"Breeze": Auxiliary fan system for Voron 2.4

"Breeze" is a simple auxiliary fan system for the Voron 2.4 printer. You can mount up to four 5015 fans on the gantry (two on the left and two on the right).

This allows to increase part cooling capabilities, which is useful especially if you want to print with PLA or PETG at high speed inside an enclosure.

Hardware BOM

(Includes affiliate links)

• For each fan mount:
  • 2 x 18mm M3 SHCS to attach the mount to the Y carriage
  • 4 x M3 nylon lock nuts (https://amzn.to/45KZXOJ). If you don't have nylon lock nuts, you can instead use 2 regular nuts tightened against each other
  • 2 x 45mm M3 SHCS (https://amzn.to/3oH3mgW)
• To shim up the bed:
  • 4 x M4 thumb nuts (https://amzn.to/43oBop5)
  • 4 x 25mm M3 screws
  • 4 x M3 hammer nuts
  • See the "Bed shimming" section below for more details.
• 5015 fans (Up to four – Two per mount): https://amzn.to/3oK7YTt (Winsinn, cheap but not super powerful) or https://amzn.to/3qyDqUY (Delta, more powerful but more expensive), or any other brands.
• Recommended for wiring:
  • Solder connectors (https://amzn.to/3NdDh2k)
  • JST PH (https://amzn.to/42jr4xv) or JST XH (https://amzn.to/43r8swW) female connectors
  • JST PH (https://amzn.to/3MJba9O) or JST XH (https://amzn.to/43peyO9) male connectors as needed.

Printed parts

• Required:
  • Print the mount(s) you need depending on whether you want to mount fans on the left side, right side, or both.
• Recommended:
  • For the right version:
    • Official Voron 2.4 XY Joint Cable Bridge, either the 2-hole or 3-hole version based on your cable chain type. You might already have it installed on your printer.
    • Official A-drive cable cover
  • For the left version:
    • Official Voron 2.4 XY Joint Cable Bridge, either the 2-hole or 3-hole version based on your cable chain type. Print it mirrored on the X axis.
    • B-drive cable cover mod

Wiring

If you install 2 fans on one side, it's recommended to splice the wires in parallel so you can connect them to the same connector on your main board.

Here is how I've spliced mine using female JST PH connectors (https://amzn.to/42jr4xv) and solder connectors (https://amzn.to/3NdDh2k):

Channel the wires through the cable chain and use the appropriate cable covers (see "Printed parts" section above).

Bed shimming

IMPORTANT - PLEASE READ THIS

It's quite likely that the fans will extend down below the bottom panel of your printer. To give the fans more clearance, you'll likely have to shim your bed up by a few millimeters.

I've done it by adding 4 extra M4 thumb nuts (https://amzn.to/43oBop5) –one at each corner– to double up on my existing thumb nuts. I also used 4x25mm M3 screws and 4xM3 hammer nuts.

After shimming the bed up, you'll also probably want to increase the height of some other components like your Z endstop and nozzle scrubber, and then update some coordinates in macros that rely on a particular Z positions (e.g. nozzle scrub macro).

Mount installation

On the Voron 2.4's gantry, note that the XY Joint is attached to the MGN9 carriage with 4 screws. Remove the two screws on the inside (Here showing the left XY Joint):

Install the fan mount using 2 x M3 18mm SHCS. Keep the screws a bit loose at first, then swivel the mount back & forth and up & down as needed to make it point in the desired direction. The actual direction will depend on your bed size, hotend position, etc. Ten, tighten the screws to secure the mount in place.

Lastly, place one or two 5015 fans on the mount and secure them using two 45mm M3 SHCS and either one M3 nylon locknut per screw or two regular M3 hex nuts per screw.

Repeat the process on the other XY joint if you want to double the auxiliary fan system's power.

WARNING: Make sure that the mount and fans don't interfere with the X, Y & Z endstops and do not come into the path of other items around the bed and gantry (for example: bed clips, purge bucket, etc.).

Klipper settings

As a reference, here are the Klipper settings and macros that I'm using. You might have to make some adjustments to fit your own printer and workflow:

[fan_generic breeze_left]
pin: PD13
max_power: 1.0
kick_start_time: 0.5

[fan_generic breeze_right]
pin: PD14
max_power: 1.0
kick_start_time: 0.5

[gcode_macro BREEZE_ON]
gcode:
    M117 Turn on breeze
    {% set speed = params.SPEED|default(100)|float%}
    SET_FAN_SPEED FAN=breeze_left SPEED={speed/100}
    SET_FAN_SPEED FAN=breeze_right SPEED={speed/100}

[gcode_macro BREEZE_OFF]
gcode:
    M117 Turn off breeze
    SET_FAN_SPEED FAN=breeze_left SPEED=0
    SET_FAN_SPEED FAN=breeze_right SPEED=0

I also set BREEZE_OFF in my PRINT_END macro to turn off the fans at the end of a print.

Slicer settings

To control the fans from your slicer, add some custom GCode in the print's “before layer change” section. For example, in Prusa Slicer: Printer settings > Custom G-Code > Before Layer Change.

{if layer_num == 2 && filament_type[0] == "PLA"} BREEZE_ON SPEED= 70{endif}
{if layer_num == 4 && filament_type[0] == "PLA"} BREEZE_ON SPEED= 100{endif}

The above code turns the fans on for PLA at 70% speed on the 2nd layer and at 100% on the 4th layer. You can play around with those settings to figure out what works well for your prints and filaments.

Demo

To see it in action, check out this live demo:

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