Since I plan on keeping the SKR Pro in an enclosure, I guess I should cool everything inside with one or two small fans, or do you deem this totally unnecessary?
Should I buy a dedicated fan controller and power everything with my power supply? I would have to get an additional 24V to 12V regulator, because of my power supply (24V 15A).
Or can I directly plug them into the SKR Pro and maybe activate them automatically, when I switch the mpcnc on, or preferably when Gcode is run (with a Gcode command)?
Does somebody have some experience with this?
I haven’t bought any fans yet, so suggestions are welcome.
24V fans are fine. My printers, and Primo are all 24V, so I just use 24V fans instead.
You could use a fan controller, but probably just ventilating the enclosure is plenty good enough. I would not want to leave the board enclosed with no ventilation myself. It isn’t as much power dissipated as it would be running heaters, but the motor current is relatively high, so the drivers should be cooled, or at least have the heatsinks exposed.
I’m planning on mounting the SKR Pro upside down, under the torsion box table of my mpcnc, but inside an electrical box. The bottom side of the table is open.
Since warm air rises, I fear that the heat from the stepper drivers and SKR Pro would be trapped locally around these components, since everything is flipped.
I thus plan to have at least one fan sucking air laterally into the enclosure, blowing it across, and maybe another sucking it out on the other side; cross-ventillation so to speak. Does that make sense?
Do you think the fan controller would be a better idea than controlling the fans with the SKR Pro?
Fan controllers have their place, where heat gets extreme and full ventilation starts to sound like a jet engine taking off. To me this isn’t one of those places. Put something like a 5015 fan blowing air over the drivers and give the air somewhere to go, and you’ll be fine. You’re not really concerned about fan noise with a CNC, even if you’re using it for a pen plotter, and the kind of noise that one or two low-CFM fans make isn’t a huge deal.
Trinamic’s datasheet for the 2209 shows a typical power dissipation of 2.8W/driver. Even with 6 drivers, add heat sinks, with a junction to case thermal resistance of 6 K/W… Yes, there’s a fair amount of heat there, but it shouldn’t be too difficult to disperse with a moderate constant airflow. Less than 20W typical. Compare that to say a high-end graphics card – a 1080ti dissipates 13W at idle. and up to 250W under full load, and then a fan controller gets important.
Don’t get me wrong. 20W is enough power to cook stuff if it’s unmanaged, but even a couple of 40mm fans in a push-pull configuration is plenty enough to handle the airflow needed to keep the temperatures manageable.
One other thing I did in my enclosure is I added baffles on the intake.
Not so much to reduce noise, but to try to reduce the amount of dust being sucked into the enclosure. I’m not sure how much it helps. I still get dust inside mine. I think it’d be easier to make sure the enclosure is somewhat easy to open so you can open it up and blow it out regularly.
