2 in 1 fan duct with seperate lower nozzle

thingiverse

Acknowledgment for rvjm21 and Ug1y for giving me an advanced starting point on this, as I realized I didn't need to start from first principles and could build on their designs. I found the original worked well but the lower duct was too close to the bed and knocked the model plus it would allow correct first layer clearance. When I saw the modified version, I thought it would be just what I needed. I saw things I wanted to change though - such as the opening at the bottom of the main duct so the fan area was totally covered by the duct. Some shaping to smooth the flow. Adjusting the lower nozzle to clear the bed and the heater block, and a wider spread of air over the model. I have since modified my design to incorporate a cone to help remove eddy currents behind the fan. I haven't printed the latest version yet. I've posted both models - the cone one hasn't been made yet; the other has and is working quite well. Modified nozzle by adding a rib because the top surface sagged after printing with the fan off. Redesigned the nozzle for a wider spread of air flow over the model, and lowered it a little more away from the heating block to lessen the effect of radiated heat. I also produced it in PLA, so it will be interesting to see how it survives. The PETG version softened and sagged a little at its closest point to the heating block.