Duet 3 Mini 5+ WiFi Maximum Ambient Operating Temperature

XZY3D

Hi Duet 3D technical team,

Can you please let me know the maximum recommended ambient temperature (degC) for operating the Duet 3 Mini 5+ WiFi before active cooling is required.

I’m currently designing a 3D printer

Thanks

chrishamm

@XZY3D We don't recommend operating Duets at higher ambient temperatures than 60C. Depending on the configured motor currents, you may already require additional cooling.

I have a spare cooling fan beneath my Duet 3 Mini 5+ which turns on when the calibrated MCU temperature exceeds 50C. I need that because I operate one of the motors at a relatively high current (1.7A).

XZY3D

@chrishamm, thanks for the information, really helpful.

I had some follow up questions:

In addition to the 5x stepper motor drivers on the Duet 3 Mini 5+ WiFi, I’ll be using a Duet 3 EB mini 2+ for one extra motor.
I’ll use 6 motors in total: 1x X motor, 2x Y motors, 1x Z motor and 2x extruder motors.

For an ambient operating temperature of 60degC what would be the maximum current you would recommend configuring the motors too before using active cooling?
Would you recommend different maximum currents for the different X,Y,Z & Extruder motors at 60degC ambient temperature?
What is the highest recommended calibrated MCU temperature (degC) during printer operation before active cooling is recommended?

Thanks,

infiniteloop

@XZY3D

Reading your posts, I’d like to make some annotations.

Most electronic components can take at least up to 80°C, but at the cost of reduced lifetime. So, the cooler they run, the longer they last.
Components who have to control substantial currents like stepper drivers, MOSFETs for fans, heaters and the like, or voltage regulators tend to get hotter than other parts on the PCB. Without thorough tests and measurements, it is quite difficult to determine cooling requirements in advance.
Air flow is essential. If the heat of said components is not moved out of the way, it piles up and results in dangerous hot spots.
In contrast to common belief, most of the heat is dissipated through the back side of the Duets - mounting them flat down horizontally can be less than optimal.
If you intend to put your Duet into a pre-heated environment (say: a heated chamber), you must calculate this as an offset to the cooling requirements of the affected components. Even summer temperatures of more than 30°C may put a passively cooled board at risk.
At an ambient temperature of 60°C, the use of a fan is mandatory. In addition, you also should feed it with fresh air from the outside (to take 5. Into account).

If you are in the design process, you are good advised to provide a fan, anyway - if it turns out to not be required, you can turn it off. If you encounter hot spots, if you need to ramp-up the current for one of the steppers, or if the sun shines bright… well, you’ll be lucky to have a fan ready.