you ask for long lasting that would be tungsten carbide but i suggest using easy to manufacture, easy to find, low cost because it will wear anyway
so copper, with little lead ( often copper sold will be 'machineable' which means lead which means higher wear ) for a key way you should be able to mill machine the electrodes and use the largest face ( dont cut with small end of rectangular prism , cut with side ) ( do the hokey pokey - put your big foot out i used to teach the operators ) use LOTS of pecking, just get a sizzle and jump away you dont have real edm equipment, just a hack so you gotta play safe and set it up vertical and submerged if possible so the jump opens up to a flood of the submerged fluid pee down the cut from above and to the side, you want to see the black puff out each jump Negative polarity ( tool neg, work pos ) If you use an r/c pulse generator then always negative tool. Short ontimes and hi freq ( say 10to50uS on and 200 or more off , 2000 is good for lash-up ) The exaggerated offtimes aid in letting the dielectric recuperate to non conductive state. The short cut times ( jump cycle ) aid in poor gap control, you actually cut while ' in the zome' but your system cant maintain the zone So you get efficiency by 'drive by edm', you go thru the zone each jump pass and get a little work done. You jump away right away and reduce the heat build up ( because you likely crashed into the work and shorted ) you're a scope kinda guy, try this... reduce the gap using a resistor divider giving max 5v and watch the process when you get more 'chairs' then you are cutting more when you flat line, you're crashing when its open voltage all the time you're missing ( old elox guys look for 'grass' like on a lawn , there was a scope on all old elox generators, the 'grass' was due to slow scope ) hth tomp On Wed, Jul 31, 2019 at 9:17 AM Gene Heskett <[email protected]> wrote: > Greetings all; > > Like Jon said on the sheldon list. woodruff keys cut into a case hardened > shaft are a bear. Carbide makes a mark, for about 5 seconds. > > So it appears I will have to dig the keyways by EDM. > > Because the electrode will go away too, what makes the longest lasting > electrode material? > > And which polarity, if it makes a difference? > > Thanks all; > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
