旋转超声锯切光学玻璃的表面形成机理研究  

Surface Formation Mechanism of Optical Glass by Rotary Ultrasonic Sawing

作　　者：沈剑云[1] 朱旭 宋伟 陈剑彬 吴海融[1] 吴贤 SHEN Jian-yun;ZHU Xu;SONG Wei;CHEN Jian-bin;WU Hai-rong;WU Xian(School of Mechanical Engineering&Automation,Huaqiao University,Xiamen 361021,China)

机构地区：[1]华侨大学机电及自动化学院,福建厦门361021

出　　处：《表面技术》2019年第2期281-289,共9页Surface Technology

基　　金：国家自然科学基金项目(51275181);福建省高校产学合作科技重大项目(2018H6013)~~

摘　　要：目的探究不同物理性能光学玻璃锯切加工的表面形成机理,以及旋转超声锯切过程中径向振动冲击对其表面特性的影响。方法首先通过显微压痕实验,对比K9与石英两种光学玻璃的硬度与断裂韧性,计算其各自的临界切削深度,并用LS-DYNA进行单颗磨粒切削的有限元仿真,分析不同物理性能光学玻璃的表面形成机理。然后对其进行旋转超声锯切(RotaryultrasonicsawingRUS)和普通锯切(ConventionalsawingCS)实验,分析径向超声振动对不同物理性能的光学玻璃表面特性的影响。结果 K9、石英玻璃的断裂韧性分别为5.232 MPa·m0.5和1.644 MPa·m0.5,临界切削深度为4.288μm和0.012μm。仿真结果表明,加工过程中,超声振动将单颗磨粒的最大切削厚度由1.1767μm提高为8.001μm。对石英与K9玻璃进行锯切试验的结果显示,对于K9玻璃,旋转超声锯切后,沟槽底部粗糙度Pa与峰谷值Pv相对普通锯切大幅降低,但石英玻璃下降幅度不大。结论超声振动增大了单颗磨粒切削厚度,使得K9玻璃的材料去除方式由部分塑性去除转变为完全脆性断裂去除,致使表面层产生微破碎,避免了传统加工过程中产生的大面积破碎和裂纹,进而提高表面粗糙度。石英玻璃因为临界切深小,在普通锯切中即为脆性去除,超声振动的影响效果稍小,对加工后表面粗糙度的影响不大。The work aims to explore the surface formation mechanism of optical glass with different physical properties by cutting process and the effects of radial ultrasonic impact on the surface characteristics during rotary ultrasonic sawing(RUS).Firstly,the hardness and fracture toughness of two optical glasses,K9 and quartz,were compared through micro-indentation experiment,and the respective critical cutting depth were calculated simultaneously.Secondly,the finite element simulation of single grain cutting was carried out by LS-DYNA to figure out surface formation mechanism of optical glass with different physical qualities.Then,the influence of radial ultrasonic vibration on the surface characteristics of optical glass with different physical properties was analyzed by RUS and conditional sawing(CS)experiments.The fracture toughness of K9 and quartz glass was 5.232 MPa·m0.5 and 1.644 MPa·m0.5 respectively and the critical cutting depth was 4.288μm and 0.012μm respectively.The simulation results demonstrated that the maximum cutting depth of single grain was increased from 1.1767μm to 8.001μm by ultrasonic frequency impact in processing.From the cutting experiment results of quartz and K9 glass,for K9 glass,the roughness and peak-to-valley of the bottom of groove after RUS were significantly lower than that by conditional sawing,while for quartz glass,the decreasing was not obvious.Owing to the higher cutting depth of single grain by ultrasonic vibration,the material removal mode of K9 glass could be transformed into brittle fracture removal mode from partial plastic removal,which makes micro-chipping of surface.The surface roughness is improved by avoiding large area cracking and cracks in conditional machining.Attributed to the lower critical cutting depth of the quartz glass,the removal mode of the quartz glass in conventional sawing is brittle removal.Therefore,the effect of ultrasonic vibration is smaller,does not affect the surface roughness significantly.

关 键 词：旋转超声锯切 光学玻璃 表面形成机理 显微压痕 单颗磨粒切削 

分 类 号：TB559[理学—物理]