Freeform surfaces are widely used in many industries for various purposes, and multi-axis CNC machining is the most adopted method for machining them due to its high accuracy and flexibility. The prevailing type of cutter used in machining freeform surfaces is the so-called ball-end type, which is simply a hemisphere and thus has a constant curvature on the cutter surface. Naturally, for a complex surface with a large deviation in curvature, a cutter shape with variable curvature will be more desirable, as we can adaptively choose a portion of smaller curvature on the cutting edge to machine those relatively flat portions on the surface so to enlarge the cutting width and hence reduce the machining time. Towards this objective, in this paper, we present an algorithm which, given an arbitrary freeform surface to machine and a general non-spherical cutter, will generate a five-axis tool path that will strive to match every cutting point on the surface with a locally optimal tool posture (i.e., the contact point on the cutter surface together with the tool orientation) as well as the corresponding optimal feed direction, while both the local gouging-free and global collision-free constraints and the cusp height requirement are all satisfied. The experimental results in both computer simulation and physical machining are also reported, which confirm that, when compared to using a simple ball-end cutter, by using a non-spherical cutter and adaptively adjusting the contacting tool posture and the feed direction, a large improvement in machining efficiency could be achieved, e.g., as much as 60 % achieved in our experiments.

自由曲面在许多行业中被广泛用于各种目的，而多轴CNC加工由于其高精度和灵活性而成为最常用的加工方法。用于加工自由曲面的刀具的主要类型是所谓的球头型，它只是一个半球形，因此在刀具表面上具有恒定的曲率。自然地，对于曲率偏差较大的复杂表面，将更需要具有可变曲率的刀具形状，因为我们可以自适应地选择切削刃上曲率较小的部分来加工表面上相对较平的部分，从而扩大切割宽度，从而减少了加工时间。为了实现这一目标，在本文中，我们提出了一种算法，给定要加工的任意自由曲面和普通的非球形刀具，将生成五轴刀具路径，该路径将努力使表面上的每个切削点与局部最优刀具姿态（即，刀具表面上的接触点）相匹配以及刀具方向）以及相应的最佳进给方向，同时满足了局部无气刨和全局无碰撞约束以及尖角高度要求。还报告了计算机仿真和物理加工的实验结果，这些结果证实，与使用简单的球形端铣刀相比，通过使用非球形铣刀并自适应地调整接触刀具的位置和进给方向，可以发现较大的可以提高加工效率，例如