面向数控渐进成形方向优化的模型曲面重建研究

Research on Curved Surface Reconstruction of Model Facing Optimization Direction of NC Incremental Forming

为了优化数控渐进成形方向,需要旋转调整数字模型的姿态,使其按照所希望的某一成形方向重新定向和定位,然而这会导致模型底面与定位面脱离,二者之间出现曲面缺少的问题。提出了基于STL(Sterolithography)模型的区域填补算法(模型底面和定位面之间空缺填补),即依据模型底面边环上点的切向量将模型底面边环投影至定位面并确定填补区域在定位面上的三角网格化区域,在对区域三角网格化的基础上运用最小二乘法进行了曲面拟合进而生成填补曲面。算法应用实例表明,此算法快速有效,生成的填补曲面平滑连续。

In order to optimize the direction of NC incremental forming, the posture of the digital model needs to be rotated and adjusted to get the re-orientation and re-position according to the desired forming direction, however this will cause that the bottom surface of the model is separated from the positioning surface to give rise to the lack of curved surface between them. Region filling algorithm （filling vacancy between the bottom plane and the positioning surface） was proposed based on STL （Sterolithography） model. Namely, according to the tangent vector of the points on the bottom edge ring, the model bottom edge was projected to the positioning surface, and filling region of triangular meshing area on the positioning surface was determined. And on the basis of the triangularization of the area, curved surface fitting was carded out by using the least square method, then filling the curved surface was generated. Application examples of the algorithm show that the algorithm is fast and efficient, and the generated filling curved surface is smooth and continuous.