金属结合剂金刚石砂轮的修整研究(Ⅲ)——修整后结合剂形态对磨粒把持情况及砂轮磨削性能的影响

用杯形砂轮修整器整形和修锐结合剂密实型金刚石砂轮时,笔者发现在磨粒后方存在一部分结合剂残留物,并把它称之为结合剂三角洲。本文首先描述结合剂三角洲形成机理及其特性,然后讨论它对砂轮摩削性能的影响。主要结论如下:(1)结合剂三角洲形成在杯形砂轮和金刚石砂轮速度矢量差之方向(修整方向),当修整方向同磨削方向不一致时,它在磨削过程中可能和工件发生接触。(2)用杯形砂轮的两边交替进行修整,不仅可以保证结合剂三角洲的方向同磨削方向一致,并且还可以通过调整金刚石砂轮同杯形砂轮的速度比来控制结合剂三角洲的后背角φ。(3)结合剂三角洲越大,对金刚石磨粒的把持力也越大,使得修整后磨粒突出高度增大。(4)结合剂三角洲纵截面积增大会降低砂轮最外表层上的切削刃密度并使磨削力增加率减小。

Studies on Truing and Dressing of Metal Bond Diamond Wheel --Influence of bond Morphology after Dressing on the Retension of Grain and Grinding Performances of wheel

It is observed by the authors that, when truing bond matrix type diamondwheel with a GC cup truer, there's behind the grain a residue of bond which we call bond tail.In this paper, forming mechanism and characteristics of the bond tail are described firstly, theirinfluence on the grinding performances of the wheel is discussed then. Following conclusions areobtained: (1)bond tail is formed at the direction of the difference between the cup wheel speedvector and the diamond wheel speed vector, namely, the direction of dressing. It may contact withthe workpiece in case that the dressing direction doesn't coinside with the grinding direction. (2)Using alternatively both side of the cup truer for dressing, one can assure not only the direction ofthe bond tail coinsident with the grinding direction, but also the rear angle controlled by adjustingthe speed ratio of the diamond wheel verse the cup truer. (3)The larger the bond tail, the higherthe retention to the diamond grains, thus the larger the protrusion height of the grains afterdressing. (4)Increased cross section of bond tail will cause decreased cutting edge density of theouter layer of wheel and decreased grinding force incrementary ratio.