Development of an electric discharge machining system; Sociotechnical actor-network evaluation of urban development plans intended to reduce automobile dependency of American cities

Nester, Henry, School of Engineering and Applied Science, University of Virginia
Francisco, Pedro, Science, Technology, & Society, School of Engineering and Applied Science
Barnes, Adam, EN-Elec & Comp Engr Dept, University of Virginia
Weikle, Robert, EN-Elec & Comp Engr Dept, University of Virginia

My technical research report documents my team’s effort to design, build, and test and electric discharge machining system (EDM). EDM is a unique manufacturing process with distinct advantages over traditional techniques in that it leaves material properties unchanged. My sociotechnical research evaluates the proposals for reducing car dependency in American cities using actor-network theory. Car depenency is unsustainable and harmful, but escaping this mode of living is difficult in part because there is low awareness of alternative proposals. Building an EDM machine requires a solid understanding of electrical engineering to design the high-speed sensing and transistor switching circuitry. Urban development proposals to escape car dependency are less directly relevant to electrical engineering, but do bear some relation: the mathematics of electrical network analysis can equally be used to model transportation networks and understand how travelers will interact with same. In addition, many electrical engineers are working to electrify the automobile, but perhaps, instead of reinforcing car dependency with updated technologies, they should be asking questions about what other directions our society could aim for.
For my technical research, I worked with three other students (Hadrian Sneed, Stephen Klem, and Nathan Hersel) to design and build a model of an electric discharge machining (EDM) system. EDM is a manufacturing process that uses small, repeated electrical sparks to slowly remove material from a block to reveal a part. Traditional machining techniques (typically using a spinning bit to remove material) are inappropriate in certain applications because the heat produced by the machining process alters the material properties of the part (for example, some metals become brittle as a result of work-hardening). EDM avoids this problem by sinking the spark energy mainly into the metal’s heat of sublimation. The research began with a literature review, which found that a key challenge would maintaining tight control of the spark energy – too much would weld the tool to the workpiece, and too little would lead to slow cutting. We designed electronics and a circuit board to solve this problem, then integrated and tested the whole system, attempting to cut through an aluminum block.
Unfortunately, even after all the bugs had been worked out, our EDM system was unable to cut metal. We determined that the root cause was that the spark gap electric field was too weak for breakdown of the water dielectric. Two solutions are apparent: improve the precision of the tool’s z-axis motion, or else raise the gap supply voltage and redesign the electronics to handle this higher voltage. Even though we did not meet the final objective, my team learned a great deal about electrical engineering (and we enjoyed working together).
In my sociotechnical research I investigated the proposals for urban development intended to reduce automobile dependency in American cities. Automobile dependency exacts heavy environmental, economic, social, and health costs and many citizens are concerned about these costs. Change is difficult in part because models of society where we do not depend so heavily on cars are not discussed in the public square – the current system seems to be the only possibility. My sociotechnical research explores relevant urban development proposals using a literature review, then analyzes one promising combination of proposals using actor-network theory to understand how a city built according to this proposal might function.
I found that the combination of multimodal development and self-sustaining neighborhoods seemed the most promising in terms of reducing car dependency in the United States. The actor-network analysis revealed the synergies and positive feedback loops which would drive the success of this proposal (briefly, policies written according to these proposals would change land-use, shrink the action-space, leading to a healthier community which votes for more of the same policies and expands its influence to surrounding areas).

BS (Bachelor of Science)
electric discharge machining, car dependency

School of Engineering and Applied Science

Bachelor of Science in Electrical Engineering

Technical Advisor: Adam Barnes

STS Advisor: Pedro Francisco

Technical Team Members: Nathaniel Hersel, Stephen Klem, Hadrian Sneed, & Henry Nester

Issued Date: