光栅刻划刀具弹性支撑机构颤振抑制性能优化

Optimization of chatter suppression performance of elastic support mechanism for grating ruling tools

机械刻划是以中阶梯光栅为主导的大闪耀角、高衍射级次光栅的主要加工方法,其大闪耀角特性使中阶梯光栅的刻划加工难度大幅增加。当光栅刻划刀对刃误差较大,或刀具非力平衡设计时,刻划过程中刀具会受到较大水平扭矩,易导致刀具颤振现象,从而影响光栅质量。为抑制刀具颤振,提高光栅刻划稳定性,针对光栅刻划刀弹性支撑机构的颤振抑制性能开展研究,提出了双层平行弹簧支撑机构。通过有限元仿真对比分析了新旧刀架机构的结构刚度和模态特性,并利用加速度传感器测试了两种刀架机构的刻划刀具颤振状态,对比了两种刀架对颤振的抑制效果。结果表明,双层平行弹簧刀架机构受刻划扭矩时,在刀具夹持处及柔性铰链处的变形较传统刀架结构分别减少了36%和24%,一阶模态提升了2.8倍。颤振信号在时域下基线两侧幅值分别降低了13.6%及22.5%。光栅刻划实验表明,新机构有利于刻划制造中阶梯光栅,所提出的刀架优化设计方法和颤振抑制技术可为光栅刻划制造技术提供理论指导。

Mechanical ruling is the main processing method for gratings with a large blaze angle and high diffraction order,such as echelle.The large blaze angle of echelle makes its ruling process difficult.When the angle between the ruling tool edge direction and the ruling direction exceeds the error or when the rul-ing tool is designed without force balance,the tool undergoes a large horizontal torque during the ruling process,which can easily lead to tool chatter,affecting the quality of the gratings.To suppress the tool chatter and improve the stability of the grating ruling process,the chatter suppression performance of the grating ruling tool elastic support mechanism is evaluated in this study,and an innovative double-layer par-allel hinge tool carrier is proposed.The structural stiffness and modal characteristics of the new and old tool carriers are compared and analyzed through finite-element simulation.The chatter state of the two tool holders is measured using an acceleration sensor,and the chatter suppression effects of the two tool holders are compared.The results indicate that when the double-layer parallel spring tool carrier is subject-ed to the ruling torque,the deformation at the tool clamping position and the flexure hinge is reduced by 36%and 24%,respectively,compared with the previous structure,and the first-order mode is increased by a factor of 2.8.The amplitude of the flutter signal on both sides of the baseline is reduced by 13.6%and 22.5%,respectively,in the time domain.The test results confirm that the proposed mechanism is ad-vantageous for echelle ruling.The proposed tool carrier optimization design method and flutter suppres-sion technology provide new theoretical guidance for grating ruling technology.