多轴机床加工复杂自由曲面的刀底干涉避免

为快速、有效地解决复杂自由曲面加工中存在的刀底干涉问题,通过刀底干涉特征分析,得出能否快速、有效地划分出刀底干涉范围是影响刀底干涉避免总体效率和精度的关键。其次,以切削点的局部几何性质为基础, 提出了刀底干涉范围的快速划分方法。第三,以切削点的切平面为媒介定义了刀底干涉特征点,该干涉特征点与刀具的刀轴矢量无关,因此这些干涉特征点既可作为初始刀轴定位的依据又可作为刀轴调整的约束。同时又构造了刀底干涉特征点的快速搜索算法。以搜索的少量干涉特征点为基础,最终得出了无刀底干涉的快速刀轴定位算法。实例分析表明,算法的应用不仅能快速、有效地解决刀具加工自由曲面的刀底干涉问题,而且刀底干涉特征点的存在也为其他形式的干涉避免打下了坚实基础。

COLLISION-FREE BETWEEN CUTTER-BOTTOM AND SURFACE IN MULTI-AXIS FREE-FORM SURFACES MACHINING

To avoid the collision between the cutter's bottom and the surface, a few measures are taken: Firstly, the feature of the collision is studied. A conclusion is drawn that the key fac- tor for the collision-free is the efficiency of partitioning the collision area from the surface. Secondly, based on the geometry property of the cutting points, the arithmetic is proposed to partition off the potential collision area from the surface. Then, by using the tangent plane of the cutter contact point, the key points of collision are defined, which are independent of the cutter locative vector. Based on this feature, these key points can be used to calculate the cutter's first location and become the restriction of correcting the cutter location. At the same time, the arithmetic for selecting the key points is designed. On the of these key points, the collision-free orientation of the cutter can be gotten. A study case shows that these approaches can not only realize the collision-free of the cutter's bottom but also provide a favorable basis for the collision-free of the cut- ter's blade or the shaft.