Bear Extruder 35mm Fan Remix

thingiverse

Human: This remix of pekcitron's great bear extruder (thanks to providing fusion360 files, which taught me a lot) has been modified. The fan mount now holds a 35mm fan instead of the commonly used 40mm Noctua or Sunon fans, which were deemed oversized for the E3D hotend and lacking in strength, especially with the Noctua. Changes: 1. 35mm fan installed instead of 40mm (https://www.tme.eu/en/details/mf35100v1-g99-a/dc5v-fans/sunon/mf35100v1-1000u-g99/) 2. Fan moved 4.5mm closer to the hotend 3. Extruder cover reduced by 3mm (adapters printable for attaching fans and shrouds) 4. Included are 1x M3x14 and 2x M3x12 screws for mounting the fan The goal was to utilize a smaller fan with static pressure comparable to the Sunon MF40100V1-1000U-G99, positioned closer to the hotend, to achieve lower temperatures at the bottom of the heatbreak before filament enters the melting area. Many users have experienced issues with the stock MK3 setup due to Noctua's insufficient power, resulting in clogs. The Sunon 40mm replacement fixed this issue and I aimed to test how much better it could get. Static Pressure Comparison: Noctua MK3 Stock Fan - 1.78 [mm H2O] Sunon 40mm MF40100V1-1000U-G99 - 4.83 [mm H2O] Sunon 35mm MF35100V1-1000U-G99 - 5.59 [mm H2O] Test: A 100K NTC 3950 thermistor was inserted into a 50mm piece of 4mm OD and 2mm ID PTFE tube until about 2/3 of the thermistor's main body protruded from the end. The tube was then drilled to 3mm for approximately 2/3 of its total length to accommodate the thermistor, which was inserted into the hotend. This setup allowed for accurate temperature measurement at the critical zone beneath the heatsink. I ran this test with the Bear extruder using the stock covers v0.6.0, v0.7.0 (still in development), v0.7.0 with two different bear booster versions, and my 35mm remix. The extruder was heated to 260C, the bed to 80C, and placed in the center of the bed with a Z height at 10mm. After a 5-minute waiting period for temperature equilibrium, I took a minimum of 45 readings to determine the average temperature. Results from my setup indicate that the Sunon 40mm fan combined with the v0.7.0 dev version performed best among all 40mm fan combinations. The 35mm fan managed to lower this temperature even further by approximately 1 degree Celsius. This was my initial test of this remix and just the second run using this testing method. We are continually improving and simplifying the procedure. Results need to be confirmed and are specific to my setup and environment. Adapters have been included to help compensate for the thinner cover when attaching common print fans and shrouds. This is my first attempt at a design, and the air path likely still requires improvement. https://a360.co/2DHCh1B https://a360.co/2SRUlzI