Theoretical and experimental study on the kerf profile of the laser micro-cutting NiTi shape memory alloy using 355 nm Nd:YAG

The NiTi shape memory alloy is attracting more and more attention in the fabrication of micro-electrical systems (MEMS) components because of its special shape memory effect and superelastic properties, especially in microactuator and microsensor applications. Laser cutting is one of the methods of micro-machining the bulk NiTi alloy. In this study, thin NiTi sheets with a thickness of 350 μm were micro-cut using a 355 nm Nd:YAG laser. A qualitative theoretical analysis and experimental investigations of the process parameters on the kerf profile and cutting quality were performed. The results show that the kerf profile and cutting quality are significantly influenced by the process parameters, such as the single pulse energy, scan speed, frequency, pass number and beam offset, with the single pulse energy and pass number having the most significant effects. Based on our analysis, the process parameters are optimized. Debris-free kerf with narrow width (≈25 μm) and small taper (≈1) is obtained.