Abstract: Extractions of internal and external contour information of revolving parts is of great importance to enable automatic generation of NC machining codes. This paper puts forward an automatic recognition algorithm for inner and outer contours of revolving parts via the “clockwise-rightmost” discriminant method. Information related to the geometric entities, saved in the systematic text structure in DXF, combined with the symmetry information of the revolving body parts, is utilized to the elimination of the redundant features such as the dimension marking, profile lines, roughness marking, form and position tolerance marking, etc. Finally the clockwise rightmost discrimination algorithm is used for the recognition of the contour anticlockwise. The algorithm demonstrates many advantages, especially the reduced computational complexity, therefore can identify the internal and external contour of the part effectively and robustly.

Key words: automatic programming, revolving body, contour recognition, extreme clockwise discrimination algorithm

摘要： 特征自动化识别与解读是回转体零件加工代码自适应生成的重要基础，而回转体内外轮廓的几何特征信息是加工轨迹生成的重要依据。针对多种信息混合的CAD载体中回转体零件几何特征解读问题，提出了顺时序最右侧判别法自动识别回转体零件的内外轮廓特征。利用DXF结构化存储的图形信息和回转体零件对称性的特点去除尺寸标注，剖面线、粗糙度标注，形位公差标注等多余线，最后沿着逆时针寻找相对于当前轮廓最右侧的路径为下一轮廓。与传统方法相比，所提出算法的复杂度进一步降低，能够准确可靠地在干扰信息中识别出零件的内外轮廓精确信息。

关键词: 自动代码生成, 回转体, 轮廓识别, 最右侧判别法