Nitinol tubes are widely used to cut various biological stents, especially cardiovascular stents. However, stent fabrication defects, such as residual stress, microcracks, and heat-affected zones (HAZs) from the laser cutting, can lead to severe clinical complications. In this study, a multiphase flow coupling model for fiber laser cutting simulation is established by considering surface tension, gravity, and recoil pressure and combining the characteristics of fluid heat transfer with phase transition dynamics. The accuracy of the model is verified through the fiber laser cutting experiments. The simulation model is used to explore the influence of the key process parameters of laser cutting on the kerf width, stress, temperature distribution, and the HAZ. The microscopic removal mechanism of the material during the laser cutting is revealed, thus minimizing the problems generated during stent forming. The simulation model can provide an optimized process plan for fiber laser cutting.
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