On Wednesday 24 February 2010, dave wrote: >Indeed, it would be nice to have EDM capabilities within emc. :-) > >Pete has always maintained that the power supply was the easy part. He >recommended using a RC source to get started and concentrate on getting >the Z motion/gap distance correct. Then work on orbiting and finally go >for a nice pulsed source. BTW there is some data that says that jumping >the current 20% for the last part of the burn cycle increases stock >removal considerably. > >Pete's system used fast comparators to adjust the voltage gap. Too low, >move up, too high move down; actually I should say step down or up. > >I was going to try a servo on Z and attempt to keep the avg current in >the right range. > > >Dave > This would be ideal where the area can be kept relatively clean because the dielectric fluid is circulating, but as I found when I was EDMing a couple of broken taps a couple of years back, it falls over when you are in a deep, blind hole, the kero gets so conductive it eventually shorts out and I had to pull the electrode, move the table for access, blow the hole clean with an air hose, and re-fill my puddle with fresh stuff, about every 20 thou. And while it did work well and the holes were salvaged, it sure was a 3 day PIMA.
I have since built a much larger, higher voltage and higher current, power supply, with a 10UF paper cap for the discharge energy, and that made short work out of some holes in a Freud saw blade, it also was make your ears ring noisy. And at my age they ring anyway, so that was actually a painful noise level even to me so I stopped it and dug my gun muffs out, and I would not allow anyone with younger & better ears to approach it without first donning a set of muffs, I have several just in case. >On Tue, 2010-02-23 at 23:54 -0600, Jon Elson wrote: >> Dave Engvall wrote: >> > I have no idea if this email still works for Pete. Pete developed a dos >> > app for steps-> servo that was pretty cute, including a C axis. As a >> > demo he threaded a file with it. >> >> OK, so he wasn't using EMC/Linux for that. it was still PLENTY cool! >> He had burned a number of >> interesting patterns into old files. >> >> > EMC does have the capability of limiting or stopping feed in a wire edm >> > setup but no ability AFIK for backing out necessary for sinker edm. >> >> If you have good flushing and a system to shut down the feed and pulser >> if a short develops, >> you may not need the backing up, but that would still be a really good >> thing for EMC to have, some day. But, really, >> if you are doing a sinker job, you don't need G-code. You position the >> X-Y to put the pattern where >> you want it, and then need some scheme that could be rigged through HAL >> to control the Z axis >> based on the EDM current. If you wanted to get real fancy, you could >> even have G-code statements >> that would set variables for start and end of burn, and these could be >> passed to a custom HAL component >> that would monitor the burn and drive the Z feed. Ummm, I'm starting >> to get itchy to make something! >> But, first, I need a good pulser. I know what I want to do, but just >> haven't gotten around to building it. >> >> Jon >> >> ------------------------------------------------------------------------- >>----- Download Intel® Parallel Studio Eval >> Try the new software tools for yourself. Speed compiling, find bugs >> proactively, and fine-tune applications for parallel performance. >> See why Intel Parallel Studio got high marks during beta. >> http://p.sf.net/sfu/intel-sw-dev >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > >--------------------------------------------------------------------------- >--- Download Intel® Parallel Studio Eval >Try the new software tools for yourself. Speed compiling, find bugs >proactively, and fine-tune applications for parallel performance. >See why Intel Parallel Studio got high marks during beta. >http://p.sf.net/sfu/intel-sw-dev >_______________________________________________ >Emc-users mailing list >Emc-users@lists.sourceforge.net >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) How can you work when the system's so crowded? ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
