Wire electrical discharge machining of helical devices from permanent magnets

Microrobots are desired for future minimally invasive medical applications. One promising area of this field is the use of screws and helical swimmers, which can be propelled and controlled by the use of external magnetic fields to induce torque or force in the microrobot. These devices have possible applications in areas such as the eye, prostate, and kidneys to name a few. This research focuses on the fabrication of screws made of neodymium-iron-boron rare earth magnets.;Rare earth magnets are brittle and are not easily machined through conventional methods. A wire electrical discharge machine was used to fabricate the devices described in this thesis. Initial test cutting showed slow machining times; therefore a Taguchi design of experiments was used to find the optimal settings for the wire electrical discharge machine. Further analysis was done to analyze the loss in permanent magnetic field in the magnets due to heating in the machining process. Finally, a fabrication method for machining the helical geometry in the magnet was developed for use on the three-axis wire electrical discharge machine. Three prototypes were manufactured and data showed that the permanent magnetic field remained intact and that torques could be induced in the machined magnets.