Modeling And Experimental Study Of Cutting Force In Micro Milling

Microfabrication technology,especially micro milling technology,possesses several advantages such as prominent capability in producing complex 3D geometry,applicability in a variety of workpiece materials and process flexibility.Therefore,it has been widely used in micro-and ultra-precision manufacturing industries.However,micro milling is not simply a downsized form of a conventional milling operation but has its own characteristics,such as size effects,including the minimum chip thickness and material's elastic recovery.In order to satisfy the development of microfabrication technology,it is necessary to thoroughly understand the mechanism of micro milling.In this paper,the numerical modeling and simulating methods are used to analyze the process of micro milling in detail,and then the cutting force is deeply studied in micro milling operation.The main research work is as follows:Calibrating tool run-out.Based on the analysis of tool run-out geometry model,including plain parallel deviating,plain tilting and space tilting,a novel method was proposed to calibrate the tool run-out in micro milling operation.Tool run-out parameters can be determined effectively through analyzing the measured contour variations and phase shifts at different axial sections.Further,the verification tests were conducted to confirm the effectiveness of the proposed method and the reliability of the tool run-out geometry model.Modeling of the cutting force.Based on the modeling process of cutting force in micro milling operation,two core parts of the model were discussed,namely the instantaneous uncut chip thickness(IUCT)and cutting force coefficients.With regard to the IUCT model,the effects of the minimum chip thickness and material's elastic recovery were integrated into the residual surface generated by the previously passing tool tips,and thus a more accurate IUCT model was established.Further,the influence of the above effects on the IUCT was discussed accordingly.With regard to the cutting force coefficients,on the basis of the “orthogonal” to “oblique” transformation theory,the cutting force coefficients was determined by non-linear curve fitting the simulated cutting force extrapolated from 2D orthogonal cutting simulations.Experimental verification of the cutting force model.Based on the established cutting force model,a series of verification experiments were given to illustrate the effectiveness of the prediction model.Then,the effects of feed per tooth,axial cutting depth and tool run-out on the cutting force were analyzed.Further,the role of material's elastic recovery was explored.