光学玻璃精密磨削表层损伤的检测技术

Detection technology for subsurface damage of optical glass during precision grinding

为实现光学玻璃高效低损伤的超精密磨削,须研究加工工艺对表层损伤的影响,发展不同工艺表层损伤的检测技术.在分析光学玻璃磨削损伤层特性的基础上,通过实验分析磨削参数对表层损伤的影响,研究工艺参数对表层损伤的影响规律;然后,采用纳米压入仪表征精磨加工损伤层的力学性能,基于纳米压入仪发展一种小尺度磨削损伤的检测技术.结果表明:表层损伤随砂轮转速的增大而减小,随砂轮进给速率和工件转速的增大而增大;其中工件进给速率对表层损伤的影响最大,其次是砂轮转速,工件转速的影响最小;针对精磨加工的表层损伤,基于纳米压入技术测得的损伤层深度为0.96μm,截面抛光方法的测量结果为1μm,二者一致性较好.结论:角度抛光方法适用于检测粗磨加工的表层损伤;通过优化加工工艺可进一步降低磨削损伤;精磨加工产生的损伤降低了表层材料的力学性能,且损伤层内力学性能的梯度变化曲线可用于快速检测损伤层的深度.

It was aimed to realize ultra-precision grinding for optical glass with high efficiency and low damage layer,the influence of grinding parameters on subsurface damage(SSD)was studied and the detection technology for SSD layer was developed induced from variable grinding processes.The influences of grinding parameters on surface damage was studied by analyzing the characteristics of SSD layer in rough ground piecework.Thereafter,the mechanical properties of the damage layer were characterized by using nanoindentation techniques and then a detecting method for fine grinding induced SSD was developed based on nanoindentation results.The result showed that SSD depth decreased with the increase of grinding wheel speed and increased with the increase of grinding wheel feed rate and piecework speed.Furthermore,the piecework feed rate had the greatest influence on surface damage,followed by the grinding wheel speed,the piecework speed had the least influence.For the SSD layer of fine grinding process,the SSD depth measured by nanoindentation technique was 0.96μm,while this depth detected by cross-sectional polishing method was about 1μm,which showed that the obtained results were in concordance in the both used methods.It was concluded that:1)Angle polishing method was suitable for detecting surface damage in rough grinding;2)SSD depth could be further reduced by optimizing the machining process;3)The SSD layer caused by fine grinding could reduce the mechanical properties of subsurface layer,and the gradient curve of mechanical properties of the damaged layer could be used to detect the depth of the damaged layer efficiently.