摘要
各种复杂的自由型曲线和曲面被广泛应用在矿山设备、汽车、航空航天等多个领域,自由曲面一般采用数控方式进行加工。针对曲面数控精加工表面质量不易满足要求的问题,文中对比研究了不同的插补方式对自由曲面表面加工质量的影响。应用3次NURBS曲线反求的方法,对一组已知的离散型值点进行拟合,计算出该拟合曲线的节点矢量和控制顶点,并在MATLAB中生成相应的NURBS曲线;按照FANUC数控系统的格式要求编写直线插补、直线-圆弧插补和NURBS插补3种不同插补方式的数控加工程序;调用3种不同的数控加工程序在数控机床上对经过预处理的工件进行精加工,然后使用表面粗糙度仪对精加工完成的曲面轮廓进行测量,获得相应的粗糙度值。对比分析直线插补、直线-圆弧插补和NURBS插补等3种不同插补方式刀具路径实际加工完成的曲面轮廓粗糙度值,结果表明NURBS插补刀具路径可以明显改善曲面精加工轮廓的光顺性,改善表面加工质量。NURBS插补能够适应数控高速加工的要求,很好地满足自由曲面高速高性能数控加工的需求。
Various complex free-form curves and surfaces are widely used in mining equipment,automobile,aerospace and other fields.The free-form surface is generally processed by numerical control machine tool.To solve the problem that the surface quality of the free-form surface machined by CNC is not easy to meet the requirements,this paper makes a comparative analysis of the influence of interpolation methods on the free-form surfaces machining quality.A set of discrete data points are fitted by using the method of cubic NURBS curve reverse.The node vector and control vertex of the fitting curve are calculated,and the corresponding NURBS curve is generated in MATLAB.According to the format requirements of FANUC CNC system,three kinds of NC machining programs with different interpolation methods are compiled.Different NC programs are used to finish the preprocessed workpiece on the NC machine with the surface contour measured by the surface roughness tester to obtain the corresponding roughness.This paper compares and analyzes the surface profile roughness of three different interpolation methods,such as line interpolation,line arc interpolation and NURBS interpolation.The results show that NURBS interpolation tool path can obviously improve the smoothness of surface finish machining profile,improve the surface machining quality,adapt to the requirements of high-speed CNC machining,and it also can meet the requirements of high-speed and high-performance CNC machining of free-form surface.
作者
霍亚光
高扬
宋绪丁
尚成厂
HUO Ya-guang;GAO Yang;SONG Xu-ding;SHANG Cheng-chang(Modern Engineering Training Center,Chang’an University,Xi’an 710018,China;College of Mechanical Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;The Key Laboratory of Road Construction Technology and Equipment of MOE,Chang’an University,Xi’an 710064,China;Xi’an Satellite Control Center,Xi’an 710043,China)
出处
《西安科技大学学报》
CAS
北大核心
2020年第4期737-743,共7页
Journal of Xi’an University of Science and Technology
基金
国家自然科学基金(51605379)
长安大学教育教学改革研究项目(0003-300103691913,201938)。
关键词
自由曲面
曲线拟合
NURBS插补
数控加工
粗糙度
free-form surface
curve fitting
NURBS interpolation
CNC machining
surface roughness
