粗金刚石砂轮微出刃磨粒的纳秒脉冲放电-化学复合修齐机理研究

In precise micro-grinding of high performance materials such as single crystal silicon carbide, sapphire and tungsten carbide alloy, truing and grinding efficiencies of diamond grinding wheel have been technical bottleneck in industrialization. Therefore, micro-tip of coarse-grained diamond grinding wheel with stable wheel profile shape and abrasive cutting edge is proposed to realize efficient and precise micro-grinding machining. However, the dressing and truing of coarse diamond grinding wheel is very difficult. This project proposes that the hybrid truing and truncating of nanosecond impulse discharge and mechanical chemical friction is employed to rapidly truncate protruded micro grains of coarse grinding wheel. The efficient and precise micro-machining of hard and brittle materials may be realized. The key of truing and truncating of coarse diamond grinding wheel is to control macroscopic form accuracy of wheel micro tip and microscopic protrusion homogeneity of protrusive diamond grains. The graphitization removal mechanism of diamond grain at nanoscale is analyzed in depth. The relationship model between nanosecond impulse discharge parameters, truing process parameters and micro-removal volume of protrusive grains is built. The influence of hybrid truncating of nanosecond impulse discharge-chemical for protrusion grain truncation of wheel micro tip is also revealed. The precision control for truing and truncating with high form accuracy of coarse grinding wheel may be realized. Compared with precise micro-grinding of fine-grained grinding wheel, the grinding efficiency and surface machining quality can be greatly improved.

在单晶硅碳化硅、蓝宝石、碳化钨合金等高性能材料的精密微细磨削中，金刚石砂轮的修整效率及磨削效率一直是产业化的技术瓶颈。因此，提出采用粗粒度的金刚石砂轮微尖端，保持砂轮轮廓和磨粒切削刃形状稳定，实现高效率、高精度的微细磨削加工。然而，粗粒度砂轮的修整非常困难，本项目提出利用纳米级脉冲放电和机械化学摩擦复合的修整修齐方法，将粗砂轮微出刃磨粒快速修平修齐，实现硬脆材料的高效精密微细加工。粗砂轮修整修齐的关键是控制砂轮微尖端的宏观修整形状精度和微观出刃磨粒等齐性，深入分析金刚石表层的纳米级石墨化去除机理，构建纳秒脉冲放电参数和修整工艺参数与出刃磨粒微去除体积之间的关系模型，揭示纳秒脉冲放电-化学复合修齐对砂轮微尖端出刃磨粒修平修齐的作用机制，实现对粗砂轮高形状精度修整修齐的精确控制。与细粒度砂轮的精密微细磨削相比，可以极大提高磨削效率和表面加工质量。

在单晶碳化硅、陶瓷、蓝宝石、碳化钨合金等高性能材料的精密微细磨削中，金刚石砂轮的修整效率及磨削效率一直是产业化的技术瓶颈。本项目提出脉冲电火花-机械磨削复合修整工艺方法将金刚石砂轮微尖端快速修整修齐，形成锋锐的微磨粒切削刃，实现硬脆材料的高效精密微细加工。研究脉冲放电参数对砂轮修整宏观形状精度及磨粒出刃高度的影响，构建脉冲放电参数与金属结合剂微去除之间的关系模型，利用精密修整修齐后的金刚石砂轮在硬脆材料表面加工制造出形状精度和表面质量可控的微阵列结构，开发出微结构LED聚合物导光板和微流控芯片的微注塑成形技术及其模芯的精密微细磨削制造技术。.微尖端修整角度误差可以控制在1°以内，模具钢模芯、单晶碳化硅、反应烧结碳化硅表面的微V沟槽磨削形状精度分别为4.05 µm，12.6 µm和11.3 µm。采用微细磨削加工的微结构模具钢进行注塑成形，可以实现聚合物元器件的高精度成形与批量化生产制造，微结构聚合物的注塑成形复制率高达99.30%，与传统光滑面导光板相比，开发出的微结构LED聚合物导光板可以提高光照约40.82%。