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Comment by adamsmith143 | Hacker News Reader

As someone not much into this scene, how useful are 3D Printers actually? I get the sense that they're very useful to hobbyists or for creating prototypes but are the plastics used suitable for production use cases?

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Somewhere between useless and a godsend. It depends upon your application. There are many choices in materials and printer set-up options that greatly change the results that you get. Depending on how demanding your application is, you may or may not find the result meets your needs. A friend that is a freelance mechanical designer for medical devices has a small, inexpensive (relatively) SLA printer, and she sometimes is running it flat-out for days doing prototypes to show clients. Instead of sending that to a service and billing it through, she gets to bill it directly, allowing for a nice margin and also giving client a discount. My friends that build hobby robots use FDM printers for a lot of functional parts -- and results vary depending mostly on how appropriately the part was designed. But a Prusa is a lot cheaper and a lot easier to run than a CNC milling machine, on the flip side a chunk of FDM plastic doesn't compete well with a chunk of aluminum or titanium. At my work, we 3D print a lot of functional enclosures and other low-mechanical-load parts for prototyping.

As you say, they are useful for hobbyists and prototypes. They don't scale well but will in future.

Today it is small/medium business territory but not a large part of megafactories just yet.

Production thoughts:

- speed. 3D printers are not speedy, the tradeoff of speed vs flexibility is clear. Iterate the design with a 3D printer, make the mould and produce with injection moulding.

- material. $$$ for capability. Cheap plastics <$500. ABS+nylon $1000-$2000. Metal is $50k - $1mil depending on what is desired. Workable for some businesses. IE specialist mechanics: https://www.youtube.com/watch?v=4jbn0ah3u9E

- Method affects end result. Resin printing is different to FDM printing etc. FDM printing works in layers that make a plastic end result not food safe. So no printing kitchen bowls/ladles etc But that leaves a lot of possibilities out there!

The hobbyist angle pros:

- not that expensive! Mine cost $300.

- handy. Keyholder hooks, odd angle shelf brackets, fixing/upgrading kids toys, etc etc

- can send model elsewhere to be printed in fancy materials. See Shapeways.com

- can print models from others. See Thingiverse.com

Hobbyist cons: - time for 3D modelling. Unless you already know how to 3D model then this will take you time to learn. I see it as a "mindfulness" hobby, like knitting/crochet etc too.

I think to some extent it's a frame of mind thing. For instance, my friend's vacuum broke for some reason or another, some plastic piece that wasn't super complicated, but was required for functionality. And rather than buying a new one, he was able to model and print the piece that broke and the vacuum is able to work again, but mileage in general probably varies.

It depends what you mean by "production." There are many kinds of plastics. Common filaments like PETG do have production uses.

A 3D printed part is unlikely to be better quality than something you can buy, assuming you can buy it. There are also lots of limitations; for example, watertight prints are difficult and limited. Also, making something food safe might require a special coating, so it's probably not worth it. (I haven't tried.)

As a consumer, there isn't likely to be anything you need that you can't order online. However, if you want to make something new, with just the right dimensions, 3D printing can be very useful for many random parts you need. Also, you can make improvements to things you buy.

I use mine to 3d print parts and then cast them in metal. They make special resins for this process, works great. I can go from Sketch - Fusion - Slicer - 3d Print - Cast in about 18 hours depending on the part size (long time to print complicated / big parts). If you're interested look in my bio there is a link to my youtube - watch the "casting gold balls" video - it basically runs through the whole process (albeit without explanation).

Without going in to it - there is a massive range of plastics and non plastics of varying quality, expense, and accessibility.

Yes, 3d printing is a legit method for production. Typically if you can have a die made for it you will be better off in the long run with casting. Dies are incredibly expensive however.

Smaller runs or highly specialised and difficult geometries benefit from 3d printing.

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