Study on Improvement Technique of Process Controllability for Mirror Grinding by Stimulating Functionality

为提高镜面磨削过程的可控性，提出了在磨削过程中保持砂轮良好性能的有效方法。首先，基于尖端分布的变化，考察了修整后工作面的生成过程。从而明确了以切割深度临界值将修整方式分为脱落和微断裂两种。此外，还发现修整过程中的火花是提高表面粗糙度的重要过程。由于火花抑制了表面划痕的产生，表面粗糙度得到了显著提高。然而，过度的火花减少了芯片的口袋，使加载变得容易，然后表面粗糙度变得更差，尽管它的尖端密度很高。其次，考察了超声活化冷却剂对表面粗糙度的改善效果。观察到，在mhz阶频率的超声波作用下，冷却剂的活化显著降低了划痕的产生和深度。然后，通过对冷却液供给状况和砂轮工作表面状况的观察和评价，对其机理进行了验证。结果表明，超声激活冷却液能够克服砂轮周围的气流，从而很容易地到达磨削点。这表明冷却剂在磨削点稳定地起作用，防止了切屑的沉积和焊接。此外，减少了车轮的磨损。在此基础上，对淬硬钢SCM435试样进行了镜面磨削试验。通过合理定量的修整工艺，形成良好的工作面，实现了镜面磨削，获得粗糙度Rz<0.4μm的磨削表面。此外，还证实了在磨削过程中，超声波活化冷却剂使磨削表面粗糙度Rz降低到0.2μm以下，使磨削表面保持良好状态。少

This research was done to improve the controllability of the mirror grinding process by proposing the effective method to keep good wheel performance during grinding by generating and evaluating the working surface condition.First of all, the generation process of the working surface with dressing was examined based on the change in the cutting-edge distribution. As a result, it was clarified that the critical value of the depth-of-cut divides the dressing mode into the shedding and the micro-breaking. Moreover, it was found out that the spark-out in dressing is an important process to improve the ground surface roughness. Since the spark-out suppresses the scratch generation on ground surface, the roughness is improved remarkably. However, an excessive spark-out decreases the chip pockets and makes loading easy, and then the ground surface roughness becomes worse in spite of its high cutting-edge density.In the next, the improvement effect of the ultrasonically activated coolant on th … More e ground surface roughness was examined. It is observed that the activation of coolant with the ultrasonic wave of MHz-order frequency decreases generating and depth of scratch remarkably. And then, the mechanism was examined based on the observation and the evaluation of the coolant supply condition and the working surface condition of grinding wheel. As a result, it was found out that the ultrasonically activated coolant is able to overcome the air flow around the wheel, and then to reach the grinding point easily. This represents that the coolant acts steadily in the grinding points to prevent the deposition and welding of chips. Furthermore, the wear of the wheel is decreased.Based on these results, the mirror grinding was tried for the specimen made from hardening steel SCM435. Consequently, the mirror grinding to obtain the ground surface of roughness Rz<0.4μm was achieved by generating a good working surface by reasonable and quantitative dressing process. In addition, it was confirmed that the ground surface roughness Rz was decreased lower than 0.2μm with the ultrasonically activated coolant that keeps working surface in good condition during grinding. Less