Principle and simulation of fixture configuration design for sheet metal assembly with laser welding. Part 1: Finite-element modelling and a prediction and correction method

The quality of the stamping process has a direct effect on laser welded she et metal assembly. The fixture plays an important role in the satisfactory metal fit-up that laser welding requires. The traditional "3-2-1" locating scheme will no longer suffice for the deformable laser sheet metal assembly , process. Because of the often poor stamping quality, a complex die fixtur e has to be employed to meet the metal fit-tip requirements. The die fixtur e corresponds to an "infinite-2-1" locating scheme where the tooling cost i s very high and yet lacks flexibility. This limits the application of laser welding. In this paper, a new locating scheme with both total locating and direct locating for welds is proposed. A total locating scheme is used to locate the overall assembly, and a direct locating scheme is used to locate the weld location, which is critical for ensuring correct metal fit-up. A finite-element model and a prediction and correction method for the direct locator configuration are developed in this paper. A case study is used to show that the proposed method is effective for sheet metal assembly, for la ser welding.