铣削方式对高体分SiCp/Al复合材料薄壁件高速铣削表面质量影响研究

Research on the Influences of Milling Way on Surface Quality of High-volume SiCp/Al Composites Thin-walled Piece in High Speed Milling

应用聚晶金刚石(PCD)刀具对高体分SiCp/Al复合材料薄壁件进行了高速铣削实验。在不同铣削速度下,研究了顺、逆两种铣削方式对薄壁件高速铣削的表面粗糙度及表面形貌的影响,提出了不同铣削方式下已加工表面的形成机理,揭示了铣削方式和铣削速度对试件切入部、中部和切出部处表面粗糙度的影响规律。结果表明:在相同的切削用量和刀具几何参数下,顺铣加工的表面粗糙度小于逆铣,且顺铣加工表面粗糙度的变化幅度小于逆铣;薄壁件在切出部的表面粗糙度大于中部和切入部的表面粗糙度;顺铣时已加工表面的形成以切削层金属的滑移为主,材料内部SiC颗粒的滑移、刻划造成已加工表面沿刀具进给方向的微观沟痕;逆铣时已加工表面主要由后刀面的挤压、摩擦作用形成;宏观上顺铣的已加工表面存在由残留面积高度形成的平行于刀具轴线方向的残留痕迹,而逆铣这一特征则不明显。

The high speed milling experiment for thin-walled piece made of high-volume SiCp / Al composites was performed with PCD tool. The influence of two milling ways such as down milling and up milling on surface roughness and surface topography of the thin-walled piece were studied in different speeds. In the two milling ways,formation mechanism of the machined surface is proposed. In different milling speeds,how the milling way influence the surface roughness in entrance,middle and exit of the test-piece are revealed. The results show that the value of surface roughness in down milling way is less than that of in up milling way in the same cutting parameters. So is rangeability of surface roughness. Moreover,the value of surface roughness at exit is bigger than that of the middle and the entrance,either down milling or up milling. For down milling,formation of the machined surface is mainly metal gliding of the cutting layer. The micro-groove marks along feeding direction of tools are formed by Si C particles' gliding and carving. For up milling,formation of the machined surface is mainly the fiction and extrusion of the flank face. In the macro level,there are theresidual marks which are formed by the height of the cutting residual area in the down milling surface,which are parallel to the axis of tools. However,the up milling surface is no this obvious feature.