The Study Of The Formation Mechanism Of Edge Defects During Milling Of SiCp/Al Composites

Since the Si Cp/Al composites have the characteristic of physical and mechanical excellently, so it is used in many fields widely. It influences the development of science and technology and also the national defense. But the edge defects occur much more easy during the manufacturing process due to the existence of Si C particles. Especially in the milling process, the edge quality is even worse.In this paper, a multi-particle micro finite element model with a random particle distribution in Si Cp/Al composites was developed using ABAQUS software. The formation mechanism of edge defects near the exit of orthogonal cutting was analyzed. The results indicate that both the brittle fracture of Si C particles and the plastic flow of Al matrix occur in the process of the edge defects formation. Additionally, the cutting speed has little effect on the sizes of edge defects but the cutting depth has a significant effect on the height and length of edge defects. The numerical results were also compared to the orthogonal cutting experimental data and found to be in reasonable agreement.In this paper, the mathematical model of the arbitrarily equivalent width of milling layer was established and it was also established the finite element model. The results indicate that the formation mechanism of edge defects by milling as same as the two-dimensional orthogonal cutting process basically. Additionally, with the increase of milling depth, the length and height of edge defects were also increasing. however, the width of edge defect was unchanged. With the increase of feed per tooth, the length and height were changed obviously, but the width was not increased. The milling speed had no effect on edge defects obviously.The experiment research indicates: firstly, in the condition of down milling, feed per tooth and cutting speed had no an influence on the quality of the edge and the entrance of the edge, but it had a great influence on the exit edge. With the milling depth increasing, the quality of the edge and the entrance of the edge were more worse, but it had no effect on the exit edge. Moreover, the size of defects obey the normal distribution. Secondly, in the condition of up milling, the more increasing of the feed per tooth, the more much worse of the quality of the edge、the entrance and the exit. With the milling depth increasing, the quality of the edge、the entrance and the exit were more worse. The milling speed had a little affect on the fluctuations of the quality, moreover, the edge quality were all very poor. No matter what kind of cutting conditions, under the up milling, the defects will be produced in the corners of the workpiece outlet. Moreover, the size of defects obey the Rayleigh distribution.No matter what kind of milling method, the average particle size were 60μm and 20μm would produced a good quality than the average particle size was only 60μm, under the same condition of milling parameters.