Enhancing sheet injection formability through tailored laser heat treatment

The increasing demand for lightweight components in the automotive and aerospace sectors has driven the development of advanced forming processes, as in the case of the Sheet-Bulk Forming (SBF). Among these, the sheet injection process, combining stamping and injection, enables the formation of complex features like ribs on metal sheets. However, when applied to medium-strength aluminium alloys, the process faces challenges, including high forming forces and limited formability, often resulting in material failure. The present study experimentally and numerically investigates the application of local Laser Heat Treatment (LHT) to achieve a specific distribution of properties as a strategy to improve the formability of medium-strength aluminium alloy AW6082-T6 in sheet injection operations. Several LHT strategies were developed to selectively reduce the mechanical strength in highly deformed regions of the sheet, thereby favouring the material flow and reducing forming loads. The results demonstrate that the local modification of the properties significantly decreases the process forces and reduces the risk of fracture and folding in critical areas. Experimental validation confirmed the numerical predictions, showing improved part quality. These findings highlight the viability of using LHT to expand the process window for SBF operations involving medium-strength aluminium alloys. The methodology offers a promising route for producing functional sheet metal components with enhanced performance.