On Sunday 28 September 2008, Jon Elson wrote: >Gene Heskett wrote: >> On Saturday 27 September 2008, Jon Elson wrote: >>> I have put a DPDT switch on >>> mine so I can run the motor off a servo amp. I can't get full RPM, as >>> my servo box has a 50 V power supply, but the servo amp gets me >>> computer-controlled variable speed and reversing. >> >> I'm running mine with a PMDX-106 interface, which gives me full control >> from its panel and from emc2.x > >But, no reversing, I assume.
Ahh, emc does have as one of its m# commands, a "start reverse", and I do have it hooked up, not terribly useful without the encoder, but ISTR it does work, I have it tied to one of those teeny relay's in the PMDX-106 which in turn is clanking a 10 amp P&B DPDT relay to swap the motor leads. So reverse works both from that teeny little toggle on the PMDX-106, or if its centered, from emc. >>> I have an encoder >>> patched on to the spindle, and can do rigid tapping, which is a hoot! >>> So, it can do something my Bridgeport can't do! >> >> If only that spindle had the power to do that, but sadly, its about tapped >> out with a 1/4" 28 tpi tap in cold margarine. Ditto for the spindle motor >> in my 7x12. I have cut threads with it using single tooth carbide bits, >> but they are a bear to sharpen correctly. That is how I cut the threads >> for the 1/2" acme bronze nuts in the new z axis of that HF mill. > >I'm a lot more interested in 4-40 and 6-32 size threads than 1/4". I might go up to 10-32 or 10-24 for interest, but 4-40/4-48 is about how much power that spindle has. I suspect without the encoder to pace the feed with, all I'd do is make more practice sessions of removing broken taps by ED means. Been there, done that, its a PIMA. :) >> How did you attach the encoder to the micromill spindle? Patented? :) > >No patents for me! Starve the lawyers! > >See the last picture here http://pico-systems.com/minimill.html for a >good view of the encoder and mount/drive. I found some nice plastic >pulleys in my junk drawer, and an oddball encoder with index. Ahh, but that's a minimill, not a micromill. I'll go get some better pix of my z axis & add them to my web page, such as it is, in a little while. I didn't have a lot to start with in the micro, so I had to do that from scratch, in this case using 1/2" acme screws. But I can set it down on the bathroom scales and show 155 pounds now, which is 150 pounds more than the original could do, direct drive from the same 425 motor. >The pulleys turned out to be 2mm pitch instead of .080", that's what you >get when you use scrapped parts, so I had to order different belts from >a specialty belt dealer. (You would almost think a 2 mm belt would work >on a .080 pulley, but they would jump a tooth every full rev or so.) >Anyway, I just bored one of the pulleys to the same ID as the toothed >nut that holds the bearing tension. I superglued the pulley on, but >that eventually worked loose. So, I made a thin spacer disc of PC board >material (so it wouldn't fatigue) and put it under the nut. I then >epoxied the face of the pulley to the disc. This has held quite well. >If it ever breaks down again, I'd be tempted to buy new aluminum pulleys >and make a custom clamp nut/pulley hub unit, but this is working quite well. > >I'm probably going to convert to all brushless motors at some time and >make a new control box with a higher voltage for the servo spindle. > >I also need to figure out how to get an on-screen RPM display. I really >wanted to work on that at the CNC Workshop, but got distracted. > The road to hell, Jon. ;-) >Jon > >------------------------------------------------------------------------- >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) It is a hard matter, my fellow citizens, to argue with the belly, since it has no ears. -- Marcus Porcius Cato ------------------------------------------------------------------------- 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
