叶片造型及多轴加工刀具轨迹研究

发布时间：2018-04-03 05:38

本文选题：NURBS技术　切入点：叶片造型　出处：《西安科技大学》2017年硕士论文

【摘要】：复杂曲面零件的精准造型、刀位轨迹规划是实现多轴数控编程及高质量加工的重要保障。叶片是典型的复杂曲面,也是航空发动机的“心脏”,其表面质量及加工效率对航空发动机性能有着至关重要的影响。因此本文旨在研究叶片几何造型、工艺及刀轨算法。基于NURBS参数曲线曲面造型技术,研究了直纹面叶片造型的数学模型;针对曲线应变能过大和曲率突变问题,采取样条插值法对叶片的型值点进行拟合,再运用遗传优化算法在MATLAB软件中对曲线进行光顺,提高了叶片截面线精度,完成了叶片的整体建模。基于叶片结构特征及技术要求,选用了螺旋铣削的加工方法;通过确定毛坯成型及余量分配、切削刀具、走刀方式、工艺路线,采用遗传算法对粗加工切削参数进行优化,完成了叶片的数控工艺设计。基于等残留高度法提出了组合曲面多刀路的螺旋轨迹构造算法,确定了刀位点、走刀步长、走刀行距、刀轴矢量等生成刀具轨迹的算法,解决了粗加工切除大余量毛坯需多次建立工序模型的复杂问题,并实现了叶片的高效加工,避免了叶片前后缘的干涉。利用NX CAM模块生成了叶片的螺旋轨迹,NX/post bulider模块开发了 2344VMC立式加工中心的专用后处理构造器,并生成与之相匹配的NC代码;通过VERICUT软件搭建机床模型,添加仿真系统,最终验证了工艺及刀具轨迹的可行性与正确性。为得到质高效优的叶片加工轨迹,论文围绕叶片的几何造型、加工工艺、螺旋铣加工刀位算法展开研究,通过优化仿真验证了其理论算法的可行性,有效提高了叶片类零件的造型精度及加工效率,为实现复杂曲面及叶片专用的CAD-CAPP-CAM-CNC 一体化的编程模块提供了理论参考。
[Abstract]:The precision modeling and tool path planning of complex curved surface parts are the important guarantee to realize multi-axis NC programming and high quality machining.Blade is a typical complex surface and the heart of aero-engine. Its surface quality and processing efficiency have a vital effect on the performance of aeroengine.Therefore, the purpose of this paper is to study blade geometry modeling, technology and tool track algorithm.Based on the modeling technology of curve and surface with NURBS parameters, the mathematical model of blade modeling on ruled surface is studied, and the spline interpolation method is adopted to fit the shape point of blade, aiming at the problem of excessive strain energy and abrupt curvature of curve.Then genetic optimization algorithm is used to smooth the curve in MATLAB software, which improves the accuracy of blade cross section line, and completes the overall modeling of blade.Based on the characteristics of blade structure and technical requirements, the machining method of helical milling is selected, and the parameters of rough machining are optimized by genetic algorithm through determining the blank forming and allowance distribution, cutting tool, cutting tool way, technological route, and genetic algorithm.The numerical control process design of the blade is completed.Based on the method of equal residual height, an algorithm for constructing multi-path helical loci of combined surfaces is proposed, and the algorithms for generating tool trajectories such as tool location, tool step size, tool distance and cutter axis vector are determined.The complex problem that rough cutting large margin blank needs to set up working procedure model many times is solved, and the efficient processing of blade is realized, and the interference of front and rear edge of blade is avoided.The special post-processing constructor of 2344VMC vertical machining center is developed by using the NX CAM module to generate the spiral track of the blade and the NX / post bulider module, and the corresponding NC code is generated, and the model of the machine tool is built by VERICUT software, and the simulation system is added.Finally, the feasibility and correctness of the process and tool path are verified.In order to obtain the high quality and high efficiency machining path of the blade, the thesis focuses on the geometric modeling of the blade, the machining technology, the cutter position algorithm of spiral milling, and verifies the feasibility of the theoretical algorithm through the optimization simulation.The modeling accuracy and machining efficiency of vane parts are improved effectively, and the theoretical reference is provided for the realization of the integrated programming module of CAD-CAPP-CAM-CNC for complex surfaces and blades.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG659

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