基于切削稳定性的高性能圆周铣刀结构优化设计理论与方法

Peripheral milling cutter is widely used for machining monolithic components in aerospace and aeronautic manufacturing industries, owing to its characteristics of high efficiency, good generality and wide application range. However, due to lack of in-depth knowledge of the cutter's dynamic mechanism, statics-based trial and error method is still the main design approach of milling cutter.This greatly limits the exploitation of the potential dynamic performance of the cutter together with its popularization.The motivation of this project is to explore the dynamic mechanism of peripheral milling cutter and the optimization of the geometry parameters from the point view of process mechanics. Firstly, foundation works covering the the following aspects will be studied. .(1)Measuring and obtaining methods of the basic parameters such as the shearing stress,shearing angle, chip flow angle, friction angle and system mode parameters..(2)Characterization approach of the cutter geometries..(3)Development of the general cutting force model, general chatter stability model and finite element generation model..Then, to obtain the dynamic explanation required in the design procedure, the relationships will be explored between the cutter's geometry parameters and the models developed above. Finally, a principle for optimizing the cutter geometry parameters will be proposed by taking into account the static and dynamic responses of the milling system simultaneously. Through the implement of this project, it can be expected to provide methodologies of exploring the cutter's process mechanical behavior from the perspective of of process mechanics, structure mechanics and optimization theory. Furthermore, the studies mentioned above constitute the basic theories for carrying out cutter design of high precision, high efficiency and reliable stability.

圆周铣刀具有高效、通用、适用范围广等特征，在航空航天整体件切削工艺中广泛应用。然而由于缺乏对铣刀动力学机理的准确把握，现有铣刀设计方法仍然基于静力学与试验结合的方式进行，严重制约该类铣刀的潜在动力学性能挖掘与普及应用。为解决这一难题，本项目将从动力学角度研究铣刀通用动力学机理与几何参数优化设计理论。在攻克剪切应力、剪切角、切屑流动角、摩擦角、系统模态等参数的测试获取方法、以及铣刀几何参数的表征等底层技术基础上，建立铣刀通用切削力模型、颤振稳定性模型以及有限元生成模型，并揭示各模型与铣刀结构参数的内在依赖关系，获得铣刀设计所需的切合工艺实际的动力学解释。在此基础上，结合优化方法，建立同时考虑静力学与动力学稳定性的铣刀优化设计理论。本项目的研究将从工艺力学、结构力学、优化理论等不同层面认知铣刀的切削力学行为，为高性能圆周铣刀设计技术的发展和应用提供关键理论基础。

以建立考虑动力学性能的圆周铣刀结构优化设计理论为目标，借助于实验研究、理论推导以及数值仿真等方法，围绕刀具设计所涉及的基础理论问题进行了研究。重要研究进展有：.1)针对传统标定方法效率低、依赖大量正交车削试验确定切削力模型中关键参数（剪切应力、剪切角、摩擦角）的状况，提出了采用“单次试验、多点采样”实测切削力替代“多次试验、单点采样”进行参数标定的简化方法。标定方法经大量试验表明适用于顺逆铣、槽铣等切削方式和任意几何轮廓刀具。.2)刀轴系统动力学特性准确识别是进行铣削过程稳定性分析的关键基础，建立了旋转刀具的刀轴系统通用动力学模型；并发展了适用于小尺寸刀具的扭转和轴向动力学特性的测量方法；实现了整个刀具关于X、Y以及Z轴的平动和转动响应的准确预测。 .3)通过有机关联延时量与刀具几何参数表征切削力，建立了多模态多时滞切削系统颤振稳定性分析的统一模型，并针对常规铣削、螺纹铣削以及多功能钻削刀具切削过程进行了切削机理揭示。.4)提出了颤振稳定性叶瓣图快速求解的时域最低包络线方法，理论推导发现，通过多模态参数解耦近似，单模态叶瓣图最低包络线能有效逼近多延时多模态叶瓣图；其计算效率随着时间积分步长的细分较传统方法可提升约85%以上。.5)建立了犁切力与后刀面压缩体积的关联模型，并通过静态铣削试验实现了犁切系数的标定，实现了了刀刃圆角半径与过程阻尼效应的统一表征。.6)基于静力学与动力学指标研究了刀具几何参数的优化方法，并通过构建考虑刀具/工件动力学参数变化的曲面薄壁件铣削动力学模型，在弱刚度构件切削工艺中开展了试验验证研究。