Research On Micro-plastic Formation Loaded By Laser Driven-flyer

In recent decades,significant progress has been made in miniaturization of components and parts.In particular,the rapid growth of the micro electro mechanical systems(MEMS)has been drawing increasing attention.Thus the micromachining and the fabrications of micro components and parts have been a key technology. Compared with micromachining method,using microforming we can easily assure the quality and precision.Even more importantly,the microforming will be a development trend due to the fact that microforming process is suitable for automation production,convenient for control and operations.We report a micro-manufacturing technology which allows the direct forming of three-dimensional metallic structures,which is developed from laser shock processing and laser shock forming technology at different scales.The technology combines laser thermodynamic irradiation and laser driving-flyer process.When a short and intense laser pulse is irradiated onto a flyer surface,the thin flyer surface is instantaneously vaporized.This vapor and plasma absorb the incident laser energy,and then expand and explode violently.The remaining thin flyer impacts the sample material at ultrahigh speed.The planar stress shock waves impacted by the flyer replicates directly three-dimensional metallic microstructures with high spatial resolution. Moreover,the replications cost is independent of the microstructures complexity.Additionally,the effect of processing parameters by laser driven flyer on the micro-formability is examined.Combined with FEM simulation,the variation of stress and strain are studied during the process of micro forming.The numerical simulation results indicate that the material deformation process is characterized by an ultrahigh strain rate.As pulse duration increases,the sample absorption strain energy also increases,sample deformation degree enlarges.The stress state of central point fluctuates between tensile stress and compression stress.The stress state of angular point is altered from compressive stress to tensile stress due to geometry and loading conditions.The duration length of pulse stress has effect on the stress state,as the increase of pulse duration,fluctuation in the stress state decreases.Therefore,laser micro-manufacturing technology will be a novel method which is characterized by low-cost,high efficiency.Nevertheless the experiments show the high potential industrial application.