Abstract: Owing to the poor rigidity of big length-diameter ratio milling cutter in aerospace structure,the cutting efficiency and machining accuracy of machine tool were reduced extremely,thus the dynamic model of a two-Degree-Of-Freedom (DOF) passive damper was established.Based on H∞ optimization criterion,the damping ratio and frequency ratio of the damper were optimized,and their influence on damping performance was researched.Structural design of the damped milling cutter was proposed based on modal and harmonic analysis.Experiments demonstrated that the stiffness of damping cutter was increased by 2.5 times,damping ratio was increased by 46.5% and amplitude of frequency response function was reduced by 74% by comparing with the non-damped cutter.Machining tests validated the improvements of machined surface quality by the damped milling cutter.

Key words: damped milling cutter, two-degree-of freedom, damper, modal test

摘要： 鉴于航空结构件中大长径比铣刀的刚性较差,严重制约了机床切削效率和加工精度的提高,建立了两自由度被动阻尼器的动力学模型,基于H∞优化准则对阻尼器的阻尼比和频率比进行优化,并分析其对减振性能的影响。提出一种内置两自由度阻尼器长悬伸铣刀结构,在模态和谐响应分析的基础上,设计加工出减振铣刀。模态测试和激振实验结果表明,相比无阻尼空心铣刀,减振铣刀的等效刚度提高了25倍,阻尼比提高了465%,刀尖频响函数的幅值降低了74%。切削实验表明减振铣刀能显著提高零件加工表面质量。

关键词: 减振铣刀, 两自由度, 阻尼器, 模态测试