Investigation of microscale laser dynamic flexible forming process—simulation and experiments

This paper presents a novel microscale laser dynamic flexible forming (μLDFF) technique on plastic forming of thin metal sheets. This process utilizes flexible rubber material as a soft punch, under the pressure generated by laser-induced shock wave, to act on the thin metal sheet. This novel technique has many new features and the forming mechanism is complex, as well as it takes place in the scale of nanoseconds, which is too short to monitor the deformation behaviors during the process. In order to reduce the experiment times and cost, this paper firstly investigates the feasibility of the process numerically using finite element software ANSYS/LSDYNA, and some key process parameters, such as hardness and thickness of soft punch, thickness of thin metal sheet, aspect ratio of rigid die, as well as laser pulse energy are detailed studied to obtain reasonable parameters. Then a series of experiments based on these reasonable parameters are conducted, and good experimental results are obtained, which verifies the feasibility of the use of simulation to guide the experiment. The results of both numerical simulations and experiments show that the use of combination of soft punch and thin metal sheet can increase the deformation depth in comparison to focusing the beam directly onto thin metal sheet, which is due to the impedance mismatch at the soft punch–thin metal sheet interface.

► A novel micro-scale laser dynamic flexible forming is presented. ► This process utilizes flexible rubber material as a soft punch to load the workpiece. ► The use of soft punch can increase the deformation depth. ► The excellent surface finish can be obtained as no tool marks are created. ► The soft punch can easily be separated from the workpiece after forming.