Micromachining of Intricate Microchannels on the Polycarbonate Using Ultrafast Laser Ablation

Ultrafast laser processing enables the fabrication of microscale structures in diverse materials without inducing heat-affected zones. The ablation and micromachining properties of polycarbonate were investigated using a femtosecond-pulsed laser with an 800 nm wavelength and a 100 fs pulse duration. Ablation threshold fluence was determined to be 0.0112 J/cm2. Response Surface Methodology based on the Box-Behnken design was applied for the optimization of the conditions of the micromachining process with respect to laser pulse energy, scanning speed, and line spacing. An increased rate of material removal by a higher laser power of 800 mW decreased in the case of the lower power of 100 mW. Line spacing became very critical because while varying from 5 to 15 mu m, it resulted in a different machining pattern. An increased scanning speed decreased the machined depth. The highest material removal rate achieved is reported as 4.9 x 106 mu m3/s under optimum conditions. Intricate microchannels with accurate dimensions fabricated in a polycarbonate disk have been ensured to have no or very minimal thermal damage. The results obtained have significant relevance to present useful information on precision micromachining of polycarbonate with huge potential for developing polymer-based microdevices.