1 大连理工大学 高性能精密制造全国重点实验室，辽宁大连6024
2 华侨大学 制造工程研究院，福建厦门36101
钇铝石榴石（YAG）晶体是制造固体激光器的重要材料，超精密磨削是加工YAG晶体等硬脆材料零件的重要方法，研究硬脆材料加工表面的微观变形、脆塑转变机理对超精密磨削加工具有重要的指导作用。为了实现YAG晶体低损伤磨削加工，获得高质量表面，基于弹塑性接触理论和压痕断裂力学，通过分析单磨粒划擦作用下材料表面的变形过程，考虑材料的弹性回复、微观下力学性能的尺寸效应，建立了脆塑转变临界深度的预测模型，并计算得到YAG晶体的脆塑转变临界深度为66.7 nm。在此基础上，通过不同粒度砂轮超精密磨削YAG晶体试验对建立的脆塑转变临界深度预测模型进行验证，并计算不同粒度砂轮在相应工艺条件下的磨粒切深。结果表明，磨粒切深高于脆塑转变临界深度时，YAG晶体磨削表面材料以脆性方式被去除，磨削表面损伤严重；磨粒切深低于脆塑转变临界深度时，磨削表面材料以塑性方式被去除，能够获得高质量磨削表面，加工表面粗糙度达到1 nm。建立的脆塑转变临界深度预测模型能够为YAG晶体的低损伤超精密磨削加工提供理论指导。
超精密磨削 YAG晶体 纳米压痕 纳米划痕 脆塑转变 YAG crystal nano-indentation nano-scratch brittle-to-ductile transition ultra-precision grinding 光学 精密工程
2023, 31(16): 2362
大连理工大学 精密与特种加工教育部重点实验室，辽宁大连116024
工件旋转法磨削是大尺寸硅片正面平整化加工和背面减薄加工的主要方法，但磨削加工不可避免地会在硅片表面/亚表面产生损伤。为了预测工件旋转法磨削硅片产生的亚表面损伤深度，优化硅片磨削工艺，根据工件旋转法磨削过程中硅片磨削表面的几何轮廓参数、硅片磨削表面的材料去除机理和压痕断裂力学理论建立了磨粒切削深度、表面粗糙度Ra和亚表面损伤深度之间的数学关系，推导出工件旋转法磨削硅片的亚表面损伤深度预测模型，并通过硅片超精密磨削试验对模型进行了验证与分析。结果表明，工件旋转法磨削硅片的亚表面损伤深度随表面粗糙度Ra的增大而增大，通过预测模型计算的磨削硅片亚表面损伤深度预测值与硅片亚表面损伤深度实测值的误差小于10%，建立的亚表面损伤深度预测模型能够为超精密磨削硅片的亚表面损伤控制和硅片高效低损伤磨削工艺的优化提供理论指导。
磨削 单晶硅片 表面粗糙度 亚表面损伤深度 grinding silicon wafers surface roughness subsurface damage depth 光学 精密工程
2022, 30(17): 2077
Author Affiliations
Abstract
1 Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian, People’s Republic of China
2 EPSRC Hub in Future Metrology, Centre for Precision Technologies, University of Huddersfield, Huddersfield, United Kingdom
3 Institute for Materials and Processes, School of Engineering, Sanderson Building, University of Edinburgh, EH9 3FB Scotland, United Kingdom
Fine finishing of tungsten alloy is required to improve the surface quality of molds and precision instruments. Nevertheless, it is difficult to obtain high-quality surfaces as a result of grain boundary steps attributed to differences in properties of two-phase microstructures. This paper presents a theoretical and experimental investigation on chemical mechanical polishing of W–Ni–Fe alloy. The mechanism of the boundary step generation is illustrated and a model of grain boundary step formation is proposed. The mechanism reveals the effects of mechanical and chemical actions in both surface roughness and material removal. The model was verified by the experiments and the results show that appropriately balancing the mechanical and chemical effects restrains the generation of boundary steps and leads to a fine surface quality with a high removal rate by citric acid-based slurry.
chemical mechanical polishing W–Ni–Fe alloy grain boundary step modelling mechanism International Journal of Extreme Manufacturing
2021, 3(2): 025103
Author Affiliations
Abstract
1 Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Educations, Dalian University of Technology, Dalian, People’s Republic of China
2 State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
3 Department of Mechanical Engineering, Chubu University, Kasugai, Aichi, Japan
4 National Physical Laboratory - NPL (United Kingdom), Hampton Road, Teddington, TW11 0LW, United Kingdom
5 Institute of Machinery Manufacturing Technology, China Academy of Engineering Physics, Mianyang, People’s Republic of China
Diamond tools play a critical role in ultra-precision machining due to their excellent physical and mechanical material properties, such as that cutting edge can be sharpened to nanoscale accuracy. However, abrasive chemical reactions between diamond and non-diamond-machinable metal elements, including Fe, Cr, Ti, Ni, etc, can cause excessive tool wear in diamond cutting of such metals and most of their alloys. This paper reviews the latest achievements in the chemical wear and wear suppression methods for diamond tools in cutting of ferrous metals. The focus will be on the wear mechanism of diamond tools, and the typical wear reduction methods for diamond cutting of ferrous metals, including ultrasonic vibration cutting, cryogenic cutting, surface nitridation and plasma assisted cutting, etc. Relevant commercially available devices are introduced as well. Furthermore, future research trends in diamond tool wear suppression are discussed and examined.
diamond tool ferrous metals wear suppression cutting chemical wear International Journal of Extreme Manufacturing
2020, 2(1): 012001
大连理工大学机械工程学院精密与特种加工教育部重点实验室， 辽宁 大连 116024
为提高铝合金薄板激光切割质量，对切割去除熔化物进行了收集、观察及测量研究。在Nd:YAG脉冲激光切割模式下，采用不同气熔比0.1898，0.2798，0.3708和0.6519，对0.85 mm厚的1000系铝合金薄板进行切割试验。试验通过超景深三维显微镜对收集的去除熔化物形状和尺寸进行观测研究。结果表明，去除熔化物颗粒由球形颗粒和蝌蚪形颗粒两种颗粒组成，其中球形颗粒平均尺寸在71~123 μm之间；高气熔比切割去除熔化物主要呈球形，颗粒尺寸较小，切割质量较好；低气熔比下熔化物主要是蝌蚪形，其中呈现的球形颗粒尺寸较大，切割质量较差。试验最终在辅助气压0.6 MPa高气熔比0.6519下获得了较高质量的切口。研究结果深化了铝合金激光切割的机理认识，有效提高了铝合金薄板的激光切割质量。
激光技术 激光切割 气熔比 熔化物形态 切割质量 铝合金薄板
大连理工大学机械工程学院， 辽宁 大连 116024
为提高缝阵天线薄板的激光切割质量，介绍了一种基于气熔比控制的激光精密切割方法。在NdYAG脉冲激光切割系统上，试验研究了气熔比对激光切割0.5 mm 厚6063铝合金薄板质量的影响，即气熔比对切口宽度、切口表面质量、重铸层和挂渣的影响。对气熔比分别为2.62，3.06和4.11的3组试件进行检测与观察，发现提高气熔比，可减小重铸层、增大切口表面光滑区、改善激光切割质量。试验获得切口顶部宽度为0.2 mm，底部无挂渣，重铸层厚度为2.03 μm，切口表面光滑区比例占切口的40%。结果表明，研究气熔比可深化对激光加工机理的认识，有效地提高铝合金薄板激光切割质量。
激光技术 激光切割 气熔比 切割质量
