整体叶轮圆角立铣刀五轴U摆线剥铣轨迹规划

Integral Impeller Fillet-end Milling Cutter Five-axis U Cycloid Stripping Milling Path Planning

摆线剥铣工艺具有加工效率高、切削力小、刀具耐用度高的优点,然而由于缺乏五轴剥铣加工的轨迹规划方法,导致高效剥铣技术难以应用于整体叶轮加工。针对该问题提出一种整体叶轮圆角立铣刀五轴U摆线剥铣的轨迹规划方法。安排系列切削力实验,验证圆角立铣刀U摆线剥铣相较于现有球头立铣刀U摆线剥铣的加工优势。在此基础上建立叶轮模型降维映射关系,将三维叶根曲线映射到二维平面上,作为边界规划降维刀触点,基于刀触点与流道两侧叶片的比例关系计算刀轴矢量和刀位点,实现圆角立铣刀五轴U摆线剥铣轨迹初步规划。计算叶根过渡面上点到刀具特征面的距离,建立圆角立铣刀与叶根过渡面的干涉判据模型。使用投影法将干涉的叶根过渡面点集向刀轴矢量投影,计算刀具的最大轴向干涉量,从而优化刀位点排除叶根过渡面干涉。最后应用叶轮加工仿真验证五轴U摆线轨迹方法的有效性,结果表明五轴U摆线轨迹能够顺利实现整体叶轮圆角立铣刀剥铣加工,加工过程中无过切干涉,残留材料均匀,可为叶轮后续加工提供良好的基础。

Cycloidal stripping milling technology has the advantages of high machining efficiency,small cutting force and high tool durability.However,due to the lack of path planning method of five-axis stripping milling,it is difficult to apply efficient stripping milling technology to integral impeller machining.To solve this problem,a path planning method for five-axis U-cycloidal stripping milling of integral impeller fillet-end milling cutter is proposed.The dimensionality reduction mapping relationship of impeller model was established,and the three-dimensional blade root curve was mapped to the two-dimensional plane as the boundary planning tool contact point for dimensionality reduction.The tool axis vector and tool position point were calculated based on the proportional relationship between the tool contact point and the blade on both sides of the flow channel,and the preliminary planning of the five-axis U-cycloidal stripping milling path of the fillet-end milling cutter was realized.The distance between the point on the blade root transition surface and the tool characteristic surface was calculated and the interference criterion model between the blade root transition surface and the fillet-end milling cutter was established.The tool's maximum axial interference was calculated by projection method,and the tool position point was optimized to eliminate the interference of the blade root transition surface.Finally,the impeller machining simulation is used to verify the effectiveness of the five-axis U-cycloidal path method.The results show that the five-axis U-cycloidal path can successfully realize the stripping-milling machining of the integral impeller with the fillet-end milling cutter,without over-cutting interference in the machining process,and the residual material is uniform,which can provide a good foundation for the subsequent machining of the impeller.