,andmicro-mill is becoming a hot spot home and aboard because of itsadvantages.Compared to other micro-fabrication techniques,the merits ofmicro-milling are as follows:fabricate micro-components with3D free formsurfaces,various engineering materials and low environmental requirements.Butbecause the fine products deburring process is not mature for themicro-milling,and the shape is critical,different optimized micro-millingparameters are required for different processing materials.Because ofthis,according to the micro-milling machining mechanism,the theoretical modelof micro milling force and the ABAQUS finite element simulation model areesTablelished,and the micro-milling experiment system is built based on HASSVF-2machine tools,so that the experiments of micro-milling with differentcutting parameters can be carried on.Finally,the experimental results ofmicro-milling are compared with theoretical and simulation models in order toverify the feasibility of these models.The influence of process parameters on the micro-milling force and the micro-groove top burr size is studied based on themicro-milling test of the7075-T6aviation aluminum alloy, which provides thebasis for the optimization of micro-milling parameters. The main contents andinnovations consist of these parts:（1）Size-effect considered finite element analysis for cutting forceprediction in micro-end milling processThe micro-milling for7075-T6aviation aluminum alloy is simulated byusing the finite element software ABAQUS/EXPLICT.The strain gradientplasticity theory is introduced into the constitutive equation of the7075-T6(J-C)Johnson-Cook aluminum alloy in order to describe the deformation behavior ofthe material during micro-milling and calculate the strain rate in the process ofmicro-milling.The characteristics of the size effect of micro-milling aresimulated by the modified J-C constitutive model.The stress-strain-temperaturecurve of the modified J-C constitutive model is plotted by MATLAB and thedata is imported into the ABAQUS software before the finite element simulationof micro-milling process considering the size effect phenomenon.Therelationship among the stress,force and the radius of the cutting edge of themicro-milling cutter is studied by the simulation of2D finite element simulation,and the experimental results show that the stress and force increase with thegrowth of the cutting edge radius.The relationship among the micro-millingforce,spindle speed,feed per tooth and axial depth of cut is studied by3D finiteelement simulation software.These simulation studies show that micro-milling force decreases with the growth of spindle speed,and with the increase of feedper tooth,this figure experiences an upward trend after decrease firstly,butmicro-milling force grows when the axial cutting depth increases.（2）Cutting tool running out considered theoretical analysis model forcutting force estimation in micro end milling processConsidering the influence of cutting tool deflection in the process of micromilling,a new model for calculating the transient cutting thickness isesTablelished.This calculation model can reflect that the cutting tool rotationangle varies from transient cutting thickness.After comparing several cuttingthickness models,the fact that the cutting thickness model of the tool deflectionis more close to the real situation is concluded.The cutting thickness is appliedand the effects of ploughing force,flow stress and elastic recovery is consideredin the calculation of the micro milling force.A theoretical model of micromilling force based on the micro milling characteristics is esTablelished.Finally,the micro milling experiment of the cutting tool with the0.1mm Rijin cuttingtool is carried out.The experimental values of the micro-milling force arecompared with the theoretical values under the same conditions in order toverify the possibility of micro-milling force theory model considering the sizeeffect and the impact of the tool deflection.（3）Research of micro-milling process parametersThrough the orthogonal test by using the0.1mm Rijin milling cutter,theinfluence of micro-milling parameters on the micro milling force,torque and the slotted burr are studied,so as to reduce the micro-milling force as well as theslotted burr by optimizing the process parameters.