Aux Fan

Contents:

• LH Stinger - Aux Fan module
• BOM
• Assembly
• Wiring and Configuration
  • Macros
  • Slicer

LH Stinger - Aux Fan module

Useful links:

• Aux Fan - Online CAD Viewer
• CAD
• STL
• Klipper Configuration

BOM

The following parts are required for the complete assembly of two auxiliary fans:

Type	Item	Quantity
Fans	9733 Blower fans (LH Stinger BOM)	2
Springs	Springs from a Ballpoint Pen	2
Heat Inserts	M3 5x4	5
T-Nut	Drop-in 2020	4
Hex Nut	M3	4
Washers	M3	8
Screw Button Head	M3 12mm	4
Screw Cap Head	M3 12mm	5
Screw Cap Head	M3 45mm	4

Assembly

• Add the heat inserts to the following locations
• The 3rd insert is required only on the left parts, and it is used to join both modules together

• Glue both parts together by using three filament strands to align the parts together
• Cut the filament strands flush when the glue has dried

1. Add threadlocker to the screws holding the flaps.
   • Insert the flaps and secure them with the button head screw and a washer on each side.
   • Make sure that the screws are not tightened all the way and the flaps will be able to pivot freely. The screws just form a pivot point for the flaps.
2. Take the spring out of a ballpoint pen and cut/shape it into form so it attaches to the mounting points.
   • Only one spring is required per module. Attach them to the other sides to have access for servicing

• Join both modules together

• Insert the blower fans into the modules lock them using the long cap head screws and the back plate

• Secure the Aux Cooling assembly to the X gantry

Wiring and Configuration

• Splice the fan wires in parallel and connect them to a fan MOSFET.
  • If the total amperage required exceeds 2A, connect them to a spare hotend MOSFET instead (splicing them might be a bad idea in this case).

• The Aux fan is by default configured as [fan_generic aux] in printer.cfg and set to pin: PD12.
• To enable it, set variable_has_aux_fan: True in mymacros.cfg

For more information please consult the LH Stinger configuration files

• By default, the Aux fan is configured act in linked mode with the Part fan.

The following options can be changed in mymacros.cfg:

variable_has_aux_fan: False    # Aux fan has to be defined as [fan_generic aux] in printer.cfg. Check example config.  
variable_link_aux: True  # Linking Aux fan speeds with Part fan
variable_aux_ratio: 1  # Ratio between Part fan and Aux when linked. 0.75 equals 75% of the Part fan speed

Macros

The MAX_FAN dropdown contains a extensive links of controls that can override the slicer set fan speeds during printing.

Controls:

• MAX_FAN (0-100%) caps the fan speed to the maximum percentage set
• FAN_MULTIPLIER (0.0 .. 1.0 .. n) multiplies the slicers set fan speed by a factor.
• MANUAL_FAN/AUX takes total control over the fan speeds, and has the following behavior:
  • -1 disables the manual fan control
  • 0 turns fan off
  • 1-100% manual fan speed
  • LINK_AUX (0/1) links the Aux fan speeds to the Part fan
  • AUX_RATIO when linked, it sets the ratio between the Part fan and Aux fan. 0.5 equals 50% of the Part fan speed

Slicer

To control the Aux fan independently and set its speed directly from the slicer's filament profile, add the following section to the filament start G-code:

MAX_FAN LINK_AUX=0