Session: IMECE Undergraduate Research and Design Exposition

Paper Number: 116491

116491 - Design, Fabrication, and Analysis of a Modular Braiding Machine for Flow-Diverting Stents 

Flow-diverting stents (FDS) have become one of the most efficient and promising endovascular biomedical devices for the treatment of aneurysms. FDS is fabricated from braided microwires that can regulate blood flow away from the aneurysmal sac to occlude aneurysm and facilitate remodeling of the blood vessel. However, the high-precision medical braiding machine for FDS and coronary stents is extremely expensive. Universities with low-resource especially in third-world countries, cannot afford these machines for research and teaching. This undergraduate research project aims to design, build and analyze a low-cost, portable, modular precision braiding machine for making FDS and coronary stents. The braiding machine parts were divided into four major modular components - spur and horn gears with a bovine track, bovine assembly, tension pully system, and electrical control unit with drive gear assembly. The parts are designed and optimized through dynamic modeling using CAD software Fusion360 and Inventor. The Inventor software was also used to generate tool paths and optimize the machining process. Horn gears, bovine assembly main body, and bovine track were machined using HAAS CNC on stainless steel, and steel spur gears were purchased from McMaster. Bovine assembly parts were designed and 3D printed using hard polymer resins. Other components, such as levers, O-rings, bearings, rods, cushions, spring etc. were obtained from local hardware shelves.The tension pully system was built using three pulleys, one tension spring, a spool holder with ratcheted gear and a lever. A prototype braider based on the four-gear system was built and tested initially, and the designs of the parts and assembly were revised, updated, and optimized. The electrical control unit was built and operated with a 24-volt power supply and Arduino Mega controller. A cut-off circuit was also built and got automatically activated in case of a collision or jam in the bovine track or malfunction in the system. Finally, a 16-gear assembly-based braiding machine was built that produced fine-meshed flow-diverting stents out of 32 nitinol microwires/strings. The effect of the rotational speed of the gears, applied tensions on the pully system on the braiding quality, and properties of the braided FDS were analyzed. The machine can deliver stents with an inner diameter ranging from 3 mm to 6 mm. The results also showed that the applied tension by the pully system at the various dynamic stages had the significant impact on successful braiding. The ability to add or subtract pulleys in the tension pully system to modify the reserve of the thread was critical for the flexibility of accepting various types and strengths of threads. This low-cost braiding machine will allow researchers to study various stents with different materials and process parameters to develop more efficient stents.

Presenting Author: Zeb Jandt University of Central Oklahoma

Presenting Author Biography: Undergraduate Research Assistant

Authors:

Mohammad Hossan Univ Of Central Oklahoma
Zeb Jandt University of Central Oklahoma