The research objective of this project is to determine the nanoscale material deformation mechanisms induced by magnetic field assisted nanomachining, and to computationally model the nanomachining material removal mechanisms. The completion of this objective will enable machining of surfaces with a roughness value less than 1 nanometer for high-aspect-ratio components such as micropores (20 microns in diameter, 200-250 microns in depth) fabricated by ion or X-ray lithographies. The research approach consists of three tasks. Task 1 is to understand the nanoscale material deformation mechanisms by free abrasive machining, which will drive the development of a model of the material removal mechanism and ferrous particle mixed slurry motion in an alternating magnetic field. Task 2 includes experiments designed to reveal the ferrous particle mixed slurry behavior and abrasive cutting motion in simulated finishing conditions. The results obtained from Tasks 1 and 2 provide feedback for Task 3: optimization of the surface finishing of micropore wall surfaces in silicon and nickel microfabricated chips.
If successful, the outcomes of this research will reveal the physical energy-based surface and sub-surface deformation mechanisms of brittle and ductile materials in the nanometer range and provide a new finishing technology to improve the surface roughness and form accuracy. Moreover, a new design concept for ion and X-ray lithography processes (including magnetic field assisted nanomachining as a post-processing step) will be proposed to achieve desired surface functionality. This new technology will lead to the development of higher value-added next generation microelectromechanical systems and emerging nanoelectromechanical systems used for a variety of equipment from healthcare products to high-resolution astronomical telescopes. The multi-disciplinary research plan will provide a stimulating learning environment for both graduate and undergraduate-level students. The investigators will develop a new mentoring program for underrepresented undergraduates to create relationships that lead to an improved support network that better engages the students in the university engineering experience and enhances their long-term retention in engineering careers.
Research activities: The objective of this research project was to investigate and understand the application of magnetic field assisted finishing to create surfaces with a roughness value less than 1 nm rms on high-aspect-ratio components, such as micropores (20 µm in diameter, 200-250 µm in depth) fabricated by ion or X-ray lithographies. The outcomes of this research pioneered the development of state-of-the-art sensing technologies, including mechanical, thermal, magnetic, optical, and chemical sensors that employ micro-nanomachined components. This research supported improvement in the accuracy, resolution, and scaling of microelectromechanical systems (MEMS) devices used in healthcare, electronics, aeronautics, and energy fields. For example, the ability to fabricate micropores with 1 nm surface roughness enables MEMS-based X-ray telescopes that have a resolution 1000 times better than the current state of the art. Also, a new approach for 3D electron microscopy for small contacts was developed. The findings were disseminated to manufacturing communities through two journal papers, three conference proceedings, seven posters, a doctoral dissertation, a master thesis, and an undergraduate honors thesis. Education activities: 1. Undergraduate and Graduate Student Scholars The primary education activity was to provide opportunities for research experience for five graduate (four PhD and one MS) and three undergraduate students. In addition to the experimental work in the laboratory, students learned how to summarize and present the results of their research to diverse audiences. Internal meetings gave the students opportunities to exchange their ideas, comments, and suggestions with their laboratory colleagues. External presentations at conferences gave students chances to discuss their research with professional researchers and engineers, which improved the studentsâ€™ knowledge and cultivated their fundamental sense of engineering and research. The graduate students mentored the undergraduate students. Such interaction broadens the educational experience for both graduate and undergraduate students and encourages the undergraduates to pursue graduate studies. 2. Integration of Research into the Classroom Greenslet developed a non-traditional manufacturing module to complement the theories of advanced precision machining and metrology techniques learned in EML 4321 Manufacturing Engineering (~150 students) and EML6934 Nontraditional Manufacturing (~20 students) by introducing both traditional and non-traditional precision machining processes and surface characterization techniques. This module provided students opportunities to fabricate nanometer-scale surfaces using Magnetic Fields-Assisted Finishing (MAF) and to analyze the surfaces fabricated by the students. Taylor integrated the research into the classroom through lecture modules on surface metrology and characterization at the nanoscale using atomic force microscopy (AFM). The module included basic theory and operation of the atomic force microscopy in EML 3520 Mechanics of Materials and EML 4220 Vibrations. These courses impacted approximately 350-450 students. At the graduate level, EGM 6936 Nanomechanics Experiment and Simulation, allowed students to learn in depth about AFM and nanoindentation through lectures, lab exercises, and tours of the PIs labs impacting approximately 15 students. 3. Outreach: (a) Annual Florida Junior Science, Engineering and Humanities Symposium (JSEHS) The JSEHS has been bringing Florida science teachers, high school students and select middle school students to UF since 1963. The main components of this program are visits to research laboratories across campus, a judged speaker competition for 11th and 12th grade student researchers, and an opportunity for 9th and 10th grade students to give presentations as practice for future judged competitions. Every year, as a part of the JSEHS, Greenslet and Taylor provides the participating high school science students and teachers laboratory tours and hands-on experience with multiple-scale (from micro- to nanoscale) manufacturing processes, material science, and magnetism. (b) Student Science Training Program at the University of Florida (SSTP) The University of Florida-Student Science Training Program offers high school students a unique and intensive learning environment designed to provide challenging and inspiring experiences and to stimulate interest in science-related careers. About 100 students participated in this program every year. For about two months in both 2012 and 2013, Greensletâ€™s laboratory hosted two students (four students in all). Taylorâ€™s laboratory hosted two students. Through their research projects, they learned fundamentals of material science, precision machining processes, and metrology. The students also gained communication and leadership skills through small group discussions, oral presentations, workshops, and practical experiences. The students gave the oral and poster presentations at the end of the program.