Has anyone tried using polypropylene for the flex component? I believe PP is used for live hinges.
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
