Parametric investigations on laser-induced forward transfer based micro-3D printing of NiTi alloy

Abstract

Laser-induced forward transfer (LIFT)-based micro-3D printing is a process in which the pulsed laser beam is used to transfer the material from thin-film deposited substrate (donor substrate) to the target substrate by inducing a high-pressure gas between the thin film and substrate. This study is focused on printing NiTi shape memory alloy using micro-3D printing for the continuous line pattern deposition. NiTi material is coated in the thin film via sputtering process, and the line pattern is deposited by CO2 laser at a wavelength of 10.6 μm for the transfer process. Numerical simulation is performed to analyze the interface temperature between the thin film and sacrificial layer. The optimized laser fluences for 1.5 μm and 3 μm sacrificial layer thicknesses are 770 mJ/cm2 and 2300 mJ/cm2, respectively. The printed pixel size decreases with an increase in the overlap, and the adhesion of pixels (with substrate) increases with an increase in the target substrate temperature. The transferred pixels are characterized using energy dispersive spectroscopy analysis and X-ray diffraction techniques. The study paves a way for the successful micro-3D printing of NiTi for potential microdevice fabrication. © 2022 Taylor & Francis.