负倒棱质量对PCBN刀具切削性能的影响
2020-12-23
作者：房祥辉，李嫚，王风奇，赵敏
单位：大连理工大学机械工程学院
摘要：采用不同原理的磨削装置对PCBN刀具进行负倒棱磨削，利用微米级的体视显微镜获取明暗分明的负倒棱圆弧轮廓图片；借助MATLAB软件提取、拟合并计算刀尖处负倒棱圆弧图像的二维轮廓数据，得到了刀尖处整体负倒棱及实际切削处负倒棱的圆弧度。结果表明：负倒棱圆弧度的大小可定量表示负倒棱的磨削质量，圆弧度越小，负倒棱表面棱边越小，刃口锯齿越小，负倒棱的质量越好。通过PCBN刀具切削加工堆焊钴基高温合金的试验，借助负倒棱的圆弧度定量地探究负倒棱质量对工件表面粗糙度、刀具磨损和切削力的影响规律。结果表明：随着实际切削处负倒棱圆弧度的增大，加工工件的表面粗糙度值随之增大；实际切削处负倒棱圆弧度对切削力、刀具后刀面磨损量、月牙洼前缘距离及月牙洼宽度影响较小；负倒棱表面上的砂轮磨削痕迹方向对月牙洼前缘距离、后刀面磨损影响较小，但对月牙洼宽度影响明显。
关键词：负倒棱；PCBN刀具；圆弧度；切削力；表面粗糙度
中图分类号：TG712；TH161文献标志码：ADOI：10.3969/j.issn.1000-7008.2020.12.003
Effect of Negativechamfer Quality on Cutting Performance of PCBN Tools
Fang Xianghui，Li Man，Wang Fengqi，Zhao Min
Abstract:The grinding devices with different principles are used to carry out negativechamfer grinding on PCBN tools，and the clear pictures of negativechamfer arc contours are obtained by means of a micronlevel stereo microscope.By MATLAB software，the twodimensional contour data of the negativechamfer arc image at the tool tip are extracted，fitted and calculated，and the arc degree of the negativechamfer at the tool tip and an actual cutting point is obtained.The results show that the arc degree′s size of the negativechamfer can quantitatively represent the grinding quality of the negativechamfer，and the smaller the arc degree，the smaller the edge of the negativechamfer surface and the serration of the cutting edge，the better the quality of the negativechamfer.The effects of negativechamfer quality on workpiece surface roughness，tool wear and cutting force are quantitatively explored through the cutting test of surfacing cobaltbased superalloys with PCBN tools.The test results show that as the arc degree of the negativechamfer at an actual cutting point increases，the roughness of workpiece surface increases，and the arc degree of the negativechamfer at an actual cutting point has a small effect on cutting force，flank wear，the distance of the crater′s front edge and the crater width，and the direction of the grinding wheel′s grinding marks on negativechamfer surface has little effect on the distance of the crater′s front edge and flank wear，but there is a significant effect on the crater width.
Keywords:negativechamfer；PCBN tool；arc degree；cutting force；surface roughness