【作者】 张勇；

【导师】 陈根余；

【作者基本信息】 湖南大学 ， 机械工程， 2015， 硕士

【摘要】 超硬磨料砂轮具有优良的磨削性能,抗磨损能力强,近年来,随着高强度、高硬度材料在生产工程和科学技术中广泛应用,致使超硬磨料砂轮应用也日益增加。超硬磨料磨具的整形和修锐问题变得日益突出,然而传统的修整方法很难对之进行有效的修整。本文所研究的激光修整法,不仅便于修整金属或树脂结合剂超硬磨料砂轮,而且热影响区小、砂轮修整损耗小、易于实现自动化、修整效率高,具有远大的发展前景。(1)设计并搭建了一套以光纤激光器为修整“刀具”,采用无暗斑匀束元件对光束进行整形的衍射聚焦激光修整系统,并对各个组成部分进行详细介绍。(2)开展了平顶激光束切向整形青铜金刚石砂轮的试验研究,获得对整形精度影响较大的三个可控参数:激光功率密度、激光束扫描速度、砂轮转速。采用优选的工艺参数对磨钝的青铜结合剂金刚石砂轮进行切向整形试验,分析整形前和整形后的表面形貌和圆跳动误差,结果显示,经激光整形后的青铜结合剂金刚石砂轮的轮廓精度较高,基本可以满足粗粒度砂轮的使用要求。对比分析了平顶激光束和高斯激光束整形后砂轮表面形貌、圆跳动误差、整形效率以及金刚石磨粒石墨化程度,结果表明,平顶激光束整形效果与高斯激光束相比整形效率更高。(3)开展了平顶激光束径向修锐青铜金刚石砂轮的试验研究,确定了本课题中平顶激光束径向修锐青铜金刚石砂轮的关键工艺参数:激光平均功率、激光光斑重叠率、激光扫描轨迹线重叠率和扫描次数。采用最佳的激光修锐参数组合对整形后的青铜金刚石砂轮进行修锐试验,结果显示,砂轮表面微观地形地貌良好,磨粒凸出高度合适,容屑空间良好。对比分析了平顶激光束和高斯激光束修锐后砂轮表面形貌及金刚石磨粒石墨化程度,结果表明,平顶激光束的修锐效果略优于高斯激光束。(4)设计了激光修整和机械法修整下青铜金刚石砂轮磨削YG8硬质合试验,通过对磨削工件表面形貌、粗糙度和磨削前后的砂轮表面形貌对比观测,总结得出,采用激光修整的青铜金刚石砂轮具有更优良的磨削性能。更多还原

【Abstract】 The profiling and sharpening of bronze-bonded super abrasive grinding wheels remain a worldwide difficult problem despite their more and more applications in the fields of precision grinding, ultra-precision grinding and difficult-to-cut material grinding over the years and significant advantages on grinding performances. However, the traditional dressing method is difficult to effectively repair and maintain. Laser profiling and sharpening method in this area has many advantages, such as, small heat-affected zone, dressing small loss, easy to realize automation, finishing high efficiency and a broad prospects.(1)The fiber laser dressing experimental system with no dark spots and beam element to reshape the diffraction of focused is desi gned. And the funct ions and features of vari ous p arts of the s yst em are described and anal yz ed i n det ails and depth s.(2)The three parameters to control the great influence on the shaping accuracy: the laser power density, scanning speed, the rotating speed of the laser profiling of bronze bonded diamond grinding wheels by fiber laser. The laser profiling experiments were carried out based on the optimized processing parameters by the bronze-bonded super abrasive grinding wheels of dull. And the surface morphology and round plastic surgery before and afte r shaping the run out error were analyzed. The results showed that the contour accuracy of bronze bonded diamond grinding wheels after laser surgery can basically meet the requirements of the coarse-grained grinding wheel. Then analyzed the surface morphology, the circular run-out error,the shaping efficiency and the degree of graphitization of diamond grits, profiled by Flat-top laser and the Gaussian laser. The results indicated that the method of profiling’ efficiency by Flat-top laser is higher.(3)In order to study the effect of the key processing parameters that including the laser power density, laser spot overlap ratio, laser scanning track line overlap ratio, and number of laser scanning cycles to laser sharpening of bronze-bonded diamond grinding wheels, experiments of laser ablation were carried out on bronze-bonded wheels. The laser sharpening experiments were carried out based on the optimized processing parameters by the bronze-bonded super abrasive grinding wheels after profiling. The results showed that the surface topography of grinding wheel is good, and the abrasive prominent is highly appropriated, so the let chip space is enough. Immediately following analyzed the surface morphology and the degree of graphitization of diamond grits. The results indicated that Flat-top laser is better than the Gaussian laser in terms of sharpening of bronze-bonded diamond grinding wheels.(4)The two bronze-bonded diamond grinding wheels after laser sharpening and Mechanical sharpening are both used to grind the YG8 cemented carbide. To sum up, the Laser profiling and sharpening of bronze bonded diamond grinding wheel has better dressing effect and the grinding performance through compar ing the surface morphology and roughness of work piece, the surface morphology of grinding wheels before and after grinding.更多还原