镜像铣加工过程中薄壁工件变形和振动的预测  

Prediction of Deflection and Vibration of Thin-Walled Workpiece During Mirror-Milling Process

作　　者：王建山[1] 何天宇 肖聚亮[1] 刘海涛[1] Wang Jianshan;He Tianyu;Xiao Juliang;Liu Haitao(School of Mechanical Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学机械工程学院,天津300072

出　　处：《天津大学学报（自然科学与工程技术版）》2022年第3期263-272,共10页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(91948301,91648202).

摘　　要：镜像铣是大型薄壁工件加工的有效方法,在航空航天等重要领域有着广泛的应用.镜像铣加工过程中薄壁工件的变形和振动是影响加工精度的主要因素,如何准确预测镜像铣加工过程中薄壁工件的变形和振动是优化加工参数、提高加工精度的关键问题.本文基于金属切削原理并考虑了薄壁工件加工过程中的弯曲变形和铣削力相互作用,建立了铣削力预估模型.在此基础上,结合薄板小变形理论和有限元法,建立了考虑加工过程中材料去除和铣削力与支撑同步运动的薄壁工件镜像铣动态力学模型.通过仿真模拟,研究了支撑刚度、支撑阻尼、主轴转速和进给率对薄壁工件变形和振动的影响规律.结果表明,在镜像铣加工过程中薄壁工件的变形随着支承刚度的增加而减小,振动幅值随着支撑阻尼的增加而减小.最后,对6061铝合金薄板的镜像铣加工实验与本文建立模型的时域和频域信号进行了比较.振动数据采集点处的模型预测结果与实验相差小于5%,二者对比结果表明所建立的模型能够对薄壁工件加工过程中的变形和振动进行准确的预测.镜像铣加工相比于直接铣削加工,薄板加工点处的振动幅值从71.61μm减小到5.71μm,对比结果表明柔性支撑结构能够有效地减小加工过程中薄壁工件的振动.本文工作有助于提高薄壁工件的镜像铣加工精度.Mirror-milling is considered to be one of the most effective methods for machining large thin-walled work-pieces,which are commonly used in aerospace and other important fields.During the mirror-milling process,the thin-walled workpieces’deflection and vibration are the main factors that distinctly affect the machining accuracy.Thus,the effective prediction of the deformation and vibration of thin-walled workpieces is crucial for optimizing the parameters and improving the accuracy.Based on the principles of metal cutting,this study develops a model accounting for the interactions between the thin-walled workpiece deflection and the applied load to predict the actual milling force.Based on the Kirchhoff plate theory and finite element method,a dynamic model is developed to simulate the deflection and vibration of thin-walled workpieces during the mirror-milling process.The effects of support stiffness,support damping,spindle speed,and feed rate on the deflection and vibration of thin-walled workpieces have been investigated.The deformation of the thin-walled workpiece decreases with increased support stiffness,and the vibration amplitude decreases with increased support damping.Mirror-milling tests of the thin-walled workpiece made of aluminum alloy 6061 are conducted to verify the developed dynamic model.Both the time and frequencydomain signals of displacement are compared with those from the tests using the established model.The differences between the predicted results and those obtained from the experiment at the vibration data collection point are less than 5%,demonstrating the effectiveness of the proposed model in predicting and analyzing the deflection and vibration of the thin-walled workpiece during mirror-milling.Under the action of a multipoint flexible following support head,the vibration amplitude of the workpiece is reduced from 71.61μm to 5.71μm.The results show that the flexible follow-ing support head can effectively suppress the vibration.The study is helpful in improving the machining acc

关 键 词：镜像铣 薄壁工件 变形 振动 预测 支撑 加工参数 

分 类 号：TK448.21[动力工程及工程热物理—动力机械及工程]