SUBJECT: Ph.D. Dissertation Defense
BY: George Mathai
TIME: Wednesday, December 5, 2012, 3:00 p.m.
PLACE: MARC Building, 114
TITLE: Burr Formation in and Abrasive Assisted Brush Deburring of Micromilled Grooves with Application to a Novel Surgical Device
COMMITTEE: Dr. Shreyes Melkote, Co-Chair (ME)
Dr. David Rosen, Co-Chair (ME)
Dr. Steven Danyluk (ME)
Dr. Ken Gall (MSE)
Dr. Timothy Olsen, MD (Emory Univ.)


Burrs severely inhibit the performance and aesthetics in machined parts besides posing a safety risk to the user and manufacturer. Abrasive assisted brushing presents a fast and effective method for deburring these parts. The dependence of deburring rate on the workpiece material, abrasive grit size, type and rotational speed of the brush is studied. The formation of burrs in micromilling of a thin nickel-titanium alloy (nitinol) foil used in implantable biomedical device applications is analyzed as a function of micromilling process parameters such as spindle speed, feed, tool wear, backing material and adhesive used to attach the foil to the backing material on the burr height. A kinematic model to predict burr widths is developed and verified through experiments. Experimental data is presented in this paper for abrasive impregnated brush deburring of 25 μm thick NiTi foils. A kinematic model is proposed to predict rate of indentation during brushing based on Hertzian indentation mechanics and is validated using experiments. Age-related Macular Degeneration (AMD) is the leading cause of blindness in the western world in those over age 50. A potential method to replace damaged tissue in AMD, is to harvest healthy donor tissue (RPE-Bruchs-Choroid) from an eye, and relocate or translocate it to the injured sub-retinal region. A novel device that mechanically supports the integrity of a graft while inside the eye during surgical correction of Age-related Macular Degeneration is designed, analyzed and micromilled from thin NiTi foil. The presence of burrs on the surface of the structure mechanically constrains the tissue.