Influence of process parameters on surface topography of nitinol manufactured by fiber laser cutting for medical applications

Abstract

The need and tendency to develop medical devices on the micron scale has created an opportunity to micro cutting processes that have the capability of manufacturing quality medical devices. Thereby, the necessity of materials that have unique features to improve the deliverability and the performance of these devices have made nitinol one of the most selected materials for this industry. Nevertheless, the study of the micro processing of nitinol tube for the application on medical devices, through fiber laser cutting and its response to surface quality has not been thoroughly researched. Hence, in this research the response of fiber laser cutting parameters, such as spot overlapping and pulse energy, on Ni-Ti alloy (nitinol) was statistically analyzed through surface quality through average surface roughness, and heat-affected zone. Results showed that spot overlap had most impact on surface quality, since surface roughness decreased increasing spot overlap, but further increase resulted on increased surface. Minimum surface roughness of 1.482 µm, with 83.72% of spot overlap and 72.16 of pulse energy. Presence of HAZ, and dross found on highest values of spot overlap and pulse energy. In conclusion, fiber laser cutting has the capability to produce high surface quality nitinol self-expanding stents.