光栅已经在光谱分析、国防科工、智能穿戴等众多重要领域得到了广泛应用。随着科技的进步与发展，新型光学仪器对光栅的基体材料性能以及槽型控制提出了越来越高的要求。金属玻璃具有独特的非晶结构以及高硬度、高强度、耐腐蚀等优异的性能，是用于光栅制造的潜在优异材料。光栅槽型的灵活控制有助于简化光学仪器的光路设计，提升其光学性能，是光栅发展的一个重要方向。然而，传统的光栅加工技术不能满足在难加工材料上进行复杂槽型光栅加工的需求。本文提出了控形振动切削（SVC）技术，对控形轨迹振动技术、SVC工艺特性及机理以及金属玻璃切削机理等方面开展研究，为金属玻璃复杂槽型光栅的加工提供全新的工艺解决方案及理论指导。首先，开发了正交方向运动解耦的二维非谐振振动切削装置，并进行刀具控形轨迹振动的精确控制方法研究。仿真与实验结果表明，所开发的振动装置能够实现500 Hz的三角形轨迹高频振动。在此基础上，结合刀具在空间的位置或者振动时间，提出了离散式周期性变化控形轨迹及连续周期性渐变控形轨迹等复杂控形振动轨迹的控制方法，为SVC技术的应用奠定了基础。接下来，开展了SVC技术的工艺特性及加工机理研究。SVC技术具有减小材料加工残留高度、表面粗糙度以及未变形切屑厚度的作用，能够实现超精密切削加工以及脆性材料的“延性域”加工。但由于周期性的瞬时切削方向变化，SVC加工容易在切出口边沿形成飞边或崩边等缺陷。在缺陷形成机理的研究基础上，提出高表面完整性织构槽阵列SVC工艺方法并开展实验验证。该工艺的关键在于控制微织构槽的高度小于缺陷形成的临界高度。实验结果表明，运用该工艺能够在铝及单晶硅上进行高表面完整性中阶梯光栅的加工。最后，研究了基于非均匀变形特性的金属玻璃切削机理，为其超精密切削加工奠定理论与工艺基础。非均匀变形特性使金属玻璃兼具脆性与延性特征，使其预变形区形成主剪切滑移区与滑移台阶，滑移台阶会向预创成表面生长。同时，非均匀变形特性具有速度敏感特性以及尺寸效应，高的切削速度以及小的未变形切屑厚度会使预变形材料软化甚至熔化，影响加工表面质量以及刀屑接触状态。综合以上研究成果，最终在金属玻璃上实现了多闪耀光栅及渐变闪耀面光栅为代表的复杂槽型光栅的加工，所得光栅的表面粗糙度低至15 nm。
Diffraction gratings have been widely used in many fields, such as spectral analysis, military industry and intelligent wear, and so on. With the development of science and technology, new optical instruments put forward higher and higher requirements on the properties of substrate materials and the control of grating’s groove profile. Bulk metallic glasses (BMGs) have a unique amorphous structure and excellent properties such as high hardness, high strength, and corrosion resistance. Thus, it is a potential excellent substrate material for gratings. The flexible control of grating grooves is helpful to simplify the light route design and improve the optical performance of optical instruments, which is an important trend in grating development. However, the traditional grating processing technology is difficult to meet the requirements of grating fabrication on difficult-to-cut materials, and it is difficult to control the grooves’ profile flexibly. In this paper, a new vibration cutting technology called shaped vibration cutting (SVC) is invented. The control strategy of arbitrary vibration locus, process characteristics and cutting mechanism of SVC and cutting mechanism of BGM are studied. It provides a new process solution and theoretical guidance for the fabrication of BMG gratings with complex groove profiles.Firstly, a two-dimensional non-resonant vibration cutting device with decoupling motion in the orthogonal direction was developed, and the precise control method of tool arbitrary vibration locus was established. The simulation and experimental results confirmed that the developed high frequency non-resonant cutting device was able to realize the triangle locus vibration with a high frequency of 500 Hz. Further more, combined with the position of the tool or the vibration time, control methods for complex vibration loci were proposed, which lays a solid foundation for the application of SVC technology. Secondly, the process characteristics and processing mechanism of SVC technology were studied. The SVC technology can reduce the residual height, surface roughness and thickness of undeformed chips, which can realize ultra-precision machining of brittle materials in ductility -regime. However, due to the periodic change of instantaneous cutting direction, SVC process is easy to induce the defects on the groove edge, i.e., burrs and edge chipping. Based on the study of defect formation mechanism, a defect-less groove array SVC process strategy was proposed and verified by experiments. The key of this process is to control the height of the grooves to be smaller than the critical height of defect formation. Experimental results confirmed that the process can be used to fabricate the echelle gratings with high surface integrity on aluminum and single crystal silicon.At last, the cutting mechanism of BMG based on the inhomogeneous deformation characteristics was found, which laid the theoretical and technological foundation for ultra-precision micro-cutting of BMG. The inhomogeneous deformation characteristics make the metallic glass both brittle and ductile. The primary shear zone and slip steps are formed in the predeformation zone, and the slip step will grow into the preformed surface. What’s more, inhomogeneous deformation characteristics have velocity-sensitive characteristics and size effect. High cutting speed and small undeformed chip thickness will soften or even melt the pre-deformed material, which impacts on the machining surface quality and tool-chip contact state. Based on the previous researches, the multi-blaze gratings and graded blaze facet gratings were finally fabricated on BMG, whose surface roughness was as low as 15 nm.
