Research On The Simulaton Analysis For The Performance Of Mechanical Micre Machining Processes

Micro-cutting is the high precision machining method that is used for machining the small parts. The features to be created by micro-cutting have the dimensions in the range from millimeter level to micron level. Because the depth of cut and feedrate are typically very small in micro cutting, materials show the size effect and the cutting edge shows the negative rake angle effect. As a result, the mechanism of micro cutting is different from that of traditional metal cutting. The traditional machining mechanism and processes cannot well describe the micro machining process. Considering the miniaturization tendency of products, the theoretical study and the cutting performance analysis of micro cutting is needed urgently in order to obtain the effect of cutting parameters on the micro cutting process, to improve the micro machining, and to improve the quality of micro machining.In the paper, the mechanisms of micro machining and traditional metal cutting process are compared and analyzed. Then, the phenomenon particular to the micro machining is obtained. Taking the features of micro cutting into consideration, the geometry model, material constitutive model, the tool-chip separation criterion and friction model are theoretically analyzed and modified based on the finite element simulation analysis of metal cutting. The geometry model and the material constitutive model suited to the characteristics of the micro cutting are established. The two-dimensional orthogonal cutting plane strain model is used by simplifying the cutter as the arc with the cutting edge radius. The modified Johnson-Cook material model and Johnson-Cook model of chip separation criterion are adopted, etc.In the paper, the methodology of finite element analysis is applied. The finite element analysis model is built for micro cutting simulations using the large-scale non-linear simulation analysis software ABAQUS. The size effect, the actual negative rake angle and the minimum cutting chip thickness and the cutting force are simulated and analyzed. Through the research analysis of the simulation results, the main factors affecting the quality of micro machining are identified. The studying results form a solid basis for studying the micro machining mechanism and improving the actual machining processes.By using single element analysis method, the ductile material AISI4340and the hard and brittle material silicon are used in the finite element simulation analysis process.In the analysis, the size effect in micro cutting process is verified, the chip forming process under different cutting rake angles, and the chip shapes under different cutting speed are obtained. Through the simulation analysis, the influence of the rake Angle, the cutting speed and the cutting edge radius on the micro cutting force is obtained. It shows that the larger cutting rake angle can decrease the cutting force, improve the quality of micro machining. The smaller cutting edge radius is helpful to the micro machining process.