
Some 3D Printed Objects Are Toxic to Fish - thealexknapp
http://www.forbes.com/sites/carmendrahl/2015/11/18/some-3d-printed-objects-are-toxic-to-fish/
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brianzelip
Holy smokes Forbes provides a painful reading experience.

Here's a post about the same study from the American Chemical Society --
[http://cen.acs.org/articles/93/web/2015/11/3-D-Printed-
Parts...](http://cen.acs.org/articles/93/web/2015/11/3-D-Printed-Parts-
Leach.html)

tl;dr, the study found the stereolithography printing[0] method to be harmful,
and less so for fused deposition modeling[1].

Many of the 3d printers you'll find around community-level makerspaces employ
fused deposition modeling (those that melt plastic filament, as opposed to
those that use liquid plastic).

[0]
[http://www.livescience.com/38190-stereolithography.html](http://www.livescience.com/38190-stereolithography.html)
[1]
[https://en.wikipedia.org/wiki/Fused_deposition_modeling](https://en.wikipedia.org/wiki/Fused_deposition_modeling)

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kazinator
While reading, it immediately occured to me: perhaps the problem can be
mitigated in the stereolithography process by exposing the object to
additional light for a fuller cure?

Then, lo and behold, there is a paragraph about this obvious step. Then, at
the end of the paragraph: _[t]he UC Riverside Office of Technology
Commercialization has filed a patent on this technology._

Please tell me this doesn't refer to the _painfully obvious_ idea of more
fully curing the finished object by shining additional UV, like is done with
tooth fillings and nail polish, not to mention entire pieces of furniture.

~~~
DanAndersen
As much as I dislike how the patent system can stifle innovation, I'd like to
point out that the fact that this step seemed obvious as you were reading the
article is not, in itself, evidence that that step is inherently obvious.

When writing academic papers that involve some new insight (in my field, it's
computer graphics), a recommended way of writing the paper is such that, by
virtue of how you describe the problem and the current shortcomings of the
state of the art, the reader should almost be able to guess what your solution
is by the time you actually reveal your own insight. If a description of a new
method is well-written, then by the end it may feel like an obvious thing to
the reader.

So, sentences like:

> Grover, Oskui, and their coworkers think that the reason stereolithography
> proved more toxic was that the 3D printed parts were leaching leftover
> building blocks that didn’t fully cure.

might be a description that hides additional background work.

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snoonan
To clarify the title, the findings are related to liquid resin-based methods
vs. the much more common FDM method (usually extruded plastic filament)
method.

The latter is usually ABS or PLA plastic, both of which are as theoretically
safe as any other plastic in your home. PLA is a bioplastic and is actually
compostable.

The resins, on the other hand, are pretty nasty and require gloves to work
with. The safety data sheets are pretty serious and even mention that they are
dangerous to aquatic life.

~~~
kazinator
For that matter, solid-based 3D printing can even use sugar, and make edible
products.

Clickbait headline: "3D printed items contribute to obesity!". :)

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MechSkep
There was no difference between the control experiment and fish exposed to
parts made with FDM.

Read the article to see how FDM could become toxic/harmful, turns out it
didn't.

