Duplicator D9 fan duct II

thingiverse

After upgrading to a bondtech extruder on my Duplicator D9 (400 MK2), I observed an increase in heat-creep induced artifacts on my low-temp material prints. Expectedly, this was due to several factors hindering proper hotend-cooling on the machine: all-metal hotend replacement of the aluminum extruder block with a plastic extruder block printer in enclosure Following my semi-failed attempt at part-cooling fan modification (https://www.thingiverse.com/thing:4044949), I decided to abandon that approach and started shopping for an overpowered 24V radial fan. This is what I found: https://www.distrelec.at/de/radialluefter-dc-dc-51x15x51mm-24v-6m-rlf-35-ebmpapst-rlf35-14n/p/15421093 I am now able to use my hotend as a hair dryer, but the actual goal was to eliminate heat-creep entirely. Although this fan is pricey, it effectively achieves that goal. A cheaper and more silent option might be better in most cases since this one draws more current than the printers mainboards can supply. Selecting a fan with a power rating matching the original would spare you from tapping 24V directly from the PSU. Other downsides include an increased noise level (which isn't an issue since it's under a cover) and more weight (very close to the x-axis, so no big deal either). To prevent duct leaks and drafts over prints, I recommend lining the x-carriage with sponge rubber. In addition to the fan and duct, you will need some tape or foil to cover that big hole underneath the original fan. You can see it in one of my pictures as yellow foil. The fan is mounted by clipping it into the duct, and the duct is held in place by 2 screws already installed on the stock hotend. Use these and maybe some shims. That's it. Good luck. ~~Further plans: A slider to split airflow and use it for extruder motor cooling or part cooling would be nice. And maybe make an adapter for the fan to suck air from outside the print chamber.~~ edit: all done. Except for the part cooling part. Outside-adapter soon to be uploaded. editedit: Instead, I made a shovel-like thing that forces strong airflow from heatsinks outlet upwards. Without this, there's a chance of causing drafts on prints. editeditedit: There's this comically overpowered fan on my printer yet my extruder motor is getting too hot to touch under certain circumstances (enclosure closed, bed at 120°C, high volume flow); considering the original fan also provided some tiny amount of cooling to the e-motor, I can imagine the lack of such to cause problems with future prints. Therefore, I decide to pressure-relief my fan with air channels that just pass through the motor block. Additionally, I tweaked some clearances to minimize escaping air even further. These make installation harder - it looks like the holes don't fit but that's intentional, so you have to use some pressure against the backplate for mounting.