激光结构磨削在氮化硅陶瓷中的磨削行为

Study on grinding behavior of laser-structured grinding in silicon nitride ceramic

用传统车削和磨削方法加工氮化硅陶瓷,难度大、加工效率低。为了提高难加工材料氮化硅陶瓷的加工精度,利用激光辅助复合加工技术,精确控制氮化硅表面激光结构化方案的尺寸,设计了4种具有相同表面积的不同氮化硅结构图案,研究了氮化硅图案几何形状对其磨削性能的影响,同时分析了砂轮转速、进给速率等磨削参数对磨削力的影响。结果发现:氮化硅的激光结构化工艺对其磨削结果有很大影响,其表面的凹槽有利于磨削液进入磨削区域,激光烧蚀则降低了氮化硅强度,磨削力最多可降低63%,可有效减少砂轮的磨损。为提高氮化硅陶瓷的加工精度,用激光辅助复合加工技术在氮化硅表面烧蚀出4种具有相同表面积的结构化图案,然后用金刚石砂轮对氮化硅表面进行磨削,研究图案结构对磨削效果的影响,并分析砂轮转速、进给速率等参数对磨削力的影响。结果表明:激光烧蚀能够在氮化硅表面产生凹槽并降低表面氮化硅的强度,从而有利于磨削液进入并降低磨削力,最高降幅达63%。同时,金刚石砂轮磨损也有效降低。磨削结构化的氮化硅表面时,砂轮转速和进给速率对磨削力的影响规律同磨削普通氮化硅时的规律一致。

Silicon nitride ceramics are extremely difficult and time-consuming to be machined with conventional methods,such as turning and grinding.To enhance the processing precision of silicon nitride ceramic grinding,in this work a method of laser structuring the surface of silicon nitride is proposed.The laser process allows to precisely control the dimensions of the generated features.Therefore,4 different patterns with equal silicon nitride surface area are produced in order to study the influence of the pattern geometry on the grinding behavior of the silicon nitride.Grinding performance of the structured silicon nitride is tested.The influences of grinding parameters such as wheel speed,feed rate are analyzed for their effects on the grinding force.It is found that the procedure of laser structured silicon nitride has a strong influence on the grinding results.The grooves obtained by laser structured silicon nitride are favorable for the flow of coolant,and the cracks generated inside the grooves weak the material locally.The laser structured silicon nitride generally allows for a reduction of grinding forces by up to 63%,and it can effectively reduce the wear of the tool.Four patterns with the same surface area were etched by laser irradiation on the surface of Si 3N 4 ceramics to improve the machining precision.The surfaces with etched patterns were then ground by using diamond grinding wheels,and the effect of pattern form on grinding effect was studied,as well as the effects of wheel speed and infeed speed on grinding force.The results indicate that laser irradiation could produce grooves on Si 3N 4 surface,where the grinding fluid are easy to enter,and that it also reduces the strength of surface Si 3N 4 and then the grinding force decreases up to 63%.Meanwhile,the wheel wear is alleviated.The influence laws of wheel speed and infeed speed on grinding force are the same with those when grinding normal Si 3N 4.