The Study Of Edge Defect Characteristics And Formation Mechanism During Turning Of SiCp/Al Composites

It is very difficult to machine Si Cp/Al composites due to the material properties, and the edge quality is hard to ensure after machining the workpiece, many problems will occur because of the lower edge quality during processing, the application of Si Cp/Al composites has been restricted seriously. Therefore, it is necessary to study the cutting properties of Si Cp/Al composites, and finding out the corresponding optimization methods is also needed to be done.In this paper, the finite element simulation and experimental methods have been adoptted simultaneously to study the fracture characteristics and the formation mechanism of edge defects when turning Si Cp/Al composites. The finite element model of 3D oblique cutting Si Cp/Al composites has been established, according to the simulation results, the edge defect formation process has been divided into eight stages. Through the establishment of the static model which contains irregular Si C particles, analyze the stress field under the interaction of particles and the matrix, study the edge fracture characteristics of Si Cp/Al composites further. A simplified model of three-dimensional turning has been built up which is compared with 3D oblique cutting, the relationship between the edge defect sizes and the cutting parameters has been studied and obtain that: the edge defect sizes increase significantly with the increase of cutting depth, increase slowly with the growth of feed, and the spindle speed almost has no influence on the sizes of edge defect. The experiment of turning Si Cp/Al composites also has been carried out and the results have been analyzed, the fracture behavior and mechanism of the composites was analyzed from the view of micro materials and fracture morphology. Study the law between cutting parameters and the edge defect size, and some conclusions had been obtained: the cutting depth and the feed have a certain influence on the edge defect sizes which are consistent with the finite element analysis, the influence of spindle speed is different from the finite element analysis and the reason had been discussed. The mathematical regression model had been built up in order to research the relationship between the cutting parameters and the edge defect sizes deeply, and the application of genetic algorithm also help to find out the optimal cutting parameters to control edge defect. Eventually, the control methods of edge quality had been proposed, such as terminal chamfering method, baffle inhibition method, and the workpiece superposition method.