| Summary: | 博士 === 國立臺北科技大學 === 機電科技研究所 === 101 === This study investigated the procedures involved in the manufacturing of stents, employed in-vitro reliability verification, and conducted mechanics simulations to derive the radial and axial retraction rates and stress distribution with stents following balloon expand and crimp behavior.
We first employed 3D graphics software to design a prototype and analyzed the different structures of the prototype and the optimized design; we then imported into finite element software ANSYS to simulate the mechanical behavior of the stent. We analyzed the different structures of the prototype and the optimized design. It is hoped that the data obtained in this study will help to improve the mechanical performance of actual stents. Moreover, geometrical structures properties also have an impact on stent characteristics and strength.
The collected data in this study verifies that the optimized design, which differs primarily in the reinforcement of the rib and structural design, facilitates a significant increase in the deformation in the radial and axial directions. In addition, the optimized design exhibits enhanced support and reduced maximum stress. The results of the optimized design provide a useful reference.
Generally, the key procedures in the process of manufacturing stents include the design of the stent structure, the selection of materials, vacuum annealing, boring and polishing, laser cutting, ultrasonic acid pickling, and electrolytic polishing.
A number of studies have investigated the interaction between various parameters such as surface area of the metal, mesh size, axial shortening rates, and support efficiency.
Optimized design can ensure that thermal stress is not concentrated during the process of laser cutting and that optimal cutting parameters are employed. Research has also shown that in surface treatment, the selection of cleaning acid, temperature, and time control in the ultrasonic acid pickling process contribute to the removal of burrs and grease.
After laser cutting, the elimination of internal stress and the restructuring of surface grains often require material adjustment and precise control of the heat treatment process to attain optimal results. In the stent machining processes of surface passivation and chromium enrichment, we analyzed the principle of electropolishing and investigated the influence of methods and procedures, the selection of polishing solution, electrode design, and the temperature, voltage, and time of polishing on the resulting effects.
Finally, stent products that meet the requirements of in-vitro testing can be manufactured. Once the stent prototype was constructed, we performed in-vitro mechanical testing, including crimping and expansion tests, a three-point bending test, and an in-vitro vascular tracking test. The primary objective was to measure the radial recoil rate and longitudinal recoil rate of the stent as well as its bending of intravascular toughness and flexibility.
This study outlines the processes involved in the development of a new type of stent. It is hoped that these results can contribute to the integrity and accuracy of associated studies in the future, including research preceding clinical animal testing and human trials, protection of patients during implantation procedures, and safe operation by medical personnel.
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