On Saturday 01 May 2021 12:25:12 Kenneth Lerman wrote: > Has anyone tried using polypropylene for the flex component? I > believe PP is used for live hinges. > If refering to whats commony called TPU, yes, abject failure as its too flexible and just folds up. Its good for those squeeze it coin purses though, and I may make some bigger ones to see if they'll sell as the one I have in my pocket is bursting with less than 2 dollars in small change in it.
> Ken > Kenneth Lerman > 55 Main Street > Newtown, CT 06470 > > On Fri, Apr 30, 2021 at 11:26 PM <ken.stra...@gmail.com> wrote: > > I haven't been following your project recently but am intrigued by > > "And it turns the armature easy enough the 3NM 3 phase motor (those > > are magic folks, > > running 50C cooler than 2 phase stuff) I'll use will not be a bit > > overstressed." Where did you end up getting your motors and what are > > you using for drivers? > > > > -----Original Message----- > > From: Gene Heskett <ghesk...@shentel.net> > > Sent: April 30, 2021 10:45 PM > > To: emc-users@lists.sourceforge.net > > Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive? > > > > On Monday 22 March 2021 09:19:19 Sam Sokolik wrote: > > > 202,200 for the outside spline and the flex gear is 200. In this > > > situation - the 202 tooth spline is stationary to the stepper. > > > The 200 tooth outside spline is mounted to the faceplate. In this > > > layout - the ratio apears to be 101:1 > > > > > > In this situation the stepper motor and the face plate spin the > > > same direction. > > > > > > With the same set of outside spines swapped - the ratio is 100:1 > > > > > > I am sure Andy can explain it. It doesn't make sense to me. > > > > > > Happy with runout... https://www.youtube.com/watch?v=eLyP2YwdstQ > > > > > > sam > > > > I am running some behind you Sam, with my project, having printer > > problems kills time and money. Finally settled on an ender 5 Plus, > > which is working passably well but I've wasted $3k getting there. > > > > Any way, I changed the design some from yours, to a 30/1 because > > those big spines print better, and by making my own bearings in > > openscad, useing crosman bb's for balls. I put a huge one with over > > 150 loose bb's directly on the outside of the moving spline, with > > only the lip of the output coupling disc (printed of course) > > interposed. And the floating spline has 3 more of those, sized for a > > good friction fit inside that spline, with both the spline and the > > bearings made as thin as practical to improve the flex life, and I > > just took the eliptical armature off the build plate and wiggled > > in into those 3 bearings inside the loose spline, so thats the > > driver armature, no commercial ball bearings anyplace like yours. > > I've made the 8mm hole in the plastic for the motor shaft into a > > prominent D-flat, and used a cbn wheel to make the flat much wider > > on the motor shaft, and this armature will be driven onto the motor > > shaft without any grub screws at all. > > No clue how long it will run before it bores that hole out and I > > have to make an alu inner for it. :( > > > > But I just now assembled it without the motor, turning the armature > > by hand, > > and it works, with no detectable backlash. And it turns the armature > > easy enough the 3NM 3 phase motor (those are magic folks, running > > 50C cooler than > > 2 phase stuff) I'll use will not be a bit overstressed. Those bb's > > will pound the plastic smooth and get smoother with use. > > > > So now its time to finish the output shaft, and make the rest of the > > housing. Which will be supported by the big bearing at the spline > > end, and 4 > > of the printed bearings at the load end. I've got the motor end > > gnawed out of some 1" stock I had, and I bought a foot of 3.125" > > thick by 6" wide stuff > > so I can make 2 output housings. That showed me the current price > > for extruded alu, scary. I also bought enough rod to make about 4 > > output shafts, > > over $200. And I've a spare 4" chuck from a TLM upgrade to a 5" to > > use on it. Or better yet, buy another 5" from LMS. > > So I'll get there, if I don't fall over first. At my age, thats > > always a possibility. > > > > I'll try to get some pix of what I've got so far, put up on my web > > page over > > the weekend. Along with some of the openscad source files. > > > > As usual, this stuff keeps me alone, safe, and out of the bars. :-) > > > > 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) > > If we desire respect for the law, we must first make the law > > respectable. - Louis D. Brandeis > > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > > > > _______________________________________________ > > 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 > > _______________________________________________ > 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
