Geeetech A20 Hotend Fan Duct

thingiverse

I recently wanted to upgrade my A20M to a single nozzle printer, eliminating the right angle turns built into the mixing hotend. The design should work for both A10/A20 and A10M/A20M models, but you'll have to confirm that for me. To start, I upgraded the hotend cooling fans to 40x40x20mm (24V) versions available on Amazon. I also swapped out the part cooling blower with a 50x15mm (24V) blower from the same online retailer. The left side fan needed some creative problem-solving to avoid hitting the X-servo and limit switch when the carriage reached its maximum extension. To resolve this issue, I designed a custom fixture that allowed me to move the fan out of the way. I also created a part cooling blower duct with a built-in BL Touch mount that fits seamlessly into place. The entire assembly is held together using M3 cap head screws and locknuts. The installation process began by mounting the left side components first, using two 12mm screws and locknuts to secure it in place. Next, I attached the left side fan to its mount, threading two 25mm screws into undersized holes with the sticker facing outward for aesthetic purposes. For the right side fan, I used two 20mm screws to attach it directly to the cage, making sure the label on the fan was facing inward. The blower mounted onto the blower duct using a single 25mm screw and locknut, while the BL Touch sensor attached via two 8mm screws and locknuts. The final step involved attaching the blower to the hotend cage using three 8mm M2 screws that previously held the original front-mounted cooling fan in place. To complete the setup, I routed the BL touch wires underneath a clip on top of the left side mount. If you want to update the location of your BL Touch Sensor relative to the nozzle in your Config.h file, follow these steps: Search for X_PROBE_OFFSET_FROM_EXTRUDER in config.h and adjust the values according to my measurements: dX = -26.5mm, dY = -42.3mm. Alternatively, you can adjust the z offset based on your measured mounting or simply tweak it in the controls menu until you achieve a good first layer. The SolidWorks files for this upgrade are included in a .zip file if you want to refine the design further. Be sure to check the fan wire connectors and replace them as needed to ensure compatibility with your specific components.