Oh, what a sturdy web we weave...
June 15, 2015 11:51 AM Subscribe
Amsterdam is planning out a new steel canal bridge that will be constructed entirely by 3D Printers. Here's a video of these special printers in action.
What is Dutch for "stunt bridge"?
posted by indubitable at 12:14 PM on June 15, 2015
posted by indubitable at 12:14 PM on June 15, 2015
I don't feel like a MIG welder would count as a 3D printer. Though it is additive manufacturing, just a poorly controlled process.
posted by TheJoven at 12:23 PM on June 15, 2015
posted by TheJoven at 12:23 PM on June 15, 2015
Wow! I hope this turns out to be as cost-effective and sturdy as it is pretty and novel. If there's anything I'd like to see more of, it's attractive, safe pedestrian infrastructure that's cheap enough to put up everywhere it's needed.
Probably not as cheap to put up as more standard steel-and-concrete, and I'm sure the cost goes up a lot based on how much space you need to cross at what height. This is practically the shortest length of space you could possibly cover while still needing a footbridge.
posted by asperity at 12:25 PM on June 15, 2015
Probably not as cheap to put up as more standard steel-and-concrete, and I'm sure the cost goes up a lot based on how much space you need to cross at what height. This is practically the shortest length of space you could possibly cover while still needing a footbridge.
posted by asperity at 12:25 PM on June 15, 2015
The angles of the proposed bridge remind me of the ruled surfaces and hyperbolic paraboloid geomety of La Sagrada Familia.
posted by the man of twists and turns at 12:29 PM on June 15, 2015 [2 favorites]
posted by the man of twists and turns at 12:29 PM on June 15, 2015 [2 favorites]
This is awesome. On the other hand those renderings are distressingly free of bystander eye protection. Welding is not a good spectator sport.
posted by phooky at 12:32 PM on June 15, 2015 [2 favorites]
posted by phooky at 12:32 PM on June 15, 2015 [2 favorites]
I think we're playing pretty loose here with the term '3D Printer'.
posted by Ratio at 12:32 PM on June 15, 2015 [1 favorite]
posted by Ratio at 12:32 PM on June 15, 2015 [1 favorite]
Interesting to see the costs for a variety of such structures versus things like pre-fabbing sections, bringing them onsite and welding them by hand. The usual trouble with new techniques is that the old system has got huge advantages of existing infrastructure, expertise and toolsets. On the other hand, it would also be interesting to have auto-design: you could take a picture of something and say "Robot! Build a bridge between these two points!" and then go home for tea.
But it is good to see positive, inventive "3D printing" (welding robots, indeed) stories like these where the end result is something that's easy to see as a good thing. There was a Radio 4 programme on earlier today about Interpol, what it is and whether it's a good thing. One of the 'good things' it claims is that it acts as a clearing-house and educator on new threats for national police forces: the example the Interpol spokesman gave at some conference somewhere (I think that's the illo at the link) was "Look! 3D printing! We've printed a light switch that's very dangerous, and a fake smoke detector that just doesn't work. These things can kill you!". Cue Devonian eye-rolling and dark thoughts about how hard it is to make something that passes even slightly for a smoke alarm or light switch with 3D printing, and if you want to worry about shoddy knock-offs, there are a thousand ways that people make them that are massively cheaper and quicker than 3D printing... (Hey, Interpol, are all those uber-dodgy Chinese phone chargers 3D printed?)
posted by Devonian at 12:42 PM on June 15, 2015 [1 favorite]
But it is good to see positive, inventive "3D printing" (welding robots, indeed) stories like these where the end result is something that's easy to see as a good thing. There was a Radio 4 programme on earlier today about Interpol, what it is and whether it's a good thing. One of the 'good things' it claims is that it acts as a clearing-house and educator on new threats for national police forces: the example the Interpol spokesman gave at some conference somewhere (I think that's the illo at the link) was "Look! 3D printing! We've printed a light switch that's very dangerous, and a fake smoke detector that just doesn't work. These things can kill you!". Cue Devonian eye-rolling and dark thoughts about how hard it is to make something that passes even slightly for a smoke alarm or light switch with 3D printing, and if you want to worry about shoddy knock-offs, there are a thousand ways that people make them that are massively cheaper and quicker than 3D printing... (Hey, Interpol, are all those uber-dodgy Chinese phone chargers 3D printed?)
posted by Devonian at 12:42 PM on June 15, 2015 [1 favorite]
. . . a fantastic metaphor for connecting the technology of the future with the city’s historic past, in a way which would reveal the best aspects of both worlds.
Gah! Why do people talk this way?
Wouldn't it be enough to say, "Printing a bridge over a canal would be really frickin' cool."
posted by Ickster at 12:49 PM on June 15, 2015 [2 favorites]
Gah! Why do people talk this way?
Wouldn't it be enough to say, "Printing a bridge over a canal would be really frickin' cool."
posted by Ickster at 12:49 PM on June 15, 2015 [2 favorites]
This is cool and pretty, but boring question: does it say anywhere what kind of steel it is? How will they prevent rust from being a problem on these spindly strands of steel?
posted by Wretch729 at 12:52 PM on June 15, 2015
posted by Wretch729 at 12:52 PM on June 15, 2015
I don't think it's at all a stretch to call this a 3d printer. It's depositing metal one little blob at a time.
posted by RustyBrooks at 12:57 PM on June 15, 2015 [2 favorites]
posted by RustyBrooks at 12:57 PM on June 15, 2015 [2 favorites]
This is awesome.
The main problem from a structural point of view is that in arc welding, the area that is rendered molten by the heat from the arc is weaker and more brittle than the surrounding material. This is called the Head Affected Zone or HAZ. Standard ASTM A500 structural grade steel has a yield strength of ~35000 psi. I can't say for sure what the strength of heat-affected A500 is, but the difference is significant. Structural steel is manufactured in such a way that gives it high ductility, that is it bends before it breaks. The benefits of this in bridge building are self-evident. Materials like cast iron may be strong but are not very ductile which leads to problems like this.
Also, as the molten material cools in the presence of oxygen, a thin layer of oxide (slag) forms on the surface of the material. The type of welding that they are using, MIG (Metal Inert Gas) uses an inert gas mixture to prevent slag from forming, however this is best done in a controlled environment to prevent wind from blowing the gas off of the weld area before the molten metal has had a chance to cool. Furthermore, it seems that they have programmed the robot to immediately move on to the next point after it breaks the arc. Ideally you would keep the welding torch over the weld for a few seconds to let the weld cool a bit in an inert environment. This layer of slag may be microscopic but creates, in effect, a little fault line for cracks to propagate. So what seems like a continuous piece of metal with uniform structural properties, is actually segmented with variable properties.
Of course you could build a bridge out of anything if you use enough of it. This is a totally cool idea, but there's no way this is the wave of the future in bridge-building.
posted by dudemanlives at 2:43 PM on June 15, 2015 [4 favorites]
The main problem from a structural point of view is that in arc welding, the area that is rendered molten by the heat from the arc is weaker and more brittle than the surrounding material. This is called the Head Affected Zone or HAZ. Standard ASTM A500 structural grade steel has a yield strength of ~35000 psi. I can't say for sure what the strength of heat-affected A500 is, but the difference is significant. Structural steel is manufactured in such a way that gives it high ductility, that is it bends before it breaks. The benefits of this in bridge building are self-evident. Materials like cast iron may be strong but are not very ductile which leads to problems like this.
Also, as the molten material cools in the presence of oxygen, a thin layer of oxide (slag) forms on the surface of the material. The type of welding that they are using, MIG (Metal Inert Gas) uses an inert gas mixture to prevent slag from forming, however this is best done in a controlled environment to prevent wind from blowing the gas off of the weld area before the molten metal has had a chance to cool. Furthermore, it seems that they have programmed the robot to immediately move on to the next point after it breaks the arc. Ideally you would keep the welding torch over the weld for a few seconds to let the weld cool a bit in an inert environment. This layer of slag may be microscopic but creates, in effect, a little fault line for cracks to propagate. So what seems like a continuous piece of metal with uniform structural properties, is actually segmented with variable properties.
Of course you could build a bridge out of anything if you use enough of it. This is a totally cool idea, but there's no way this is the wave of the future in bridge-building.
posted by dudemanlives at 2:43 PM on June 15, 2015 [4 favorites]
After you. No, please, after you.
posted by Splunge at 4:37 PM on June 15, 2015 [1 favorite]
posted by Splunge at 4:37 PM on June 15, 2015 [1 favorite]
dudemanlives: "Ideally you would keep the welding torch over the weld for a few seconds to let the weld cool a bit in an inert environment. "
Because you are using a robot instead of a human you could tent the construction envelope and have the entire volume bathed in an inert gas. And use something like TIG welding so you could have your building metal independent of your electrode.
posted by Mitheral at 7:15 PM on June 15, 2015
Because you are using a robot instead of a human you could tent the construction envelope and have the entire volume bathed in an inert gas. And use something like TIG welding so you could have your building metal independent of your electrode.
posted by Mitheral at 7:15 PM on June 15, 2015
What in hell are they thinking? Unless you use a 4D printer you have no control over how long it will last.
posted by George_Spiggott at 8:33 PM on June 15, 2015 [5 favorites]
posted by George_Spiggott at 8:33 PM on June 15, 2015 [5 favorites]
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