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Harmonic drive? Boy. Another project to sidetrack..

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  • #31
    The output of the stl is fine enough - I think it is just the limitation of the 3d printer. They are much finer than what you show - more like step resolution of the printer motion. It isn't bad. 10 minutes of work with sand paper smooths them out.

    sam

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    • #32
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      • #33
        forgot to post this.. 3d printed prototype then the actual thing...

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        • #34
          Very cool project! What type of filament are you using?

          I wonder if a softer filament (nylon?) for the flex gear may quite the drive? Or maybe print some ‘tires’ for the drive bearings?
          When I get Time... I'll...

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          • #35
            Getting there - have the face plate started - need to drill and tap a bunch of holes... need to grind the wheel bearing to preload it.. (it is a bit loose)

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            • #36
              I would be interested in what wheel bearing you used and in the setup/results after you grind it. Grinding the bearing to increase preload / reduce play is a interesting subject itself.

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              • #37
                Originally posted by Sparky_NY View Post
                I would be interested in what wheel bearing you used and in the setup/results after you grind it. Grinding the bearing to increase preload / reduce play is a interesting subject itself.
                The edge of the endcap would rock up and down a total of about .004" before molesting the bearing (about 3 inches out from the center)... I ground about a total of .003" ish on one of the inside races.. Now it has slight drag to when preloaded.

                sam

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                • #38
                  another painful video

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                  • #39
                    Found out pla can't handle it... <6hrs of running

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                    I printed a flex gear out of petg and it ran for over 36 hours.. I think that should be good for hobby...

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                    I finally drilled the holes in the face plate - should be able to do some destructive torque testing now...

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                    • #40
                      It looks like you already have a plan for torque testing, but just in case: AC induction motors are really convenient brakes. With the armature driven, DC current is applied to the winding. The strength of the current controls the braking force. May require excessively high current at really slow speeds, so maybe that excludes it for you.

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                      • #41
                        Happy with the run-out of the face plate.. (for what it is)

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                        • #42
                          Sharpie! Happy with the results.. For playing anyways.

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                          • #43

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