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Anelok: ABS meets acetone, part 1

Werner Almesberger werner at almesberger.net
Sun Feb 12 03:51:10 UTC 2017

paul at kristianpaul.org wrote:
> Could try to add more slices and thinner layers to your  builds?

I did try that, but only with PLA so far, not ABS. Here are a few
side-by-side comparisons. The cases on the left were printed with
a layer thickness of 50 um, the ones on the right with 100 um.


One can see that the steps on the top of the side wall are smoother
with 50 um. The side looks smoother, too, if somewhat chaotic, but
that's hardly noticeable when handling the device.

Both have the problem of unwanted deposits at the edges of the
curved surfaces. In Cura there's an experimental feature called
"coasting" that may help.

The large bottom plate of the 100 um case has some patterns after
the screws. These were caused by me not making the piece lay flat
on the table (or, rather, Cura not doing as it was told, and me
not checking - trust is good but control yields better prints) and
are not related to the resolution.

Speaking of chaotic, this is what happens with a flat surface held
by support (this is a work-in-progress part, so the geometry is a
bit confusing):


100 um actually looks tidier. 50 um also produces "noise" at
strange place, e.g., inside the battery contact area.

That the flat surface after the side wall is very smooth at 50 um,
but has a diagonal pattern at 100 um, is caused by imperfect build
plate calibration (these prints were made without a raft). Again,
not related to the resolution.

A last one:


Here, the 100 um side feels much smoother than the 50 um side.
Also the curvature looks smoother.

So I think there's no clear winner here. 50 um improves some
details, but many aren't really noticeable in real life. And it
trades some problems for others. I still have to do some more
testing with ABS, though.

My printing time for all the case parts is currently about 4.5
hours at 100 um, and about 11 hours at 50 um.

> (0.3mm nozzle etc..)

Might be worth a try. Some problems seem to be caused by insufficient
flow, especially "under-printed" layers. So these may get worse. But
having more lines may help elsewhere.

By the way, all the design files are in the directory alt13/ of

If you still have a 3D printer, you could give it a try yourself ;)

The most important parts:

- an-top.slvs is the main structure (top surface, side walls,
  battery compartment with contact pockets)

- an-mid.slvs is a middle part that goes between PCB and the bottom
  cover. It also has two "shoulders" that cover the battery cables,
  though that may be a misfeature, given that they turned out to be
  fairly fragile.

- an-bot.slvs is the bottom cover

- an-but.slvs are the buttons

To use these files, you need SolveSpace:

- Werner

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