微铣削中考虑刀具跳动的瞬时切厚解析计算方法

New Mathematic Method of Calculating Instantaneous Un-deformed Chip Thickness with Tool Run-out in Micro-end-milling

通过研究刀具实际切削过程中的余摆线轨迹及其影响,提出一种新的瞬时切厚解析计算方法,并针对两齿、四齿的情况给出瞬时切厚的具体计算公式。在两齿和四齿铣槽工况下,分析刀具跳动量和跳动角度对各齿切削过程的影响。该方法考虑刀具的综合径向跳动(包括主轴跳动,刀具制造安装误差等综合形成的径向跳动值),适用于微铣削中任意齿数刀具瞬时切厚的计算。通过与宏观铣削中的传统切厚计算公式、BAO模型和Newton-Raphson等数值法对比,量化指出了微细铣削加工与传统宏观铣削加工的一些不同,同时验证了提出的方法具有计算简洁、精度高和通用性强的优势。基于该模型进行了微铣削铣槽试验中切削力的预测,预测结果和试验结果相符良好,验证了模型的正确性和实用意义。

A new mathematic method of calculating instantaneous un-deformed chip thickness is established through analysis of true cutting tool tip trajectories. Two specific formulas are given in condition of two-flute and four-flute micro end milling. Then cutting process of each tooth with tool run out is analyzed by applying the new method in two-flute and four-flute micro slot milling. This new method considered comprehensive radial cutter run-out which include the spindle run-out and assemble errors and can be used to calculate the un-deformed chip thickness of cutting tools with any number of teeth. The accuracy and practicability are verified and some differences between micro milling and traditional milling process are pointed out by comparing the new method with other methods such as Bao＇s and Newton-Raphson method. Cutting force is predicted based on the new method in micro slot milling experiment. The simulation result shows a very good agreement with experiment data.