Research On Enhancement Of Enclosure Algorithm And Blank Nesting System Of Stamping Parts

In the production of automotive stamping parts, the proportion of sheet metal cost often reaches above 60%, and therefore improving material utilization is the key to save the cost. Blank nesting is an important part in the process of sheet metal stamping. Traditional manual nesting depends on the experience of engineers, and it goes along with low efficiency and high error rate. It is a trend to achieve auto-optimized nesting. Not only can auto-optimized nesting systems shorten the production cycle and reduce the cost, but also they can improve the production efficiency and reduce the labor intensity of workers.Blank nesting belongs to two-dimension irregular shape nesting, and it is quite complicated. The two existing algorithms of enclosure regular polygon nesting and No-Fit Polygon nesting are very important. However, there exist some limitations in both algorithms. The existing algorithm of enclosure regular polygon nesting is less time-consuming, but it can cause material waste of the concave area. The nesting result of the No-Fit Polygon nesting algorithm is compact, but it usually takes a long time.An improved algorithm, named enclosure horn, is proposed based on the full study of the solving process of two-dimension irregular shape nesting and characteristics of all kinds of nesting algorithms. The algorithm adopts horn shape to enclose irregular parts, and it avoids the pre-processing of transforming concave polygons to convex polygons. Therefore, it can avoid material waste of the concave area to a great extent, and effectively improve the nesting accuracy.The BNW(Blank Nesting Wizard) system of stamping parts is developed on NX platform based on existing nesting algorithms and the newly proposed enclosure horn nesting algorithm. Multiple types of nesting are realized, such as enclosure rectangular nesting, enclosure horn nesting, one-up nesting, two-pair nesting.Finally, hundreds of automotive parts are used to test the system. And then comparisons are made with the existing commercial software, FTI FormingSuite, in respects of material utilization, nesting type, time consuming and constraints. It proves that this system has reached the level of commercial applications.