• FiniteBanjo@lemmy.today
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        8 months ago

        And even then, the filament needed at this scale will take another several years, and a few days for shipping.

        Also, it doesn’t do well in sunlight or high humidity for prolonged periods of time, so we’ll need maybe 20 to 30 years to work out a solution for that problem.

        • IrritableOcelot@beehaw.org
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          8 months ago

          I can only assume they’re trying to talk about concrete 3D printing, but oh boy is that not ready for anything which needs strength.

              • CanadaPlus@lemmy.sdf.org
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                7 months ago

                Yeah, but how much worse than normal unreinforced concrete? (Which is actually fine if you aren’t worried about tension)

                  • CanadaPlus@lemmy.sdf.org
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                    7 months ago

                    Certain arches or domes, maybe a lining for a tunnel. A tower if it’s not very windy. Really just all the stuff the Romans built, since that’s what they were working with, and their volcanic ash-based cement was somewhat weaker than modern cement.

                    It would be pretty hard to print between rebar. You’d need a crazy multi-axis head, and at that point it’s probably cheaper to just build a form. If they can achieve some significant strength with long fibers, which seems likely, you could spool that into the stream of concrete, but just concrete is already an actively researched problem. Printing one big form in foam or plastic and then filling it could be considered. The manual equivalent certainly makes a great building, especially in harsh climates where insulation is a concern.

    • lightnsfw@reddthat.com
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      8 months ago

      Just cut up the model into a million smaller parts and post them on thingiverse so everyone on that site that already has a 3d printer can print one out and mail it to baltimore. EZ

    • Zacryon@feddit.de
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      8 months ago

      To be fair, you don’t need a very huge 3D printer for that, if you divide it into a lot of smaller parts which can be assembled later.

      Idk, if we can already print steel though and whether we can make it structually sufficiently stable.

      • intensely_human@lemm.ee
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        8 months ago

        So our proposal is we prefab a bunch of metal pieces and assemble them on-site?

        As opposed to our current method where we carve bridges out of a big block of metal?

        • Zacryon@feddit.de
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          8 months ago

          Hahahaha absolutely. :D The difference is, that they come from a 3D printer and that’s cool.

        • CatOnTheChainWax@lemmy.today
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          7 months ago

          Seriously, how we make bridges now with giant CNC machines is so inefficient! And all these people saying we should print lots of blocks to put together are totally forgetting about Legos, we all just need to donate our old Legos to Baltimore and let kids from anywhere come volunteer to build it. Free bridge and free child labour! Everyone wins

      • hascat@programming.dev
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        8 months ago

        I find it difficult to believe that breaking down steel to be 3d printed into large structures for a bridge is faster or more energy efficient than casting the parts instead.

      • Skua@kbin.social
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        8 months ago

        We can indeed print steel with direct metal laser sintering. I think that the object needs heat treatment afterwards, though to be fair it is almost ten years since I properly read up on it and things have probably advanced since then

      • CanadaPlus@lemmy.sdf.org
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        8 months ago

        Maybe, we could just print off rectangular prism-shaped modules, around the right size to fit in a hand, and then assemble them on site. We could even make them out of ordinary clay and fire them for strength. I wonder why nobody has thought of that. /s

        3D printing has it’s place, but more conventional methods have theirs too. If you are counting on a lot of human labour anyway you might as well not reinvent the wheel.