Whole-layer cooling system for Ender 3 & other bedslingers

thingiverse

The parts provided here are part of a cooling setup for high-speed printing on Ender 3 and other bed-slinger type printers with an X gantry that moves up with Z. The basic concept is using two 80 mm fans to move cool air across the entirety of the latest layer, since the toolhead is expected to be moving so fast that any fans mounted on the toolhead will not stay in one place long enough to completely tool the extruded material. On CoreXY machines and other printers where the toolhead stays at fixed height and the bed moves down, there's a standard solution to this problem: fixed-position side fans with ductwork to pass a sheet of cool, fast-moving air across the layer just below the nozzle. However, on a printer where the nozzle moves up with Z, the fans need to move up with it, or be so large as to cover the entire print volume (e.g. large mains-powered box fans). My approach to the problem is mounting the fans off the back of the 2020 gantry extrusion (the only side of it where they're non-interfering with the X carriage or other things) and tethering the top to the extruder mount so that it can't sag. The first iteration on this idea had the fans actually mounted just to the E-motor bracket, pointed down 15°, with no duct. This worked fairly well, but wasted a lot of the capacity by failing to direct the air flow well at all. My second iteration was modeled on the side fans I'd seen on high-performance CoreXY printers, as a duct focusing the air at just the height it's needed at. This turned out to restrict the flow too much for my fans, which could not deal with an increase in pressure. It might work well with much more powerful fans, however, so it's worth revisiting. My third iteration replaced the duct with just a hood to direct the airflow downward and forward but without any hard restrictions. It seems to perform very well, but could use some further tuning of mounting angle and other details. This thing is posted as a WIP, with the iterative designs posted in case they're useful. So far only the third iteration is up.