2014-12-17: The openings can be adjusted now, I prefer to have a thin shield.
This is a re-work of my initial electronic mount for the K250 from Ultibots.
The original one by ultibots is well designed but stabs into the stand of the K250 not leaving room for other mounts.
The picture shows an earlier version, the uploaded is slightly wider so the distance between the RAMPS and the fan is bigger.
RUMBA version available as thing 597188
Check the G-code that it is complete till the top of the print. setting $fn to high values increases the size of the STL file till slic3r can't slice it anymore.