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I don't think you have answered the question even remotely. What about 3d printing prohibits using parts in aircrafts? Are you aware "3d printing" can produce

I don't think you have answered the question even remotely. What about 3d printing prohibits using parts in aircrafts? Are you aware "3d printing" can produce many types of materials, including metal, and not just plastic?

wlesieutre 6y ago
It’s been used for several rocket engines
- WalterBright 6y ago
  Interesting. Are they man-rated engines? Which parts? Since rocket engines tend to be single-use only, fatigue strength wouldn't be much of an issue.
  - wlesieutre 6y ago
    SuperDraco on SpaceX’s crew dragon capsule aren’t used in the launch, but it’s the launch escape system. [1] SpaceX also apparently prints the main oxidizer valve in Falcon 9’s Merlin 1D, which isn’t a single use vehicle, but who knows what components get replaced between launches. [2] As of 2016, the Raptor engine being developed for ITS (now Starship) was 40% printed by mass, but I have no idea how much of that was for faster prototyping and if they might be using less in later production. [3] Rocket Lab’s Rutherford engine for their Electron rocket. [4] More in the works from Relativity Space, Launcher, NASA, and others I’m sure. We’ll see what pans out. [1] https://en.wikipedia.org/wiki/SuperDraco https://en.wikipedia.org/wiki/SuperDraco [2] https://3dprint.com/10830/spacex-3d-print-oxidizer-valve/ https://3dprint.com/10830/spacex-3d-print-oxidizer-valve/ [3] https://www.nasaspaceflight.com/2016/10/its-propulsion-evolution-raptor-engine/ https://www.nasaspaceflight.com/2016/10/its-propulsion-evolu... [4] https://en.wikipedia.org/wiki/Rutherford_(rocket_engine) https://en.wikipedia.org/wiki/Rutherford_(rocket_engine)
    - WalterBright 6y ago
      The block diagram of the Raptor engine is just sick - it's brilliantly simple! I suspect that parts of it are 3D printed because of the difficulties in machining the shapes necessary. That may make it worthwhile to use lower-strength 3D technology and compensate by having more weight, but I'm just speculating. I'd love to just set one of those engines on a bench and take it apart. It's interesting to see von Braun's turbo-pump innovation is still the go-to technology after nearly 90 years. Also the fuel pre-heater used as the nozzle cooler.
      - wlesieutre 6y ago
        It's not the first full-flow staged combustion engine ever built, but it is the first to get off the test stand and fly. Looks a lot more complicated in real life compared to the block diagram https://en.wikipedia.org/wiki/SpaceX_Raptor#/media/File:SpaceX_sea-level_Raptor_at_Hawthorne_-_2.jpg https://en.wikipedia.org/wiki/SpaceX_Raptor#/media/File:Spac... And the Super Heavy booster is supposed to have at least 28 of those. At one point it was 37.
        WalterBright 6y ago
        > a lot more complicated in real life compared to the block diagram Sure, jet engines are like that, too. Steam locomotives, too, they are festooned with pipes and things. I once spent some time at a museum tracing the tubes trying to discern their purpose. (I've seen many engines in a museum, simply none of them had any sort of detailed explanation of what you're looking at. Too bad, so sad. Just a couple sentences "This is an XYX motor from a GHZ." Making it boring.) It would be fun to see what all the tubes on the raptor engine are for.
  - brg 6y ago
    Thanks for your co tribute is to this discussion, it is a well reasoned opinion. In response to your question, there are a few articles easily found including a wiki page in 3D printed space craft. No manned rocket as of yet, but orbit has been achieved. https://additivemanufacturingtoday.com/spacex-uses-dmls-to-3d-print-inconel-superdraco-engine-chamber https://additivemanufacturingtoday.com/spacex-uses-dmls-to-3...
Jtsummers 6y ago
The issue is going to be whether the 3d printed parts can fit the requirements for the conditions the prior parts were used in. Can laser sintering produce a bolt or pin that can withstand the same forces as other manufacturing techniques? Or will there be weaknesses in it. There are some parts that shouldn't be a problem, but many others where serious study is going to be required to verify that the aircraft won't break in a catastrophic way while in flight. As a non-3d printing example: A drone aircraft used a COTS product as its drive shaft. The same part was bought for years, no problem. Suddenly the drones started literally falling from the sky. Turned out the COTS product had changed manufacturing source and the quality of the steel was inferior, leading to frequent failures. 3d printed parts need to be reliable enough to replace things like that, or we need to tone down our enthusiasm and realize most of the 3d printed parts are going to be door handles and similar non-stressed or non-critical parts.
- systemvoltage 6y ago
  Composites are the way to go in Airframes, the amount of effort poured into this area is incredible. I think the new 787 (haha "new") is primarily composite and so is the A350.
  - redis_mlc 6y ago
    > Composites are the way to go in Airframes Well, not really - that's mostly an HN fanboi comment. - composites are often the same weight as aluminum when all is said and done - composites normally are only good for subsonic flight because of skin heating - large-area composites require multiple large autoclaves, etc. when normally there's only one. - composites are more difficult to repair than metal. If a baggage cart hits your composite fuselage or wing, how do you fix that? How long will that take? Metal is high-tech to me, not composites.
- monocasa 6y ago
  Wouldn't 3d printing potentially make it easier to flatten the supply chain and help guarantee predictability?
systemvoltage 6y ago
I haven't but I guess the goal was to give a perspective of what it takes to design a normal part from 6000 series aluminum and see what has to happen to certify it. You can extrapolate from there. We didn't have 3D printing as an option back then and I don't think it makes any sense even today. Sure, for prototyping it is valuable but even then we would make prototypes from the actual process (CNC) because then we can test the mechanical properties. Most people think prototyping is holding the part in the hand and seeing how it looks. Perhaps if youre doing ergo work. If 3D printing can go through rigorous process of understanding variation, void forming, failure modes, repeatability and reproducibility tests, sure it can be used. My question is - why? Perhaps a part can be made so that it saves so much weight with its shape that is not easily machinable. Then it makes sense. There are so many hurdles. In some ways, 3D printed parts are considered "composite". It would need to go through some rigor as some of the theory/proceedings laid out in a book like this: https://www.amazon.com/ICAF-2019-Manufacturing-Proceedings-International/dp/3030215024 https://www.amazon.com/ICAF-2019-Manufacturing-Proceedings-I... It is very much under study and scrutiny.
- deleted 6y ago
  [deleted]
- bArray 6y ago
  I suspect 3D printing aircraft parts becomes more viable my the day, especially as the materials, accuracy and reliability improve. I can appreciate that not _everything_ is a candidate for some form of printing, but I can imagine quite a few parts are. Some examples: 1. Highly specialized missions that require custom parts. The mission parameters themselves might be quite volatile, imagine some engineering team cooking up some mission critical sensors at the last moment to be used for this mission only. 2. Small incremental improvements that can be rolled out fleet wide. Usually these aircraft will have at least _some_ issues with the hardware, and the military answer is typically to write more SOPs. Instead they could 3D print a clip to stop that darned wire hitting the hot pipes when you open the panel. 3. Broken parts in remote locations could potentially be fixed whilst in those locations. You don't have to rely on some distribution network to fix your aircraft when you can build a patch and get it through one or more trips safely until a proper service. 4. The ability to semi-break away from the need of manufacturing.
spaghettios 6y ago
You’re not even wrong. Parent is explaining past the level you’re working at. Closest you can get is their mention of composites. I’ll flip the script: show us some 3D printers that can output specific phases of steel, for example, and then we can talk.
- systemvoltage 6y ago
  Hey, I would also like to learn if these things exist and whether anyone in aviation is using them. More curious about how they would certify these things - machining is so well understood over many decades that the risk tolerance against anything else would pretty high.
- deleted 6y ago
  [deleted]
WalterBright 6y ago
Weight is the implacable enemy in aircraft design. This means the minimum amount of material for each part. This means the strongest / weight materials, and manufacturing methods that reliably achieve it. For metal parts, this means forgings, which are 3x stronger than castings. The forging process is also pretty reliable compared to castings. Forging is also expensive, the only thing more expensive is a hogout from a billet. In order to be usable for critical airplane parts, a 3D printed part would have to have the strength and reliability of forgings - and of course be cheaper. BTW, on my hot rod engine I replaced all the moving parts in it with forgings, and the bell housing is a steel forging, too (stock is cast aluminum), because I like my feet.
- deleted 6y ago
  [deleted]
- wlesieutre 6y ago
  Did a bit of looking at the USAF’s interest in this, it sounds like it’s not about structurally critical parts so much as avoiding supply chain problems on obscure little bits. They recently made a metal anti-ice gasket for a turbofan engine: https://www.flightglobal.com/fixed-wing/us-air-force-produces-first-3d-printed-metal-part-for-aircraft-engines/139643.article https://www.flightglobal.com/fixed-wing/us-air-force-produce... For non-metal parts, this looks cool too: https://www.sciencedirect.com/science/article/abs/pii/S1359835X18303002 https://www.sciencedirect.com/science/article/abs/pii/S13598...

wlesieutre 6y ago

It’s been used for several rocket engines

WalterBright 6y ago
Interesting. Are they man-rated engines? Which parts? Since rocket engines tend to be single-use only, fatigue strength wouldn't be much of an issue.
- wlesieutre 6y ago
  SuperDraco on SpaceX’s crew dragon capsule aren’t used in the launch, but it’s the launch escape system. [1] SpaceX also apparently prints the main oxidizer valve in Falcon 9’s Merlin 1D, which isn’t a single use vehicle, but who knows what components get replaced between launches. [2] As of 2016, the Raptor engine being developed for ITS (now Starship) was 40% printed by mass, but I have no idea how much of that was for faster prototyping and if they might be using less in later production. [3] Rocket Lab’s Rutherford engine for their Electron rocket. [4] More in the works from Relativity Space, Launcher, NASA, and others I’m sure. We’ll see what pans out. [1] https://en.wikipedia.org/wiki/SuperDraco https://en.wikipedia.org/wiki/SuperDraco [2] https://3dprint.com/10830/spacex-3d-print-oxidizer-valve/ https://3dprint.com/10830/spacex-3d-print-oxidizer-valve/ [3] https://www.nasaspaceflight.com/2016/10/its-propulsion-evolution-raptor-engine/ https://www.nasaspaceflight.com/2016/10/its-propulsion-evolu... [4] https://en.wikipedia.org/wiki/Rutherford_(rocket_engine) https://en.wikipedia.org/wiki/Rutherford_(rocket_engine)
  - WalterBright 6y ago
    The block diagram of the Raptor engine is just sick - it's brilliantly simple! I suspect that parts of it are 3D printed because of the difficulties in machining the shapes necessary. That may make it worthwhile to use lower-strength 3D technology and compensate by having more weight, but I'm just speculating. I'd love to just set one of those engines on a bench and take it apart. It's interesting to see von Braun's turbo-pump innovation is still the go-to technology after nearly 90 years. Also the fuel pre-heater used as the nozzle cooler.
    - wlesieutre 6y ago
      It's not the first full-flow staged combustion engine ever built, but it is the first to get off the test stand and fly. Looks a lot more complicated in real life compared to the block diagram https://en.wikipedia.org/wiki/SpaceX_Raptor#/media/File:SpaceX_sea-level_Raptor_at_Hawthorne_-_2.jpg https://en.wikipedia.org/wiki/SpaceX_Raptor#/media/File:Spac... And the Super Heavy booster is supposed to have at least 28 of those. At one point it was 37.
      - WalterBright 6y ago
        > a lot more complicated in real life compared to the block diagram Sure, jet engines are like that, too. Steam locomotives, too, they are festooned with pipes and things. I once spent some time at a museum tracing the tubes trying to discern their purpose. (I've seen many engines in a museum, simply none of them had any sort of detailed explanation of what you're looking at. Too bad, so sad. Just a couple sentences "This is an XYX motor from a GHZ." Making it boring.) It would be fun to see what all the tubes on the raptor engine are for.
- brg 6y ago
  Thanks for your co tribute is to this discussion, it is a well reasoned opinion. In response to your question, there are a few articles easily found including a wiki page in 3D printed space craft. No manned rocket as of yet, but orbit has been achieved. https://additivemanufacturingtoday.com/spacex-uses-dmls-to-3d-print-inconel-superdraco-engine-chamber https://additivemanufacturingtoday.com/spacex-uses-dmls-to-3...

Jtsummers 6y ago

The issue is going to be whether the 3d printed parts can fit the requirements for the conditions the prior parts were used in. Can laser sintering produce a bolt or pin that can withstand the same forces as other manufacturing techniques? Or will there be weaknesses in it. There are some parts that shouldn't be a problem, but many others where serious study is going to be required to verify that the aircraft won't break in a catastrophic way while in flight. As a non-3d printing example: A drone aircraft used a COTS product as its drive shaft. The same part was bought for years, no problem. Suddenly the drones started literally falling from the sky. Turned out the COTS product had changed manufacturing source and the quality of the steel was inferior, leading to frequent failures. 3d printed parts need to be reliable enough to replace things like that, or we need to tone down our enthusiasm and realize most of the 3d printed parts are going to be door handles and similar non-stressed or non-critical parts.

systemvoltage 6y ago
Composites are the way to go in Airframes, the amount of effort poured into this area is incredible. I think the new 787 (haha "new") is primarily composite and so is the A350.
- redis_mlc 6y ago
  > Composites are the way to go in Airframes Well, not really - that's mostly an HN fanboi comment. - composites are often the same weight as aluminum when all is said and done - composites normally are only good for subsonic flight because of skin heating - large-area composites require multiple large autoclaves, etc. when normally there's only one. - composites are more difficult to repair than metal. If a baggage cart hits your composite fuselage or wing, how do you fix that? How long will that take? Metal is high-tech to me, not composites.
monocasa 6y ago
Wouldn't 3d printing potentially make it easier to flatten the supply chain and help guarantee predictability?

systemvoltage 6y ago

I haven't but I guess the goal was to give a perspective of what it takes to design a normal part from 6000 series aluminum and see what has to happen to certify it. You can extrapolate from there. We didn't have 3D printing as an option back then and I don't think it makes any sense even today. Sure, for prototyping it is valuable but even then we would make prototypes from the actual process (CNC) because then we can test the mechanical properties. Most people think prototyping is holding the part in the hand and seeing how it looks. Perhaps if youre doing ergo work. If 3D printing can go through rigorous process of understanding variation, void forming, failure modes, repeatability and reproducibility tests, sure it can be used. My question is - why? Perhaps a part can be made so that it saves so much weight with its shape that is not easily machinable. Then it makes sense. There are so many hurdles. In some ways, 3D printed parts are considered "composite". It would need to go through some rigor as some of the theory/proceedings laid out in a book like this: https://www.amazon.com/ICAF-2019-Manufacturing-Proceedings-International/dp/3030215024 https://www.amazon.com/ICAF-2019-Manufacturing-Proceedings-I... It is very much under study and scrutiny.

deleted 6y ago
[deleted]
bArray 6y ago
I suspect 3D printing aircraft parts becomes more viable my the day, especially as the materials, accuracy and reliability improve. I can appreciate that not _everything_ is a candidate for some form of printing, but I can imagine quite a few parts are. Some examples: 1. Highly specialized missions that require custom parts. The mission parameters themselves might be quite volatile, imagine some engineering team cooking up some mission critical sensors at the last moment to be used for this mission only. 2. Small incremental improvements that can be rolled out fleet wide. Usually these aircraft will have at least _some_ issues with the hardware, and the military answer is typically to write more SOPs. Instead they could 3D print a clip to stop that darned wire hitting the hot pipes when you open the panel. 3. Broken parts in remote locations could potentially be fixed whilst in those locations. You don't have to rely on some distribution network to fix your aircraft when you can build a patch and get it through one or more trips safely until a proper service. 4. The ability to semi-break away from the need of manufacturing.

spaghettios 6y ago

You’re not even wrong. Parent is explaining past the level you’re working at. Closest you can get is their mention of composites. I’ll flip the script: show us some 3D printers that can output specific phases of steel, for example, and then we can talk.

systemvoltage 6y ago
Hey, I would also like to learn if these things exist and whether anyone in aviation is using them. More curious about how they would certify these things - machining is so well understood over many decades that the risk tolerance against anything else would pretty high.
deleted 6y ago
[deleted]

WalterBright 6y ago

Weight is the implacable enemy in aircraft design. This means the minimum amount of material for each part. This means the strongest / weight materials, and manufacturing methods that reliably achieve it. For metal parts, this means forgings, which are 3x stronger than castings. The forging process is also pretty reliable compared to castings. Forging is also expensive, the only thing more expensive is a hogout from a billet. In order to be usable for critical airplane parts, a 3D printed part would have to have the strength and reliability of forgings - and of course be cheaper. BTW, on my hot rod engine I replaced all the moving parts in it with forgings, and the bell housing is a steel forging, too (stock is cast aluminum), because I like my feet.

deleted 6y ago
[deleted]
wlesieutre 6y ago
Did a bit of looking at the USAF’s interest in this, it sounds like it’s not about structurally critical parts so much as avoiding supply chain problems on obscure little bits. They recently made a metal anti-ice gasket for a turbofan engine: https://www.flightglobal.com/fixed-wing/us-air-force-produces-first-3d-printed-metal-part-for-aircraft-engines/139643.article https://www.flightglobal.com/fixed-wing/us-air-force-produce... For non-metal parts, this looks cool too: https://www.sciencedirect.com/science/article/abs/pii/S1359835X18303002 https://www.sciencedirect.com/science/article/abs/pii/S13598...