Creality Ender 3 S1 Sprite/Pro Extruder Part Cooling Fan Duct

Disclaimer: Due to duct tips having close vicinity to the nozzle, use at your own risk of failed print depositing globs covering/melting the ducts.

Low-profile part-cooling duct for stock Creality Sprite Sprite-Pro extruder 40x40 part cooling fan. Original duct is simple, low-restriction and hence high volume/efficiency. However, also because of its simplicity, it doesn't aim flow near the nozzle, let alone the backside of it. It's especially bad for PETG where you don't want draft on printed layers or they'll curl, which can be prevented with stock duct by reducing fan percentage but on the flip side won't give enough cooling on the freshly laid out part.

My goal in designing this duct is to aim at the shortcomings of the stock duct while maintaining (and even increase) clearance to printed part, minimizing added visibility obstruction to the nozzle and printing progress, all the while focusing airflow towards the nozzle from slightly above and around. This is WIP (work-in-progress) as I always want to direct more airflow to the back but in fear of reducing efficiency and overall flow. I might eventually upgrade to 5015 blower which I already have in hand, but I don't want the extra weight and I want to see how far I can push the stock blower.

I use this overhang challenge (https://fullcontrol.xyz/#/models/b70938) to stress-test cooling efficiency and direction all around print (see picture of purple tower printed with PLA with 95 degrees of overhang). So far results seem to suggest not any less overall cooling than stock duct but more even around the print. In addition, I don't need to turn down part cooling for PETG in fear of curling because this duct directs air away from where it might curl to where it needs most cooling.

Designed with DesignSpark Mechanical v5. Please print with opening-end facing bed (like most fan ducts should). No support required. Comments welcome for suggestion as this is WIP.

2022-10-26: Uploaded version 2.0. Side ducts don't reach in to nozzle as close to avoid being melted according some reported. Front duct reaches in further for better front cooling. Side duct arms span farther apart to enhance viewing of the nozzle in operation from the side.

2023-01-17: Uploaded version 3.0. Thinner side ducts outlet to get further below heatblock silicon sock while reaching close to nozzle as much as possible without being melted. Better shaped side ducts to maintain as much flow until the newly designed flat-nozzle output to increase speed/direction of air flow towards nozzle. New side duct profiles also reduce overhang angles when printed with orientation such that input opening sits on the bed (no support required).

2023-03-27: Uploaded version 3.1. Thicker inner walls on the side ducts to prevent generating gcode in area with only single (0.4mm) wall thickness.

2023-04-04: Uploaded version 3.2. Increased bottom and right side walls to reduce leak and guide air flow into right side duct inlet at a smoother angle. Unlike 5015 blower, the 4010 blower housing is not optimized for air flow path, resulting in pressure build-up on the right side inlet and in worst case back flow. A workaround for those experiencing back-flow could try tape up bottom-half of the fan inlet. It may seem like it would impede air inlet flow but back-flow is negative in-flow so taping up the bottom-half in such case actually helps increase in-flow AND forces more air out of the ducts.

2023-04-07: Uploaded version 4.0 Total rework of the ducts and inlets to maximize flow and reduce restrictions by enlarging outlet “nozzles” and inside passages while keeping good wall thickness and limit the increase in outside dimensions.

2023-04-26: Uploaded version 4.1 with enlarged outlets to further reduce back pressure. Also revised enter duct to raise and retreat outlet a bit while angling the duct to direct output more downwards. Remember you can try taping down bottom half of the fan inlet like I do in the picture to force a little bit more ram air through to the outlet than to back flow.

2023-05-23: Uploaded version 4.2 with even more widened outlets and further retreated center outlet to further reduce back pressure. Also uploaded a version without internal leak-guard in respond to a report suggesting it's causing some rare issue.