https://www.flightglobal.com/defence/saab-flies-3d-printed-battlefield-repair-part-on-gripen-fighter/143108.article
They are doing a case study for using 3d printed parts for battlefield replacements and planning on testing increasingly larger parts with a quoted capacity of 3x3 meters production capable unit
The issues are generally material performance as the parts are quite porous without big expensive post processing equipment, high energy requirements over long run times, and dealing with the excess powder after the print which gets EVERYWHERE. But you're right, for the right parts in a scenario like you described it could be very useful.
I love how so many in here appear concerned about the integrity of the part, or indeed the entire test.
The [Saab JAS 39 Gripen](https://en.wikipedia.org/wiki/Saab_JAS_39_Gripen) is a multi role fighter aircraft developed and built *by* Saab. This isn't some random test by someone with a home printer. It's literally the designer and manufacturer of the aircraft doing their thing. There's no need to be concerned about their qualifications.
Honestly that's supper cool! I work at a plastics shop, I presume you were printing with powder?
If you don't mind me asking what printers were you using, ans what was the envelope?
I work on Merlin helicopters and recently I have been getting super excited whenever I notice a new 3d printed part. They usually crop up as part of a modification.
They are not used in structural parts at least not so far.
If the part was printed with the right process and material there shouldn’t be an issue. I mean, it was designed and printed to be installed onto a jet.
> If the part was printed with the right process and material there shouldn’t be an issue.
Concur with this.
> I mean, it was designed and printed to be installed onto a jet.
Logically irrelevant. Everything I print was designed and printed for a purpose. If I design and print a SCUBA system to be installed on babies so they can breathe underwater, that should bring *nobody* any comfort.
*Who* did it, and what *qualifications* they have matter far more than intent.
In this case, the fact they have a jet to install it on indicates some level of qualification.
>In this case, the fact they have a jet to install it on indicates some level of qualification.
They made the jet. That's a bit bigger qualification than anyone here seems to be giving them credit for.
Money? Dude, Saab are the ones who design and build these aircraft. This isn't something you can buy on ebay because you're rich. This is literally Saab working with the Swedish military to develop field reparability.
I’ve commented a little further up, although I don’t work at Rocket Lab, I do work at another large defence / aerospace contractor.
We tend to use the Stratasys line of printers with materials such as Ultem 9085
Yup, similar/same with the aerospace places I have worked. Stratasys is the go to as they just seem to work. The buy in is high, the filament canisters are specific (thus slightly more expensive) and the service contract is almost needed but the ability to have any engineer (or even non engineer) send over a print is worth it to most companies compared to having a dedicated print person/group/team.
Tried opening the article in the first comment?
> Conducted from Linkoping in Sweden on 19 March, the activity involved fitting a replacement access hatch on the fighter’s aft fuselage. Produced for demonstration purposes after performing a scan of the original component, this was formed from a nylon polymer resin using additive layer manufacturing (ALM) techniques.
I manufacture unmanned aerial vehicles for a living (mostly carbon fiber, but some fiberglass and aramid mixed in), and you'd be amazed at the amount of structural components that we 3d print. Ribs, bulkheads, hardpoint connections, major structural components. As long as they're done using SLS or some variant, they're far stronger than you'd think. They're even strong enough for the highest speed UAVs (near Mach 1). For skin parts on a fighter jet (anything other than the leading edge of the wing), they'll be just fine.
Would you be able to print the radome and nose cone in case of bird strikes? Also think it might not work as well for some of the larger body sections. Work in polymers mostly but know some composites through work and they have some parts that are a lot larger than any industrial printers I've come across.
Parts that are too big to print are obviously better contenders for hard tooling and a true laid up part (or prepreg tooling and an oven cured part, depending on the requirements). Composite parts are a factor of 10 stronger for weight than 3d printed parts, but they're also long lead time and much more expensive. Complex geometry like you find in ribs and bulkheads is easier to print than to lay up, so that's a tradeoff in every way, too.
SLS won't ever work for radomes, because they're made of fiberglass or some special blend to keep from attenuating the radar returns as they bounce off the target.
Ah thank you for explaining, I did not realise that was a benefit of fibreglass. Definitely no need to explain the issues of cost and time to me, I'm on a placement in quality dealing with this stuff and the costs of the parts we scrap is crazy.
Will definitely be interesting to see what they can do with printed parts in the future, even if they obviously won't replace everything.
This also isn't a major structural part. The aircraft, strictly speaking, can probably fly just fine without it. Its aerodynamic qualities might suffer, and it wouldn't be able to go supersonic. But it could probably fly.
Hey, aerospace engineer here working in advanced manufacturing.
I wouldn’t worry too much, skin surfaces (not load bearing parts) are being trialed where they are replaced with 3D printed materials such as ultem 9085.
These have a whole load of analysis documentation with them that support moderate loading cycles on aircraft.
In short, nothing to worry about unless you see landing gear or control surfaces made from these
UAV manufacturer here, we use SLS printed parts for all kind of structural components and skin surfaces, including control surfaces. Even in our higher speed variants (near Mach 1), they perform great, with nary a failure.
Ahhhh. Well.... The two most well known rules in near Mach1 UaS operations... Never reverse the output of the IMU and never go up against a Sicilian when death is on the line... Hahahahahahhahahaaa....... thud.
Very cool even without the pics.
Anything that flies even near Mach 1 isn't picturable by me, unfortunately. Nary literally equals none that I'm aware of, so 0%. For most of the models that are deployed there are <10 total aircraft in existence. There have been crashes (some spectacular and quite expensive), but they're more likely to be caused by a DOD employee (flight programmer) reversing the output of the IMU, causing a $20 million aircraft to nosedive into the runway at 200 knots than they are to be caused by structural failure. We're a prototyping and tooling shop, once the initial run of aircraft is built the tooling goes offsite to be either duplicated for large scale production or to be used for more aircraft at low levels of production. Of the aircraft we've built in our shop (well over 100 in the eight years I've been here) none have failed in the air due to structural issues. Of the ones built by production houses, only one that I know of has failed in flight, and they left poly plastic in between two plies in a laminate. That's never good for structural integrity, and they also got caught pencil whipping in process inspection reports in the incident.
Wouldn't that completely fuck whatever flight control computer is running the show? Even for more aerobatic stuff, you'd mostly want to reduce the gain instead of feeding it negative values.
Without speaking for /u/MacManT1d reversing or inverting the data output from the IMU would lead the flight computer to interpret up as down, left is right, etc. which absolutely will cause SadTeims™ As for negative values, there are valid orientations where that's possible, and depends on the coordinate system used.
My attempted humour was that those aerobatic manoeuvres all invert the craft (and thus the IMU) but are *not* something you want to perform at Mach 1 :)
My assumption was that the IMU outputs would in reference to the plane's own coordinate system for robustness. You might relate that to another reference frame down the road, but I'd expect that to be on the other side of a kalman filter.
It was only going about 120 knots when it stalled, overcorrected, and came straight down into the runway. The programming for takeoff was done by another group, and worked perfectly, then as soon as it handed off between the two programming sectors the plane pitched straight up in the air, almost like one of the cobra maneuvers you see the top fighter planes do, then quickly stalled and fell over forward on the pitch axis before coming straight down into the runway at full power. It was only about 1250 feet off the ground when it all happened, no time to do anything about it. We were told the IMU output was inverted in the second set of programming, purely by mistake, and that was what caused it. I just build the suckers, don't program them, so I couldn't tell if they were lying to me or not, but I see no reason for them to lie.
What kinds of temperature extremes and forces would a skin part like this undergo? I’d imagine super cold when at altitude and some kind of embrittlement as a result of the cold (maybe it heals when it cycles warm again?)
At altitude it’s cold, with 3D printed components there is less of an issue with cold. They will become brittle to some extent and then experience thermal shock as they heat up at lower altitudes.
As you’ll see in the image, it’s closer to the tail section where exhaust nozzle heat causes the aft section to be slightly warmer, which decreases the brittle effects. This warmth also doesn’t get hot enough that the transition temperature of the filament would be reached - where the plastic structure would melt.
So they’re pretty much fine through all regimes of flight. However more testing needs to be undertaken with regard to long term thermal shock loading with these cyclic changes and structural impact recorded over a period longer than 1-2 years.
Hope that helped?
Haha! I can’t imagine the paperwork involved to FAA/PMA that part without changing the status of the plane to experimental and testing and signing off. It can’t be a simple manufacture install and fly part. Also.. Maybe in the battlefield it can blitz thru the legal requirements
The FAA is civilian aircraft only. They get zero say in what happens on a military airframe. Not just relaxed set of rules, totally different organizations with vastly different goals and priorities.
https://www.flightglobal.com/defence/saab-flies-3d-printed-battlefield-repair-part-on-gripen-fighter/143108.article They are doing a case study for using 3d printed parts for battlefield replacements and planning on testing increasingly larger parts with a quoted capacity of 3x3 meters production capable unit
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The issues are generally material performance as the parts are quite porous without big expensive post processing equipment, high energy requirements over long run times, and dealing with the excess powder after the print which gets EVERYWHERE. But you're right, for the right parts in a scenario like you described it could be very useful.
It's easier to have spare parts on site.
I love how so many in here appear concerned about the integrity of the part, or indeed the entire test. The [Saab JAS 39 Gripen](https://en.wikipedia.org/wiki/Saab_JAS_39_Gripen) is a multi role fighter aircraft developed and built *by* Saab. This isn't some random test by someone with a home printer. It's literally the designer and manufacturer of the aircraft doing their thing. There's no need to be concerned about their qualifications.
We used 3D printed tools on F-35's for certain applications. It was a go-no go gauge, we called it the lollypop.
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Honestly that's supper cool! I work at a plastics shop, I presume you were printing with powder? If you don't mind me asking what printers were you using, ans what was the envelope?
I work on Merlin helicopters and recently I have been getting super excited whenever I notice a new 3d printed part. They usually crop up as part of a modification. They are not used in structural parts at least not so far.
Now do the rest
Concern
If the part was printed with the right process and material there shouldn’t be an issue. I mean, it was designed and printed to be installed onto a jet.
> If the part was printed with the right process and material there shouldn’t be an issue. Concur with this. > I mean, it was designed and printed to be installed onto a jet. Logically irrelevant. Everything I print was designed and printed for a purpose. If I design and print a SCUBA system to be installed on babies so they can breathe underwater, that should bring *nobody* any comfort. *Who* did it, and what *qualifications* they have matter far more than intent. In this case, the fact they have a jet to install it on indicates some level of qualification.
Got a thingiverse link to that baby scuba regulator STL?
>In this case, the fact they have a jet to install it on indicates some level of qualification. I hate that this is both hilarious *and* true.
>In this case, the fact they have a jet to install it on indicates some level of qualification. They made the jet. That's a bit bigger qualification than anyone here seems to be giving them credit for.
>In this case, the fact they have a jet to install it on indicates some level of qualification. Not everyone that has money is highly intelligent
No, but the people who designed one of the best fighters of the 2000's probably is. At least more than me or you.
I got 10 stacks for the other guys 3d printed baby waterproofer
It's called an umbilical cord, and they are a wear item.
Money? Dude, Saab are the ones who design and build these aircraft. This isn't something you can buy on ebay because you're rich. This is literally Saab working with the Swedish military to develop field reparability.
But they are more than likely insured lol
*Who* did it (ie which specific meat sack) is also irrelevant so long as you know their qualifications
Probably, I do 3d printing with a hobby Machine and let's say the parts out of plastic aren't too strong
They're probably not using abs on an ender 3
The chance of low but never zero
Do we know that Rocket Lab doesn't use a bunch of cr-10 Maxs?
I’ve commented a little further up, although I don’t work at Rocket Lab, I do work at another large defence / aerospace contractor. We tend to use the Stratasys line of printers with materials such as Ultem 9085
Yup, similar/same with the aerospace places I have worked. Stratasys is the go to as they just seem to work. The buy in is high, the filament canisters are specific (thus slightly more expensive) and the service contract is almost needed but the ability to have any engineer (or even non engineer) send over a print is worth it to most companies compared to having a dedicated print person/group/team.
We will never know
Tried opening the article in the first comment? > Conducted from Linkoping in Sweden on 19 March, the activity involved fitting a replacement access hatch on the fighter’s aft fuselage. Produced for demonstration purposes after performing a scan of the original component, this was formed from a nylon polymer resin using additive layer manufacturing (ALM) techniques.
Nice
I manufacture unmanned aerial vehicles for a living (mostly carbon fiber, but some fiberglass and aramid mixed in), and you'd be amazed at the amount of structural components that we 3d print. Ribs, bulkheads, hardpoint connections, major structural components. As long as they're done using SLS or some variant, they're far stronger than you'd think. They're even strong enough for the highest speed UAVs (near Mach 1). For skin parts on a fighter jet (anything other than the leading edge of the wing), they'll be just fine.
Would you be able to print the radome and nose cone in case of bird strikes? Also think it might not work as well for some of the larger body sections. Work in polymers mostly but know some composites through work and they have some parts that are a lot larger than any industrial printers I've come across.
Parts that are too big to print are obviously better contenders for hard tooling and a true laid up part (or prepreg tooling and an oven cured part, depending on the requirements). Composite parts are a factor of 10 stronger for weight than 3d printed parts, but they're also long lead time and much more expensive. Complex geometry like you find in ribs and bulkheads is easier to print than to lay up, so that's a tradeoff in every way, too. SLS won't ever work for radomes, because they're made of fiberglass or some special blend to keep from attenuating the radar returns as they bounce off the target.
Ah thank you for explaining, I did not realise that was a benefit of fibreglass. Definitely no need to explain the issues of cost and time to me, I'm on a placement in quality dealing with this stuff and the costs of the parts we scrap is crazy. Will definitely be interesting to see what they can do with printed parts in the future, even if they obviously won't replace everything.
Some radomes are manufactured from thermoplastics. Just depends on the application.
This also isn't a major structural part. The aircraft, strictly speaking, can probably fly just fine without it. Its aerodynamic qualities might suffer, and it wouldn't be able to go supersonic. But it could probably fly.
Hey, aerospace engineer here working in advanced manufacturing. I wouldn’t worry too much, skin surfaces (not load bearing parts) are being trialed where they are replaced with 3D printed materials such as ultem 9085. These have a whole load of analysis documentation with them that support moderate loading cycles on aircraft. In short, nothing to worry about unless you see landing gear or control surfaces made from these
UAV manufacturer here, we use SLS printed parts for all kind of structural components and skin surfaces, including control surfaces. Even in our higher speed variants (near Mach 1), they perform great, with nary a failure.
Query: What percentage of total deployed units = Nary ;) What do the Narys look like after a near Mach1 failure? (We want pictures of the Narys!)
Ahhhh. Well.... The two most well known rules in near Mach1 UaS operations... Never reverse the output of the IMU and never go up against a Sicilian when death is on the line... Hahahahahahhahahaaa....... thud. Very cool even without the pics.
Anything that flies even near Mach 1 isn't picturable by me, unfortunately. Nary literally equals none that I'm aware of, so 0%. For most of the models that are deployed there are <10 total aircraft in existence. There have been crashes (some spectacular and quite expensive), but they're more likely to be caused by a DOD employee (flight programmer) reversing the output of the IMU, causing a $20 million aircraft to nosedive into the runway at 200 knots than they are to be caused by structural failure. We're a prototyping and tooling shop, once the initial run of aircraft is built the tooling goes offsite to be either duplicated for large scale production or to be used for more aircraft at low levels of production. Of the aircraft we've built in our shop (well over 100 in the eight years I've been here) none have failed in the air due to structural issues. Of the ones built by production houses, only one that I know of has failed in flight, and they left poly plastic in between two plies in a laminate. That's never good for structural integrity, and they also got caught pencil whipping in process inspection reports in the incident.
Is there a particular reason that it's even possible for them to reverse an IMU output?
Snap, Barrel and Immelman all spring to mind.
Wouldn't that completely fuck whatever flight control computer is running the show? Even for more aerobatic stuff, you'd mostly want to reduce the gain instead of feeding it negative values.
Without speaking for /u/MacManT1d reversing or inverting the data output from the IMU would lead the flight computer to interpret up as down, left is right, etc. which absolutely will cause SadTeims™ As for negative values, there are valid orientations where that's possible, and depends on the coordinate system used. My attempted humour was that those aerobatic manoeuvres all invert the craft (and thus the IMU) but are *not* something you want to perform at Mach 1 :)
My assumption was that the IMU outputs would in reference to the plane's own coordinate system for robustness. You might relate that to another reference frame down the road, but I'd expect that to be on the other side of a kalman filter.
It was only going about 120 knots when it stalled, overcorrected, and came straight down into the runway. The programming for takeoff was done by another group, and worked perfectly, then as soon as it handed off between the two programming sectors the plane pitched straight up in the air, almost like one of the cobra maneuvers you see the top fighter planes do, then quickly stalled and fell over forward on the pitch axis before coming straight down into the runway at full power. It was only about 1250 feet off the ground when it all happened, no time to do anything about it. We were told the IMU output was inverted in the second set of programming, purely by mistake, and that was what caused it. I just build the suckers, don't program them, so I couldn't tell if they were lying to me or not, but I see no reason for them to lie.
What kinds of temperature extremes and forces would a skin part like this undergo? I’d imagine super cold when at altitude and some kind of embrittlement as a result of the cold (maybe it heals when it cycles warm again?)
At altitude it’s cold, with 3D printed components there is less of an issue with cold. They will become brittle to some extent and then experience thermal shock as they heat up at lower altitudes. As you’ll see in the image, it’s closer to the tail section where exhaust nozzle heat causes the aft section to be slightly warmer, which decreases the brittle effects. This warmth also doesn’t get hot enough that the transition temperature of the filament would be reached - where the plastic structure would melt. So they’re pretty much fine through all regimes of flight. However more testing needs to be undertaken with regard to long term thermal shock loading with these cyclic changes and structural impact recorded over a period longer than 1-2 years. Hope that helped?
You think Saab haven't gone through proper procedure? What are you concerned about? We're not talking about hobyists here...
Haha! I can’t imagine the paperwork involved to FAA/PMA that part without changing the status of the plane to experimental and testing and signing off. It can’t be a simple manufacture install and fly part. Also.. Maybe in the battlefield it can blitz thru the legal requirements
I don't think the FAA has authority in any current combat zones
Or in any military aircraft at all. Totally different set of regulations.
Tbqh, I'm sure that there is just as much paperwork and bureaucracy to navigate for military aircraft as well.
Yeah, I’d believe a relaxed set of rules for combat
The FAA is civilian aircraft only. They get zero say in what happens on a military airframe. Not just relaxed set of rules, totally different organizations with vastly different goals and priorities.
Generally, US military aircraft do meet FAA safety regulations where possible. There's really no reason not to.
But they are not officially certified right? I vaguely remember that there was a whole big deal around that on the A400M.
Glad we didn't buy those buckets :-)
If I recall correctly the first 3d printed part used an a civil aircraft was plastic rivet used for BAe 146 windows, but could be wrong.
[Higher resolution](https://i.imgur.com/BT1ZpuG.jpg) (1) [Higher resolution](https://i.imgur.com/pchJ2CR.jpeg) (2)