基于曲面分层的大型螺旋桨GMA增材制造

为了实现曲面复杂零件的高精度高效率增材制造，开发了高适应性的曲面分层算法.采用从空间角加权法向方向平移三角网格控制点的策略，生成与初始分层曲面等距的曲面簇，与模型求交运算，从而获得了每层曲面切片轮廓.在此基础上，使用基于体素化和曲面积分思想的曲面等距路径规划算法，获得了分层曲面上的等距轮廓偏置路径，保证了零件曲面轮廓的成形精度并进行了试验验证. 试验采用六轴机器人与旋倾变位机作为运动机构，使用熔化极气体保护电弧(gas metal arc，GMA)增材制造方法，在一个外径为0.2 m的圆柱金属管上，实际堆敷了直径1 m的扭转棱形螺旋桨.经过扫描检测和模型比对，得到桨叶的成形尺寸标准偏差为1.1 mm，最大偏差在3.0 mm以下.结果表明，对于特定曲面零件如螺旋桨的增材制造，曲面分层算法可以提高成形的效率和表面质量.

GMA additive manufacturing of large propeller based on curved layer

In order to realize high-precision and high-efficiency additive manufacturing of parts which have complex curved surfaces, a highly adaptive curved layering algorithm is developed in this paper. The strategy of translating the triangular mesh control points from the space angle weighted normal direction has used to generate the surface cluster which is equidistant from the initial layer, and the slice contour of each layer is obtained by intersection operation between the surface cluster and the model. On this basis, the isometric contour offset path on the curved layer is obtained by using the surface equidistant path planning algorithm based on the idea of voxelization and surface integration, which ensured the forming accuracy. Six axis robot and rotary displacement machine are used as the motion mechanism. Finally, a 1 m diameter torsional prismatic propeller is actually deposited on a cylindrical metal pipe with an outer diameter of 0.2 m by using gas metal arc (GMA) curved layer additive manufacturing method. After scanning detection and model comparison, the calculated standard deviation of blade forming dimension is 1.1 mm, and the maximum deviation is less than 3.0 mm.The results show that curved layering algorithm can improve the forming efficiency and surface quality for the additive manufacturing of parts with specific surface parts such as propellers.