Study And Development Of Continuous Uufold System Of Progressive Die Based On NX

Strip design is a very critical step in the progressive die design process. For complexparts, the traditional design method is to use the empirical formula to calculate sheet metalparts unfold by hand, and get the shapes of each station on the strip. While using theempirical formula to calculate the unfold of bending area and free surface, the calculatesteps are complex and easy to make mistakes. However, the existing sheet metal unfoldsoftware can only realize the fully unfold of bending area, but unfold by angles. For freesurface, they can only realize unfold by trimming line or completely unfold. What’s morethe unfold result is surface, not the sheet metal body, which can not be directly applied tothe design, so these methods have some limitations in practical applications. So developsheet metal body unfold system integrated CAD platform is rather necessary in assistingprogressive die complex three-dimensional strip design and improving the design quality.This subject comes from the national natural science foundation project (No.50905067)" The fast simulation model and the key algorithms of complex car structuremulti-station progressive die strip design ". Integrated UG/NX platform, developed thesheet metal body unfold system for progressive die strip design.By researching the existing CAD sheet metal unfold and complex progressive diesheet metal parts unfold methods, paper proposed a method which combine geometry withfinite element inverse algorithm. Developed the complex progressive die continuousunfold system based on NX platform to realize the intermediate shapes design ofprogressive die strip layout, and the unfold results are sheet metal bodies. Geometryunfold is combined with empirical formula and geometry knowledge, which can realizeunfold by angle of the bending areas. Finite element inverse approach unfold method canunfold complex surface to intermediate shapes. At the same time, the formability of theunfolded area is presented in the post-processing system, which can assist structure designand process planning. The developed system alows to view the shapes and thepost-processing results of any unfold steps. At last, the sheet metal unfold function is showed by the actual application, and thedimensional accuracy of the unfold system is verified that can reach the actual processrequirement.