Extrusion process for fabrication of pressure-driven steering guidewire

Abstract

Actively steering guidewires and catheters have been researched as an interventional procedure has been developed. Although research has been conducted on actively steering actuators driven by an internal pressure, the body part of the guidewire has not been considered. The body part of the guidewire must satisfy the mechanical properties for the functions to operate, and the outer diameter must be small to be able to fit in small vessels. Since the pressure-driven actively steering guidewire has a hollow tube shape, it is, however, difficult to satisfy both requirements simultaneously. This paper proposes the design of an extrusion process for manufacturing the body part of the pressure-driven micro guidewire. The body part of the previously proposed pressure-driven micro guidewire is redesigned in terms of dimension and construction to be fabricable with the extrusion process. The optimal land length of the die is determined by performing fluid flow simulation of the extrusion process. The extrusion process is designed so that the redesigned body part of the guidewire can be fabricated in an integrated form with a single extrusion process. The body part of the redesigned guidewire is manufactured using the proposed extrusion process system. Experiments have shown that the fabricated guidewire body part has different surface shape compared to the design. The coil part has a lumen, but it is extruded as a convex shape along the coil. The limitations of the proposed extrusion process are analyzed and improvement plans are proposed.