塑性加工条件下射流颗粒冲击去除效应

针对在微观上存在尖锐突起、凹坑和划痕等缺陷的光学元件,提出用低质量分数磨料水射流冲击的方式对其进行处理。从弹性接触出发,对射流中粒子与元件发生塑性接触的临界速度进行了推导,并引入了塑性转入脆性加要的临界速度,从而对射流的塑性去除阶段作了明确的界定。针对常用的两种光学材料K9和石英玻璃,结合具体参数对使其处于塑性去除阶段的射流速度进行了模拟计算,利用单颗粒冲击去除模型,在塑性去除范围内对两种材料的冲击去除进行了模拟计算。结果表明:石英玻璃进入塑性去除的临界速度高于K9玻璃,而进入脆性去除的临界速度低于K9玻璃,因而使石英玻璃处于塑性去除阶段的射流速度范围为K9玻璃相应速度范围的子区间;在塑性去除阶段,各材料的去除量皆随着冲击速度的增大而增大,但较硬的石英玻璃更不耐冲击,较K9玻璃更容易被去除。

Removal effects of waterjet particle impinging in ductile manner

For process of optical components having defects such as sharp projections, pits and scratches at the micro, abrasive waterjet impinging with low mass concentrations is proposed. Starting from the elastic contact, the critical velocity of plastic contact between components and waterjet particles is deduced. The critical impinging velocity of ductile to brittle transfer is introduced. Thus the velocity range of the ductile removal is clearly defined. Combined with specific parameters, K9 and fused silicas velocity range of the ductile removal are simulated. Using the single particle impinging removal model, these two materials' impinging removal in ductile removal manner is simulated. The results show that the critical velocity of plastic contact for fused silica is higher than K9s, but the velocity of ductile to brittle transfer is reversed. Thus, the velocity range of ductile removal for fused silica is a subinterval of that for K9. The impinging removal of these two materials increases with the increase of impinging velocity. However, the harder fused silica is less resistant to impinging than K9 and it is easier to be removed by impinging.