箱底薄壁瓜瓣镜像铣削加工稳定性分析  

Stability Analysis for Mirror Milling of Thin-Walled Melon Flap on Box Bottom

作　　者：秦旭达[1] 刘雪峰 张绍璞 崔鑫 刘见 李士鹏[1] Qin Xuda;Liu Xuefeng;Zhang Shaopu;Cui Xin;Liu Jian;Li Shipeng(School of Mechanical Engineering,Tianjin University,Tianjin 300350,China;Tianjin Aerospace CZ Rocket Manufacturing Co.,Ltd.,Tianjin 300462,China)

机构地区：[1]天津大学机械工程学院,天津300350 [2]天津航天长征火箭制造有限公司,天津300462

出　　处：《天津大学学报（自然科学与工程技术版）》2024年第11期1161-1169,共9页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(52075380,52275459);天津市自然科学基金资助项目(21JCYBJC00610).

摘　　要：贮箱箱底采用薄壁瓜瓣拼焊技术成形,瓜瓣尺寸大、壁厚薄,针对其镜像铣削加工过程中的易发生颤振问题,提出一种薄壁瓜瓣镜像铣削加工的稳定性分析方法.首先,根据铣削力的相互作用关系,将整个镜像铣削加工系统分为机床主轴-刀具子系统和工件-辅助支撑子系统,建立由再生效应产生的动态切削厚度模型和圆弧铣刀动态铣削力模型,建立同时考虑刀具端径向两个方向和工件端法向振动的刀具-工件-辅助支撑系统三自由度动力学模型.然后,基于锤击实验法获取机床主轴-刀具子系统、工件-辅助支撑子系统的动力学参数,基于半离散时域法对薄壁瓜瓣镜像铣削加工稳定性进行预测.最后,开展薄壁瓜瓣镜像铣削加工实验,分析提出的薄壁瓜瓣镜像铣削加工稳定性预测方法的准确性.结果表明:辅助支撑的引入使工件远离卡具位置法向局部刚度最高提升了约7倍,与刀具径向刚度相近,都处在1×10^(7) N/m数量级,刀具端和工件端的动力学特性会同时影响整个镜像铣削系统的加工稳定性,铣削动力学模型中工件子系统和刀具子系统需同时考虑.建立的三自由度动力学模型及预测的稳定域具有较高的预测精度,对实现薄壁瓜瓣的稳定高效加工具有重要的理论意义和工程应用价值.针对3.35 m级贮箱箱底薄壁瓜瓣镜像铣削加工,考虑到精加工中薄壁瓜瓣减薄厚度要求,主轴转速选择在6000~7000 r/min范围时,推荐切深选择1.0 mm.The bottom of storage box is formed using thin-walled melon flap welding technology.However,the melon petal is large and the wall is thin.To address the problem of chatter during mirror milling,a stability analysis method for thin-walled melon flap mirror milling was proposed.First,on the basis of the interaction of milling forces,the entire mirror milling machining system was divided into a machine spindle-tool subsystem and a workpiece-auxiliary support subsystem.A dynamic cutting thickness model generated by a regeneration effect,a dynamic milling force model of an arc milling cutter,and a three-degree-of-freedom dynamic model of the tool-workpieceauxiliary support system that considered both the radial direction of the tool end and the normal vibration of the workpiece end were established.Then,based on the hammer experiment method,the dynamic parameters of the machine spindle-tool subsystem and the workpiece-auxiliary support subsystem were obtained.The semi-discrete time domain method was used to predict the stability of thin-walled melon flap mirror milling processing.Finally,we conducted experiments on the mirror milling of thin-walled melon flaps and analyzed the accuracy of the proposed stability prediction method. The results show that the introduction of auxiliary support increases the normal local stiffness of theworkpiece away from the fixture position by about seven times,similar to the radial stiffness of the tool and in theorder of 1×10^(7) N/m. The dynamic characteristics of the tool end and workpiece end simultaneously affect the machiningstability of the entire mirror milling system. The workpiece subsystem and tool subsystem in the milling dynamicsmodel must be considered simultaneously. The established three-degree-of-freedom dynamic model and predictedstability domain have high prediction accuracy. This has important theoretical significance and engineering applicationvalue for achieving stable and efficient machining of thin-walled melon flaps. For the mirror milling of thin-walledmelon f

关 键 词：贮箱箱底 薄壁件 稳定性分析 镜像铣削 

分 类 号：TG54[金属学及工艺—金属切削加工及机床]