The heatsink is not a good fit under the Archim, you can see the board bow as the fasteners are tightened.
@tutley I don't know how much is to be considered normal, but you can visibly see the bow looking against the power supply and hear the board bowing as the fasteners are tightened. Seems excessive to me.
One measurement taken near each of the bottom fasteners for the Archim from top of power supply to PCB: 28.75/28.86mm
One measurement taken from top of the PSU to the PCB behind the Z-motor connectors: 27.75
After looking at @logan 's machine, it does seem that the bow on the archim is a bit excessive. There is some concern because once the drivers heat up this will potentially bow worse due to thermal expansion.
The heatsinks we are using on alphas are slightly thicker than the ones that were milled for the prototypes. I believe the prototype heatsinks were 9mm tall. The drawing was changed to use standard bar stock at 9.53mm tall. The piece i measured that logan had was closer to 9.75mm tall. Which is still in spec according to the drawing.
Install of all 20 milled heat sinks went smooth, a slight bit of compression but not bowing the archim that I could see.
All of the archims that were previously installed with heat sinks that were too large have been marked with a "B" on the USB housing.
The fix is merged into master now.
$ git diff master --name-only production_parts/machined_parts/board_heatsink/Archim_board_heatsink.fcstd production_parts/machined_parts/board_heatsink/Archim_board_heatsink.pdf production_parts/machined_parts/board_heatsink/Archim_board_heatsink.step