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Flexible shaft - the best of both worlds?

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Posted · Flexible shaft - the best of both worlds?

I should ask him about that next time I see him


lol. Note that Bas works only one flight above and 20 meters distant from Erik. I think if he tried he could hold his breath and run to Erik's desk without taking a breath (would be difficult but possible). :)


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    • 2 months later...
    Posted · Flexible shaft - the best of both worlds?

    Hi guys I wrote about using the Flex3Drive, probably mostly stuff you already know though


    Hi Frank,

    would it be possible to add some pictures or more details about the mounting on the back of the UM2 to your article ?

    Thanks and regards,


    So sorry I've been missing. All I did is bend some steel pipe strapping into L brackets, you need to grind the holes a bit if they don't fit. Then just mount it to the back of the UM2, but leave the hole open so you can route the stepper motor wires cleanly

    I will post pics soon. I am currently in China visiting family

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    Posted · Flexible shaft - the best of both worlds?

    At Open Bionics, we've managed to crack the second filament issue. We started with the Flex3drive U2 head, and with a bit of tweaking managed Ninjaflex out of the Flex3drive, and PLA out of the bowden.

    Firstly, we redesigned the coupler between the stepper and flexible shaft, as it was skipping badly. We stuck a bit of bowden above the nozzle to stop the filament bulging out the gap (circled, A). The flex3drive head is slightly taller than the U2 head, which meant it hit the casing when the head homed - so we had to fudge the endstop a bit.


    The trick to adding the second filament is to rotate parts A and B through 90', so that the Flex3 extrudes down the right hand nozzle, instead of the left. Parts C and D are rotated 180', so they face the front of the U2. It's necessary to cut a groove for the linear bearing in part B (circled, B) to allow this change to happen. You can see the unused original groove on part B at 90' to where it should be. It should then be possible to thread the bowden down to the left hand nozzle (you may need to trim a few bits of plastic to get it down easily). The Flex3drive axle goes down the far left corner in the picture.

    Finally, we popped a grub screw through the top part (circled, C), to hold the bowden in place for the extra filament. It may be necessary to do this for the linear bearing as well, depending on how good your cutting was!

    ... and it works beautifully.


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