Anelok: next round of case parts 2/2: parts galore

Werner Almesberger werner at
Wed Jan 21 16:08:54 UTC 2015

With all the model fixing done, it was time to spin the mill again.
This is what came out:

Run #3:

Well, that didn't go too well. The mill almost completely ground away
the ceiling of the case. This was caused by the table of my mill
flexing in the Z direction and me pushing it down a bit too firmly when
setting up the tool position, so it came up by almost 1 mm while

Not much to be done here. But what survived of the part looks good.

Run #4:

This is the other extreme: about 1 mm of extra material were left at
the bottom. I had to use hammer and chisel to get this one out of the
acrylic block.

Was that me over-compensating for my previous mistake ? The inner
structure provides a first hint:

These islands around the rondels and at the window shouldn't be there.
Except for the (tall) bezel elements, the ceiling should be completely
flat. I eventually found that the laptop controlling the mill had lost
network connectivity and thus didn't finish the job. There's a first
time for everything ...

My milling process now makes a local copy of all files involved and
then runs from that copy. Time for another try.

Run #5:

Perseverance finally paid off. This one is almost perfect. There are
some thin pieces of acrylic left at the top but they can be easily
sanded off. They are there because my toolpath didn't include a slight
overshoot at the bottom layer, to make sure the cut goes completely
through the workpiece.

There's still one thing missing, though.

Run #6:

Yup, the bottom shell. This one went so smoothly it was almost
boring ;-)

Now, putting it all together, we get:

Everything is at its place - and the OLED will fit even better once
I remove the protective cover with the green tab on the side :)

Looking good as well, but the battery connector seems to touch the
floor. It shouldn't do that. Hmm ...

Now, there are still issues: USB hits the floor, preventing the case
from fully closing, and the battery connector may indeed be doing
something similar on its side.

Measuring the case thickness showed that it's about 1 mm too thin. This
is something that happens quite often, as a consequence of my mill's
imprecise table height. The battery connector has a nominal clearance
of 0.5 mm and the bottom of the USB receptacle has only 0.2-0.3 mm, so
if 1 mm is missing, it's no surprise that things won't close.

Maybe I'll just make a bottom part that's 1 mm "too deep", to compensate
for these problems.

Last but not least, the switch. This is exactly how the design says it
should be. But the knob is almost impossible to reach, especially on my
2014 board where the switch is recessed by 0.5 mm. Not a concern for
now, though.

So, the case design looks good now, and only some detail issues and
equipment limitations remain.

- Werner

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