Design and Fabrication of NiTi Frame Utilizing for Endobronchial Valve

Abstract

This study aims to design and fabricate the NiTi frame for Endobronchial valve (EBV) utilizing shape memory alloy wires. In order to evaluate the transformation and mechanical properties, heat-treatment at 450°C, 500°C and 550°C respectively for 10 minutes are carried out. Results from differential scanning calorimeter (DSC) and load-unloading test by universal tensile testing machine were used to select the heat-treatment condition for NiTi frame fabrication. Moreover, NiTi frames were fabricated by braiding 12 wires together by braiding machine with take up speed of 10, 15, 20 and 25 mm/sec respectively and constant carrier speed at 25 rad/sec. It is confirmed that all specimens show superior superelasticity at body temperature. Radial force of frame was measured by Mylar test at 37°C. Heat-treatment temperature at 500°C was selected since the highest stress for induce Martensite and recovery stress was obtained. The highest radial force was obtained in NiTi frame fabricated with taking up speed of 15 mm/sec. It is able to be concluded that NiTi frame can be illustrated for Endobronchial valve frame in future work.