A comparative study on the effect of CO2 laser parameters on drilling process of polycarbonate and PMMA polymers complemented by design expert

Abstract

In this research, micro-drilling with a CO2 laser was conducted on two types of polymer, polycarbonate (PC) and poly methyl methacrylic (PMMA), due to their desirable chemical and physical characteristics. Design-Expert analysis has been used to better understand the laser drilling process and reduce the number of experiments needed. Based on Box–Behnken design (BBD), the experiments were designed to examine the influence of the laser parameters on the micro-drilling process. The impact of parameters, such as power (P), exposure time (t), and focal plane position (FPP), on the depth, entry diameter, and heat-affected zone (HAZ) was investigated using the statistical analysis technique ANOVA. To conduct virtual tests alongside the experimental study, the temperature distribution of the drilling mechanism was simulated using the COMSOL Multiphysics program. The refined accuracy of the simulation predicted the geometry of the hole and presented outcomes that favorably correspond with the experimental results. Experiments were optimized using numerical optimization to attain the ideal hole in CW mode for various values of laser power, exposure time, and FPP. A significant improvement in hole quality was achieved. The acquired data were validated using confirmation tests. The outcomes for the ideal full hole revealed the minimum HAZ (60 μm), with a minimum diameter (360 μm), and 1 mm hole depth occurred at zero FPP for PMMA, with laser power of 3 W and at 0.17 s. Meanwhile, for PC, the ideal hole with minimum HAZ (90 μm), minimum diameter (350 μm), and 1 mm hole depth was achieved at zero FPP, with laser power of 3.6 W and at 0.1 s.