Anelok: next round of case parts 1/2: fixing issues

Werner Almesberger werner at
Wed Jan 21 13:32:07 UTC 2015

First, let's quickly review the problems of the first case. I've named
it for the CNC run number, #2 (#1 would be the MDF predecessor).

1) The wall around the PCB should be 0.8 mm but looked more like 0.5 mm.

   Measurements confirmed this. Strangely, the CAD model had it at 0.8
   mm. This turned out to be a bug in the new slicer: when flipping a
   part, I reversed the Z coordinates of all the vertical facets but had
   forgotten to also reverse the Z coordinates of the horizontal facets.
   It's rather surprising that the result still looked almost right ...

2) The thick base of the right-hand rondel (the rounded rectangle
   keeping OLED and the PCBs in place) didn't support the PCB.

   This was a genuine error in the model. Easily fixed.

3) The hole for the USB receptacle was off-center.

   This turned out to be me mistaking Python for Perl. Python copied C's
   handling of division and integers. So 3 / 2 is 1, not 1.5.

4) The large silo capacitor almost didn't make it into the capacitor

   This was caused by the differences between 2014 and 2015 boards: in
   the 2015 board the edges are 0.5 mm further out, but most of the
   components are at the same place. I took the measurements from the
   2015 layout but my board is from 2014. The model now adjusts the
   capacitor position accordingly.

5) Rim did not let the sub-board enter.

   As already discussed, I had simply forgotten about this.

I also thought of adding a little cylinder to act as light pipe for the
LED, but rejected the idea when I saw that this cylinder would protrude
a mere 0.2 mm from the bezel in that area. Something will have to be
done to that area to leave a small window through which the LED can
shine, but perhaps extending the rim a bit and then making a hole would
be better.

- Werner

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