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Comment by jansan | Hacker News Reader

Just to confirm that I understand this correctly, that clear case is really 3D printed? I don't follow 3D printing too closely, but I did not think that something like this would be possible.

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I've just been getting started with FDM printing since this summer, and after getting to know the limitations of my printer I'm even more amazed at the smoothness and resolution that some resin printers are getting. (I've even heard of people starting to print optical lenses[0], which I can hardly imagine.) You can really see the difference in resolution in the image with the different bottom shell!

0: https://www.cuddleburrito.com/blog/2015/10/13/3d-printing-vi...

> heard of people starting to print

That article is dated 2015! If they could do that seven years ago, what is state of the art now?

Note that the lenses do require extra work after the initial printing: "Finally, endless sanding and polishing created a clear-enough lens."

I would have assumed some post-processing would be necessary to create a polished surface, but what really blows me away is that it's possible to make the entire interior void-free and consistently dense to create a transparent lens with no air bubbles or interior pockets. I can't even do that molding resin by hand.

It's SLA resin printed by PCBWay.

https://www.pcbway.com/rapid-prototyping/3d-printing/plastic...

I did not think so either, although, SLA is the one method I'd guess, if I had to, just going by the main picture. SLA is indeed the process they used, but what really surprised me was that it's offered as a 3D printing service from JLPCB and PCBWay.

Yeah this is definitely an SLA print. SLA is capable of amazing quality with respect to both dimensional tolerances and overall appearance of finished product.

I've been on the fence about getting one. This post might be the thing that pushes me over the edge.

HN readers: what SLA printers do you recommend?

I have an SLA printer (Prusa SL1) and rarely use it

Unless you get an industrial printer, dimensional accuracy gets messy with SLA. Slicers can try and compensate, but you end up having to work around warping

For organic shapes like figures I'm sure it's great, but as someone who prints functional items 99% of the time I'd rather tune an FDM printer than fight with my messy SLA machine

Good to know. How bad exactly would you say accuracy is? Are we talking about a few hundreds of micrometers or a millimeter or more?

Tenths of a millimeter not much worse than FDM in vacuum... the problem is those tenths vary based on shape (even more than with FDM), and can be non-uniform across a surface (flat surfaces tend to end up warped pretty easily)

We had a form labs printer at work and while the resolution was great, it was very messy to deal with, parts were brittle, curing took a long time, support structure was annoying to remove (and very time consuming to remove traces of), and over weeks or months most parts with any significant feature longer in one dimension warped. I don’t think anyone used it once as soon as we got an FDM printer.

> and over weeks or months most parts with any significant feature longer in one dimension warped

That's alarming. How bad are we talking about, like millimeters or fractions thereof?

I really, really like the appearance of the case from TFA and would love to build similar enclosures for my projects, but if that comes at the expense of noticeable long term dimensional instability, no thanks.

In a 10cm part, could get someone 3mm of warping perpendicular to the longest dimension. Admittedly, this can be mitigated by adding ribs and being careful about curing, but between this, messiness and brittleness, it was just fussy compared to FDM printing.

This was already five years ago so I wouldn’t discount the technology altogether, I would just check for the printer and material you’re interested in.

I have an Epax 3D and I've been pretty satisfied with it, although it does have a pretty small build area.

I don't get how they got it so clear and without support marks.

Did some searching because I was impressed with the quality as well, and I think they may technically be using polyjet instead of SLA.

Some people have talked about SLA. We have a Project MJP at work (https://www.3dsystems.com/3d-printers/plastic). It uses UV cured resins for its printing, it also prints in wax for the support structures, so you can just melt them away with an oil bath afterwards.

The quality of the results is excellent - you can print some really fine detailed parts. The downside is cost (print and the materials) and the fact that the materials involved are pretty nasty - they come with some major warnings about causing infertility and cancer just for coming into contact.

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