[philso]

In speaking with a number of teams while walking around the pit areas, it seems that they have less trouble with stuff falling in and shorting out the controllers if they are mounted on a vertical surface.

When you are first putting the robot together, you may want to cover up all the vents with tape.

Alternatively, use known bad controllers as "mechanical samples" to get the mounting holes marked and drilled (if you don't pre-drill the panels). Once you are confident that all the drilling is done, replace the mechanical samples with the real ones. Of course, you will want to mark the mechanical samples prominently. I have done this at work with the IGBT's at work when building up prototype inverters.