
Printers Meant to Make Rockets - petethomas
https://www.bloomberg.com/news/articles/2017-10-18/these-giant-printers-are-meant-to-make-rockets
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Animats
Space-X makes the Dragon engine block by 3D printing.

It makes sense. Rocket engines are mostly a big single piece with lots of
internal voids. The fuel is used as a coolant, so there are channels inside
the engine bell and some other sections. It's mostly plumbing.

That's the kind of part where 3D printing is useful. Making a big object with
internal plumbing out of multiple parts is a fabrication headache. NASA's
engines have vast amounts of welding work in them. High-pressure joints are
always a problem. Making something with few or no joints is just better. It
still has to be inspected, but that's what industrial-sized CAT scanners are
for.

(Most of the real-world problems in both rockets and nuclear power involve
plumbing and welding.)

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robotresearcher
Sure, but on the other hand in 3D printing everything is a joint/weld.

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alex_duf
Am I correct to say that means you only need to get it right once?

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robotresearcher
Once or millions of times depending how you count.

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cbanek
It sounds like an interesting idea, but I'm not sure I buy it.

It makes sense that building single use rockets is expensive, and with only
one launch to amortize the construction cost, labor is a huge factor
(materials in a rocket are pretty normal: a lot of carbon fiber, aluminum,
titanium, etc). But with reusable rockets, you are bringing that cost way
down. If you are able to launch and land 5 times on the same rocket, then
effectively you've brought the cost of the rocket to 1/5th of what it used to
be.

"a handful of the arms can work together to create the rocket’s entire body as
a single piece"

Once you get into reusable rockets, I'm not sure that trying to 3d print the
whole thing will turn out. Why? Because you need replaceable parts. You need
to be able to tear down, inspect, and replace parts as each part of the rocket
has a different lifetime. If you make the rocket as one giant piece, and use
efficient methods (reduce weight, size, etc), that it would be much less
serviceable over its lifetime.

"We want to get to 1,000 moving parts, fewer than a car."

This is why subassemblies of cars are so expensive, even if you only need to
replace a small part of one assembly.

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usrusr
My gut feeling about rocket building is that it's not the labor for building
parts and putting them together which makes them expensive but the labor for
inspecting, reinspecting and then reinspecting once more before putting parts
together, only to do some more inspecting on the combined subassembly. The
launch is the first true dress rehearsal and the rocket equation leaves little
room for "engineering math" (calculate to seven digits, then multiply by two
for safety).

My gut feeling about 3D printing is that it just makes it worse. How do you
inspect a welding line as long as a rocket's dry mass?

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cbanek
For a liquid fueled rocket you have many opportunities before launch such as
firing the engine in a test stand, etc. For the whole rocket you can do a
static fire, or even a full duration fire to test the components. Mostly when
you are moving you are worried about the mechanical loads on the rocket
instead of having to worry if parts were put together correctly. Of course,
even this level of testing takes a lot of money, capital, and of course labor.

For a solid fueled rocket, you're right that pretty much you have one shot,
and you can't turn it off if something goes wrong.

> My gut feeling about 3D printing is that it just makes it worse. How do you
> inspect a welding line as long as a rocket's dry mass?

In general, the way you do this is to move it lengthwise through an x-ray
scanner, so you can inspect the full length by moving the rocket through. I'm
not sure if 3d printing makes this easier (because there's not really welds,
it's one piece) or harder (you have to be able to inspect the inside of
something), but it is certainly tricky.

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TeMPOraL
> _because there 's not really welds, it's one piece_

Wait, isn't the result basically just one giant, continuous weld?

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cbanek
I guess you can think of it that way, but it probably depends on the
technology used by the printer at that point. My thought was that for the 3d
printer, at least it's one consistent piece with no seams or edges that are
later welded together. The welds can have imperfections/weaknesses and need to
be inspected. Materials can also have weaknesses and imperfections, either on
a batch level or individual area level, and need to be tested/inspected. For a
printed piece, I would expect the strength to be generally consistent
throughout the piece (of course still might be weaknesses based on design
shape, thickness), but of course, you'd still want to inspect it.

PS - totally not an expert on 3d printers or materials or welding

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ptero
I am not an expert on either, but in general 3D printers lay out the material
in thin layers (with each layer laid out line by line). Thus you have lots of
potential seams everywhere two points laid at different times touch.

I think modern technologies prevent seams forming at most of those points, but
the potential (impurities, dirt, etc.) still remains so must be tested.

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usrusr
I could imagine some technology that takes advantage of future layers not
being there yet to validate the most recent layer on the same pass, and the
one that the current layer will be built upon (as that might have suffered in
the time since it has been laid) in a way that is exclusive to this
manufacturing method. But as you move to bigger and bigger one-piece parts,
you would probably also want your process to support undoing a few layers on
failure detection to forego scrapping the whole part.

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abledon
They have a fricking PROTOSS[1] logo in their factory (3:22).

That is Awesome! Seeing how the protoss warped in objects from another spot...
I guess to them 3D printing is the precursor to that.

[1][http://wiki.teamliquid.net/commons/images/thumb/e/e4/Protoss...](http://wiki.teamliquid.net/commons/images/thumb/e/e4/ProtossIcon.png/200px-
ProtossIcon.png)

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josinalvo
You got hit by teamliquid's anti hotlinking filter

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nostalgiac
Open the link in incognito, or just hit enter on the address bar again so the
referrer is removed and it's a direct resource request. (refresh won't work).

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marcell
I know very little about rockets and 3D printing, so maybe someone can answer
two things for me:

1\. Does 3D printing make sense for large projects like rockets, which will be
used in extreme conditions? I thought it was more for prototypes.

2\. How does this compare to SpaceX, which is attempting to reuse rockets? How
important is this fixed cost if you use a rocket 100 times?

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wavefunction
SpaceX 3d prints SuperDraco[0]

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

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toomuchtodo
There are some SpaceX alumni at Relativity.

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maxander
I would speculate that their eventual end goal is to be bought out by either
SpaceX or Blue Origin. A small space launch startup focusing on one technology
isn’t going very far on its own, and few other companies would have an
interest in their approach.

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toomuchtodo
Another possible exit scenario is to be acquired by ULA or another cost plus
contractor who is grasping at straws to become competitive against SpaceX's
reusable vehicles.

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rdl
After watching
[https://www.youtube.com/user/AgentJayZ](https://www.youtube.com/user/AgentJayZ)
videos (a guy in Canada who works for/owns an industrial/military turbine
engine refurbishment shop and publishes great videos on a lot of the details),
I've thought about trying to 3d print an inefficient, cold, boring, small jet
turbine -- I know GE has already done a reasonable job of it, but making one
which can be made at the lowest possible cost and skill level as a learning
experience would be interesting. Unfortunately the machines are still a bit
too expensive for recreational use.

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lucaspiller
Shapeways are a printer service, with a whole bunch of materials including
metals that are rare on consumer machines. However one of the advantages of 3D
printing is you can create rapid prototypes - if you need to order and wait
for someone else to make your model you lose that.

[https://www.shapeways.com/materials](https://www.shapeways.com/materials)

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jacobolus
You can’t print anything like a jet engine with Shapeways. Their metal print
options are designed for stuff like custom jewelry.

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rdl
I was thinking something like:
[https://www.ge.com/reports/post/118394013625/these-
engineers...](https://www.ge.com/reports/post/118394013625/these-
engineers-3d-printed-a-mini-jet-engine-then/)

I think you can do a crappy jet engine out of boring sintered stainless steel
(316L), barely. Particularly if you could throw in some basic stuff from
McMaster-Carr (seals/bearings/etc.)

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Ice_cream_suit
North Korea now use filament winding machines to make lightweight, long range
airframes for it's rockets and ICBMS. It takes large spools of advanced
composite filaments as the input and outputs airframes.

Impressive for such an impoverished nation.

[http://www.38north.org/2017/08/melleman082517/](http://www.38north.org/2017/08/melleman082517/)

[http://www.armscontrolwonk.com/archive/1203086/wound-
filamen...](http://www.armscontrolwonk.com/archive/1203086/wound-filament-
airframes/)

[http://edition.cnn.com/2017/08/23/asia/north-korea-
missile-p...](http://edition.cnn.com/2017/08/23/asia/north-korea-missile-
program-photos/index.html)

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glenngillen
ARC Engines were one of the companies graduating at the recent TechStars demo
day in Adelaide. As another commenter pointed out it seems much of the
innovation is the improvements you can make to the internal chamber design
through 3D printing. I also gather they’re onto (at least) their second
generation of working rocket

[http://arc-engines.com](http://arc-engines.com)

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Gertig
The next step towards Von Neumann Probes!

[https://futurism.com/von-neumann-probe/](https://futurism.com/von-neumann-
probe/)

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bhhaskin
I wish I could read the article, but there was just too many ads.

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DiThi
And autoplay video, without easy way to stop it. Ugh.

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bhhaskin
Most of these "news" outlets are becoming more and more aggressive with
advertising.

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bitwize
It's either ads, subscriptions, or they'll run cryptocurrency mining on your
hardware. Journalism ain't free, kiddos.

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imglorp
I'd rather a micropayment system with browser plugin that decrements your
account on sites you agree to pay per page view. I don't mind paying $0.02 to
read a decent article but I really don't want a bunch of CPU load DOS'ing my
machine or malware screwing with it or my privacy.

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gaetanomarano
the most interesting part of the project is the engine ::: x.co/newlab

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imglorp
Is this spam?

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ricardobeat
Warning: article behind a paywall.

