Observations on Debris Composition and Size Distribution in WEDM.

The study of the actual conditions in the discharge gap is a matter of large interest in area of WEDM. It is known that gap width and the presence of electrically conductive debris particles are the dominant factors affecting dielectric breakdown strength. Whereas, little information of that in WEDM is available, probably because of the difficult access to inter-electrode gap, wire vibration, etc. In this work the results of experimental observations of debris composition, morphology and size distribution of particles in WEDM are presented. A device designed to collect water from the working region and a set of WEDM experiments have been proposed. Techniques such as Energy Dispersive X-Ray Fluorescence Spectroscopy, laser diffraction, SEM and TEM have been used to characterize WEDM debris. Results show that debris in the gap is dominated by the presence of Cu-Zn from the wire. The presence of spherical particles in the range 1-20 μm has been confirmed. Histograms of particle volume and amount have been obtained, revealing the presence of massive amount of sub-micron and nanometric particles, most of them oxides of metals coming from the electrodes. The conclusions will be useful for future simulation work about particle movement and electrical fields in the working gap in WEDM. [ABSTRACT FROM AUTHOR]