PDC纤维微刃刀具精密切削n-WC/12Co涂层的试验研究

Study on Precision Cutting of n-WC/12Co Coatings Using PDC Fiber Cutter

基于YAG激光切割方法制备了截面尺寸为10mm×0.6mm×0.3mm的聚晶金刚石复合片(polycrystalline diamond compacts,PDC)纤维,进行了纳米碳化钨(n-WC/12Co)涂层的PDC纤维精密切削加工,纤维切削深度为微米级,切削前角分别为-30°和0°。开展了PDC纤维切削加工和金刚石砂轮(SD80N100B、SD600N100V)磨削加工的比较分析,采用Kistler测力仪对切削力进行了在线测量。基于扫描电镜对n-WC/12Co涂层加工表面形貌的观察分析,发现0°前角的PDC纤维切削加工能获得比SD600N100V金刚石砂轮磨削更好的表面形貌,-30°前角的PDC纤维切削加工与金刚石砂轮磨削加工所获得的试件的表面形貌相似,当切削深度较大时,加工表面存在碎粒状损伤形貌。基于n-WC/12Co涂层的物理与力学性能,探讨了PDC纤维切削加工机理。

This study is to investigate precision milling of nanostructured WC/12Co（n-WC/12Co） coatings experimentally by using PDC fiber of sectional size 10mm×0.6mm×0.3mm,which were prepared by cutting PDC with YAG laser.The depth of cut of per fiber was smaller than that in the conventional milling but larger than the individual grit depth of cut in grinding,and the rake angle of fiber milling was-30° and 0° respectively.During cutting experiments,a piezoelectric force transducer（Kistler model 9257BA） was used to measure cutting forces on line,and a scanning electron microscopy（SEM） was utilized for observing the machined surfaces.Moreover,n-WC/12Co coating was ground by using SD80N100B and SD600N100V,and the ground surface was compared with that milled by PDC fiber.The study verifies that a diamond fiber cutter with zero rake angle results in better surface finish than the 600# diamond wheel.On the other hand,the diamond fiber cutter with-30° rake angle results in large ratio of normal to tangential forces and the resulting machined workpiece shows a surface with granular surface roughness and also obvious microcracks at an increased depth of cut.Finally,the material removal mechanism of n-WC/12Co coating cutted by PDC fiber was discussed herein.