Abstract: To achieve the effective reuse of existing NC machining process,a similarity assessment method for pocket features based on Medial Axis Transform(MAT)was presented.A pocket feature was converted into 2D outline graph of machining region,and the graph's MAT was introduced and adopted as the reference tool path.Parameters of the Locally Inscribed Circles(LICs)were extracted,and the feasible domain of cutting tool radii and corresponding set of efficient cutting arc-lengths were constructed based on the dependence mapping relationship between radii of LICs and limit cutting tool.The effective representations of geometric attributes and machining attributes of cutting tools were realized.A hierarchical similarity assessment model was constructed and the global similarity of the two pockets was calculated.The experimental results showed that the method could be regarded as the judgment of NC process reuse and meet the requirement of engineering application.

Key words: pocket features, medial axis transform, cutting tools, similarity, numerical control machining

摘要： 为实现对已有槽腔特征数控加工工艺的有效重用,提出一种基于中轴变换的槽腔特征相似性评价方法。将槽腔特征转化为二维加工区域轮廓图,利用中轴变换算法获取轮廓图中轴并作为参考刀具路径;提取局部内切圆参数,依据局部内切圆半径与极限刀具半径的关联映射关系,构建加工刀具半径可行域以及对应有效切削弧长集,实现加工刀具几何属性和切削属性的有效表征;构建层次化相似性加权评价模型,计算两槽腔特征的整体相似性。实验结果表明,该方法能够作为数控工艺重用的判断依据,提高数控加工工艺编制效率,满足企业的实际应用需求。

关键词: 槽腔特征, 中轴变换, 加工刀具, 相似度, 数控加工