Abstract

Today, miniaturization is evident in almost every field of manufacturing. Laser micromachining can produce high-precision microstructures and micro-components. The current project proposes an air jet-assisted laser micromachining for the fabrication of 3D microstructures and micro-molds. In the developed laser micromachining system, MATLAB algorithms were used to control the galvoscanner mirrors to direct the laser beam in the x and y-directions. Further, an adjustable stage was used to enable the movement in z-direction to facilitate 3D laser micromachining.
Laser parameters such as overlap, laser power, and the number of pulses were varied to investigate the performance. The results were analyzed in terms of machining depth, surface roughness, and machining accuracy to obtain optimum parameters for micromachining. For the micromachining setup developed as part of this work, a laser with 532 nm wavelength, 1.1 W power, 80% overlap between spots, and 400 pulses per spot provided optimum results, a roughness of 1.89 µm, and depth of 21.31 µm. Concordia logo was selected as a complex shape to perform a 2D micromachining. This experiment was conducted with the optimum parameters on four different scales starting from 4 mm down to 1 mm. The aim was to find how accurate is the micromachining to generate features on small scales considering the spot size is 60 µm in our setup.
The goal of this study is to present a high-precision 3D laser micromachining system. An experiment was designed to generate a 3D pyramid to ascertain the feasibility. While machining layer-by-layer, melt debris presented a significant challenge. To overcome this, an air jet was directed towards the machining area to clear the melt debris in situ. The results were investigated by interferometer and confocal microscopes in terms of machining depth and surface roughness in each layer.
Subsequently, a 3 mm diameter gear was selected as a complex shape to investigate the ability to fabricate features such as corners and edges accurately. In the final step of this research, the pyramid and gear were used as molds to fabricate the polydimethylsiloxane (PDMS) structures. The micrometric features such as corners and edges were accurately molded.