Femtosecond laser precision machining of carbon film based on aramid paper substrate

Carbon film has many applications in flexible electronic devices (FED) due to its low cost and high conductivity. However, it is difficult to remove carbon film from the substrate without damaging it. This research explores the use of femtosecond laser, which has minimal thermal effect and non-contact processing, for carbon film ablation. The main objectives are to determine the ablation threshold of carbon film and aramid paper, to optimize the laser ablation parameters and scanning path, and to analyze the ablation mechanism and quality. The results show that the optimal laser fluence is between 0.22 J/cm2 and 1.45 J/cm2, and the optimal scanning method is grid scanning method. The laser ablation achieves a removal depth of 9.4 μm and a minimum Sa of 3.0 μm. Raman spectroscopy confirms the complete removal of carbon film and the transformation of graphite to amorphous carbon. The ablation process is mainly governed by combustion and evaporation. A resistance strain gauge is fabricated using laser ablation to demonstrate its potential in carbon film FED manufacturing.