On Monday 02 November 2015 05:12:32 andy pugh wrote: > On 2 November 2015 at 02:26, Gene Heskett <[email protected]> wrote: > > Found it! That is a quite simplified version that assumes some > > unseen mechanism to run the drawbar, and a straight out the side of > > the wheel exit strategy. > > Yes, that is how the demo is set up, but the actual sequence is set by > a G-code subroutine, so is reasonably easy to change. > > All the carousel module does is interpret carousel position feeback > and issue motor movement commands for a tool carousel. Everything > else is handled elsewhere. In the examples it is by G-code, but it > would interface with Ladder just as easily. > > As you need to move the head up and down and issue spindle speed > commands I think that you will find G-code more convenient, moving the > head from ladder is more difficult. > > Also, that example includes spindle orient. You might want to consider > a spindle orient commands rather than a spindle start command.
I've no clue how a velocity servo could do that neatly because of the inevitable variations in bearing friction. This is the cause of some spindle heating in this mill, and I've played with the tension a wee bit, but haven't explored their replacement with higher quality bearings. I am well aware that this thing is NOT a Hardinge. > The docs say that M19 is limited to R-values of 0-360 but you can > force movement in one direction or the other. I think that a string of > 180 degree moves could be used to unscrew the drawbar by a requested > amount. It also has a built-in timeout in case things stick. Precluding that is one of the reasons for the head gearshift. In low gear, I don't think stickage would ever be a problem. The torque is there, all I have to do is give it some "good gulf". Referring to Gulf Oil's best refinery output. "Tipping the can a little higher" etc etc. Jon's pwm-servo amp can do 20 amps at 160 volts, this motor originally could do 2250 revs on the OEM traic (or scr) controller, which for some reason unk to me was restricted to about 1100 revs in reverse. I have about 107 volts of DC available, at 11 amps CCS, but can do 40 till the wall breaker trips. Jon's servo has a 16 amp current setting limit, so I can make it do things with authority. It can do about 2850 revs on this controller, but only for 3 minutes or so before an internal thermal limit shuts it down for a 1 minute (approximately) cooldown. However, leaving it at 2750 for half an hour produces only a 10F thermal rise looking at the motor. In that same half hour, the bottom of the spindle will be close to 200F! Piss poor bearings IMNSHO. But, the size of a 10 pocket wheel precludes making it on this machine, not enough Y travel, unless I can A: Borrow a 6 to 8" rotary table, or B: figure out how to cut off the back 4 pockets, making a 6 pocket wheel (more than enough said stupid) G-Code wise that is not impossible, and is likely the path I will follow here since the only rotary table I have is both a piece of junk I have motorized, and a 4" whose braking clamps are a brass thumbscrew and in-capable of holding it against the cutting forces involved here, it WILL move to its backlash limits. That was nearly a show stopper when I made those sprockets for the bandsaw fence lashup a couple years ago with your code help. That backlash made the tooth too wide, and I had to file them about 3 thou wider before they would enter a piece of #25 chain. Still a little sticky, but it works, which was the point of that project. Not your fault. If I were to remake them again, I'd program in backlash takeup moves at the peaks and gully's of the tooth. I do need to get a bigger, more precise table and motorize it, but $500+ (plus another sky hook in the ceiling for a rope hoist to handle it with, I use a deer hoist, 3 sheeves wide, small nylon rope for that sort of thing) to get that going isn't $omething I want to $pend ATM. It will happen eventually unless I fall over first though. So a truncated wheel, carrying 5 tools seems like the best way fwd right now. Raw material may dictate that as I have either the whole deck panel from an Ampex VR1200, ( liberally drilled here and there for hole to mount stuff when it really was a VR-1200) or better yet, a few pieces of its 4" wide stiffening skirt thats not cut up yet. If I put the axle hole on the edge & make a cap to clamp it to the rotating shaft with, the rest of it should be wide enough for a 5 pocket half wheel. That, if I can whack away the code, I can get going yet today on the small mill as it can do about 5" of Y motion. That way I won't have to move the jig on the 704's table. Needs more coffee though, I'm not quite up to speed for the day yet. So attack the code next. I can see where arcbuddy.py is going to get a workout. :) > The > advantage would be that you could ensure that the drabar thread > remained engaged. > > My milling machine has a sturdy cast cap over a "clllar" ??? > the drawbar on > the horizontal spindle. If you unscrew far enough it actively ejects > the taper. Same with these R8's, takes a couple turns, but could be tightened up by judicious removal of metal from the bottom of the bar retainer cap. Good excuse to slather some molysulfide grease on the drawbar heads contact flange. 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
