Duet Wifi + Ender 3: cooling with stock electronics box

rlogiacco · 6 Jan 2019, 16:07

Hi, I'm still waiting for my Duet Wifi to reach my inbox, but I've already started tinkering on how I can install the board, so I ended up looking at this page, in particular, the section regarding cooling.

I'm hoping I can adapt the Ender 3 stock electronics box and I've designed a pair of mounting brackets, but I'm wondering if my solution will be good enough for cooling.

I've ended up with a couple of cooling options and I wish your input on which one to choose:

a 60mm fan sucking air from the top of the stepper drivers (air flow directed outward)
a 40mm x 10mm air blower (one of those used as part cooling) blowing air on the bottom from front to back of the board, via a flow guide (not drawn)
two 40mm x 10mm fans (those used for hot end heat sink cooling) blowing from the opposite side where the drivers are located, positioned roughly 1/3 down, 2/3 up

I can also use the first solution mounting the board upside down (so sucking air from the bottom), but I'm not very happy with that as all the connectors will be inaccessible unless I unscrew the board from the brackets...

Also, consider the Ender 3 stock electronics box has plenty of vents on the bottom and has a 5mm gap from the rest surface.

Due to the very limited space inside the box, I'm unable to apply any combination of the above, the only viable combination would potentially be the underside blower and the stock 40mm fan from the top, both pulling air inside...

Which option would you suggest, if any is viable?

Does the firmware report the drivers' temperature so I can monitor my solution without risking of blowing the driver chips?

What is the suggested operating temperature for the drivers?

Must I design a totally new electronics box and ditch the stock one completely?

Phaedrux · 6 Jan 2019, 17:43

Have you seen this? https://duet3d.dozuki.com/Wiki/Mounting_and_cooling_the_board

I think the first option may be the best bet, as it pulls warm air out of the case and draws cool air in from the opposite side. The option with the Noctua fans blowing across would also be alright I think.

The cooling requirements for the board and driver chips isn't extreme since the drivers are properly heatsinked by the copper layers of the board itself. As long as you aren't running above 2a current for your motors it doesn't take much to keep it in check.

You can thermostatically control the case fan based on the CPU temp. The drivers themselves only have a temp warning and temp limit flag which are around 80c and 100c I think.

dc42 · 1 Jun 2019, 22:02

You won't need any fan cooling at all for a Duet WiFi controlling an Ender 3.

The firmware reports the CPU temperature. It can't read the driver temperatures, but it will tell you if they report an over temperature warning or shutdown.

rlogiacco · 7 Jan 2019, 15:32

@phaedrux

@phaedrux said in Duet Wifi + Ender 3: cooling with stock electronics box:

Have you seen this? https://duet3d.dozuki.com/Wiki/Mounting_and_cooling_the_board

Yes, I've seen the page you linked, I linked it myself

I think the first option may be the best bet, as it pulls warm air out of the case and draws cool air in from the opposite side. The option with the Noctua fans blowing across would also be alright I think.

Thanks a million

rlogiacco · 7 Jan 2019, 15:37

@dc42 said in Duet Wifi + Ender 3: cooling with stock electronics box:

You won't need any fan cooling at all for a Duet WiFi controlling an Ender 3.

Are you saying I can just go along with the stock 40mm fan pulling air inside the box? That would be great, I could just need a mounting bracket in that case...

The firmware reports the CPU temperature. It can't read the driver temperatures, but it will tell you if they report an over temperature warning or shutdown.

Ok, thanks. Let's say I wish to monitor the driver temperatures with a thermocouple applied on the package (for sake of assuring everything works fine), what is the suggested operating temperature?
If I go for the 40mm fan I wish to monitor the situation for a few hours to ensure nothing gets too hot...

dc42 · 7 Jan 2019, 19:32

@rlogiacco said in Duet Wifi + Ender 3: cooling with stock electronics box:

Ok, thanks. Let's say I wish to monitor the driver temperatures with a thermocouple applied on the package (for sake of assuring everything works fine), what is the suggested operating temperature?

I suggest about 60C. The over temperature warning kicks in at a die temperature of around 100C.

3dmntbighker · 1 Jul 2019, 20:48

I have a Pro with a Maestro. I just stuck a blower fan on top pulling air out around the driver area under the Duet. I drilled a hole in the top since the Pro has the vent on the bottom, and the board mounts upside down. My board NEVEr reports over 40C so far. So as DC says, you probably don't need a fan at all. The Ender doesn't tax the board.

https://www.thingiverse.com/thing:3197999

dc42 · 8 Jan 2019, 09:55

@3dmntbighker said in Duet Wifi + Ender 3: cooling with stock electronics box:

I have a Pro with a Maestro. I just stuck a blower fan on top pulling air out around the driver area under the Duet. I drilled a hole in the top since the Pro has the vent on the bottom, and the board mounts upside down. My board NEVEr reports over 40C so far. So as DC says, you probably don't need a fan at all. The Ender doesn't tax the board.

https://www.thingiverse.com/thing:3197999

The advice I gave was specifically for the Duet WiFi (or Duet Ethernet). The drivers on the Maestro get hotter than those on the WiFi/Ethernet, so I can't say that you don't need a fan for a Maestro driving an Ender 3. My guess is that if the currents are set to no more than 800mA then it may be OK without a fan.

Please note, the CPU temperature reported by the Duet needs to be calibrated before you rely on it. There is a wiki page about this.

Phaedrux · 8 Jan 2019, 17:51

@dc42 said in Duet Wifi + Ender 3: cooling with stock electronics box:

@3dmntbighker said in Duet Wifi + Ender 3: cooling with stock electronics box:

I have a Pro with a Maestro. I just stuck a blower fan on top pulling air out around the driver area under the Duet. I drilled a hole in the top since the Pro has the vent on the bottom, and the board mounts upside down. My board NEVEr reports over 40C so far. So as DC says, you probably don't need a fan at all. The Ender doesn't tax the board.

https://www.thingiverse.com/thing:3197999

The advice I gave was specifically for the Duet WiFi (or Duet Ethernet). The drivers on the Maestro get hotter than those on the WiFi/Ethernet, so I can't say that you don't need a fan for a Maestro driving an Ender 3. My guess is that if the currents are set to no more than 800mA then it may be OK without a fan.

Please note, the CPU temperature reported by the Duet needs to be calibrated before you rely on it. There is a wiki page about this.

I've added a note to the cooling page specific to the Maestro as well as the tip on using the MCU temp as a proxy to control a chassis fan.

3dmntbighker · 9 Jan 2019, 00:25

@dc42 said in Duet Wifi + Ender 3: cooling with stock electronics box:

@3dmntbighker said in Duet Wifi + Ender 3: cooling with stock electronics box:

I have a Pro with a Maestro. I just stuck a blower fan on top pulling air out around the driver area under the Duet. I drilled a hole in the top since the Pro has the vent on the bottom, and the board mounts upside down. My board NEVEr reports over 40C so far. So as DC says, you probably don't need a fan at all. The Ender doesn't tax the board.

https://www.thingiverse.com/thing:3197999

The advice I gave was specifically for the Duet WiFi (or Duet Ethernet). The drivers on the Maestro get hotter than those on the WiFi/Ethernet, so I can't say that you don't need a fan for a Maestro driving an Ender 3. My guess is that if the currents are set to no more than 800mA then it may be OK without a fan.

Please note, the CPU temperature reported by the Duet needs to be calibrated before you rely on it. There is a wiki page about this.

Yeah, I have nothing over 800. And my board mount channels air past the driver area where my blower fan pulls the air out. Mine is probably over kill. As for calibration, I just watch the increase from ambient If it's 22 at power on and never exceeds 40 I'm pretty sure I'm good.