3D Printing Forum

Hi,

I am trying to understand the configuration of the fan(s) used in 3D printers. As I understand there can be 2 fans :

1. External cooling fan that is pointed towards the part that we are printing.
2. Extruder fan that helps cool the extruder drive mechanism,

Ramps 1.4 has D9 connector for a fan connection and M106 command turns ON this connector. Where do I have to connect the second fan ? Which gcode command deals with it ?

Though I do not know much, hope this in some information that has been collected will be of use to you.
Multiple fans are discussed here using D6 and D11 pins.

This works with a dual external Fan module and describes using 2 (PWM controllable) channels (D6/D11) .

Then incorporating them adding the code from How to configure Marlin to enable fans.
You can use this code or simply write your own using this as an example.

On my machine, the extruder fan is always on. Therefore, it was wired into the 12v (in my case) power input to the control board.

That is to say there is NO control over this fan. It is always on.