On Tuesday 23 September 2008, [EMAIL PROTECTED] wrote: >Hi >I am interesting in EMC2 and EDM – electro discharge application. I want >to use it for burning/removing broking taps from holes. >I know it been done already. Is any documentation or paper about >controlling EMC2 with EDM process?
For tap removal, which I have done with 6-32 taps in blind holes, the inability to keep fresh kerosene at the work interface limits the usefulness of any controls cuz you are always backing the electrode out of the hole to blow away the debris and put a few drops of fresh kerosene in. Running with the workpiece insulated, and a clip on the electrode to ground the electrode, and the electrode spinning a 100 rpm or so gave me the best results, often 2 or 3 minutes of runtime before it shorted out from the debris in the kerosene. I had made a modeling clay dam to hold it about 1/8" deep around the electrode, but the kerosene also tended to wash that away, requiring 'maintenance'. I found solid brass rod for an electrode just sharpened itself to a bullet, and that small brass tubing from the hobby shops stock worked better. That would have allowed fluid to be gravity fed if I had wanted to stop and drill a hole in the tubing and rig a reservoir with a leakproof hole in the bottom, but that would have been a lot like work. My power supply at the time was borrowed from the motor supply I built, so was lower voltage (28 volts) and lower current (.6 amps) than what might be optimal, and I have since obtained parts for about 8x the power at 2x the voltage. The capacitor I used is and will be a 5 microfarad, 600 volt rated oil/paper type in a can about the size of a cigar box. But I've not broken any more taps to give me an excuse to try it out. >I think it can be useful machine for many mfg co. It is, but there, some provision for circulating the fluid at the working interface is made must be made. Once that is done, I think the currents can be turned up considerably. It took me about 4 hours to remove about 5/8" of broken tap per tap, so I was parts of 2 days doing it. That was expensive Hansen(Irwin) taps, the 3rd one I used was an elcheapo Mibro from Lowes, it finished the next 17 holes in that job and is still sharp. That was about 3x the number of holes a Hansen could tap. Go figure... I've also heard of folks putting a solenoid coil on the electrode driven to lift the electrode by the current through it so it vibrates up and down which seems to me to be a better way, but I haven't tried it. It seems to me that could be better done with a piezo device in theory. Make it flex the electrode downward with a rise in the applied voltage. Either of those ideas would also tend to pump the fluid better I'd think, increasing the time between clean outs & replacement. >Thanks >Aram > > > >------------------------------------------------------------------------- >This SF.Net email is sponsored by the Moblin Your Move Developer's challenge >Build the coolest Linux based applications with Moblin SDK & win great > prizes Grand prize is a trip for two to an Open Source event anywhere in > the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ >_______________________________________________ >Emc-users mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The world has many unintentionally cruel mechanisms that are not designed for people who walk on their hands. -- John Irving, "The World According to Garp" ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
