Investigation of large area sheet forming with laser shocking spot by spot

The paper presents a large-bottom cup formed by multiple-spot laser shocking. A 3D finite element model was developed with computational hardware and software resources to simulate the shape evolution process of cup manufactured by gradual-increasing-shot laser shocking along a specified path. A series of intermediate cups were fabricated correspondingly to verify the predicted results. The effect of key processes, such as impact order, imposed pressure of shock wave and the covering ratio of laser shocking spot, on the final geometric shape of formed cup was also investigated and analyzed. The results of numerical simulation and experiment show that small deformation induced by each single-spot shocking is gradually accumulated to larger deformation, and multiple-spot laser shocking can form the large conic cup well. The sheet forming precision is not affected by the order of laser shocking, but is seriously decreased by the improper pressure of imposed shock wave. When the covering ratio of laser shocking exceeds threshold value, sheet forming precision is not changed any more even if the covering ratio increases. In general, the multiple-spot laser shocking forming is a technology of sheet incremental forming, and it can enlarge greatly the scope of sheet forming with laser shocking. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The study demonstrates that multiple-spot laser shocking can effectively form a large conic cup. The order of laser shocking does not affect the sheet forming precision, but improper pressure of imposed shock wave significantly decreases the precision. Once the covering ratio of laser shocking exceeds a threshold value, the sheet forming precision remains constant.