摘要
由于光学玻璃高硬度、高脆性和低断裂韧性的力学性能,边缘损伤已成为光学玻璃加工的常见缺陷形式,严重制约了加工质量的提高。基于BK7光学玻璃的钻削试验,分析了孔入口和出口边缘损伤的基本特征;利用脆硬材料的压缩断裂理论,探讨了孔口损伤的形成机理;研究了钻削参数对孔口损伤的影响规律。在此基础上,初步探索了旋转超声钻削(Rotary Ultrasonic Drilling,RUD)和旋转超声啄式钻削(RUPD)工艺对孔口损伤的抑制效果。结果表明“局部崩边”是孔入口损伤的主要形式,“整体剥落”和“不连续崩碎”相互叠加是孔出口损伤的表现形式;金刚石磨棒端面磨粒的刻划切入所导致的亚表层侧向裂纹扩展是造成入口损伤的重要原因,而中位裂纹扩展和轴向压溃是出口损伤的主要成因。RUD能够有效抑制孔口损伤,其最大入口崩边尺寸和最大出口剥落尺寸分别为普通钻削的15%~50%和45%~65%。RUPD能够促进磨屑和脱落磨粒的排出,因此可以获得更小的出口损伤。
Optical glass is the key material for manufacturing optical devices such as lenses and filter mirrors.Owing to its high hardness,high brittleness and low fracture toughness,edge damage has been the major defect during the machining of optical glass.Based on the drilling experiment of BK7 optical glass,the damage characteristics at the entrance and exit of the machined hole were analyzed;subsequently,the formation mechanism of edge damage was discussed by using the compression fracture theory of brittle materials;and finally,the influence of drilling parameters was studied.Consequently,the suppression effect of Rotary Ultrasonic Drilling(RUD)and Rotary Ultrasonic Pecking Drilling(RUPD)on edge damage was studied.The results indicate that‘local edge chipping’is the main form of the entrance damage,and the superposition of‘layer separation’and‘discontinuous chipping’is the main character of the exit damage.The subsurface lateral crack expansion,caused by squeezing the tool end abrasive,is the main cause of generating entrance damage,whereas the middle crack expansion and axial collapse are the main causes of exit damage.The RUD has a clear effect on the reduction of hole edge damage its maximum entrance chipping size Lin_max and the maximum exit separation size can be decreased by 15%—50%and 45%—65%of common drilling,respectively.The RUPD can promote the expulsion of abrasive scraps;thus,achieving less exit damage than the RUD.
作者
马利杰
刘红文
屈海涛
王占奎
苏建修
MA Li-jie;LIU Hong-wen;QU Hai-tao;WANG Zhan-kui;SU Jian-xiu(School of Mechanical and Electrical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2020年第7期1528-1538,共11页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.U1804142)。
关键词
光学玻璃
钻削
孔口损伤
形成机理
抑制工艺
optical glass
drilling
hole edge damage
formation mechanism
suppression method
