| The high strength and wear resistance of SiCp/Al establishes a grim challengefor cutting，the hard and brittle silicon carbide particles are distributed in thealuminum base, so the friction becomes extremely serious during machining，especially the tool wear is serious，the tool life is short and processing quality isdifficult to control，all of these make the SiCp/Al typically hard to cut. Therefore,to carry out the study of milling SiCp/Al is of great significance to improve thequality and performance of products of military enterprises and to speed up the paceof manufacturing technology upgrading in corporations.Starting from the assumption of periodic arrangement of microscopicstructure，equivalent analysis of Non-homogeneous material is raised；based on thehomogenization theory and M-T model， the equivalent prediction formula ofelastic modulus of SiCp/Al material is drawn. The equivalent thermal conductivitycoefficient of SiCp/Al is predicted and the formula for calculating the thermalconductivity is obtained based on the law of thermal resistance， and theapplicability of equivalent model is analyzed.The uncertainty of mechanicalproperties of Non-homogeneous material is solved，and the reference data for FEMis provided.Based on the Johnson-Cook Thermal coupling formula，the chip separationcriteria is defined.The2-D and3-D finite element model of the milling process oftwo-teeth PCD tool and three-teeth YG6X tool are established, extrusion andseparation process of chip is simulated，the simulation and experimental resultshave good consistency. The traditional model stable which can only be used instable cutting is improved，influence of tool angle on the chip formation process、cutting force、temperature and stress is analyzed.The milling process of SiCp/Al is systematically analyzed, the experiment ofmilling are launched with four kinds of solid carbide alloy tools and PCD veneertool, the milling force and surface toughness are measured by force dynamometerand surface profilometer, the impact of tool material and cutting parameters（n、fz、p）on cutting force and surface roughness are systematically analyzed, also themilling force formula is obtained by regression analysis method based on the results of orthogonal test，the cutting parameter is optimized under the object of minimumcutting force.For the problem of serious tool wear durning milling SiCp/Al, the experimentalstudy of milling SiCp/Al is launched by four kinds of solid carbide mills and PCDveneer tool, the wear pattern is observed by scanning electron microscope andstereomicroscope, the wear mechanism and variation of wear are analyzed, the lifeof different tools are obtained, the influence of tool wear on cutting force andsurface roughness are analyzed, the optimized tools for rough and finish machininghigh volume fraction SiCp/Al are obtained respectively.The YG6X tool and PCD tool are applied as rough and finish machining toolrespectively to successfully machine high volume fraction SiCp/Al motorframework, the surface quality is high and the difficulty of machining SiCp/Al issolved. |
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