High-speed micro-electro-discharge machining
Abstract
If the speed and precision of micro-electro-discharge machining (micro-EDM) processes can be significantly enhanced, then they have the potential to be used for a wide variety of micro- and meso-machining applications. Toward this end, a better understanding of the impacts the various machining parameters have on material removal has been established through a single discharge study of micro-EDM and a parametric study of small hole making by micro-EDM. The single discharge study revealed craters resembling spherical caps surrounded by a rim of re-solidified metal. The volume of an individual crater varies linearly with applied energy while its diameter is related to the cube-root of applied energy. Modeling the micro-EDM discharge as an instantaneous spherical heat source allows accurate prediction of material removal by a single discharge. The main avenues for improving the speed and efficiency of micro-EDM are in the areas of more controlled pulse generation by the power supply and more controlled positioning of the tool electrode during the machining process. Controlling the gap between the tool and workpiece is critical to the microEDM process and operating at a larger gap spacing by using increased applied voltage proved beneficial. Further investigation of the micro-EDM process in two dimensions leads to important design rules, specifically the smallest feature size attainable by the process. While the smallest feature realized in the present study was 12μm, the lower bound on feature size appears limited only by existing power supply technology. An estimation of minimum feature size attainable is obtained by measuring Rz of a characteristic surface.
Degree
Ph.D.
Advisors
Chandrasekar, Purdue University.
Subject Area
Industrial engineering
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