铣削力及铣削表面微观形貌分维数的研究

【作者】 胡家国；

【导师】 李迎；

【作者基本信息】 南京理工大学 ， 机械制造及自动化， 2004， 硕士

【摘要】 高速切削是最近二十年崛起的一门先进制造技术。国外在高速切削机理方面做了大量研究工作。国内在这方面的研究相对滞后，急待开展或深入相关课题。 针对铝合金的高速铣削过程中的铣削力及铣削表面微观形貌分形机理进行了研究。首先从切削力对加工过程的影响，切削力的基本关系入手；建立了铣削力理论模型；分析了高速进给轴驱动系统的动力特性，结合动态轴的静态定位误差方程，指出高速切削与常规切削的差异；高速铣削条件下，切削力所引起的挠度影响刀具的动平衡，给出了动平衡临界转速计算方法；实验测定铣削力，通过分析铣削力的变化，来推测加工过程中是否存在切屑瘤，验证铣削方式的合理性；编程实现铣削合力精确值的计算；然后从总体上分析了切削力随切削速度变化的趋势。简要介绍了分形的基本概念，并对其发展历史进行了论述；基于工程粗糙表面的微观形貌具有统计自相似分形特征，因此任何传统的对粗糙表面定量的描述，都随测量尺度的改变而变化，未能涉及到表面形貌的本质特征；文中将分形几何学应用于高速铣削表面微观形貌的研究，明确给出了重要分形指标——分维数的物理含义；采用计算机模拟生成一些具有分形特征的典型图形；基于W-M函数模拟出不同分维数的表面轮廓曲线，建立了分形参数与传统表面精度指标间的关系；采用结构函数法计算出高速铣削表面轮廓的分维数。更多还原

【Abstract】 High speed cutting is an advanced machining technique, which develops very quickly in the last two decades. A lot of research has been done on the mechanism of high speed cutting at abroad. However, relative research is lagging behind at home in the field, correlative project needs to be launched out or deepened urgently.Based on high speed milling of aluminum-alloy, analyzing milling-force and fractal mechanism of high speed milling surface micro-topography. First, start with cutting force affects machining process and cutting force basic relationship; establish the theoretical model of milling force; analyzing dynamic characteristic of high speed feed drive, combined with the static error equation, point out the difference between high speed cutting with normal speed cutting; under the condition of high speed milling, cutting force is evocative of deflection of cut tool, which affects cut tool’s dynamic balance, a effective method is pointed out to determine the critical speed; experiment has been done in order to measure milling force, by analyzing cutting-force fluctuating rule so as to deduce whether exist built-up edge in the machining process or not, validate the rationality of milling style; programming realized calculating precise milling resultant force; later, analyzing varied trend of cutting force according to different cutting speed as a whole; the basic concept of fractal geometry is introduced, and the development of fractal geometry is discussed; on the basis of engineering rough surface micro-topography is form of statistical self-similarity, therefore, any traditional quantitative description of rough surface varies in accord with the change of measure scale, and never touches the natural properties of surface profile; this paper applies the fractal geometry to the research on surface topography of high speed milling, the meaning of fractal dimension, which is important in fractal research, is described; apply with computer to simulation classic figure with fractal characteristic; surface profile with different fractal dimension has been simulation based on W-M function; and indicates the relation between the dimension and the surface roughness; the fractal dimension of high speed milling surface micro-topography is calculated by the structure function method.更多还原