Duet 0.8.5 Enclosure with Active Cooling - Comments, Complaints, Suggestions, etc...

So I spent some time this morning at work drawing up an enclosure for my Duet 0.8.5 with what I'm calling active cooling. I'm after some suggestions/complaints/comments/improvements/etc... primarily to poke holes in my design. I am currently printing this to see how it fits, but I am hoping it will provide the level of cooling that one might need for the Duet running a higher than normal current on a stepper driver.

The files are currently on Thingiverse, but I have included a basic picture minus the cover lid.



Edited 1 time(s). Last edit at 08/01/2016 03:07PM by PDBeal.

Looks good, but I think it could benefit from some improvements:

- It's more important to cool the underside of the board than the top. I suggest you mount the board higher so that the fan blows more air over the underside.

- If you will be using a large heated bed current, then you should also blow air over the space between the two large terminal blocks, where the bed mosfet and the VIN PCB trace are.

- The air at the end of the board farthest from the fan has nowhere to go, so the E1 stepper driver won't be cooled very well. I suggest you put the air exit vents to the left of the holes for the Reset and Erase buttons.

HTH David

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
- It's more important to cool the underside of the board than the top. I suggest you mount the board higher so that the fan blows more air over the underside.

I had considered going higher, but I'm thinking bend radius on the plug in cables and the height when the connectors are plugged in as I have planned to put a cover on this box.

Quote
dc42
- If you will be using a large heated bed current, then you should also blow air over the space between the two large terminal blocks, where the bed mosfet and the VIN PCB trace are.

In this case, I was considering a fan on top of the cover plate blowing down in this area.

Quote
dc42
- The air at the end of the board farthest from the fan has nowhere to go, so the E1 stepper driver won't be cooled very well. I suggest you put the air exit vents to the left of the holes for the Reset and Erase buttons.

Underneath of E1 there is a curved deflector to send the air under the CPU and towards the exit vent slots. Of course, I have not modeled this with any sort of air flow modeler to know if my deflector will work or not.

Cooling the CPU isn't important because it doesn't geneate much heat. The parts that need cooling most are the PCB below the stepper drivers and the bed heater mosfet area.

Instead of a fan blowing air down on the board, a fan blowing air up underneath the board would be more effective. It would cool the stepper.drivers more directly and the air flow would not be impeded by components and wires.

For a Duet mounted vertically, passive cooling by convection is normally adequate, as long as air can enter the enclosure at the bottom near the back of the board and escape at the top. The convection can be aided by a small fan at the bottom.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hey PD, as it's shown in the first image it won't work.

You don't have enough space on the power input for cabling and the stepper side can benefit from a bit more room.

Air flow must be under the board for any real cooling benefit and ideally should have a little turbulence to aid in heat transfer.

I have a Duet WiFi case design on thingiverse and I am planning a 085 version as well that channels the air flow underneath.... Sorry on iPad so no link at the moment.

Cheers
Phil

I really did think about printing an enclosure, but when it came to it, it just didn't seem logical to enclose the heat around it so to speak.

So as you can see from the picture I just raised my board up to allow airflow underneath and the two fans which came from a car-boot €1.00 sale, fans were on a plate to cool a laptop.

Luckily they both flow over the board really well and the rear most one actually does flow some air under the board, since doing this I have seen temps dropping by around 10c in the board area as a whole and a 7c drop in temp at the CPU



Edited 1 time(s). Last edit at 08/02/2016 06:23PM by Calvinx66.

I've been working as well on a crude model of a duet case, as the ones I saw on Thingiverse does not really address the flow of air underneath the board. I'm still in the process of refining it but you can take a look and let me know what you think.