This 2 piece fan duct can be used to limit/direct the direction from which air is sucked into the fans or blown out. Once the fan plate and fan duct are printed, they can be glued togehter. I used super glue, which works fine.
You could try printing the fan duct without support, but that will most likely result in ugly fillets. Therefore, I would suggest using 'supports from build plate only' function within your slicer.
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