I found that PLA fan ducts kept melting against the lower aluminium heat sink. I needed a low profile holder for the fan duct that also kept the top of the hot end clear.
It works beautifully.
It also makes it very easy to mount fans on both sides of the hot end for dual extrusion support.
Print with support. 0.2mm layers.
Connect to fan duct with M3x10 capscrews.
Updated (Mk2) with a simplified design with thicker support arms. Mk1 was just too fragile.