An active guide wire with shape memory alloy bending actuator fabricated by room temperature process

An active guide wire of 0.5 mm outer diameter has been developed. The guide wire has a simple and flexible structure that consists of a NiTi shape memory alloy (SMA) bending actuator with meandering shape and a bias coil that is covered with thin polyurethane, tube. It can bend to one-direction by heating with electric current and is restored by the bias coil. Large current was necessary to bend the guide wire in water, however, it could bend over 60degrees. The rise of the surface temperature of the guide wire was less than 5 degreesC in water. The SMA bending actuator has been photo-fabricated from a flatten SMA sheet which was spread flat after it was memorized in curve-shape. In order to fabricate the actuator below the transition temperature of the SMA. a room temperature photo-fabrication process has been also developed. 2002 Elsevier Science B.V. All rights reserved.