Cover for Adding an 80 mm Noctua Fan to the MK4 Electronics Box

Active cooling of the xBuddy board on the MK4 inside an enclosure at higher temperatures
36
113
7
1467
updated May 8, 2024

Description

PDF

I had some problems with my MK4 crashing when I printed at high(er) temperatures in my Original Prusa Enclosure, see attached photos of the display screen shortly after the crash(es). I watched the temperatures of the board (accessible via Info > Sensor Info on the printer display) and saw that the temp for the xBuddy board reached well above 70 °C, especially when printing at high temperatures of the heated bed (100 - 110 °C). In the assembly instructions I saw that there are 3 thermopads between the board and the back of the electronics box which is right next to the heated bed. I concluded that there is a possibility for heat being conducted in the wrong direction, i.e. from the back wall of the case to the xBuddy board instead of away from the board. So I disassembled the board, removed the 3 thermopads from the underside of the board and filled the space between the back of the board and the back wall of the case with cork sheets. I had adhesive 1 mm cork sheets that I cut to size, for three sheets I made cutouts for the protrusions that were in contact with the thermopads before to get the cork flush. After that I added some other sheets with just cutouts for the screw holes up to the height of the thermopads (about 2 mm). I glued (with EC360 heat conductive glue) 5 Raspberry Pi heatsinks (about 7x7 mm, 6 mm high) onto the chips that had the heatpads on the other side of the board before. Those are the TMC2130 stepper drivers and the mosfet for the heated bed, see photo. Then I mounted the board back into the case. I had designed a cover for an 80 mm Noctua fan (12 V) that fits on the case and has enough clearance for the movement of the x-axis motor. With the fan running, the temperature for the xBuddy board stays well below 70 °C even during longer prints with ASA or PC filament, see screenshot from temperature tab in OctoPrint. Since installing the fan I never had a printer crash, an error screen or a fail in the middle of a print.

UPDATE 2024, April 10: Some have asked me in the comments how I am powering the fan. I have decided on a more permanent solution for this now. I use a string of 64 SK6812 LEDs to light the enclosure, which is powered by a 5V/3A phone charger and controlled via the OctoPrint plugin "WS281x LED Status". I have checked the power consumption on the Noctua fan and it needs around 0.7 W. I use a step-up converter to get 12V for the fan. For controlling it in OctoPrint I use the wiring schematic and components explained on the github page for the plugin I use.

UPDATE 2024, May 8: Added the requested recesses for the hex nuts used for attaching the fan to the cover. The updated files (.3mf, .step, and .f3d) have “v11” in the name. I have not printed the new version (yet), but I hope it works for you. :-)

Tags



Model origin

The author marked this model as their own original creation.

License