摘要
针对复杂多曲面体清根加工刀位轨迹的生成问题,提出了一种基于点搜索的清根轨迹生成方法。在采用单刀清根时,球头刀刀心点到多曲面体所在的自由曲面以及多曲面体表面的距离相等,只要搜索到刀心轨迹上的所有点,即可生成单刀清根轨迹。据此,文章将多曲面体作为研究对象,通过将多曲面体以及搜索的基本初始点映射在曲面的参数域内,确定参数域内的所有搜索初始点及相应的搜索方向,沿搜索方向在参数域内搜索清根加工的切触点,并在物理空间判断相应的刀心点是否满足距离条件,满足的点即为搜索的目标点,所有目标点形成清根加工的刀心轨迹线,根据该曲线即可生成单刀清根的到位数据。在此基础上,通过生成不同尺寸刀具的单刀清根轨迹线,计算多刀加工的切触点,生成了多刀清根加工的到位数据。最后,结合航空发动机叶片阻尼台的加工,生成了其单刀清根轨迹和多刀清根轨迹并进行了切削加工实验。算例与实验结果表明文中方法加工结果符合加工精度要求,加工表面质量较好,说明了点搜索方法在多曲面体清根轨迹生成中的有效性和实用性。
Traditional methods for generating clean-up toolpath are based on STL models or surface offset methods. We present the point-searching method which adopts the integral multi-patch solid model to generate pencil-cut and fillet-cut clean-up toolpath. For pencil-cut with ball-end cutter, the distance between the ball-end center and the solid model equals to the distance between the ball-end center and the part surface. The point that satisfies the distance requirement is on the cutter center curve. While searching points on the cutter center curve, initial points are selected on the part surface and converted into the parameter domain. Search center and search direction are then determined according to the initial points. Search operation is then carried out to search every point that satisfies the distance requirement, anc[ the cutter center curve can be generated with the searched points. Given tool orientation for each point on the curve, cutter location （CL） can be found at the tool-tip along tool orientation. As for fillet-cut, we use different sizes of ball-end cutters to generate a set of cutter center curves. For each point on the curves, two cutter-contact （CC） points and two CL points of the selected ball-end cutter can be obtained. All the CL points form the fillet-cut toolpath. Within the point-searching method, the multi-patch model is considered as a whole one, no single surface on the solid model is taken out for special consideration, surface offset and intersections can be avoided and the searching process is steady. Computer implementation and practical examples are also presented in this paper. The results show that the proposed method is feasible and efficient.
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
2009年第3期351-356,共6页
Journal of Northwestern Polytechnical University
