采用波长为355 nm、脉宽为18 ns的紫外激光器,开展了镍基电镀金刚石砂轮的修整试验研究,对4个关键工艺参数——扫描填充形式、脉冲光斑重叠率及线重叠率、激光平均功率和循环扫描次数进行优化.结果表明,紫外激光修整镍基电镀金刚石砂轮时,当采用环形扫描填充形式,激光光斑重叠率和扫描轨迹重叠率均为35％时,修整后的砂轮表面地形地貌较为良好,并且当激光平均功率Pavg一定时,电镀砂轮表面的烧蚀深度与循环扫描次数N近似成正比.

A triangulation-based closed-loop control system with high-precision couple charged device (CCD) laser displacement sensors was used to true and dress a bronze-bonded diamond grinding wheel online with an acousto-optic Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. The microscopic surface topography of the trued and dressed grinding wheel was observed using a three-dimensional (3D) microscope with an ultra-large depth of field. The results showed that the diamond abrasives were uniformly distributed on and protruded from the surface of the bronze bond, which indicated good topography of the grinding wheel. Orthogonal grinding experiments were conducted on the laser-dressed bronze-bonded diamond wheel, and three quality evaluation indices, the grinding ratio, the grinding force ratio, and the workpiece surface roughness, were measured and calculated. The results of the grinding experiment were systematically analyzed using a gray relational analysis. Under the experimental conditions of this study, the dominant factor that affected the quality evaluation indices was the laser spot diameter, followed by the pulse duration. The laser power was a secondary factor.

In this study, an online, efficient and precision laser profiling approach that is based on a single-layer deep-cutting intermittent feeding method is described. The effects of the laser cutting depth and the track-overlap ratio of the laser cutting on the efficiency, precision and quality of laser profiling were investigated. Experiments on the online profiling of bronze-bonded diamond grinding wheels were performed using a pulsed fiber laser. The results demonstrate that an increase in the laser cutting depth caused an increase in the material removal efficiency during the laser profiling process. However, the maximum laser profiling efficiency was only achieved when the laser cutting depth was equivalent to the initial surface contour error of the grinding wheel. In addition, the selection of relatively high track-overlap ratios of laser cutting for the profiling of grinding wheels was beneficial with respect to the increase in the precision of laser profiling, whereas the efficiency and quality of the laser profiling were not affected by the change in the track-overlap ratio. After optimized process parameters were employed for online laser profiling, the circular run-out error and the parallelism error of the grinding wheel surface decreased from 83.1μm and 324.6μm to 11.3μm and 3.5μm, respectively. The surface contour precision of the grinding wheel significantly improved. The highest surface contour precision for grinding wheels of the same type that can be theoretically achieved after laser profiling is completely dependent on the peak power density of the laser. The higher the laser peak power density is, the higher the surface contour precision of the grinding wheel after profiling.

A novel online tangential laser profiling method was developed in this study. The system consisted of a pulsed fiber laser, a surface grinder, a motorized three-dimensional (3D) translation stage, laser displacement sensors and a laser power meter. Online tangential laser profiling was conducted on coarse-grained (120#) bronze-bonded diamond wheels. When the laser power exceeded 40 W, the laser beam simultaneously removed the diamond grains and the bronze bond to produce a smooth wheel surface. The mean circular runout error and the axial gradient error of the grinding wheel surface decreased from 203.4 and 67.6 μm to 9.5 and 0.8 μm, respectively, indicating that the wheel contour accuracy improved significantly after profiling. The diamond grains on the grinding wheel surface were graphitized during laser profiling. However, blowing a protective argon (Ar) stream or spraying water mist from the side during profiling decreased the extent of graphitization compared to that in air.

为了研究青铜金刚石砂轮光纤激光辅助侧吹修锐效果,通过青铜结合剂轮,开展功率密度与去除深度以及烧蚀区域表面形貌关系的研究,利用超景深三维扫描显微镜对烧蚀结果进行观测.结果表明:激光功率密度是光纤激光修锐青铜金刚石砂轮的核心工艺参数,激光功率密度为5×107 W/ cm2时,既保证较高结合剂材料去除效率,又可以获得微观形貌较为理想的青铜结合剂轮表面.采用优化的工艺参数开展了光纤激光修锐青铜金刚石砂轮的试验,借助SEM电镜扫描和超景深三维显微镜对添加侧吹气体前后金刚石磨粒形态和砂轮表面形貌进行观测.结果表明:辅助侧吹修锐,不仅能减少覆盖在金刚石磨粒表面的熔融物,而且能在一定程度上抑制石墨化的产生,金刚石磨粒凸出于结合剂表面适宜高度,砂轮表面形貌明显优于未添加侧吹气体时.