
3D-printing a stainless steel bridge full of sensors - pasta
https://mx3d.com/smart-bridge/
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Robotbeat
This looks incredibly expensive with a lot of touch labor. The surface is
incredibly gnarly due to being basically made entirely of welds. You'd want to
grind that puppy smooth on the railings, etc.

One thing that I think is finally entering the mainstream is that 3D printing
is actually a MUCH more labor-intensive process than typical mass production
techniques.

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zeta0134
The amount of time investment is really surprising coming into it, even as a
hobby developer. The media portrayal seems to imply that you download a model,
press a button, and out pops this perfectly printed part hot off the bed. The
reality is more like

1\. Calibrate the Z-axis again because that end-stop is glitchy 2\. Apply some
sort of adhesive to the print surface 3\. Print with support (wait 5-20 hours)
and hope nothing goes terribly wrong causing you to start over at step 1 4\.
Carefully remove the support material, hope the delicate bits of the part
don't snap off in the process, if so start over at step 2 5\. Sand, polish,
and generally clean the part

That's just for my hobby printer making, let's not mince any words, rather low
quality prototype parts and figurines. I can't imagine the complexity that
goes into printing these huge structures with production quality requirements.
It's impressive, and I'm sure they're making the most of the tech since it can
accomplish certain things that would be quite difficult in other mediums (the
embedded sensors seem like such an awesome idea) but the time investment seems
like it would certainly be quite high.

Other than the coolness factor, I'm not sure it's more efficient than ordinary
construction techniques, but I'm also just a hobbyist with a desk printer; I'm
sure the folks actually working in that industry have much better insight.

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lozaning
>The media portrayal seems to imply that you download a model, press a button,
and out pops this perfectly printed part hot off the bed

I happily do exactly this all day with my several year old Makerbot. I print
in 3D just about as reliably as I print something with ink on paper.

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gene-h
_" Autodesk is supplying the cloud services that will power the bridge’s data
collection and processing"_ So the first question is what happens when all
these services eventually become obsolete over the bridges life time or if
autodesk goes bankrupt?(Of course that may be unlikely if this proposed
'infrastructure as a service' business takes off) _" These sensors will
collect structural measurements such as strain, displacement and vibration,"_
Now since the bridge has vibration sensors, could one not potentially do gait
recognition on people walking across the bridge? And since all this data is
stored in 'the cloud,' we now have a bridge which could potentially leak user
data. Now to make a ridiculous slippery slope argument, the end result of this
may be the house of cards construction building use in Vernor Vinge's
Rainbow's End[0], where building s are literally constructed like a house of
cards and computer controlled stabilization is used to prevent them from
falling over.

[0][https://en.wikipedia.org/wiki/Rainbows_End](https://en.wikipedia.org/wiki/Rainbows_End)

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Svoka
Hopefully by the time Autodesk goes under, we'll have good understanding of
how it behaves. Also, no need to dramatize, we have bridges without sensors. I
guess surveyors would have to include this one as well.

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DrNuke
3D-printed structures behave very differently compared to your usual,
continuous materials which are bolted, jointed or welded together, in that re-
balancing loads and reactions. Another issue is how they cope with aggressive
environments. This is a real-life experiment, something someone would however
do, so let’s what happens. I’m confident they will be fine, we are even having
3D printed components for nuclear power plants already.

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Robotbeat
In this case, it behaves like one giant weld, because that's what it is.
Fairly well understood, and this has large margins so will be fine.

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haggy
Do you have experience with 3D printing? I have pretty extensive experience
with 3D printing plastics and I can assure you that it's nothing like plastic
weld. How is 3D printed steel like a contiguous weld?

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Robotbeat
They literally use a welding machine on a robot arm, that's how. Powder bed
metal 3D printing is different, however.

(And I would argue that FDM _is_ essentially plastic welding, too.)

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edoo
There must be a large vision for something down the road given the partnership
list and that the application is effectively frivolous. They solved 12m
pedestrian bridges a long time ago.

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tachyonbeam
This looks like it's a massive PR stunt more than anything. The kind of cool
project big companies want to have their name associated with. I was hoping to
find more details about the technology used to build it, the compromises
involved, etc.

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agumonkey
I was wonder how much of our world would change if we had bidirectional
material design. Things that would communicate in one way or another their
internal status just a bit, to avoid finding faults too late.

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pasta
Or use the data and feed it to the self learning program that will design the
next bridge.

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agumonkey
true but I appreciate objects that speak a bit instead or planning in advance
and being in the blind afterwards

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xdze2
I would be curious to know the technological differences with
[https://www.relativityspace.com/stargate](https://www.relativityspace.com/stargate)

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opencl
MX3D describes their machine as "Standard Robot + Standard Welding Machine +
MX3D’s proprietary software". The stargate machine appears superficially
similar aside from using multiple 'print heads'. From their pictures and
description it looks like one is a welder and one is a milling machine, no
clue what the third one is.

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q3k
Testing in production with good enough metrics is fine unless it's AN ACTUAL
BRIDGE.

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geezerjay
I agree, but the bridge design appears to be extremelly robust (i.e.,
extraordinarily oversized) and it will be subjected to foot traffic, which has
a negligible service load.

It's a pretty sculpture that people can walk on. That's it.

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DrNuke
Robust aka oversized does not counter brittle fracture, though, which is the
main concern with 3D-printed artifacts. It depends on the material / the alloy
but also on the technological process we generally call printing.

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Robotbeat
It actually does, since it reduces the local stress. Risk of fracture due to
defects and repetitive loading is dramatically reduced (by order of magnitude
or more) by increasing the material margins.

It's a short foot bridge, so it's pretty easy to design it with significant
enough margin.

That said, it's not a very good idea nor a scalable solution to, like,
anything. More like an art project.

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DrNuke
Yes, you are basically saying that this particular artifact is just like a
bridge-shaped pancake made of polystyrene and hosting very few ants at any
given time. Which is actually an art project.

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Robotbeat
I think that's overstating it. This bridge is plenty strong, just very
inefficient and expensive.

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zwieback
Kind of cool but also the type of wasteful project that gives "3D printing" a
bad name.

