Marines 3D-Print Part To Repair Multi-Million Dollar Fighter

The good news: all you need to complete the repair you’re working on is one small part. The bad news: it’s only available in a larger, expensive assembly. The worst news: shipping time is forever. We’ve all been there, and it’s a hard pill to swallow for the DIYer. Seems like a good use case for 3D-printing.

Now imagine you’re a US Marine, and instead of fixing a dishwasher or TV remote, you’ve got a $123 million F-35 fighter in the shop. The part you need is a small plastic bumper for the landing gear door, but it’s only available as part of the whole door assembly, which costs $70,000 taxpayer dollars. And lead time to get it shipped from the States is measured in weeks. Can you even entertain the notion of 3D-printing a replacement? It turns out you can, and it looks like there will be more additive manufacturing to come in Corps repair depots around the world.

Details of the printed part are not forthcoming for obvious reasons, but the part was modeled in Blender and printed in PETG on what appears to be a consumer-grade printer. The part was installed after a quick approval for airworthiness, and the grounded fighter was back in service within days. It’s encouraging that this is not a one-off; other parts have been approved for flight use by the Marines, and a whole catalog of printable parts for ground vehicles is available too. This is the reality that the 3D printing fiction of Lost in Space builds upon.

And who knows? Maybe there are field-printable parts in the disposable drones the Corps is using for standoff resupply missions.

[via 3D-Printing Industry]

71 thoughts on “Marines 3D-Print Part To Repair Multi-Million Dollar Fighter

  1. Lots of aircraft parts are that way. The springs that push the crew entry handles out on F-15Es would wear out and break. Couldn’t just buy the spring, you had to buy the whole handle assembly. Then either take the new one apart to get the spring, or replace the whole assembly, which is riveted in place. Someone came up with a new spring that consisted of a piece of bent spring steel riveted into the handle channel.

    1. When you send something new into the field, you use reliability engineering and common sense to decide which parts to stock where in the world, and at what assembly level. The F-35 is relatively new, but after some experience and operating hours, reports should filter back to the engineers and logisticians about common failure modes and the most efficient ways of rectifying them. Integrated Logistic Support is the science of efficient repairs and maintenance in the military world. No excuse for a mature platform like an F-15, though.

    1. Since it was designed with taxpayer dollars, wouldn’t it all be public domain?

      (An F-35 recently had a landing gear accident on Eglin AFB… Maybe they need a 3D printer too.)

      1. Not exactly public domain, no – defense articles don’t follow the same legal rules as commercial/consumer items. Maybe patent as someone else mentioned, but it’s far more likely that this is determined by the terms of the development contract: if the government funded development of the item there’s a good chance they own the design & technical document package and have the rights to reproduce it. (Or put it out for bid at contract renewal, etc.)

        I don’t think this is a parallel to the John Deere or other DMCA related cases at all, as it is a mechanical part design and has nothing to do with software copyrights.

    2. No. For several reasons (IA~AL, but I do deal with IP in this way in one of my jobs):

      First, there is no copyright on a part like this, There may be design patent, but not copyright.

      If it was copyrighted, this would be fair use, even under DCMA.

      Also, the law has long since allowed for repair/replacement parts to be freely manufactured and sold (ref: any NAPA, Pep Boys, or Autozone.) There is a long, long history in the law here, and I am too lazy to look for the references (and limitations) in my IP files

      As they recreated the model themselves, no one could even claim misuse of copyrighted design drawings/digital model.

      1. IANAL, but you may wish to revisit your statement or otherwise provide clarification for the rest of us. Check-out the many farmers whose tractors require manufacturer intervention using authorized repair mechanics and technicians for the simplest repairs. The farmer (or his/her designee) is not allowed to perform repairs. Here is but one link…

        1. Isn’t the essence that parts that require ecu calibration/resetting/authentication is the one struck by DMCA since you “drumroll” have to use John Beer’s software to manage it?

        2. As I understand it you could fit any piece of plastic to your tractor that you want. What has been made essentially impossible is interfacing with the on-board computer in order to find faults, so you might not ever be able to find out which piece of plastic you need to replace.

        3. The issue there is that the software running on the tractor is copyrighted. While farmers can replace physical parts, they have to get the tractor’s computer to accept them for the tractor to work. Because they would be using or modifying the existing software, which is copyrighted, the tractor companies claim it’s illegal. If you re-write the tractor software entirely there’s nothing the company can do, but doing a full clean-room re-write is an enormously expensive and time consuming process. So the legal conundrum is: companies have copyright on software they develop, but consumers also have a right to repair. How do you balance those rights in a way that is fair and not excessively burdensome to either side?

          1. ” How do you balance those rights in a way that is fair and not excessively burdensome to either side?”

            Current solution is Ukrainian firmware, but the “fair” way is not buying such equipment in the first place, and telling the manufacturer why. Remember this kind of equipment is EXPENSIVE and money does talk. Other is pulling a Compaq and writing alternative, but compatible firmware. Makers still sell hardware, but everything else is someone elses responsibility.

        4. The difference between a copyrightable entity, and, in particular, one that is also covered by regulations regarding circumvention of computer security measures, and a physical part. Note that the security measures need not actually exist for those rules to apply. In addition, in cases like the tractor, there are specific contractual issues, as well. If you have recently bought (manufactured within last 5 to 10 years, depending on the make and model) a motor vehicle, you have signed similar contract.

          The rules, laws, and interpretations in the copyright world are rather bizarre, but it is surprising what is, and is not, acceptable as fair use, both within and outside the standard fair use categories. The whole picture goes WAY beyond my current expertise. I only know the specifics I deal with, and pass anything else along for advice (happens maybe once a year in my realm, daily for some of the people I work with).

        5. The tractor issue is an Apple like EULA evil. Basically you paid for it but you don’t own it. The end user license defines you as the end user, not the owner. You will do with it only what they say you can. You agreed to this when you paid for it. This is the sad state of affairs we find our selves in.

          1. This is why I stopped using Itunes. I’d buy a song, then several weeks later it would tell me I didn’t have the rights to the song anymore and remove it from my music library. It blew my mind that I could pay real money for something and they could just take it away again.

    3. What do you think will happen they will run out of gold and can’t print more money, or the CIA and contractors will stop assisting drug cartels to fund foreign and domestic ops “off the books”?

  2. Too bad only the military can do this. The FAA is rather dogmatic about every part on an airplane being approved for flight and certified, yada yada. When I was a teen, my uncle once needed to remove his external transponder antenna from his Cessna and switch to an internal unit. The problem was that left a small tear-drop shaped hole in the fuselage where the external antenna had previously been attached and the FAA-Approved patch which was nothing more than a teardrop shaped piece of aluminum was crazy expensive. He had me cut a piece of aluminum to the proper size and shape and file it smooth. It was made clear to me that we were breaking the law by doing so and that it had to look really good so the plane would pass inspection.
    The plane passed inspection.

    1. And yet a person can take a normal light aircraft (say something like a Wilga) and modify it almost beyond all recognition, and still get it certified by the FAA if it is registered as an “Experimental” aircraft.
      The specific example I am referring to is a Wilga 2000 named “Draco” that Mike Patey heavily modified, including changing the wings, control surfaces, stabilizers, all internal parts, and tripling the horsepower by adding a turbine engine. He got permission from the FAA before doing the work, but created almost all of the parts himself (many out of carbon fiber using homebrew methods that could be done by almost anyone), except the engine and avionics.

      1. Then he did a dumbass move and attempted to take off in a cross wind so strong it had the downwind gear strut fully compressed. Got it up just long enough for the wind to tip it and flip it. The only casualty was his wife broke a fingernail. He’s working on rebuilding Draco.

        Given that the plane could take off in an extremely short distance, he could’ve asked the tower for permission to take off *across* the runway, directly into the wind. Release the brakes, go to full throttle and it likely would’ve been airborne in three feet or less. Wasn’t anyone else out there to be in the way.

  3. But it’s just a bumper for a door!

    I’m thinking some sort of epoxy or glue that dries rubbery would be easier. Maybe just a big glob of silicone caulk. Or, if it has to be more of a geometric shape get one of those big pink erasers and cut it to size.

    Yah, I know. everything probably has to be approved. But.. if someone bothered to put the 3d printed design through the approval process they might as well put ‘big blob of caulk’ through the process too. Obviously there IS a path for getting non-traditional solutions approved.

    “As a commander, my most important commodity is time,”

    Yeah well there are a couple of ways to interpret that statement. If he means the time to get the aircraft back into commission then sure, if none of my above solutions are acceptable then 3d printing may be just the thing. That’s kind of an awkward way to say that though. It sounds more like he is talking about his own time. Printing is still a slowwwww process. You can walk away while it prints but you never want to walk too far for fear of failed prints and sometimes even building fires. If his own time is important it might make sense just to place the order and go on with the rest of the task list until the part finally arrives.

    Maybe as a commander he has plenty of underlings who can run the printer and who’s time is not an important commodity.

      1. Um, no. They certainly vary in output quality, consistancy and safety but they are all similarly slow. I’ve used Makerbots (both old and recent models), Creality, A8 and own a RepRap. I’ve been present while people used printers from plenty of other name brands, both reputable and not so much. Regardless of the printer all but the smallest parts take quite a bit of time to print.

        Maybe you meant commercial printers? Did you mean those big boxes that cost 10s of thousands of dollars? I wouldn’t know how fast those work.

        Or did you mean they are safe to leave running when you leave the premises? A quality printer is certainly safer. So is a cheap one if you have the knowledge to perform certain low-cost improvements. Safer doesn’t mean safe enough though. You really shouldn’t go farther than you can smell the smoke for more than a few minutes.

      1. I imagine a lot of repair depots are like that. Military, or otherwise. As for the military they do have a leg up in being able to get a better quality, and capable printer than most of us. As for parts, they probably do like the rest of us, as the first post suggested and use off-the-shelf parts and materials to solve problems.

  4. Good hack and probably no increased risk on aircraft failure.
    Anyway some comments which suggest doing this in airliners scare the hell out of me.
    I don´t wanna sit in a fly-by-wire vehicle 30000 feet high, in the middle of the ocean with a aileron connected to a kitchen sink hose.

    1. Why would moving the concept from a fighter jet to an airliner automatically mean going from sensible replacements to scary hacks?

      I wouldn’t care if they used a piece of old chewing gum for a door bumper if it’s job is just to keep some internal maintenance access door from vibrating or something non-critical like that. It wouldn’t make the slightest difference if we were talking about a fighter jet, commercial airliner or just a small hobby craft. The kitchen-hose aileron hack though would make me nervous in any of those planes.

      I don’t understand the connection you are trying to make!

    1. I assume a bumper like this is an acutator stop and would be internal to the airframe when the landing gear door is closed.
      This “should not” affect the radar signature at all…

  5. And how does Lockheed Martin feel about that….. What happens when the plane has issues caused by this part? (yes, it is just a piece of plastic, but accounting for all of a plane’s variables and MTBF must be considered for pilot and flight deck crew safety). Does the 3D printed material have the same specs as the original part? Will it hold up for the same time frame? (F-35B came out in 2006, so the plane could be up to 12 years old) Hopefully, someone reviewed AND documented all of the appropriate factors before giving a green light for this.

    A real concern is who will draw the line at what can be 3D printed for this plane?

    1. They probably ordered the real thing at the same time they started printing it. You can get some usage out of the 3D printed part and then install the real part when it gets in weeks later. Speculation: It’s a “non-stocked” part, LM has to pull a single one from a much further back warehouse in the supply chain rather than the closer warehouse that stocks the whole door assembly.

      1. If the 3D printed part does not fly apart or melt, and if it does fail, will the pieces get lodged someplace bad? We just had the blurb here the other day on he SST and how hot that got from wind friction alone. Do you really wanna make parts out of PLA that would be exposed to that heat and airspeed?

        If the subcontractor will not provide the pieces in finer granularity, the contract with that sub sucked, unless they would have liability issues if you DIY and screwed it up.

    2. The certifying organisation is there for a reason! The article says the part went through a “quick approval”. I don’t know the USA set up, but here is Australia the authorised engineering organisation (MDO now under DASR) would perform an assessment – considering strength, aerodynamics, system safety etc – and then certify that it was good to go if appropriate. The OEM doesn’t have a say in what you fit to your aircraft. They can provide support, but they are not the certifying authority.

    3. They probably feel very bad because they were not able to charge (rip off) the government 70.000,- for a plastic bumper. If they are really concerned about reliability or reputation, they should sell the worn part separately.

    1. You can probably get the real part but it will just take a lot longer since LM isn’t keeping the part in stock at the warehouses closer to the end of the supply chain. They would have to go much further back into the supply chain to find stock. That’s assuming there are parts to spare, everything might already be accounted for then LM is going to have to contract out making some extras.

    2. One of the key winning aspects for the F-35 is it being built by suppliers in nearly all the United States. It’s much easier to get support for a project if every Senator and Representative has a factory owner in his back yard pushing for it. This also means that there are a lot of sub-assemblies because not every state is going to have enough high-tech manufacturing, but they will have people who can turn a screw driver.

  6. Military peoples in general, and deployed jarheads in particular, have done field improvisations since Washington crossed to Delaware (and some of the ‘sailors’ made the return crossing inebriated). Was quite amazed by some of the clever stuff done by sailors and Marines during desert shield/storm.

    Humans, while quite clever as individuals, are still a primitive and destructive tribal people at the societal level.

  7. “Details of the printed part are not forthcoming for obvious reasons, ”

    Yeah, I don’t see any obvious reasons. Unless you’re one of those people who masturbates over security clearances and classifications, and who thinks that a plastic bumper on a military jet is somehow secret.

    PS:The Chinese, Russians, and everyone else who cares to know, probably already has extensive blueprints for things that are *actually* secret.

  8. Should this not also be a formal inquiry into why these companies are purposefully only selling an excess of the serviceable parts strictly for profit, One would think that things such as door jamb guides and bumpers wear rails would all be stocked up.

    1. It’s the same with car parts: LED rear lights for a BMW cost @300,- and only the whole assembly is available. The controller PCB (simple linear current regulator) is just clipped in and would be easily replaceable. It is not sold alone. Luckily it is nearly as easily repairable: Resolder the 1206 size current shunt. The only problem: The PCB is a 3mm Aluminium-core PCB. It’s best to preheat it to something like 120°C. But that was quite easy with an old clothes iron put upside down in a vise.
      I think the failure mode is thermal expansion, which affects the big resistor more than other components, as it’s own power dissipation was quite modest, but the whole alu-PCB heats up by the power dissipation of the regulator. Of course together with shitty solder (lead free). The stupid environmentalists which forced us to use that crap did not think about shorter product lifetimes by more brittle solder.

  9. I hope they posted that on Thingiverse.. when those F-35s come up used – Spares or repair on ebay in a few years time, I might need one of those little plastic widgets to get mine going.

  10. Doesn’t anyone question why the government can’t order any part they want including a plastic bumper or an F-15 door handle spring? This is just some guys making up for someone else in the system not doing their job. I’m quite certain the manufacturer will sell any part the government wants to pay for.

  11. I see they took lessons from Brother, maker of printers and knitting machines. For the latter, they had a metal rod that held various parts. The parts can be removed from the rod yet if any part failed only the entire assembly was available as a replacement. The most common part to break is the yarn break sensor mounting bracket.

    I was sent a mast assembly with the broken bracket, had it measured, modeled, printed, fitted and mailed back the same day.

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