型腔铣削加工光滑螺旋刀轨生成算法

Smooth Spiral Tool Path Generation for Pocket Milling

针对传统行切、环切刀轨存在方向突变的拐角,不适用于型腔快速铣削的问题,提出一种新的刀轨生成算法。首先通过线性插值型腔边界的等距多边形生成螺旋状折线,然后以指数函数分布规律插入控制顶点,以这些控制顶点所定义的B样条曲线为基础规划最终刀轨。所生成刀轨不需要离散成大量小直线段即可直接用于具有NURBS插补功能的高速数控系统;另外,刀轨可以任意阶连续,从而减小切削力的变化幅度,避免方向突变,提高加工效率和加工精度。

Conventional direction parallel and contour parallel tool path patterns are inapplicable for high speed pocket milling because of sharp turning corners. To solve this problem, a new tool path generation algorithm is presented. Firstly, a spiral fashion polyline is created by linear interpolation the polygon which is offsetted from pocket boundary. Then, the control points are inserted into the polyline under exponential regularization. Finally, the smooth tool path is generated via B-spline curve fitting. The tool path can be sent directly to machine controller with NURBS interpolation function and need not be discreted to huge amount of short line segments. Additionlly, the path is C^n continuous smooth. Therefore the magnitude and change range of cutting force will be decreased, and meanwhile the cutting performance and machining accuracy of pockets will be im proved.