Layer fan/parts cooler/blower working examples

[TwiHul]

Sorry to ask about something that’s so common but I’m having problems with something that everyone else seems to be finding easy. The search function in this forum isn’t helping me search for this either.

I want to set up a parts cooling fan but I’m having no luck. Earlier I was using Marlin 1 but had to change to Marlin 2 to get 3D Touch working. I’ve done a lot of fiddling so I’m going to dump this all out in bulletpoints.

Using Marlin 1 (can’t use with 3D Touch):

• Two different 2 pin fans only worked at full speed
  One 3 pin fan worked properly (can’t use because it’s noisy and vibrates)
  Everyone else seems to get 2 pin fans working that they can control

Then I upgraded to Marlin 2:

• 2 pin fans don’t work at all
  Multimeter shows it at constant 12 volts when turned on
  Shows negative 12 volts when turned off (like it just flipped the polarity)

I’m connecting to the positive and common on the PWM pins on a GT2560 board. Any help is appreciated.

What I’d mostly like to ask though, does anyone have an example of end to end setting this up? Most examples on the internet just don’t do it in detail, mostly they just cover printing the brackets for the nozzle. I need to know about wiring and firmware changes.

[William]

Hi, the cooling fan is always on when the printer is turned on.
What can be controlled is the blower on the outer end of the extruder,
which will be turned on after the printer starts printing a few layers.

[TwiHul]

Yeah, that’s the one I’m talking about. But as I’ve said, it isn’t working how other people seem to describe it. I’m not even sure if have the correct type of fan. I wouldn’t typically say a 2 pin fan can be speed controlled but everyone talks like it can be. When I search PWM on 40mm fans they almost all come back as 2 pin.

[quinbot]

I'm very interested where this thread goes as I am also trying to add a layer fan to my ProW. Stock firmware. Haven't tried much as I've just bought the fan (Noctua) but so far it just stays on constantly.

[Martin-UK]

Hi. Did anyone get anywhere with this? I am also trying to control the extruder head fan from the PWM socket. There is code in the Marlin for turning a the fan on and off but there is no reference to which fan it might be. I assume the PWM???

[William]

Hi. Did anyone get anywhere with this? I am also trying to control the extruder head fan from the PWM socket. There is code in the Marlin for turning a the fan on and off but there is no reference to which fan it might be. I assume the PWM???

Hi, pwm can be controlled by slicing software or screen,
The other fans are always on when the printer is turned on.
to cool.

[Martin-UK]

Thanks for the reply. I have a 5V PWM fan connected to the PWM socket on the main board. Plus I have the code "M106 S255" in the Marlin code. But the fan does not switch on. I noticed that the 3 pin PWM socket has a + - connected but the yellow tacho wire goes no where. That is the same for all the fan sockets. Looking at the schematic for the GT2560 I can see the PWM is controlled by a MOS Fet and this is driven by the CPU. Do I need a firmware update so the CPU can recognise the Marlin code? I am using Cura_SteamEngine 4.5.0 to generate the G code.

[Martin-UK]

Hi. Could you please answer the question in my comments?

Regards

Martin-UK

[quinbot]

I have a 5V PWM fan connected to the PWM socket on the main board. Plus I have the code "M106 S255" in the Marlin code. But the fan does not switch on.

Bit late but just following up for future searchers, I added this Noctua 3-pin fan and it does work with my stock i3 Pro W. I only bought the Noctua because the stock board cooling fan was so noisy but it turns out that's because of the fan mount. I added stand-offs between the fan and the frame and now it's much quieter. I'm sure I could have used any 3-wire fan for the layer cooling.