This thing is a new take on my previous work making an extension duct to allow the very common dual extruder Active Cooling Fan from thruit00 (http://www.thingiverse.com/thing:537918) to work with the stock FFCP2016 (and other models) side blower fan (http://www.thingiverse.com/thing:1746693).

As I was working on fixing things I decided it might be nice in some cases to be able to control the air flow to the right or left extruder. I began playing with the idea of integrating a basic damper that would restrict air flow to one side or the other. This is the result.

It does not fully restrict airflow to the blocked side, but I would estimate that it is at least 70-80 occluded based on simple tests with a suspended thread.

Printing the duct can be a little bit of a pain, as some slicers want to bridge over very long distances. No supports were needed but could be used at the openings if required. I usually print it with a 180 rotation about Y.

I have only printed the back plate with the part that goes inside the duct on the build plate (-80 degree rotation about X in my case) with supports to allow the rectangular plate portion to be parallel to the heated bed. Other methods might work better.

Getting the actuating part to move can be a little bit of a pain. I used needle nose pliers and rocked it back and forth till it broke free and moved easily.

I have printed this at 0.1 mm, 20% infill with ABS.