双光束修整凹曲面树脂金刚石砂轮及其磨削性能研究

The dressing difficulty of diamond form grinding wheels (especially concave nonmetal-bonded grinding wheels) has become one of the bottlenecks restricting the development of the precision and surperprecision technology of parts with complex surfaces. On the basis of preliminary research, this project presents a novel method for dressing of concave resin-bonded diamond grinding wheel using “collimated” and “flat-topped” double laser beams. The molecular dynamics and experimental methods are used to study picosecond laser cutting and cutting characteristic of single grain. The mechanism of graphitization and removing of diamond grain will be revealed, and the influence rules of change of rake/relief angles, and the graphitization of the diamond grain on the grain’s cutting performance will be expounded. A multiphase and multifield coupling model of multiangle incident ultraviolet laser sharpening of resin-bonded diamond grinding wheel block will be developed to predict the surface landform of a sharpened form grinding wheel. The corresponding relation between the power density, the deflection angle of laser beam and the section profile of form grinding wheel will be built, and the influence rule of the coupling effect of heating, force and phase transformation during laser processing on the bond’s retention capacity will be revealed. The experiments of picosecond laser profiling, double beam dressing and form grinding will be carried out to analyze the impact of dressing parameters on dressing precision and efficiency, geology and landform of grinding wheel’s surface, and grinding wheel’s grinding performance. And the process optimization theory of double beam dressing will be developed. The completion of the project will provide reliable solutions for high accuracy, high efficiency, and low damage dressing of superabrasive grinding wheels with complex curved surfaces.

金刚石成形砂轮（尤其是凹曲面非金属基砂轮）修整困难已成为制约复杂曲面零部件精密与超精密加工技术发展的瓶颈之一。在预研基础上，本项目提出一种“平行”“平顶”双光束修整凹曲面树脂金刚石砂轮的新方法。拟结合分子动力学和实验方法研究皮秒激光切割单颗磨粒和单颗磨粒切削特性，揭示金刚石磨粒石墨化与去除机理，阐明因激光整形而导致的磨粒前/后角改变、磨粒石墨化对磨粒切削性能的影响；建立可预测修锐后成形砂轮表面地貌的多角度入射紫外激光修锐砂轮块的多相、多物理场耦合模型，构建激光束功率密度、偏摆角度与成形砂轮截面廓形之间的对应关系，揭示激光加工热、力、相变耦合效应对结合剂把持性能的影响规律；开展皮秒激光整形、双光束修整、成形磨削实验，分析修整参数对修整精度与效率、砂轮表面地质地貌、砂轮磨削性能的影响，形成双光束修整工艺优化理论。本项目的完成将为实现复杂曲面超硬磨料砂轮精密、高效、低损伤修整提供可靠的解决方案。

基于超硬磨料成形砂轮的磨削工艺是近年来在航空航天、汽车工业、工程机械等领域中应用日益广泛的难加工材料复杂曲面零部件的重要加工手段。而超硬磨料成形砂轮修整技术的创新与发展是实现复杂曲面零件精密与超精密磨削的关键技术。本项目探究了单脉冲能量、线重叠率等工艺参数与整形前后磨粒几何形貌、拉曼光谱特征信息的映射关系，揭示了磨粒表层石墨化对磨粒切削性能的影响规律；建立了树脂结合剂金刚石砂轮块的复合材料模型，进行了脉冲激光修锐砂轮的有限元仿真，开展了脉冲激光修锐树脂结合剂金刚石砂轮块实验研究，得到了单脉冲能量、点重叠率、线重叠率等工艺参数对修锐后砂轮表面微观形貌与组织的影响规律，量化了修锐后砂轮表面树脂结合剂、金刚石磨粒的损伤情况；提出一种圆弧形砂轮激光修整新方法，并开展了圆弧形砂轮激光修整实验研究，分析了对刀偏移误差对修整后砂轮表面几何精度与微观形貌的影响规律，实现了圆弧形树脂金刚石砂轮脉冲激光精密、低损伤修整。本项目所获研究成果可为实现超硬磨料成形砂轮精密、高效、低损伤修整提供可靠解决方案。项目组目前正在开展相关成果转化和应用，与相关企业合作研发工业应用级的超硬磨料砂轮脉冲激光修整装备。