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孔加工过程中镗杆的切削颤振影响着表面加工质量和加工精度,约束阻尼型镗杆可有效抑制这种切削振动,但其作用机理未被完全研究清楚,导致其抑制振动的效果一般。对约束阻尼型镗杆的结构优化、材料优选及减振性能进行了理论和实验研究。首先,根据Kelvin-Voigt粘弹性力学模型理论建立了镗杆的动力学模型,研究证实增大镗杆的静刚度和结构损耗因子能提高其减振性能从而提高孔加工质量;其次,基于建立的约束阻尼型镗杆静刚度和结构损耗因子理论公式,对其进行结构优化、材料优选。结果显示:存在一个最佳尺寸范围可减小镗杆在主要工作频域段上的振动,同时所选用的阻尼层应具有较小的弹性模量和较大的材料损耗因子,约束层材料应具有较大的弹性模量;最后,设计制造4种不同材料的约束阻尼型镗杆,通过模态实验获得静刚度、结构损耗因子,并与理论计算结果进行对比分析,同时研究切削过程中约束阻尼型镗杆的材料及切削参数对减振性能的影响。结果显示:约束阻尼型镗杆能有效减小径向振动以提高加工质量,不同材料的约束阻尼型镗杆在切削过程中径向振动差别较大,优化后的钢-PMMA-硬质合金镗杆在不同切深及转速下的径向振动加速度较小且更加稳定。
The cutting flutter of boring bar affects the quality of surface machining and machining precision during the hole machining. Constrained damping boring bar can effectively restrain this cutting vibration, but the mechanism of its action has not been fully studied, resulting in its general effect of suppressing vibration. The structural optimization, material optimization and vibration damping performance of constrained damped boring bar are theoretically and experimentally studied. First of all, based on Kelvin-Voigt viscoelastic model theory, the dynamic model of boring bar is established. It is proved that increasing the static stiffness and the structural loss factor of boring bar can improve the vibration damping performance of the boring bar and improve the quality of the boring. Secondly, Constrained damped boring bar static stiffness and structural loss factor of the theoretical formula, its structural optimization, the material is preferred. The results show that there is an optimal size range to reduce the vibration of the boring bar in the main frequency domain and the damping layer should have a smaller elastic modulus and a larger material loss factor. Finally, the design and manufacture of four kinds of restraint-damping boring bars of different materials were used to obtain the static stiffness and the structural loss factor through the modal experiments, and compared with the theoretical calculation results. At the same time, the constraint in the cutting process Effect of Damping Boring Bar Materials and Cutting Parameters on Vibration Reduction Performance. The results show that constrained damping boring bar can effectively reduce the radial vibration to improve the machining quality. The radial vibration of the constrained damping boring bar with different materials varies greatly during cutting. The optimized steel-PMMA-cemented carbide boring The radial acceleration of the rod under different depth of cut and rotation speed is smaller and more stable.