MECHANICAL PROPERTIES OF OBJECT OBTAINED WITH MICRO-EDM DEPOSITION PROCESS

摘要

This paper describes the influence of the working conditions on the process performance and the mechanical properties of the structures obtained by a new deposition process using micro-EDM (micro electrical discharge machining). A bending test was used to measure the strength of the bond between the work surface and the deposited object. The experimental results showed that the higher the discharge current, the higher the bond strength between the deposit and the workpiece surface. This result was due to the difference in the internal structure of the deposited objects. Low discharge current settings (0.8A) lead to the formation of a high number voids, whereas high discharge currents (12A) lead to a more compact void-free internal structure. The size and distribution of the voids were obtained through the observation of cross section SEM photographs of column-shaped objects. The external surface of the column shaped deposit also changed according to the discharge current used; low discharge currents lead to a smaller deposit diameter with a smoother lateral surface when compared to the results obtained at high discharge current settings. In order to obtain smooth complex shaped microstructures with a uniform compact internal structure, different methodologies were tried. The best result was obtained by increasing the discharge cycle, due to an increase in the energy input into the system, which also lead to a four-fold increase in the deposition rate as well.