Hotend Fan Blows on Printed Part

[mikedkelly]

The hotend assembly on the Stealthburner for the Phaetus Rapido 2.0 causes air from the hotend fan to blow on the printed part. When I print tall single-wall parts with sparse infill using ASA, I need cooling to be 0% or else the walls will warp. The leakage is due to the rib that wraps around the hotend on the rear half of the assembly being raised 1cm to accommodate the routing of the thermistor wire. Fan air blows through the cooling fins of the hotend below that rib and gets deflected downward instead of sideways through the exhaust ports. I am trying to figure out a way to deflect that air, but a redesign of that rear part would be ideal.

 

[mikedkelly]

The hotend assembly on the Stealthburner for the Phaetus Rapido 2.0 causes air from the hotend fan to blow on the printed part. When I print tall single-wall parts with sparse infill using ASA, I need cooling to be 0% or else the walls will warp. The leakage is due to the rib that wraps around the hotend on the rear half of the assembly being raised 1cm to accommodate the routing of the thermistor wire. Fan air blows through the cooling fins of the hotend below that rib and gets deflected downward instead of sideways through the exhaust ports. I am trying to figure out a way to deflect that air, but a redesign of that rear part would be ideal.

I was able to make the changes from the original CAD files. I'll give them a test and post them if they work well.

 

[mikedkelly]

Are the holes that bleed air from the hotend fan into the part cooling ducts critical for nozzle cooling? I removed them, but don't want to risk thermal runaway or heat creep. I will re-calibrate the PID for the nozzle and then keep an eye on temps. I can always add them back if needed.