中文摘要：

在板材数控渐进成形中，为满足节省材料、降低成形加工载荷的要求，提出了基于STL（sterolithography）模型的数控渐进成形板料尺寸自动确定方法。利用板材件底面边界多边形的最小矩形包围盒确定了板料的长、宽；根据板材件厚度的正弦减薄规律确定了板料的厚度，并生成了板材件厚度分布颜色云图。通过对不同形状的板材件比较分析表明，本方法较传统方法能够节省板料9．4％～23．5％。基于有限元分析的数字模拟结果表明，采用本方法确定的板料尺寸完全可以加工成形出预期的板材件。

英文摘要：

To meet the needs of saving materials and reducing the forming load in sheet metal computer numerical con- trol （CNC） incremental forming, a method of automatically determining the size of the sheet metal based on STL （Ste- rolithography） model was proposed. The length and width of the sheet metal was determined by using the minimum ar- ea bounding rectangle of the undersurface polygon of the sheet metal part. The sheet thickness was determined accord- ing to the sine law of sheet thinning, and the color cloud picture of the sheet thickness distribution was generated. The sheet metal determined by this means was saved 9.4% to 23.5% than by the traditional one. The results of the numer- ical simulation based on the finite element analysis demonstrate that the sheet metal size determined by this method can be formed into the expected sheet metal.