perfect ... to next time ... bkt
Il giorno mar 16 ott 2018 alle ore 10:28 Gene Heskett <[email protected]> ha scritto: > On Tuesday 16 October 2018 03:33:30 theman whosoldtheworld wrote: > > > unfortunately I'm not always at the pc ... I'm often away for work ... > > so .... but your problem made me think of something that I did a while > > ago ... a vision system that chose cards from a pile .... one of the > > problems was to find the symbols of the playing cards .... a basic > > part of the program was to identify the circle as a geometric figure > > .... so I thought: you fix the laser to the spindle ... shoot at a > > webcam that is on the tailstock .... at this point the center does not > > matter and even the cone of light with opencv we always identify the > > center of that kind of circle that the laser prints on the webcam ... > > the center will be very precise and you with a piece of iron you can > > always get to the center of the design you get on the webcam ... there > > is a bit of code to do ... but it can be a nice tool. Having said that > > today's LDVTs are very precise, they already have on board an > > electronics dedicated to the measurements and can have both digital > > and analog outputs ... so that you can use the mesa Analog input card > > > > > The 7i90 has no analog input. Any A/D would have to be fed into the pi in > 8 bit pieces, 16 or 24 bits accurate and let the pi do the calcs. And > it doesn't have the iron for that job. And googling for LVDT gets me > to the omega pages, where a non-contact is $290 USD, but in a machine > with over 1 thou of backlash, probably a decade of accuracy overkill for > this job. I was able to get it within a thou Sunday with the laser, and > thats close enough for the girls I go with. I made all the corrections > with Z moving left and x moving in. With the backlash comp in use, that > should also get me close enough to fine tune an internal MT5 taper. But > I've already made it fit the taper I have after grinding the bent > spindles internal taper concentric again, and I'm out of steel in that > adapter getting there. To get the wobble I'm getting reduced further > will likely need to have both backing plates removed from the chucks, > remounted and the face fined up with the toolpost grinder. They were > last touched with a freshly sharpened HSS tool, leaving a fine powder > floating in the air. > > Fixing bent spindles is a cast iron bitch. But I am gradually getting it > usable. > > > Il giorno lun 15 ott 2018 alle ore 00:13 Gene Heskett > > <[email protected]> > > > > ha scritto: > > > On Saturday 13 October 2018 18:43:25 Gene Heskett wrote: > > > > On Saturday 13 October 2018 16:10:16 andy pugh wrote: > > > > > On Sat, 13 Oct 2018 at 15:03, theman whosoldtheworld > > > > > > > > > > <[email protected]> wrote: > > > > > > I think for your pourpose the better idea was using a very > > > > > > precise LVDT and put the measure of your axis in a table for > > > > > > make a good backslash linearization kinematics file .... > > > > > > > > > > Or use a dial indicator and a notebook. > > > > > > > > And a long, perfectly straight rod, turning slowly enough not to > > > > beat the $100+ dial to bits, and try to get an average reading. > > > > I'd need a 34" rod, a dog to turn it and an MT5 dead center, none > > > > of which I have. > > > > > > > > And from my experiments this afternoon, I am going to have to find > > > > a single spot beam green laser, this red line pistol cartridge > > > > model isn't going to give me good data, ever with its rotating - > > > > pattern beam. I've put a layer of cloudy poly on the cds and it > > > > helps, but it all goes to hell the instant the knife on the > > > > toolpost starts to interrupt the beam since the beam isn't round, > > > > and there does not seem to be a null at exactly half the beam > > > > blocked. I changed the drive belt to get more spindle revs, but at > > > > 1200 revs the front bearing is smoking in about 6 or 7 minutes > > > > with the bolts loose. And the reading still wanders around since > > > > the spindle is not synchronized with the meters A/D. So I've got > > > > to find a different way. I was hoping I wouldn't have to putz > > > > with building a camera, but that might yet be the only way. > > > > > > > > I'm getting my cataracts fixed starting next week, so this project > > > > is on hold for the time being. > > > > > > Actually, blame it on oldtimers I guess, but I thought what would > > > happen if I put a honking big cap across the CDS cell, so I went out > > > and stuck a 4700 UF cap across it. This made the settling time > > > several seconds, but worked a treat, so now I have it well within a > > > thou from just clearing the 4 jaw with the side of a carriage, which > > > is -3.500 in machine coords based on my homing, on out to around 23 > > > inches. There seems to be a bump there, or the bellows is pushing, > > > or perhaps I don't have that screw bearing properly adjusted. Shop > > > made bracket by an amature, me. :( Thats about 1.5" from running > > > into the tailstock. So I feel like I actually accomplished > > > something for a change. Murphy was present and up to his usual > > > mischief, the mouse battery died in the middle of it, and of course > > > I had to come into ther house ands get one out of the coyote.den, > > > and I'd give my left one to have a switch on the DVM to disable its > > > timeout shutoff feature. Batteries for it I have. > > > > > > FWIW, the maximum correction was about 3 thou, in the middle of the > > > bed, most corrections were under a thou. there's a bump in the > > > middle of the ways that I can't see, or feel thru a paper towel > > > wiping it. > > > > > > But its better than it was. > > > > > > > Many many thanks for all the help and ideas I've been offered, > > > > even if my explanations lacked clarity, its appreciated, a lot. > > > > > > Thanks again everybody. > > > > > > -- > > > 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-developers mailing list > > > [email protected] > > > https://lists.sourceforge.net/lists/listinfo/emc-developers > > > > _______________________________________________ > > Emc-developers mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-developers > > > > -- > 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-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
