https://youtu.be/nhHDrK6sCRs
On Wed, Jan 27, 2021 at 3:56 PM Gene Heskett <ghesk...@shentel.net> wrote: > On Wednesday 27 January 2021 16:04:45 Chris Albertson wrote: > > > This is a machine-tool related list. Many of us have 3D printers > > too. So if you have both additive and subtractive tools available and > > want to make a harmonic drive may be the best option is to make a > > hybrid design with some parts of the drive made with different > > techniques. > > > > Metal really is the best material for anything that needs to flex > > because metal can be made so thin and is still strong when thin. 3D > > printed plastic must be about the worst material for this. > > > > So I ask, Would it be possible to design an easy to make flex gear? > > I think so. Most of the flex cup is made on a lathe then you mill > > the teeth on the outside. I think it could be machined from a short > > section of large-diameter steel tube. Then a bottom plate is press > > fit. > > > > Maybe I could cut the teeth first, like making a gear, then place the > > part in plastic holder and chuck the holder in a lathe and bore the > > center out until the ring is very thin. The trick is to support the > > ring with a 3D printed rigid backing fixture while boring it. > > > > The rest of the harmonic drive could be plastic. > > > > The big question for the group here is if the flex ring is something a > > normal person could make one at a time. What kind of metal is best? > > Is this kind of metal available in tiny quanity > > > > On Wed, Jan 27, 2021 at 12:36 PM Gregg Eshelman via Emc-users < > > > > emc-users@lists.sourceforge.net> wrote: > > > Instead of a one piece flex cup, how about making a flex ring that > > > connects to a rigid base with teeth or pins - something that > > > interlocks but allows radial movement of the flex ring with respect > > > to the base? No constant bending back and forth to break the print > > > layers apart. > > I like this idea too. Cut or 3d print, the equ of a small pitch box joint > on the bottom of the flex gear, matched to engage the "fingers" on the > output disk, it could slid in and out radially on these "box": pins, and > do it without the flex that normally breaks the cup off the disk at that > joint. That would replace the spot that is the major breaking point, > with a hinge like joint, which might prolong its life by many times what > it is now. > > The splined part would then need to be restrained axially to keep it from > wearing the ends of the cylinder it becomes, from rubbing on the > housing. Perhaps a very mild dovetail? But that would lead to backlash > and problems assembling it. > > Enough extra length on the cups pins to project a thou or so past the > disk and drive a flat head 0-80 screw in the the end of the pin, pin > sized so the angled underside of the head would prevent it from pulling > apart. Wouldn't take a screw per pin, one in every 4th or 5th pins > should do it. 3d print a bit of the 0-80's underside head angle on the > disks fingers and screw head could actually sit below the disk face. > > 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