Wow. A printed wing spar or wing torque box (center section), or landing gear should be a massive weight saving. Not to mention a savings in resources.
Why would it save weight, unless the materials were stronger? You still have to have the right material in the right places to take the loads and have the right dynamics properties. What it could save is manufacturing time and cost. There might be some parts where you can save weight by leaving out material that can’t be machined out later, but not for the parts you mention.
3D printing can produce a optimal shape impractical by conventional machining. But this doesn’t work out unless the material produced has strength at least similar to the conventional product.
Google “World’s Largest 3D Printed Titanium Aircraft Part”.
That’s very interesting. I wonder how the part compares to milled parts in terms of fatique resistance and other mechanical properties.
This story from last August is also interesting. A rocket engine injector is not your typical 3D printed part.
I remember that Jerry Pournelle, when he was talking about the planning days for DC-X and other SSTO plans, said that Max Hunter wanted to get one flying as close to orbit as possible, then figure out where weight wasn’t needed for structural strength and cutting it away. This just reminded me.
To the greatest extent possible, future spacecraft should be made using this technology. This will allow a long duration mission to carry some 3D printers and be able to reproduce almost any part needed. If you actually constructed the spacecraft in orbit from raw printer materials, you wouldn’t have to make it strong enough to withstand launch G loads. That could greatly reduce structural mass even further.
I can go from sand/soil, to ore, to ingots. What’s the -cheap- and -light- way to go from ingots to the pre-sintering powder?
(My understanding of the terrestrial methods … not sure they scale down.)
For some metals spraying into an inert atmosphere might work, producing a metallic snow.
I’ve been thinking of general operating guidelines for off-Earth habitats and spacecraft lately. One of the things I keep coming back to is the idea of designing for operating in a “degraded” mode. Specifically, in complex systems something somewhere is going to be frequently broken at any given time. If you design a system with redundancy and abort modes in mind then it will be possible to survive such breakages, but you’ll have a low rate of “mission success”. However, if you design systems such that most failures result in continued operation above the design minimum and result in non-emergency scenarios then you have a system which is vastly more robust. Many real-world systems work this way through a long history of evolution toward that design pattern, but we can use the same principles in designing new systems.
Some decades ago somewhat wrote a paper for the IEEE that compared human fatalities from genetic problems to work done for NASA one the reliability of complex systems, which showed that they had the same curves for probably the same reasons, with the conclusion that humans were complex systems with dual redundant backups because the life-cycles and failure rates were so similar.
What you see in the failure rate of such systems is a spike in the early period as the equipment with two defective systems (genes or dual manufacturing defects) get weeded out, which is the childhood deaths, and then a long period where most system work (normal healthy people with at least one good copy of a critical gene), and then a small tail to extends on out (centenarians) for the people who received two good copies of every critical component.
Surprisingly, the medical community was highly receptive because the approach described and explained what they’d been pondering for decades and put it all in a simple yet completely different and understandable perspective.
You could flip the observation around, allowing for triple or quad redundancy (which biology generally only creates with plants that are double up on chromosomes as they become diploid, triploid, etc.)
Some organisms also significantly change their developmental trajectory (basal metabolism) due to their womb environment, and based on studies of WW-II famines in Scandinavia, these organisms include humans.
As a caveat, I’ll note that we’re learning more and more how our metabolism is determined by our gut bacteria, and these might be significantly altered during a war-induced famine, so the “genetic programming” that the researchers see may be just the effect of shifting gut bug populations due to famine, and the babies pick up a sample of the surrounding gut bug population after they’re born.
Dang. How to bring this random digression to a conclusion?
Future spaceships should be designed with hidden pantries (much like the Millennium Falcon’s smuggling holds) so storm troopers from the secret Nazi moon base can’t loot all the food. The spaceships should also have redundant systems because the storm troopers will get to destroy or disable anything obvious.
I’m being a bit flip because the gut-bug explanation of the metabolism and heart disease research just occurred to me. The crux of what I read was that children born during the lean times tended to suck up fat and such, as if they were optimized to a low calorie environment compared to peers born before or after the lean times. But wouldn’t it make just as much sense that in the absence of fat, fat eating gut bacteria suffered, so they weren’t passed on in very well to that group of children, who then are freed to absorb all the fats because they didn’t get the bacteria that break them down?
I’m thinking that perhaps a gut-bug explanation is more parsimonious than having a special genetic trigger that activates in the womb to determine basal metabolism based on the mother’s calorie intake.
But I digress yet more. What I’m really striving for is an award for the best digression on a blog, drama, or comedy from the Academy of Motion Pictures or the People’s Choice Awards, and I don’t think anyone can top a digression from 3-D printing of titanium aerospace parts to the monster that lives in my intestines, which could easily be a SyFy original movie except that I can’t write that badly, though Lord knows I try.
Apologies to everyone who lost brain cells reading this, but I lost more than a few of my own writing it. It was a slow day on Rand’s blog.
You can see your suggested design approach in several critical systems. On your car, if the anti-lock brakes controller fails, you still have brakes just without the anti-lock feature. If your power steering fails, you can still steer the car only with more effort. IIRC, Boeing’s approach to fly-by-wire works in a similar manner. This is in contrast to a fighter’s approach to fly-by-wire, where you have multiple redundant controllers backed up with an ejection seat.
On a spacecraft, you can design your systems so that the same tasks can be performed manually while the atomated system is repaired. For an interplanetary mission, the navigation system can be backed up by the crew performing celestial navigation as used in Apollo. Your automated life support system would be designed to allow manual control if needed. You’d use the same approach across as many systems as possible. For Apollo, the astronauts themselves operated all the controls (they had strong union rules!). For future missions, you could allow ground controllers to back up the astronauts to reduce their workload in an emergency. I think they can already do this on the ISS but I’m not sure.
I wonder if it’ll be possible in our lifetimes to combine the versatility of 3D printing with the material strength of forged parts?
I’m pretty sure I could do that now, just by designing simpler forging dies that work the part from something close to a precision casting to a finished product, instead of having for forge the part from an ingot. Decades ago I devoted a whole lot of thought to automating mass and custom chain maille production (which is a hard problem, but I had some interesting approaches), A year or so ago I saw several possible ways to forge aluminum isogrids with moving triangular dies, but the bulk material shifts are somewhat extreme because you have to forge I-beam type sections out of flat plate while making them into triangles. The aluminum has to move a whole lot to get the final shape, and the movement may not give the desired grain orientations.
If you instead 3-D printed a preform, you could set it up so the forging operation was not only vastly easier, but so that the material flows were in the directions you wanted. I didn’t consider the same concept from castings because an aluminum that casts well tends not to forge well, and vice versa.
Hmmm, I see you mentioned this before on Selenian Boondocks. So let me see if I understand the desired ideal die motion.
You start with a flat plate and an isogrid pattern of dies (basically a tiling of triangular dies with perhaps a few choices as to how you squeeze the triangles together). Each triangular die starts a bit undersized and presses into the plate (with a flat rear plate to keep material from going that way). The material spreads into the gaps between dies. The dies expand horizontally with similar pressure and force to the original die motion (impossible motion I gather, but we’re speaking of ideal not real) squeezing that material up the shrinking gaps between triangular dies. Then a plate die behind the triangular dies presses down. The material which welled up in the isogrid pattern now is pressed over the rear of the triangular dies, creating an I-beam cross-section, but with a triangular hole centered on each triangular die’s center.
Now one does another impossible motion of the triangular dies and shrinks the die horizontally so that it is small enough to pull through the hole centered on it and all the dies are extracted. The result is a flanged, forged isogrid structure on one side of your aluminum plate. Does that sound about right?
Wow. A printed wing spar or wing torque box (center section), or landing gear should be a massive weight saving. Not to mention a savings in resources.
Why would it save weight, unless the materials were stronger? You still have to have the right material in the right places to take the loads and have the right dynamics properties. What it could save is manufacturing time and cost. There might be some parts where you can save weight by leaving out material that can’t be machined out later, but not for the parts you mention.
3D printing can produce a optimal shape impractical by conventional machining. But this doesn’t work out unless the material produced has strength at least similar to the conventional product.
Google “World’s Largest 3D Printed Titanium Aircraft Part”.
That’s very interesting. I wonder how the part compares to milled parts in terms of fatique resistance and other mechanical properties.
This story from last August is also interesting. A rocket engine injector is not your typical 3D printed part.
I remember that Jerry Pournelle, when he was talking about the planning days for DC-X and other SSTO plans, said that Max Hunter wanted to get one flying as close to orbit as possible, then figure out where weight wasn’t needed for structural strength and cutting it away. This just reminded me.
To the greatest extent possible, future spacecraft should be made using this technology. This will allow a long duration mission to carry some 3D printers and be able to reproduce almost any part needed. If you actually constructed the spacecraft in orbit from raw printer materials, you wouldn’t have to make it strong enough to withstand launch G loads. That could greatly reduce structural mass even further.
I can go from sand/soil, to ore, to ingots. What’s the -cheap- and -light- way to go from ingots to the pre-sintering powder?
(My understanding of the terrestrial methods … not sure they scale down.)
For some metals spraying into an inert atmosphere might work, producing a metallic snow.
I’ve been thinking of general operating guidelines for off-Earth habitats and spacecraft lately. One of the things I keep coming back to is the idea of designing for operating in a “degraded” mode. Specifically, in complex systems something somewhere is going to be frequently broken at any given time. If you design a system with redundancy and abort modes in mind then it will be possible to survive such breakages, but you’ll have a low rate of “mission success”. However, if you design systems such that most failures result in continued operation above the design minimum and result in non-emergency scenarios then you have a system which is vastly more robust. Many real-world systems work this way through a long history of evolution toward that design pattern, but we can use the same principles in designing new systems.
Some decades ago somewhat wrote a paper for the IEEE that compared human fatalities from genetic problems to work done for NASA one the reliability of complex systems, which showed that they had the same curves for probably the same reasons, with the conclusion that humans were complex systems with dual redundant backups because the life-cycles and failure rates were so similar.
What you see in the failure rate of such systems is a spike in the early period as the equipment with two defective systems (genes or dual manufacturing defects) get weeded out, which is the childhood deaths, and then a long period where most system work (normal healthy people with at least one good copy of a critical gene), and then a small tail to extends on out (centenarians) for the people who received two good copies of every critical component.
Surprisingly, the medical community was highly receptive because the approach described and explained what they’d been pondering for decades and put it all in a simple yet completely different and understandable perspective.
You could flip the observation around, allowing for triple or quad redundancy (which biology generally only creates with plants that are double up on chromosomes as they become diploid, triploid, etc.)
Some organisms also significantly change their developmental trajectory (basal metabolism) due to their womb environment, and based on studies of WW-II famines in Scandinavia, these organisms include humans.
As a caveat, I’ll note that we’re learning more and more how our metabolism is determined by our gut bacteria, and these might be significantly altered during a war-induced famine, so the “genetic programming” that the researchers see may be just the effect of shifting gut bug populations due to famine, and the babies pick up a sample of the surrounding gut bug population after they’re born.
Dang. How to bring this random digression to a conclusion?
Future spaceships should be designed with hidden pantries (much like the Millennium Falcon’s smuggling holds) so storm troopers from the secret Nazi moon base can’t loot all the food. The spaceships should also have redundant systems because the storm troopers will get to destroy or disable anything obvious.
I’m being a bit flip because the gut-bug explanation of the metabolism and heart disease research just occurred to me. The crux of what I read was that children born during the lean times tended to suck up fat and such, as if they were optimized to a low calorie environment compared to peers born before or after the lean times. But wouldn’t it make just as much sense that in the absence of fat, fat eating gut bacteria suffered, so they weren’t passed on in very well to that group of children, who then are freed to absorb all the fats because they didn’t get the bacteria that break them down?
I’m thinking that perhaps a gut-bug explanation is more parsimonious than having a special genetic trigger that activates in the womb to determine basal metabolism based on the mother’s calorie intake.
But I digress yet more. What I’m really striving for is an award for the best digression on a blog, drama, or comedy from the Academy of Motion Pictures or the People’s Choice Awards, and I don’t think anyone can top a digression from 3-D printing of titanium aerospace parts to the monster that lives in my intestines, which could easily be a SyFy original movie except that I can’t write that badly, though Lord knows I try.
Apologies to everyone who lost brain cells reading this, but I lost more than a few of my own writing it. It was a slow day on Rand’s blog.
You can see your suggested design approach in several critical systems. On your car, if the anti-lock brakes controller fails, you still have brakes just without the anti-lock feature. If your power steering fails, you can still steer the car only with more effort. IIRC, Boeing’s approach to fly-by-wire works in a similar manner. This is in contrast to a fighter’s approach to fly-by-wire, where you have multiple redundant controllers backed up with an ejection seat.
On a spacecraft, you can design your systems so that the same tasks can be performed manually while the atomated system is repaired. For an interplanetary mission, the navigation system can be backed up by the crew performing celestial navigation as used in Apollo. Your automated life support system would be designed to allow manual control if needed. You’d use the same approach across as many systems as possible. For Apollo, the astronauts themselves operated all the controls (they had strong union rules!). For future missions, you could allow ground controllers to back up the astronauts to reduce their workload in an emergency. I think they can already do this on the ISS but I’m not sure.
I wonder if it’ll be possible in our lifetimes to combine the versatility of 3D printing with the material strength of forged parts?
I’m pretty sure I could do that now, just by designing simpler forging dies that work the part from something close to a precision casting to a finished product, instead of having for forge the part from an ingot. Decades ago I devoted a whole lot of thought to automating mass and custom chain maille production (which is a hard problem, but I had some interesting approaches), A year or so ago I saw several possible ways to forge aluminum isogrids with moving triangular dies, but the bulk material shifts are somewhat extreme because you have to forge I-beam type sections out of flat plate while making them into triangles. The aluminum has to move a whole lot to get the final shape, and the movement may not give the desired grain orientations.
If you instead 3-D printed a preform, you could set it up so the forging operation was not only vastly easier, but so that the material flows were in the directions you wanted. I didn’t consider the same concept from castings because an aluminum that casts well tends not to forge well, and vice versa.
Hmmm, I see you mentioned this before on Selenian Boondocks. So let me see if I understand the desired ideal die motion.
You start with a flat plate and an isogrid pattern of dies (basically a tiling of triangular dies with perhaps a few choices as to how you squeeze the triangles together). Each triangular die starts a bit undersized and presses into the plate (with a flat rear plate to keep material from going that way). The material spreads into the gaps between dies. The dies expand horizontally with similar pressure and force to the original die motion (impossible motion I gather, but we’re speaking of ideal not real) squeezing that material up the shrinking gaps between triangular dies. Then a plate die behind the triangular dies presses down. The material which welled up in the isogrid pattern now is pressed over the rear of the triangular dies, creating an I-beam cross-section, but with a triangular hole centered on each triangular die’s center.
Now one does another impossible motion of the triangular dies and shrinks the die horizontally so that it is small enough to pull through the hole centered on it and all the dies are extracted. The result is a flanged, forged isogrid structure on one side of your aluminum plate. Does that sound about right?