Rubber Bands And O-Rings Give 3D Prints Some Stretch

Sometimes it would be helpful if a 3D printed object could stretch & bend. Flexible filament like TPU is one option, but [NagyBig] designed a simple bracelet to ask: how about embedding rubber bands or o-rings into the print itself?

Embedding objects into prints usually involves hardware like fasteners or magnets, but this is the first one (we can think of) that uses rubber bands. Though we have seen rubber bracelets running on printed wheels, and o-rings used to provide tension on a tool holder.

The end result is slightly reminiscent of embedding 3D printed shapes into tulle in order to create fantastic, armor-like flexible creations. But using rubber bands means the result is stretchy and compliant to a degree we haven’t previously seen. Keep it in mind the next time you’re trying to solve a tricky design problem; an embedded o-ring or rubber band might just do the trick.

9 thoughts on “Rubber Bands And O-Rings Give 3D Prints Some Stretch

  1. Interesting, but I’d worry the rubber bands will be degraded by the heat coming off the cooling filament when embedded like that. Not sure how heat tolerant they are, but I know I’ve seen a few melty stuck together ones that should never have seen hugely high temperatures. But that could easily be a chemical degradation.

    Also have to ask for something like bracelet what is wrong with simply tying an elastic chord together after threading it through your printed beads – time honoured, cheap, probably a faster less annoying process than hanging around waiting to put to band in at the right time, and really not difficult (at least with a little bit of tooling – I used to do a few of those for Nan every time I’d go round, small pliers or perhaps better the locking forceps to hold on to the stretched elastic, tie knot and let the elastic pull the thing closed the small amount you needed open to tie the knot).

    Which leads to the biggest downside to embedding into a single print – when the oring or rubber band fails, which it will, it is not likely replaceable – so when possible avoid this design concept. Even if you replace the idea with a drill out plastic rivet that holds the parts together around their captive oring you are saving so much print time and materials with only have to replace the failed elastic element and a few rivets (that may well be a direct use for those squitty little offcuts of filament that you can’t feed through the machine and the ruined soldering iron tip).

    1. I believe you can get rubber for high temperature gaskets, but as this is only going to be hot briefly once probably not necessary?

      Also, easier than tying could be joining the rubber with a dab of CA glue.

      But whilst this example is trivial to do another way, this technique could be used for more complex things.

      1. Not sure you can get high temp and particularly elastic at the same time, but I’m no expert on rubbery stuff. Though I suppose silicone may meet your needs as well.

        And yes I agree it may be ideal or at least useful sometimes, I just don’t like the idea of captive wear components – as that makes the whole part junk when they fail.

  2. I have used elastic cord – like is sewn into clothes – to hold segmented models together. A hidden knot at each end sets the tension. They are not ‘cast in’ but added at assembly. One or more lengths of floral wire can be added so poses will stay, like those old toys that the wire would stick out if you played with it too long.

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