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In high speed milling aeronautical part, tool condition monitoring(TCM) is very important, because it is prone to get a chatter owing to the low stiffness of thin-walled structures. And the TCM is key technology for automated machining. In this paper, aiming to chatter monitoring in thin-walled structure milling, a variational mode decomposition – energy distribution(VMD-ED)method is proposed to improve the identification accuracy. And a moving average root mean square – mean value(MARMS-MV) ide... 相似文献
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《中国航空学报》2022,35(8):249-264
Currently, industrial robots are considered as an alternative towards traditional machine tools. Especially for the large-scale parts milling, robotic flexibility and low cost make it possess the irreplaceability. However, the milling chatter caused by its weak rigidity hampers robotic application and promotion severely in aviation industry. Rotary ultrasonic milling (RUM) technology with one-dimensional axial vibration has been proven and approved on avoiding robotic chatter. Based on this, the research of project team demonstrates that longitudinal-torsional composite ultrasonic milling (CUM-LT) involving separation characteristic has a greater advantage than RUM in terms of chatter suppression. Thereby, the CUM-LT as a new means is applied to avoid processing vibration of robotic milling system. And its influence mechanism on stability improvement of weak stiffness processing system is clarified. Meanwhile, the approaches to strengthen separation effect are provided innovatively. Moreover, a new analysis method of robotic CUM-LT (RCUM-LT) stability is proposed on the basis of ultrasonic function angles. The simulation and experimental results indicate that compared with robotic RUM (RRUM), stability regions of separated RCUM-LT (SRCUM-LT) and unseparated RCUM-LT (URCUM-LT) are improved by 124.42% and 39.20%, respectively. The addition of torsional ultrasonic energy has a wonderful effect on the milling chatter suppression of low stiffness robots. 相似文献
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基于动力学仿真技术的TC4整体叶轮铣削参数优化 总被引:3,自引:1,他引:2
针对某航空发动机TC4整体叶轮在数控加工过程中存在颤振、加工效率低及因加工变形而导致局部超差等问题,提出了相应的铣削参数优化解决方案。在进行切削力系数辨识试验获取TC4材料的切削力系数及锤击试验获取加工系统动力学特性参数的基础上,通过综合使用自行开发的铣削加工动力学仿真软件SimuCut和国外的CutPro软件进行动力学仿真与优化,获得了优化的切削参数。使用优化的切削参数进行加工,有效地消除了颤振和因加工变形引起的局部超差,提高了加工效率。 相似文献
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Milling of the thin-walled workpiece in the aerospace industry is a critical process due to the high flexibility of the workpiece. In this paper, a flexible fixture based on the magnetorheological(MR) fluids is designed to investigate the regenerative chatter suppression during the machining.Based on the analysis of typical structural components in the aerospace industry, a general complex thin-walled workpiece with fixture and damping constraint can be equivalent as a rectangular cantilever beam. On the basis of the equivalent models, natural frequency and mode shape function of the thin-walled workpiece is obtained according to the Euler–Bernoulli beam assumptions. Then,the displacement response function of the bending vibration of the beam is represented by the product of all the mode shape function and the generalized coordinate. Furthermore, a dynamic equation of the workpiece-fixture system considering the external damping factor is proposed using the Lagrangian method in terms of all the mode shape function and the generalized coordinate, and the response of system under the dynamic cutting force is calculated to evaluate the stability of the milling process under damping control. Finally, the feasibility and effectiveness of the proposed approach are validated by the impact hammer experiments and several machining tests. 相似文献
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针对一类典型流线型曲面——叶片的高效数控铣削加工方法研究,提出了基于加工系统动力学仿真分析的高效切削参数优化技术,该方法是提高切削加工效率,保证零件加工精度和表面质量的有效手段.首先,辨识得到加工零件材料的铣削力系数;其次,利用锤击试验分别得到机床-刀具系统及弱刚性零件结构的动态特性,同时利用有限元方法进行模态分析,并与试验结果进行对比分析,可辅助验证锤击试验结果的正确性,在此基础上仿真得到铣削颤振稳定域曲线,然后对建立了基于加工系统动态稳定性的高效数控铣削加工参数优化系统进行高效铣削参数优化;最后,依据优化的铣削参数制定零件铣削加工工艺,试验得到了加工质量合格的叶片,其加工效率较传统方法有显著的提高. 相似文献
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《中国航空学报》2021,34(6):54-66
Fixtures are a critical element in machining operations as they are the interface between the part and the machine. These components are responsible for the precise part location on the machine table and for the proper dynamic stability maintenance during the manufacturing operations. Although these two features are deeply related, they are usually studied separately. On the one hand, diverse adaptable solutions have been developed for the clamping of different variable geometries. Parallelly, the stability of the part has been long studied to reduce the forced vibration and the chatter effects, especially on thin parts machining operations typically performed in the aeronautic field, such as the skin panels milling. The present work proposes a commitment between both features by the presentation of an innovative vacuum fixture based on the use of a vulcanized rubber layer. This solution presents high flexibility as it can be adapted to different geometries while providing a proper damping capacity due to the viscoelastic and elastoplastic behaviour of these compounds. Moreover, the sealing properties of these elastomers provide the perfect combination to transform a rubber layer into a flexible vacuum table. Therefore, in order to validate the suitability of this fixture, a test bench is manufactured and tested under uniaxial compression loads and under real finish milling conditions over AA2024 part samples. Finally, a roughness model is proposed and analysed in order to characterize the part vibration sources. 相似文献
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针对航空铝合金薄壁工件铣削加工时易出现的颤振以及切削效率低的问题,从动力学角度出发进行了深入的分析研究,提出了通过采用保持工艺系统高刚性的加工过程工艺优化与铣削加工动力学仿真结合的方法进行铣削加工.试验结果证明本法可以收到很好的效果,较好地解决了航空铝合金薄壁结构工件加工的颤振问题,提高了工件的加工表面质量和切削效率. 相似文献