The estimation of cutting forces and specific force coefficients during finishing ball end milling of inclined surfaces
The estimation of cutting forces and specific force coefficients during finishing ball end milling of inclined surfaces
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DOI：
10.1016/j.ijmachtools.2014.10.006
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发表时间：
2015-02
影响因子：
14
通讯作者：
S. Wojciechowski
中科院分区：
文献类型：
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作者：
S. Wojciechowski
大多数应用于球头铣削工艺的切削力模型仅包括切削参数（例如进给率、切削深度、切削速度）的影响，并根据槽铣削过程中校准的系数来估计力。此外，这些模型主要没有考虑径向跳动现象。然而，这种方法可能会导致过大的力估计误差，尤其是在雕刻表面的精加工球端铣削过程中。此外，大多数切削力模型都是针对轴向切削深度超过 0.5 mm 的球头铣削工艺制定的，因此它们并不直接面向精加工工艺。因此，本文提出了一种适用于精加工球头铣削的精确切削力模型，其中还包括表面倾斜和刀具跳动的影响。作为这项工作的一部分，还开发了比力系数校准的新方法。该方法基于在具有各种表面倾斜度的球头铣削过程中进行校准以及应用瞬时力信号作为输入数据。此外，还分析了比力系数与每齿进给量、切削速度和表面倾角的函数关系。为了精确确定切削的几何元素，在计算切削截面积和切削刃有效长度的方程中考虑了径向跳动。研究表明，刀具跳动和表面倾角对切削力的定量和定性都有显着影响。所制定的模型能够在较宽的切削参数范围内估计切削力，确保相对误差值低于16%。此外，所开发的模型考虑了刀具的径向跳动现象，使得模型的相对误差比不考虑径向跳动的模型减少了7%。
The majority of cutting force models applied for the ball end milling process includes only the influence of cutting parameters (e.g. feedrate, depth of cut, cutting speed) and estimates forces on the basis of coefficients calibrated during slot milling. Furthermore, the radial run out phenomenon is predominantly not considered in these models. However this approach can induce excessive force estimation errors, especially during finishing ball end milling of sculptured surfaces. In addition, most of cutting force models is formulated for the ball end milling process with axial depths of cut exceeding 0.5 mm and thus, they are not oriented directly to the finishing processes. Therefore, this paper proposes an accurate cutting force model applied for the finishing ball end milling, which includes also the influence of surface inclination and cutter's run out. As part of this work the new method of specific force coefficients calibration has been also developed. This approach is based on the calibration during ball end milling with various surface inclinations and the application of instantaneous force signals as an input data. Furthermore, the analysis of specific force coefficients in function of feed per tooth, cutting speed and surface inclination angle was also presented. In order to determine geometrical elements of cut precisely, the radial run out was considered in equations applied for the calculation of sectional area of cut and active length of cutting edge. Research revealed that cutter's run out and surface inclination angle have significant influence on the cutting forces, both in the quantitative and qualitative aspect. The formulated model enables cutting force estimation in the wide range of cutting parameters, assuring relative error's values below 16%. Furthermore, the consideration of cutter's radial run out phenomenon in the developed model enables the reduction of model's relative error by the 7% in relation to the model excluding radial run out.