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  1. #1
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    3D printing titanium dropouts and tubes

    I know this topic has been discussed here before, but I thought I would add a recent development. 3D printing is being used by Charge bikes in the UK to produce production parts. Can complete frames be far behind?

    Charge Bikes - Printed Ti
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  2. #2
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    Hi

    it should be possible to "print" a frame using this kind of technology BUT have a look at that machine, it must be about ten times bigger, what will end up that either the laser or the part with the powder can't be fixed installed and must be moveable. This will increas the dimensions of that machine immensely. This will increase the cost as well...
    Then on the other hand, you don't know how lon it took to build those small dropouts if it takes you a day to print a whole frame (what might be not enough) you won't find a lot of people to pay for it. Then you have to heat treat the frame, as it is titanium you need an oven that you can run either on vacuum or in an inert atmosphere (Argon) and then you have the finishing work on the frame what will be manual work. So all together it might be really interesting to build a frame using this technology, especially the possibility of 3D hollow structures (internal gussets)... but affordable - NO

  3. #3
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    Those parts are effectively castings. Which means that they're probably only developing about 30% of the strength of a cold-worked tube. They're also probably not a nice high-strength alloy like 6/4 or 3/2.5, but something closer to CP. Neither of which is an issue for a part that's dominated by bulk, like a dropout, but printing a tube that's worth spit is decades away.

    I will also be willing to lay a small wager as to the durability of these parts: I bet they'll crack. Castings suck.

  4. #4
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    So freaking cool.

  5. #5
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    Quote Originally Posted by BigHank53 View Post
    Those parts are effectively castings. Which means that they're probably only developing about 30% of the strength of a cold-worked tube. They're also probably not a nice high-strength alloy like 6/4 or 3/2.5, but something closer to CP. Neither of which is an issue for a part that's dominated by bulk, like a dropout, but printing a tube that's worth spit is decades away.
    Well, it's a rapidly-solidified "casting", to give fine structure (good mechanical properties). Also, notice in the video, they used 6-4 Ti powder, so it's heat-treatable to high strength.
    whatever...

  6. #6
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    it's really sintering, which has been used to good effect for quite some time. Would be interesting to see how it holds up

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    Ah, I skipped the video, as I'm already familiar with the sintered rapid prototypes. 6/4 is definitely a lot better than CP. It would be nice to know what the actual tensile strength is. Sintered parts can be really, really strong: Ford uses sintered connecting rods in a lot of their engines. The last time I checked, though, the process for those uses tons of pressure to compact the metal powder before it's heated.

    It will be interesting to see how these work out.

  8. #8
    Obi
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    ^That. I'd want to see the stress and fatigue analysis first as well as cutaways of post-production versus post use versus post failure grain structure, etc.

    Effectively though, IMHO it's still "potentially" a more viable part than say glorified plastic(s).

    Your mention of Ford's rods in the new engines is great and is a good jumping off point. IIRC Ford's rods are steel though, and as you said, produced under severe pressure (and inherently heat) which fuses the material differently than a laser can ever re-create.

    What am I saying here is basically the day a laser can say, make a diamond with duplicate traits as one earth made or similarly man made, apply that to frame materials and we'll talk.

    Steel until then.

  9. #9
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    Quote Originally Posted by BigHank53 View Post
    ... is decades away.
    Thinking like a Victorian... where 10 decades in the future, people would be flying around in steam-powered airships. Completely missing out the development of internal combustion engines (prop planes) and jet-engines (ducted fan & turbo-jet).

    3D printers are like computers, where as when computers were in their infancy, then computer scientists envisioned truly massive future supercomputers, taking up whole buildings. Of course, Moore at Intel saw that every 18 months, the same piece of semiconductor got twice as complex (providing twice the computing power)... or the same computing power, 18 months down the line will cost just half.

    So the shiny new computer you're sitting at right now, is 100x more powerful than the one a decade ago. 10,000x more powerful than 2 decades ago. I assume our average age around here is 35... the computer we have at our disposal is 10 million(!!) times more powerful than typical computers at the time. Or another way... the smartphone for US$400 right now, the computing power available would have cost US$4 billion today's dollars back in 1987.

    Back to 3D printers... DMLS as used there whilst can produce "fully dense" parts, they are indeed like cast items and lack the ultimate strength. However, we already have the technology to make very strong printed 3D printed metal (Ti alloy) parts... using electron beam melting. It is already used to make turbine blades for aero engines... problem is right now, it is an extremely expensive process (though cheaper than growing a single-crystal metal). 1000MPa tensile strength...

    Check: Titanium 3D Printing in Action - Electron Beam Melting (EBM) - YouTube

    Of course... being able to use a 3D printer to fully print a bicycle frame... you'd made a monocoque-type structure and have an internal honeycomb/criss-cross struts, like bird bones for example.

    Customisability comes free with 3D printers... so whilst, current build volumes are limited to approx 20cm cubed, with a cost of ~US$150/hour. I would wager someone will show a fully printed metal frame within 5 years (costing US$50,000 say) and will be the commercial fabrication of choice by 2025. No more x-small, small, medium, large, x-large nonsense.

  10. #10
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    this is one of those subjects where I was originally very skeptical, and once I saw it in action I was totally blown away. I do hate hype though, and 3D printing has been the subject of hype for a very long time.

    It's funny that the only place that they used the benefits of 3d printing is to put a logo inside the window of the dropout. You could replicate this dropout with normal technology. In fact, it looks like something that I'm pretty sure I've seen on a Walmart bike.
    Last edited by unterhausen; 10-02-2012 at 05:26 PM.

  11. #11
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    I work in a facility where the guy from EOS in germany comes to tell us all about the latest developments This is the kind of facility where single crystal parts are grown and turbine blades and hollow supported aircraft panels and printed carbon fibre and you probably have heard of the dreamliner and rolls royce He is however after selling the latest technology to us ,surprisingly last visit the official line was it will be 5 years before printed titanium is ready for the prime time consumer products officially its not the same strength in all 3 directions and limited by build direction

    moral of the story the cycling press will always try to tie some fancy (EADS in this case) research facility in to hype up their product EOS supply the EOSint to EADS and also Rolls Royce

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    Printing Ti has been around for many years already. Accuracy has always been a big issue (think sand casting texture). Porosity and strength are also not where they should be.
    Maybe some day but it is a very slow process and has a long way to go.

  13. #13
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    Can you print a Samurai sword ?!
    www,chernibikes.com

    HAND CRAFTED RIDING MACHINES @ Face Book
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  14. #14
    dru
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    I think a lot of this stuff will remain extremely high end niche. Turbine blades come to mind. Cost is the reason here. The alloy has to be refined to a high purity even before the 3d process can start and the power demands and cost of the 3d equipement is sky high. It only makes sense where the present cost of manufacture is sky high or has a relatively high reject rate such as investment cast turbine parts.

    Drew
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  15. #15
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    Quote Originally Posted by dru View Post
    I think a lot of this stuff will remain extremely high end niche. Turbine blades come to mind. Cost is the reason here. The alloy has to be refined to a high purity even before the 3d process can start and the power demands and cost of the 3d equipement is sky high. It only makes sense where the present cost of manufacture is sky high or has a relatively high reject rate such as investment cast turbine parts.

    Drew
    Drew the technology for making turbine blades is single crystal growing it into the single blade with no grain structure so to speak this has also started to make inroads into turbo and medical applications

  16. #16
    dru
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    Wow, I am solidly behind the times. I had a quick peek!

    Drew
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  17. #17
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    Quote Originally Posted by compositepro View Post
    Drew the technology for making turbine blades is single crystal growing it into the single blade with no grain structure so to speak this has also started to make inroads into turbo and medical applications
    seeing the singe crystal and in comparison the older radial crystal (think 6 or 8 crystal grains running along the blade instead of one) turbine blades in my materials science classed was quite impressive. All the requirements for cleanliness to not start any crystal grown at some imperfection or dirt is also pretty crazy. This was back in the early 90's so the single crystal blades were relatively new.

    nothing too much of value to add here, but I will be looking over info as I can find on what they are doing for strength on the printed Ti parts.

  18. #18
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    you can download the data from EOS you will see quite readily where the material has a weakness in the build layer

    The chaps at rolls royce are building a 90 million facility just for research into growing blades
    takes a while to get your head round the single process its quite beautiful

  19. #19
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    Quote Originally Posted by alexchannell View Post
    Printing Ti has been around for many years already. Accuracy has always been a big issue (think sand casting texture). Porosity and strength are also not where they should be.
    Maybe some day but it is a very slow process and has a long way to go.
    Apparently the process which Charge are using results in material with the mechanical performance of plate titanium.

    Also the surface finish is good - all they do is tumble the parts in ceramic beads and they get this finish:


  20. #20
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    That tech looks nice, but it really seems like they wasted all of the potential of a 3d printer. Diameters don't match, tangents don't match, why bother? If you are going to print a part, make it exactly right.

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