A Morphological Study on Femtosecond Laser Machining of Thin NiTi Sheet for Biomedical Application: Parameter Optimization to Device Fabrication

The present work originates from the need for optimizing the efficient machining of a thin superelastic NiTi sheet (0.2 mm) using a laser. The low austenite‐finish temperature (–3.32 °C), high superelastic limit (5.97%), and elastic modulus of NiTi (31.9 GPa) make it compatible for the fabrication of dental splints (DS). The optimization of femtosecond laser parameters is performed using a Taguchi L 8 array. The kerf taper is found to depend primarily on laser speed, with a higher kerf width at the entry side than at the exit side. Material removal at the kef entry and exit is dominated by vaporization of the material and shearing action of the argon gas. An insignificant effect of heat near the cut surface is observed, as the wt% of Ni (44.1–48.47%) and Ti (35.19–38.32%) is nearer to pristine NiTi (Ni: 49.65%, Ti: 38.59%). Based on the optimization results, the smallest kerf taper is obtained at 6 mm s −1 , 200 kHz, and 20 μJ pulse −1 . DS is fabricated using these optimized parameters. The morphology is observed to exhibit no surface cracking and DS with the smallest interaperture distance achieves the highest strength and stiffness. Hence, the article illustrates the approach to design optimization of NiTi alloy medical structures, which can serve as a useful guideline for the fabrication of medical devices.