Suppressing Fracture Defects and Rebound Effects in Laser Dynamic Micro-forming using Plasticine Medium
摘要
In the process of laser dynamic micro-forming, workpieces are prone to fracture defects and rebound effects under the action of high laser shock waves. This study addresses the above problems by introducing plasticine as a flexible medium. Plasticine is used to absorb excess shock wave energy, indirectly increase the stiffness of the workpiece, and extend the loading time. Systematic numerical simulations and experimental comparative studies were conducted to investigate the forming results of 20 μm, 30 μm, and 40 μm thick workpieces with and without plasticine. A 20 μm-thick workpiece has a maximum rebound of 12.93 μm at 835 mJ laser energy, which reduces to 7.68 μm with plasticine. A 30 μm-thick workpiece reaches a maximum rebound of 13.23 μm at 1690 mJ laser energy, and it becomes 7.23 μm after adding plasticine. A 40 μm-thick workpiece exhibits a maximum rebound of 13.43 μm at 1800 mJ laser energy, and the rebound drops to 3.58 μm when plasticine is introduced. Furthermore, energy dispersive spectroscopy (EDS) was employed to analyze the types and contents of chemical elements in areas of intense collision, and the data revealed that the carbon content decreased after adding the plasticine medium compared to direct shock, with the carbon content in area 3 specifically dropping from 28.86% to 5.25%. The results of experiments and numerical simulations demonstrate that plasticine can alter the loading mode of laser shock waves, preventing local excessive forming speed that would otherwise lead to fracture defects and rebound effects in the workpiece, thereby enhancing the forming quality of the workpiece.