On Thursday, 28 April 2022 17:43:01 EDT andrew beck wrote: > Gene > Just use a counter with classic ladder. > > Easy as > Never used classic ladder. Don't know anything about it, but I do know hal pretty good, this counter and its friends are all in the hal file.
I just went out to check progress and found evidence it was out of synch, which can only be mechanical. If the driver looses synch, it shuts down So I took the drive apart and found it was being funkity again, had room to skip a tooth now and then. So I'm making a new armature with about a . 1mm increase in diameter and another .1mm increase in eccentricity, which should put a stop to the clicking sound of skipping a tooth. This is my own design of harmonic drive based on the loose belt idea. Since A: the used ones on ebay for $500 & have about all the goodie used up, and B are way too big physically, and I didn't need the torgue one of those can deliver, I thought I'd make my own little one on a 3d printer, using crosman bb's for bearing balls. Total cost, about a $tenner. The one I finished off yesterday already had a few thousand hours running on my kitchen counter since last September, pretty good for a shade tree project. It had a 50/1 gearset in it but was a bit slow, so the guts I put back in it were for a 40/1 ratio. But that change in the spline size, needed an armature with a bit more eccentricity, and thats 3 hours later on the 3d printer. That, and I've been playing with the roundness of the bb track to move the pressure off the edges of the track which causes bearing race splitting, putting the pressure closer to the center of the track, which reduces the splitting forces on the races. But I overshot that a hair, so this one is tweaked to fit the inner races .15mm tighter. That tweak along with the teeny increase in the eccentricity should fix it for a thousand or 3 hours. That limit will have been reached when the eccentricity finally breaks the loose belt, a 5 minute life in PLA but with the resiliance of PETG, quite a long time. 6 months running on my kitchen counter, no belt breakage. bearing race failures have been it. So, if you've the time, teach me how to use classic ladder for this. Thanks Andrew. > On Fri, 29 Apr 2022, 08:13 gene heskett, <ghesk...@shentel.net> wrote: > > On Thursday, 28 April 2022 14:55:24 EDT andy pugh wrote: > > > On Thu, 28 Apr 2022 at 19:50, gene heskett <ghesk...@shentel.net> > > > > wrote: > > > > Ack the switches on the driver, its doing a /16 microstep. its a > > > > 1.2 > > > > degree per full step 3 phase motor. the motor is now driveing a > > > > 40/1 > > > > harmonic drive, and the harmonic drive has a 53 tooth output > > > > sprocket, > > > > which is timing belt driving a 60 tooth on the axle turning the > > > > chuck > > > > with the home switch on it. And that home switch is whats driving > > > > the > > > > 100 turn counter. > > > > > > I have no idea why you need a 100 turn counter. > > > > To drive a couple comps to capture the number of steps issued to > > drive it exactly 100 full turns. That I should be able to divide by > > 100 to get the counts per turn, then divide that by 360 to get the > > number of steps per degree. But that gets me a very small number > > that doesn't appear to be related, cuz a command to move it 360 > > degrees=1 full turn is much less than a turn. This 3 phase motors > > encoder is not available to linuxcnc, only to the motors driver. And > > for this, real accuracy is needed, as it determines the mm per > > thread as well as a consistent stopping point. Its also a two start > > thread, as much so the plastic nut halves are identical while 2 > > start speeds up the vise movement as most vise screws are too slow > > for a wood worker and supply enough grip to damage the wood. > > > > I do the 2nd start on the unwind backstroke by lifting the tool at > > the > > end, rotating it an additional 180 degrees, put the tool back down, > > then run both y back to its origin and b back to 180 degrees. > > Cutting the back side of a buttress thread is all that needs cut, > > but it must fit the tpmm of the nuts. I can calculate the b turns > > required from the total distance which varies with the y start as it > > effectively slides up and down the z slope, but nothing is correct > > if the b scale isn't, hence the emphasis on a dead accurate > > calibration by measureing the counts for 100 360 degree turns. > > > > Do you have a better way? > > > > > If this is about swapping tools mid-job on this wooden screw, then > > > why > > > not just write two G-code programs, One to start with and one to > > > finish with? > > > > That part is already done. 2 subroutines. Its calibration of the b > > axis thats being a problem child. > > > > Thank you Andy. > > > > > -- > > > atp > > > "A motorcycle is a bicycle with a pandemonium attachment and is > > > designed for the especial use of mechanical geniuses, daredevils > > > and > > > lunatics." > > > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > 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, 1940) > > If we desire respect for the law, we must first make the law > > respectable.> > > - Louis D. Brandeis > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
