3D printing parts is FAA approved?
Crash occurred in UK
A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
21–30 of 223 posts
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#223D printing parts is FAA approved?
I'm not sure Gloucestershire is under FAA jurisdiction.
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#23I wonder what material it was printed with. edit: It was ABS-CF, which shouldn't be used under stress long-term in higher temperatures than maybe 65-70°C, or lower depending on the blend.
Lower, according to the report "Two samples from the air induction elbow were subjected to testing, using a heat-flux differential scanning calorimeter, to determine their glass transition temperature. The measured glass transition temperature for the first sample was 52.8°C, and 54.0°C for the second sample" Yeah, they might have used ABS-CF filament, but unless they got it from a good brand that uses good resin and…
Some manufacturers fudge the Tg.
Polymaker Polylite ABS has a claimed Tg of 101°C but the HDT curve clearly shows it starting to lose strength at 50°C, for example.
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#243D printing parts is FAA approved?
You may want to ask about the LAA: Light Aircraft Association.
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#25At a glance, that looks like worse than merely the negligence of using a new technology. The whole point of 3D printing is that the material is moldable when hot but rigid when it cools. And people really should be aware that engines get hot.
Bought it at a get-together.
Like gunshows, it’s a magnet for bad ideas.
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#26At a glance, that looks like worse than merely the negligence of using a new technology. The whole point of 3D printing is that the material is moldable when hot but rigid when it cools. And people really should be aware that engines get hot.
I think the main issue is that many filament manufacturers mislead or outright lie about their filament capabilities.
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#27This is the mechanical equivalent of vibe coding. 3D printing itself isn't exactly to blame but the negligence of the company that created and sold this part and omitted it's use from an inspection.
Just because a part has the shape of an engineered part does not make it compatible, strong, safe, and fit for purpose. This part could have likely been fine if it used a different material such as Ultem.
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#28I wonder what material it was printed with. edit: It was ABS-CF, which shouldn't be used under stress long-term in higher temperatures than maybe 65-70°C, or lower depending on the blend.
I wonder who installed it. Was the pilot home 3D printing mods for their plane? And is that even allowed? Super concerning if there was a company behind the installation. I'd think any semi competent engineer would know better. Edit: from the report - "A modification application was made to the LAA in 2019, by the aircraft owner2 , to replace the engine’s throttle body fuel injector with a mechanical fuel injection s…
In addition to what other users have mentioned, the airplane changed hands in August 2024, after the modifications were made.
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#29The part was claimed to be ABS-CF. UK AAIB tested the part and found it to have a Tg of approximately 53C. The Tg of ABS is far higher, around 100C. I suspect that the part may have been accidentally printed with PLA-CF (which has a Tg of approximately 55C.)
The original part was fiberglass/epoxy with the epoxy having a Tg of 84C.
Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat
#30Earlier quoted context omitted.
CF-ABS > An alternative construction method for the air induction elbow, shown in the Cozy Mk IV plans, is a lamination of four layers of bi-directional glassfibre cloth with epoxy resin. The epoxy resin specified for the laminate has a glass transition temperature of 84°C, after the finished part has been post-cured. The aircraft owner stated that as the glass transition temperature listed for the CF-ABS material wa…
I think an extended quote shows that this was a really bad call: “ The aircraft owner stated that as the glass transition temperature listed for the CF-ABS material was higher than the epoxy resin, he was satisfied the component was fit for use in this application when it was installed. A review of the design of the laminated induction elbow in the Cozy Mk IV plans showed that it featured a section of thin-walled alu…
[deleted]