Micro-punching of aluminum foil by laser dynamic flexible punching process

A novel microscale laser dynamic flexible punching technology combining flexible punching and laser shock forming is presented. The ultrahigh strain rates of workpiece's material and soft punch driven by dynamic shock load are the significant feature of this process. In the present study, arrays of 300 mu mx300 mu m square holes with good sheared edges quality are obtained on 20 mu m Al foils. The shearing behavior is also investigated through investigating cross section of punched hole. As a piece of polyurethane rubber loaded by the ultra-high transient pressure of laser supported detonation wave (LSD) is employed as soft punch, the new process has such advantages as homogenizing pressure, easy demould and reducing springback. To study more details in an extremely short interval, simulations are conducted by ANSYS/LS-DYNA and LS-PrePost. The methods of Finite Element Mesh (FEM) and Smoothed Particle Hydrodynamics (SPH) are used. The relationship between soft punch thickness and corresponding minimum punching energy for various workpiece thicknesses is revealed. In addition, the material flowing behavior around the sheared edges has also been discussed. The results in this paper indicate that the present process is promising to fabricate high quality micro holes in the micro scale application.