3D printed bike

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  • Deserves a picture.

  • Gosh.. I want it!

  • In addition to elegance and € component selection, the lugs on that Moorhuhn are also worthy of note, the stiffness, strength and weight appear to be optimised (presumably with some form of topology optimisation) via an internal lattice

  • Another interesting, recent effort is this by BMW-backed optimisation software Elise.
    The frame is printed so I doubt it's particularly cost effective. Like that WAAM weld-bike earlier in the thread, losing the constraints of tubes and lugs opens opportunities and enables generative design algorithms to do their thing within defined constraints.
    According to their LinkedIn “The pipes of the Bionic Bike are not hollow at all points and have no uniform thickness. Instead, they consist of a completely new lattice construction on the inside in high-loaded areas.
    In this way, the frame is custom-made for a specific user. For a lighter cyclist, the algorithm would construct it differently without much effort. Once the DNA is created, you could also easily change the bike type and transform the folding bike into a mountain bike in no time. It thus frees the developers from many constraints and helps them to create better products”


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  • The outer skin of the frame is very thin and beneath it, the lattice is doing all the heavy lifting...

    As with any design activity that relies on a digital model to drive the entire frame design, the old adage of crap in, crap out applies, but I'm guessing that after a few decades of carbon frame design the models must be pretty accurate.

  • Here's another nice topology optimisation project, a Hope top crown/stem for a Fox fork designed by Landmark University in Nigeria.


    And you can download the STL from GrabCAD too if you fancy knocking one up!

  • the lugs on that Moorhuhn are also worthy of note, the stiffness, strength and weight appear to be optimised (presumably with some form of topology optimisation) via an internal lattice

    At the Advanced Engineering show at the NEC last year, I think it was Renishaw had 3D printed polished Ti bars on display. They were track sprint and TT bars used by various Olympians including Chris Hoy. They were thin wall Ti with a lattice core (which they were being a bit vague about, presumably because it was their IP). They were made in multiple pieces and bonded together, not welded. They claimed they could make them stiffer than an equivalent carbon bar - something me and my F1 colleague found surprising. However, given the complicated shape of a curved bar and the very directional qualities of carbon, it’s quite probably the case.

  • Reynolds actually sell a 3D printed Ti dropout also
    https://www.reynoldstechnology.biz/reyno­lds-3d-printed-titanium-dropouts/

  • ^ The simple fact is it's wasteful and time consuming cutting parts like those out of solid titanium. In a lot of cases it makes much more sense to 3D print. An example in F1 are those tiny Nessie separators on the the front wing (centre left of image). They are sometimes one piece and are hogged out of a solid chunk of Ti the size of a house brick! The fatigue was too much for components like those, but the loading is far lower on a dropout.


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  • Atherton raising a £600k funding round on crowdcube
    https://www.athertonbikes.com/crowd-cube­
    https://youtu.be/x-bbCq3NUoo

  • Absolutely - The costs/complexity associated with CNC machining Ti is good news for metal AM - you can cut take an existing design and deliver a commercial benefit and then add further technical benefits on top of that.
    It's a similar story with Inconel which is relatively straightforward to print but a pain to machine.

    Without a cost advantage, it's harder to sell the 'unlimited potential' of AM to someone who already has a cheaper solution that works - why take the risk?

  • It's a similar story with Inconel which is relatively straightforward to print but a pain to machine.

    In racing it was basically the same with all the 3D printed materials. Big cost and time savings coupled with the ability to make more complex shapes, strength and stiffness almost identical to conventional materials, but poor fatigue life. So it was suitable for static components like roll hoops and flanges, but no good for suspension or engine components.

    I saw a whole 3D printed exhaust manifold in Inconel when I was at the team. It was paper thin! No idea who made it.

  • I quite like the approach taken by Bastion, they're marketing the fact that they apply some fairly sound engineering - see the sections on testing, reporting and tuning factors on their webpage

    I was pleased to see that they also polish their lugs automatically with what looks like some push-in inserts to protect the bond face.


    The main tubes are filament wound by a sub-contractor but they wind their own chainstays

    Overall the finish is pretty neat and tidy, you can see why people would drop some serious cash on this and AM is being put to good use too

  • looks a bit like the old GT thermoplastic frames

  • Yes, that's what I thought when I first saw the Robot Bike Company offerings too

  • Really hoping for some of these cool lugs/parts/dropouts/braze-ons to be made and released to the "consumer" framebuilding community in the near future
    It would open up a lot of doors for bike makers who are constrained by available parts

  • yeah thatd be super cool, Ive had it in the back of my mind for a while as something that would be nice to do. Havent really found the time to commit to it.

    there's these guys that a few other builders have got stuff printed in ti/stainless.
    http://www.tc-rapidprototype.com/About.a­spx?ClassID=25

  • Absolutely
    It'd be great to have an app in which you modify angles and features from a library of parametric lugs and dropouts. The CAD file of your lug or dropout could then be approved for purchase or downloaded to modify the asethetics or check within a CAD assembly.

    316 stainless is the most common material that can be printed and welded/soldered.

  • It really would open up a lot of design possibilities.

    I love this type of thing:

    By Prova. Seamless, very elegant

  • ooh yeah thats very tidy

  • 316 stainless is the most common material that can be printed and welded/soldered/bonded.

    FTFY

    I just checked actually. I've only ever bonded carbon with Ti or Al and didn't know if the chromium interfered with the bond. Doesn't appear to, as long as the surface is correctly prepped.

  • 🤔

    Not as expensive as I thought it would be, Materialise charges more than double. The question is of course whether it'd be strong enough.


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  • Is this what master wants?

  • It was more of a thought experiment, seems to be a pretty risky thing to gamble with.

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3D printed bike

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