正前角金刚石磨粒磨削钛合金仿真与试验研究

Simulation and Experimental Study on Diamond Grit with Positive Rake Angle Grinding Titanium Alloy

为研究正前角金刚石磨粒磨削加工的机理,论证正前角磨削的可行性,采用有限元仿真软件ABAQUS建立单颗金刚石磨粒磨削Ti6Al4V钛合金过程的模型,对比研究不同工艺条件下具有正、负前角的单颗金刚石磨粒磨削过程中磨削力的变化规律.在此基础上,分别针对飞秒激光加工的正前角金刚石磨粒和原始的负前角金刚石磨粒开展钛合金磨削试验,采用测力仪测量磨削力,并将测得的磨削力与仿真结果进行对比;观测磨削加工表面形貌,测量表面粗糙度,将正、负前角磨削时的磨削力、磨削加工表面形貌和表面粗糙度进行对比.结果表明,在单颗金刚石磨粒磨削中,磨削力随着磨削速度的增大而减小,随着磨削深度的增加而增大,随着磨粒前角由负到正而逐渐减小,仿真得到的磨削力与试验结果的变化趋势基本吻合.相比于传统的负前角磨削,正前角金刚石磨粒具备良好的耐磨性,磨削表面磨痕较浅、加工缺陷少,表面粗糙度值降低58%~66%,可有效提高磨削加工表面质量.

In order to explore the mechanism of positive rake angle(PRA)grinding for diamond grit and to demonstrate the feasibility of PRA grinding,the finite element simulation software ABAQUS was used to establish a grinding model of Ti6Al4V titanium alloy with single diamond grit.Then,the change law of grinding force in the grinding process of single diamond grit with PRA or negative rake angle under different process parameters was studied and compared.On this basis,titanium alloy grinding experiments were carried out for the PRA diamond grit fabricated by femtosecond laser and the original negative rake angle diamond grit.The grinding force was measured by the dynamometer and compared with the simulation results.The grinding surface morphology was observed,and surface roughness was measured.Furthermore,the grinding force,grinding surface morphology and surface roughness between PRA and negative rake angle grinding were compared.The results show that,in single diamond grit grinding,the grinding force decreases with the increase of grinding speed,increases with the increase of grinding depth,and decreases gradually as the rake angle varies from negative to positive.And the trends of grinding force obtained by simulation are basically consistent with the experimental results.Compared with the traditional negative rake angle grinding,the PRA diamond grit also has good wear resistance,and the grinding surface with PRA diamond grit has the advantages of shallow grinding traces,fewer machining defects,and the surface roughness is reduced by 58%~66%,which can effectively improve the surface quality of grinding.