Research On Micromould Based Laser Shock Embossing Of Thin Metal Sheets

Because of the complex manufacturing technology, the long period and the poor reproducibility, the existing micro fabrication technology of the micro electro mechanical systems (MEMS) isn’t suitable for batch production. Recently, the micro fabrication technology based on conventional forming processes becomes keystone of research. Due to the size effect, much work still needs to be done. Thus the invention of new processes is also desirable. In this paper a new embossing process based on micromould is studied which uses laser-generated shock wave to form the work piece.Laser shock embossing was taken as the research object and the basic forming mechanism was expatiated. Laser shock embossing experiment was designed and accomplished. The effect of defocusing and laser energies on the deformation was investigated experimentally. Micro-channel structure was successfully fabricated on metallic foil surface using laser-generated shock wave. The experimental results were observed by Stereomicroscope and a digital microscope (Keyence VHX-600). Through the observation, it can be found that the work piece has a high spatial resolution at the micron-level and the good surface quality is accomplished.An analysis procedure including dynamic analysis performed by ANSYS/LS-DYNA and static analysis performed by ANSYS is presented in detail to attain the simulation of laser shock embossing to predict the surface deformation. The research results have shown the possibility of replicating micro-channel structure on copper foil using laser-generated shock wave.we carried out researches on the fracture in laser shock embossing and found that laser induced shock waves can realize micro punching of thin sheet metals. Micro holes of 250μm in diameter were successfully punched on sheet metal of 10μm in thickness by single pulse, and the good edge quality was obtained. The micro die-opening is produced by electrical discharge machining (EDM) using the copper electrode ofφ22oμm. The novel process of micro scale laser high speed punching is also numerically studied. In addition, this method can be used to fabricate noncircular micro-holes on thin sheet metals with noncircular micro die-openings.Micromould based laser shock embossing holds promise for achieving precise, well-controlled, low-cost, high efficiency of three-dimensional metallic microstructures, and is suitable for batch production. The research provides a strong technical basis for the engineering application of laser shock embossing and laser high speed punching."...