Laser Cutting Simulation Of Nitinol Stent Alloy With Moving Heat Flux

Nitinol stents are widely used in treating plaque buildup in blood vessels. Laser cutting has been widely used to manufacture Nitinol stents. It is well known that conventional laser cutting is a thermal process which induces thermal damage to stent material and, therefore, produces poor surface integrity, short fatigue life, and compromised corrosion resistance. However, few theoretical studies have been done to understand the laser cutting mechanism. In this research, a finite element simulation of laser cutting of Nitinol SE508 alloy has been developed with user loading subroutine to model time/space-dependent moving heat flux. The superelasticity properties of SE508 were also incorporated in the simulation. The predicted cutting kerf is compared and verified with the experimental data. Temperature field during laser cutting process is also predicted to better understand the laser ablation mechanism and thermal damage to work material. In addition, the development of thermal stress during laser cutting and residual stress are also investigated.