Flexible manufacturing of sheet metal parts based on digitized-die

Digitized-die forming (DDF) is a flexible manufacturing technology through which a variety of three-dimensional sheet metal parts can be produced in a DDF system. It eliminates the need to design and produce the conventional die. The central component of DDF system is a pair of matrices of punches, the punches are controlled by computer and the desired shape of die is constructed by changing the heights of punches. Based on the flexibility of DDF, new forming processes are designed that cannot be realized in conventional stamping. In varying deformation path DDF, a sheet part is manufactured along an optimal forming path, and large deformation can be achieved for the material with poor formability. In sectional DDF, a sheet part is formed section by section, and this technique makes it possible to manufacture large-size parts in a small DDF press. A closed-loop forming system was built by combining DDF with rapid 3D-shape measurement system. It is used to compensate for material springback and improve dimensional accuracy of the formed part. And a DDF system with multi-point blankholder control system was developed to control the material flow, thereby to prevent sheet parts from wrinkling and tearing. The DDF integrated system is described, and the detailed forming procedures are explained in the paper. Typical examples are presented showing the applicability of the DDF technology. (c) 2006 Elsevier Ltd. All rights reserved.