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A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

bbc.com

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Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#151

Post by cedilla »

averynicepen wrote: post #105
elicash wrote: post #57

Earlier quoted context omitted.

In what way is this like vibe-coding -- or do you just mean both are bad? According to the report: > The aircraft owner who installed the modified fuel system stated that the 3D-printed induction elbow was purchased in the USA at an airshow, and he understood from the vendor that it was printed from CF-ABS (carbon fibre – acrylonitrile butadiene styrene) filament material, with a glass transition temperature3 of 105°…

3D printing is to mechanical engineering what vibe coding is to computer science. With the rise of accessible 3D printers that can print engineering materials, there are a lot of people who try to create functional parts without any engineering background. Loading conditions, material properties, failure modes, and fatigue cycling are all important but invisible engineering steps that must be taken for a part to func…

Ehh.

Everything you need to consider is really not that much when it comes to most typical consumer 3d printing projects. Mostly because they are usually about stuff like "fixing a broken tashcan". The engineers who made that bullshit plastic part that broke after a year probably knew all about area moment of inertia, but that doesn't mean I need to to print a replacement part that lasts longer - or not, in which case I'll just iterate on my process.

I really don't get the dismissiveness, and frankly, I've never experienced that from engineers in my life. They just seem delighted when someone, kid or adult, tinkes with additive manufacturing.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#152

Post by cloudfudge »

Ntrails wrote: post #99
serf wrote: post #82

Earlier quoted context omitted.

>I think by vibe coding he means taking these things at face value instead of rigorously looking if they are up to the standard. Yeah, exactly -- which is why it's a stupid phrase for what happened here. Not every negligence is somehow equatable to an AI pitfall, it's just on parents' mind so it's the only metaphor that gets applied. A poorly fit hammer in a world of nails. I say this as an engineer/proprietor with y…

I think the idea was that 3D printing made doing a thing accessible, previously required solid fundamental knowledge (and very expensive kit). Now you can just take some specs off the internet and press go. The comparison does not seem as absurd to me as it does to you. vOv

The lesson here is that one should never attempt analogies on HN, because people can't just relax and try to see the point of the analogy. They are compelled to fixate on the fact that an analogy is different from the thing it is being compared to.

I see multiple examples of it in this thread.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#153

Post by ComputerGuru »

phkahler wrote: post #117
ohazi wrote: post #4

Actual report: https://aviation-safety.net/wikibase/487013 Material was CF-ABS

>> Material was CF-ABS With a glass transition temp of 105C. And yet "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."

Which is not coincidentally roughly the Tg of PLA.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#154

Post by crumpled »

defrost wrote: post #128
phoronixrly wrote: post #111

Earlier quoted context omitted.

I call bullshit. 3d-printing is just a manufacturing method. Basic woodworking is much cheaper and more accessible than 3d-printing, do you call it vibe-coding?

If you carve a wooden part with "the right shape" for an engineering application that the part lacks the physical properties that allow it to perform under load stress ... then yes, that's vibe carving. Looks good - falls apart in practice, and a junior can't tell the difference as they "look the same" to the inexperienced eye. From practical experience, you cannot just replace a tyre on a car with any old bit of woo…

> then yes, that's vibe-carving.

This whole thread is a stretch, IMO. But, I like this phrase.

As a fabricator (large wood CNC, laser cutting and engraving, 3D Printing, UV Printing, Welding). I put engineering into a whole different job scope. I can make whatever you tell me really well, not vibe-carving.

I don't necessarily write the specs or "engineer" anything. I'm just saying, don't blame the medium, 3D printing. The fact is a fabricator is not necessarily an engineer, regardless of the medium.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#155

Post by ComputerGuru »

teamonkey wrote: post #3

The actual report[1] holds the answer to the question you’re asking. CF-ABS (or so claimed) [1] https://www.gov.uk/aaib-reports/aaib-investigation-to-cozy-m...

With a melting temperature that jist happens to be the same as PLA.

They should sue the seller.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#156

Post by ComputerGuru »

zkmon wrote: post #83

I hope 3-D printing becomes obsolete when robots can achieve the same efficiency with using the standard construction materials. That should take away all benefits of 3-D printing over regular builds.

You don’t need a robot, especially in the colloquial sense meaning humanoid. Better additive manufacturing techniques than desktop FDM printers exist, and CNCs can turn these parts out from much better materials all day.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#157

Post by defrost »

crumpled wrote: post #154
defrost wrote: post #128

Earlier quoted context omitted.

If you carve a wooden part with "the right shape" for an engineering application that the part lacks the physical properties that allow it to perform under load stress ... then yes, that's vibe carving. Looks good - falls apart in practice, and a junior can't tell the difference as they "look the same" to the inexperienced eye. From practical experience, you cannot just replace a tyre on a car with any old bit of woo…

> then yes, that's vibe-carving. This whole thread is a stretch, IMO. But, I like this phrase. As a fabricator (large wood CNC, laser cutting and engraving, 3D Printing, UV Printing, Welding). I put engineering into a whole different job scope. I can make whatever you tell me really well, not vibe-carving. I don't necessarily write the specs or "engineer" anything. I'm just saying, don't blame the medium, 3D printing…

Don't get me wrong, wood is great, I've made a lot of things and replacement parts from appropriate woods.

Using scrublands wood (slow growing tough long grain mulga) as a skid when a rubber tyre destroys itself is an old old hack passed on by my father (he's still kicking about despite being born in the early 1930s).

In the early 1980s I used to enjoy hanging out with Chris Brady and helped out making jigs to assemble snare drums: https://www.youtube.com/watch?v=jdBHtUN5gAE

His jarrah, wandoo, and sheoak snares are still loved: https://www.youtube.com/watch?v=tKmDuu5Iba4

Point being, I don't blame processes (3D printing, etc) for part failure, that comes down to whether the shape and material are fit for purpose, whether material grain structure can be aligned for sufficient strength if required, whether expansion coefficients match to avoid stress under thermal changes, etc.

Engineering manufacturing can sometimes be suprisingly holistic in the sense that every small things matter including the order in which steps are performed (hysteresis) .. there's more t things than meet the eye.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#158

Post by cloudfudge »

bsder wrote: post #148
ToucanLoucan wrote: post #85

Earlier quoted context omitted.

Also, strictly as a combo 3D-printing and engine enthusiast: Never with a GUN to my head would I install 3D printed parts in a CAR engine, let alone in an aircraft engine. This is spectacularly poor judgement on the part of the owner.

> Never with a GUN to my head would I install 3D printed parts in a CAR engine, let alone in an aircraft engine. The fabrication technology doesn't matter. The qualification process, on the other hand ... This is the primary reason why I never got a pilot's license. I suspect I would spend far too much time making sure the maintenance was up to standard and far too little actually enjoying flying.

> The fabrication technology doesn't matter. The qualification process, on the other hand ...

Well, yes, but... In this case the fabrication technology and the lack of qualification process likely go hand in hand. They wouldn't have a qualification process unless they were manufacturing enough of these that plastic 3d printing wouldn't be cost effective. The shortcut is the point.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#159

Post by shmeeed »

carabiner wrote: post #91
fudged71 wrote: post #27

This 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.

Vibe coding can make code that is suitable for production. 3d printed plastic can not be a substitute for a fiberglass-metal part.

It absolutely can. Not all 3D printing is kids' toys.

In the end it depends on the application. Vibe coded flight management systems, anyone?

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#160

Post by jacquesm »

lazide wrote: post #146
jacquesm wrote: post #135

Earlier quoted context omitted.

> 3D printing (especially using filament) allows idiots to enter entirely new areas of endeavor. That's true for any tool.

And when someone makes a new affordable tool that opens up making new types of things…. What happens?

Stuff gets made.

Just imagine, chainsaws, lathes, welders and now 3D printers. What will they come up with next to give these irresponsible dilettantes a way to create their own objects... what we need here is some proper gatekeeping. Maybe a certificate or two, and some very expensive software that proves that you're a company that is serious.

And while we're at it we should forbid home brew software too.

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