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Comment by LargeTomato | Hacker News Reader

It is a shame we're seeing a divestment in 3D printing technologies. Relativity Space recently descoped their entire 3D printing department, but I believe they still may be using some commercially-acquired printers.

I hope we can see someone else take up the mantle on complex 3D printing manufacturing. There's an Indian space company that is trying to do what Relativity did. I hope it works out for them.

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It's been amazing to watch the 3D printing space grow as far as it has. In just the last 10-20 years it's gone from something only dedicated people were able to build and get reasonable results to high precision devices any hobbyist can get their hands on for a few hundred bucks.

I have two resin printers and a PLA printer and I never expected at-home capability to get this far this fast.

But, that's still all effectively plastic we're talking about. I think the problem with metals is still well.. metals. The same types of metallurgy needed for 3D printing have been researched and hit almost a dead end with injection molding (I know there are some metal injection molding systems out there, but it's not hit anywhere near the strength of machined steel yet)

People are 3d printing metal right now with LPBF, DED, and Wire EDM. For LPBF the challenge is controlling keyholing and lack of fusion defects through the process parameters.

BBarn, how far along are the circularity tools, can I turn clean used plastic jugs back into feedstock worth using to make 3D stuff?

There are many designs for DIY filament makers that use 2L pop bottles.

Which kinds of plastic are reusable as filament?

HDPE and PET are the most common I’ve seen in the community, which probably accounts for the majority of beverage containers you’ve ever encountered.

Something like a PET milk jug is harder since you’d need to shred it and remelt a good portion of the jug into filament since the handle area would be hard to deal with, which is hard to do in a DIY manner. Same for reprocessing failed prints and scrap support pieces of prints, plus various coloring agents and manufacturer additives make a blend of recycled bits inconsistent. It’s probably easier to DIY a high temp composter than to recycle PLA.

But there’s a ton of people out there with jig designs to spiral cut a normal cylindrical bottle and feed it into a hotend that creates filament from it. Here’s one example https://www.printables.com/model/768657-petalot-plastic-bott.... YouTube has dozens of videos of these in action. Generally speaking you won’t get as good of results as commercial filament since filament diameter needs to be carefully controlled and it affects flow rate which then affects resulting print quality. If you print something simple, large, and practical it’s fine, if you need something finely detailed it can be fiddly.

I thought Relativity Space pulled back on their use of 3D printing for the major fuselage parts, saving it more for the engine components, etc., which SpaceX was already doing.

I believe you are correct. Relativity is now only printing engines, just like SpaceX, Rocket Lab, Astra, Firefly, Stoke, and others. They are no longer a company driving forward 3D printing technology and that's too bad.

- "It is a shame we're seeing a divestment in 3D printing technologies."

Is there other data to support that claim we can browse? I was under the impression the opposite was true but would love to know more if i'm missing something.

Check out Mantle

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