The Influences Of Cutting Parameters On SiCp/Al Composite Materials

Si Cp/Al composite materials with their excellent mechanic performance have become a new type of material and been widely used in the machining and precision ultra-precision fields including aeronautical and space technologies, medical devices, laser electronics etc. However, due to the existence of reinforcing particles in materials, inner stress becomes uneven, and composite materials are prone to crack, eventually evolved into edge defects in the entrance and exit of workpiece. Edge defects are key obstacles in the application of Si Cp/Al composite materials, because of mutability and vigorous randomness of size and morphology. This article, based on the present situation, explores influences of cutting parameters on Si Cp/Al composite materials processing edge defects, and provides more valuable reference for the following mechanical processing. The main contents and innovations of this article are as follows:1.Influences of cutting edge radius on Si Cp/Al composite materials under orthogonal cuttingDesign two-dimension cutting model, and simulate establishment process of edge defects through ABAQUS finite element software. Then the establishment process are derived into: shearing deformation, crack production, crack propagation and fracture. Analysis results show that, cutting force is the important factor that produces defects is concluded. Change cutting edge radius, analyze influence of the cutting forc on export edge defects, and obtain the relation between cutting edge radius and cutting force, edge defects: with increase of cutting edge radius, cutting force, edge defects are both increasing.2.Influences under minimal cutting depth of cutting edge arc in two-dimension state,and the relation of cutting depth and chip morphologyThrough finite element simulation, formula between cutting edge radius and minimal cutting depth is derived, namely,h 0.5r. Analyze influences of cutting depth on cutting process and Si Cp/Al composite materials’ normal chip morphology discontinuous serrated chip, and combined with the experiment, the relation between cutting depth and chip shape can be found: with the increase of cutting depth, extent of chip sawtooth is increasing, and so do the width and length of sawtooth.3.Influences of cutting parameters(cutting edge radius, tool rake angle) on edge defects under three-dimension angle and orthogonal cutting stateDesign three-dimension oblique angle, orthogonal cutting model and analyze influence of cutting edge radius, tool rake angle on cutting force and edge defects through finite element simulation and conclude that cutting force and edge defects have the same tendency as cutting edge radius, namely, they are both increased with the increase of cutting edge radius, but the relation with tool rake angle is opposite. This is that due to the increase of tool rake angle, cutting layer deformation decreases, resulting in the decrease of inner stress, and then the reduction of crack source, and therefore the reduction of edge defects. Besides, through the comparison of situations in orthogonal angle and oblique angle state, the influence of tool cutting edge inclination angle on cutting process can be obtained. The existence of tool cutting edge inclination angle decreases impact force when tools touch workpiece. More than this, cutting in the tool cutting edge inclination angle direction reduces friction area of the chip tool and so does the harshness of the cutter, and thus improves the surface quality of integrity.4.Research on cutting-tool wear when cutting Si Cp/Al composite materials:PCD tool is believed to be the ideal tool to deal with metal matrix composite. Combined with cutting experiments to analyze the tool wear form, this article explore the wear mechanism of different surface of tools, where electric die grinder is important wear form of flank, and also is the main wear form in these materials’ process; The existence of viscous aluminum substrate causes adhesive wear of the cutter; Bue abscission and growth bring about tipping phenomenon in cutting edge of the cutter.