ALPHA RELEASE - Dual Fan Mod for Mk4 for Faster PLA Printing

DISCLAIMER:

This is a very early release of this model and is intended for experienced users only until further development has been completed. Many quality-of-life features are lacking, and this should be seen as an early prototype rather than a completed model.

Instructions:

Printing:

Print out of a temperature resistant material with a 0.4 nozzle. The Hotend Mount can be printed with 0.2mm layers, but it is critical to print the Duct Assembly with 0.15mm layers to ensure the topmost overhangs come out properly. If you are having issues with this area, feel free to add supports. Print orientation is shown in the picture below.

Installation:

For installation, you will need the following hardware:

• 9x M3x8mm Socket Head Screws
• 2x Mk4 Part Cooling Fans

After printing both the Hotend Mount and Duct Assembly, splice in a second fan by soldering in the red and black wires from the two fans. The yellow wire should not be spliced as only one fan should be reporting its RPM to the loveboard. I HIGHLY recommend having two new fans to do this with so you can fall back on your existing fan if there are issues.

Remove all wires from the clip on the side of the fan housing and run them directly from the back of the fan as shown below.

After turning off the printer, remove the existing fan door by removing the screw on the hinge and unplugging the fan.

Once removed, take off the hotend fan by removing the two screws holding it to the heatblock to prepare to attach the Hotend Mount. Keep the two screws as we will be using them shortly.

Slide the Hotend Mount onto the right side of the hotend fan, allowing the locking claw to slide into the matching cutouts in the hotend fan.

Reuse the two hotend fan screws to secure the hotend fan along with the Hotend Mount to the heatblock. A hole in the bottom of the Hotend Mount is provided to get an Allen wrench through to secure the bottom screw.

Once fully secured, place the fans on the left and right sides of the Hotend Mount and secure with three M3x8 screws. The holes on the fans are 2.85mm, so there may be resistance getting them through the first time. I recommend running the screws all the way through the fan holes before mounting the fans and turning the screw until it spins more freely to make tightening it to the Hotend Mount easier. Route the wires to avoid the hotend fan intake as best as possible.

Once the fans are connected, attach the fan duct and secure with the middle M3x8 screw and tighten down before staring the two screws on each side. Ensure the screw holes on each side remain aligned as you tighten. Once tightened, secure the sides of the duct with two more M3x8 screws.

Plug in the fan cable and turn on the printer. To test, run the print fan via the LCD and verify both fans are spinning.

Notes:

After installing, your heatbed temp may need to be increased by 5 or 10 degrees to compensate for the fans cooling it down.

From my limited testing, PLA works just fine with both fans running at 100%, but you may want to increase your minimum layer time to prevent the model from getting over cooled on short layers.

The input shaper will be slightly off after installing this. Recalibration for just the X axis can be done by following the Klipper documentation, but changing to the EI shaper instead of the MZV shaper might also work. I have not done too much work into this yet.

Future Roadmap (In no particular order and subject to change):

• Add cable organization channels to the back of the Hotend Mount to route cables better
• Make a jig to hold the hotend fans and wires to make splicing easier
• Redesign the Hotend Mount to allow the fans and duct to be removable and installable via magnets similar to how the BambuLab print head functions