On Tuesday 28 April 2009, Dave Engvall wrote: >On Apr 28, 2009, at 5:31 AM, Gene Heskett wrote: >> On Monday 27 April 2009, Kirk Wallace wrote: >>> I don't know enough about EDM. Does this look like a good EMC2 >>> project? >>> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170321678813 >> >> Auction closed now. I don't think I'd want to put $500 into it >> since edm can >> be done, although non-automatically for under a $100 bill, I've >> done it >> several times here. > ><snip> > >> Did anyone ever come up with a method to automate the feed via emc >> for this? > >As for gap .... Pete will tell you that when it sounds like frying >bacon it is just right.
As was my judgement, but a 10uf cap at 75 volts & 3 or 4 amps is noisy! Even my 74 year old ears were complaining. Very loud bacon. :) >A few years ago Pete Gruendeman , gruendeman AT att.net, brought a >sinker edm to fest. >Nice RC unit including a C axis so he could thread. A 1/4-20 thread >in a file is pretty cute. What would you use for electrode? Keeping that tip sharp enough to reach the bottom of the thread seems to look like a major problem to me. I'd assume that a much smaller cap than my 10uf would also give a smoother surface? Does Pete by chance have a web page? >It used a custom program written in compiled Basic under DOS. The >gap sensor was a >couple couple of comparators. The Z was driven by a stepper/servo. >He planned to use parallel springs to hang a small X/Y (+- 0.01) for >orbiting. I just turn the spindle on at lazy rpms, my ground connection is just the wire, spread around the tubing and twisted on the other side, propped up to stay out of the way. It polishes the tubing. Just enough run-out in hobby brass tubing to work rather nicely, and shorts seem to be self clearing after a couple of turns if I just stop the z and let it set still turning. I assume he was watching the peak and average voltages? With a 20 volt band gap, high starts the stepper at whatever speed its set at, and a low average stops it. Let the rotation clear a short by stirring in fresh dielectric fluid. If I did it often enough (once a year doesn't meet my definition of 'often enough') I'd see what I could come up with for hardware. >Don't know if he ever got it finished. > >Steve Stallings may know the status of this project. > >Dave Thanks Dave. -- 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) <netgod> Feanor: u have no idea of the depth of the stupidty of american law ------------------------------------------------------------------------------ Register Now & Save for Velocity, the Web Performance & Operations Conference from O'Reilly Media. Velocity features a full day of expert-led, hands-on workshops and two days of sessions from industry leaders in dedicated Performance & Operations tracks. Use code vel09scf and Save an extra 15% before 5/3. http://p.sf.net/sfu/velocityconf _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
