Thanks Guy!
@rooiejoris could you have a look? 
Cheers,
Filemon
A Fairphone certified Hub told me that the print was way much better with 2 shells. What do you think about it ? Have some of you tried this option ?
I know this is an old thread, but nobody mentioned the solution, so:
Cooling with an additional fan like this Hanging mount for Ultimaker heatbed fan by hreese - Thingiverse helps a lot.
