The intention was to induce a controlled effect allowing greater metal removal rates with a more even distribution of discharges (see Figure 6). Unfortunately, most of these additives settled to the bottom of the work tank or were filtered away.

Eventually, "chemical satellite electrodes" were discovered by Oel-Held. These chemical satellite electrodes having no specific weight or size, are permanently suspended in the dielectric and cannot be filtered out. Under the influence of electrical current, these chemical satellite electrodes align themselves along the lines of electric flux in the electrical field. Channels of increased conductivity greatly enhance the general characteristics of the dielectric- allowing faster, more even spark distribution. In conventional dielectrics, electrons flow directly from the workpiece to the electrode. With this discovery most electrons are attracted to the chemical satellite electrodes where they lose part of their kinetic energy, which reduces electrode wear.

Summary
After careful consideration of the previously- mentioned data, it is established that this new fluid offers a high flash point, low viscosity, no health hazards, and a life span at least five times greater than mineral-based products. The evolution of synthetic dielectrics has more than met the challenge of today's EDM machines.

For more information call Peter Knowles of HIRSCHMANN Engineering (Buffalo Grove, IL) at (847) 419-9890.