自由曲面多轴加工中行距的高精度计算

Constant Scallop-height tool-path Planning for Surface Interpolation and the Evaluation of Errors

在自由曲面加工中,行距的计算精度直接影响着曲面的加工精度和加工效率。现有的行距计算方法,要么过于简略而导致计算精度不高;要么只追求计算精度而忽略计算效率。文中提出以圆弧或双圆弧样条来逼近曲面的法截线,再以此为基础进行行距计算。该算法在保证行距计算精度的前提下,尽可能地提高了算法的计算效率。此外,该算法每一次的行距计算时间相对稳定,因此适用于定周期插补计算。实例分析结果表明即使在曲面几何性质变化较大的情况下,该算法能够保证行距的计算精度及计算效率。

The calculative precision of the cutting breadth has a significant effect on the machining precision and the machining efficiency for free-form surface machining. For traditional arithmetic, there are two oppositional approaches to calculate the path interval. One approach is very simple, but its veracity is not enough for complex surface. The other approach is very complicated, so its calculative efficiency is low. A new approach is presented to calculate the path interval. A spline of circle is adopted to approach the transversal of surface. Then the arithmetic based on the spline is proposed to calculate the path interval. In the proposed methodology, the calculative efficiency is fully improved on the condition of meeting the need of machining precision. Furthermore, the algorithm's time needed by calculating path interval is steady. So it is suitable for periodic interpolation. Two study cases verify the applicability of this new approach of Constant Scallop-height tool-path planning.