Implementation of CL points preprocessing methodology with NURBS curve fitting technique for high-speed machining
Implementation of CL points preprocessing methodology with NURBS curve fitting technique for high-speed machining
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DOI：
10.1016/j.cie.2014.12.018
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发表时间：
2015-03
期刊：
影响因子：
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通讯作者：
Jichun Wu;Huicheng Zhou;Xiaoqi Tang;Jihong Chen
中科院分区：
文献类型：
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作者：
Jichun Wu;Huicheng Zhou;Xiaoqi Tang;Jihong Chen
由于直线/圆弧插补的局限性，以NURBS曲线为代表的参数插补在机床计算机控制中发挥了关键作用。为了获得最高质量的零件，生成的轨迹必须准确地描述所需的刀具路径。但是，由于某些限制，无法直接从CAD模型生成NURBS刀具路径。提出了一种基于NURBS曲线拟合技术的高速加工CL点前处理方法。首先对CL点进行预处理，不合适的CL点可以分为三种情况：距离短、相邻距离不等和尖锐点。对每一种情况进行识别和修正，可以提高NURBS曲线的拟合质量。然后使用CL点、角点和距离规则来提取每个分割的CL点。利用二分法，利用CL点对NURBS曲线进行了有效的拟合。如果在这种情况下使用曲线没有优势，将直接输出CL点。在波面CL点上进行的仿真实验表明，该方法在保持误差容限的前提下，使NC块减少到3.3%左右。加工实验表明，该方法能在提高加工质量的同时，缩短加工时间约19%。
Due to the limitations of linear/circular interpolation, parametric interpolation typically represented by NURBS curves, has played a key role in the computer control of machine tools. To achieve the highest quality parts, generated trajectories must describe the desired toolpath accurately. However, a NURBS toolpath cannot be generated directly from a CAD model, due to certain limitations. CL points preprocessing methodology with NURBS curve fitting technique for high-speed machining is proposed in this paper. CL points are initially preprocessed, and unsuitable CL points can be grouped into three problematic cases: short distance, unequal adjacent distance and sharp points. Each case is identified and corrected, which can improve the fitted NURBS curve quality. CL points corner and distance rules are then used to extract CL points for each segmentation. Using the bisection method, a NURBS curve is efficiently fitted using CL points. If there is no advantage to using a curve in this case, CL points will be output directly. The simulation performed on CL points for a wave surface demonstrates that the proposed approach reduces the NC blocks to about 3.3%, while staying within the tolerance of deviation. The machining experiment shows that the proposed approach can increase the machining quality while reducing the machining time by about 19%.