摘要
目的 快速、准确预测微晶玻璃在研磨加工过程中的亚表面损伤状况,制定合理的加工工艺。方法 通过建立微晶玻璃的离散元模型,仿真分析了研磨压力等研磨工艺参数对工件亚表面损伤的影响规律,并采用角度抛光法对研磨后微晶玻璃的亚表面损伤状况进行了实验验证。结果 采用W14金刚石固结磨料垫研磨微晶玻璃,当研磨压力为10 kPa时,工件亚表面裂纹层深度为1.75μm,当研磨压力降低至3.5 kPa时,工件亚表面裂纹层深度为1.38μm;随着研磨压力的降低,亚表面微裂纹数量减少。研磨残余应力层分布深度大于微裂纹层的,且在微裂纹的尖端存在较大的残余拉应力。结论 角度抛光法得到的亚表面裂纹层深度与仿真结果一致,偏差范围为-10.87%~11.29%,残余应力仿真结果与试验结果的偏差为7.89%。离散元仿真能够比较准确地预测固结磨料研磨微晶玻璃的亚表面损伤状况,为其研磨抛光工艺参数的制定提供了理论参考依据。
Glass-ceramics with its superior chemical,physical and mechanical properties is widely used as a key material in the manufacturing of optical components in the fields of aviation,aerospace,and defense and military industries,etc.However,subsurface damage caused by the manufacturing process can seriously affect the strength of the parts,stability of performance and other service characteristics.The common method for detecting subsurface damage is mainly experimental measurement after processing,which can cause damage to the workpiece.Although the simulation analysis method can perform subsurface damage prediction,it fails to complete the detection of residual stress.Therefore,the evaluation of glass-ceramics surface and subsurface damage is to remain a challenge.In order to quickly,accurately and comprehensively predict the subsurface damage of glass-ceramics during the lapping process,the work aims to establish a discrete element model(DEM) of glass-ceramics with Corning 7972 as the model standard,and simulate and analyze the effect of lapping process parameters on the subsurface damage of the workpiece under the lapping pressure of 3.5,5,7,10 and 15 kPa,respectively.At the same time,lapping tests were designed on the precision polishing machine.The glass-ceramics wafer with 7.5 cm diameter and 5 mm thickness was selected as workpiece under the same lapping pressure as simulation conditions.The lapping parameters were set to the workpiece speed of 80 r/min,the lapping disc speed of 85 r/min,the lapping fluid flow rate of 80 mL/min,and the lapping time of 30 min.The subsurface damage layer of the lapped glass-ceramics was detected and calculated by the angle polishing method(APM).The reliability of the discrete element simulation was verified by comparing and analyzing the experimental results with the simulation results.The results show that the depth of subsurface crack layer of glass-ceramics is 1.86,1.75,1.73,1.63 and 1.38 μm at 15,10,7,5 and 3.5 kPa respectively.The depth of subsurface crack layers by simulation tests at the same pressures is 2.07,1.87,1.75,1.56 and 1.23 μm.The number of subsurface micro-crack drops with the decrease of lapping pressure.The distribution depth of lapping residual stress layer is greater than that of micro-crack layer,the residual stress in the x direction is mainly compressive stress,and that in the y direction is mainly tensile stress.As the lapping pressure decreases,the stresses in both the x and y directions have a tendency to gradually decrease,and there is a larger residual tensile stress at the tip of the micro-crack.The surface and subsurface damage such as longitudinal and transverse micro-crack,and residual stresses exists in glass-ceramics after fixed abrasive lapping process.The regulations of the depth of the subsurface crack layer obtained by the angle polishing method are consistent with the pattern of the simulation results and its deviation is in the range of-10.87%-11.29%.The deviation between the residual stress simulation results and the experimental results is 7.89%.Therefore,discrete element simulation analysis method can accurately predict the subsurface damage of glass-ceramics lapped by fixed abrasive lapping,and it provides a theoretical reference for the formulation of lapping and polishing process parameters.
作者
王科荣
宗傲
牛凤丽
张羽斐
朱永伟
WANG Kerong;ZONG Ao;NIU Fengli;ZHANG Yufei;ZHU Yongwei(College of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;Jiangsu Key Laboratory of Precision and Micro-manufacturing Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;Mechanical&Electrical Engineering College,Jinhua Polytechnic,Zhejiang Jinhua 321000,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第2期158-167,共10页
Surface Technology
基金
浙江省教育厅科研项目(Y201941341)
装备预研共用技术项目(50923021502)
江苏省“六大人才高峰”高层次人才项目(JXQC-010)。
关键词
微晶玻璃
固结磨料研磨
亚表面损伤
残余应力
离散元仿真
glass-ceramics
fixed abrasive lapping
subsurface damage
residual stress
discrete element simulation
