Optimization of PC micro-drilling using a continuous CO2 laser: an experimental and theoretical comparative study

Abstract

Laser drilling on polymers has many applications in various industries, such as sensors, aerospace, medical devices, and microelectronics. In this research, a CO2 laser machine was employed for micro-drilling PC samples. Design–Expert analysis was applied to understand the laser drilling process better. Based on a Box–Behnken design (BBD) of the experimental software, 17 experiments were designed to examine the laser parameters’ influence 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 analysis of variance (ANOVA). Quadratic regression models were applied to model different hole factors throughout the process. The experiments were optimized using the developed objective model as a function to attain the best hole. The outcomes revealed that a full hole with a 351-μm diameter and 102-μm HAZ was obtained at 0 FPP, with a laser power of 4 W, and at 0.15 s. To conduct virtual tests alongside the experimental study, simulation of the drilling mechanism’s temperature distribution was achieved via the COMSOL Multiphysics program. The simulation’s refined accuracy was able to predict the hole’s geometry and presented outcomes that favorably corresponded with the experimental results. A numerical optimization technique was used to generate an ideal hole by minimizing or maximizing the objective function, achieving full holes of 350-μm diameter and 90-μm HAZ, obtained at 0 FPP, with 3.6 W, and at 0.1 s.