I am not sure of the grade of aluminium or dielectric. But we have sparked 1000's of tools before using the same dielectric with no problems. Although this particuler job has been on the machine longer than most (about a week). It is only on one flat surface that the problem has occured on at...
I have recently been edm machining a large aluminium mold tool. on clearing away edm deposits from the bottom of the cavity i have found lots ( about 30 ) small indentations with raised edges about 0.010" 0.25mm deep. They look as though a sharp object has been pushed into the surface I know...
