磁流变抛光消除磨削亚表面损伤层新工艺

Removal of subsurface damage in grinding by magnetorheological finishing

针对传统光学加工技术难于精确测量和控制亚表面损伤的特点,提出用磁流变抛光替代研磨工序并直接衔接磨削的新工艺流程。采用自行研制的磁流变抛光机床KDMRF-1000和水基磁流变抛光液KDMRW-2进行了磁流变抛光去除磨削亚表面损伤层的实验研究。结果显示,直径为100mm的K9材料平面玻璃,经过156min的磁流变粗抛,去除了50μm深度的亚表面损伤层,表面粗糙度Ra值进一步提升至0.926nm,经过17.5min磁流变精抛,去除玻璃表面200nm厚的材料,并消除磁流变粗抛产生的抛光纹路,表面粗糙度Ra值提升至0.575nm。由此表明,应用磁流变抛光可以高效消除磨削产生的亚表面损伤层,提出的新工艺流程可以实现近零亚表面损伤和纳米级精度抛光两个工艺目标。

As traditional optical machining technologies can not test and control the subsurface damage in grinding precisely,a new optical machining process was introduced,in which a Magnetorheological Finish（MRF）was used to replace the lapping and to follow the grinding processing.A experiment to remove the subsurface damage caused by grinding was carried out by using a KDMFR-1000F polishing machine and KDMRW-2 water based MR.The experimental results indicate that after rough polishing for 156 min firstly,the 50 μm（depth）subsurface damage of the K9 flat glass has been removed and the surface roughness is 0.926 nm.Furthermore,with a fine polishing for 17.5 min,the 200 nm（depth）glass surface can be removed and the ripples caused by rough polishing are also eliminated,which improves the surface roughness to 0.575 nm.These results show that the propose optical machining processing with MRF can remove effectively the subsurface damage caused by grinding and can provide a high surface roughness below 1 nm.