Mooz 2  - Electronics cooling

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This short article describes how i improved the cooling for the electronics in my Mooz 2.

Have you ever got random resets while printing after 20-30 min or even after hours of printing? If yes one possible cause can be the overheating of the main bard of the printer.

The main reason for overheating is the poor ventilation of the board, it is placed under the printer in closed plastic box and on top of all also the stepper motor controllers, 3 of them, are placed on the same board. The result...you can easy go to 85C-90C inside this assembly.

How do we fix this issue? There are several ways, the easiest is to use the card in open air, just remove it from the original location and place it outside. This solution is simple but also a bit dangerous for the integrity of the electronics.

The one i am using is to have a fan on the electronics plastic cover that blows cool air from under the printer directly on the board, the parts i am using are listed below:

1. 12V fan - bought from aliexpress

2. WLFT 404 37 X 37 - Thermal Gap Pad - bought from Elfadistrelec

3. KB5 Standard Computer Case Fixing Screw - i have them from a computer case

4. Heat sink - 7mm wide, max 10mm in height

5. 8 M3x16 countersunk screws 

6. 4 M3 nut

7. 3D printed spacers

8. Diode like 1N4148

9. Wires

10. You will need also an electric screwdriver to drill some holes, a good knife to cut plastic, soldering iron and skills to handle the tools

 

Steps to follow

1. Remove the power supply and the cables

2. Remove the board from under the printer (look the the assembly manual if you forgot how to assemble the printer)

3. Place the self adhesive thermal pad on the heat sink, make sure the pad is well placed and covers the whole metallic surface

4. Place one heat sink on each motor controller chip (easy to identify because you will see 3 smaller PCBs with a square black chip on top on the main PCB) and press on it in order to stick on the chip.

5. Locate the power circuit on the board. I connect the fan directly to the plug so that the fan is ON independent of the power switch. 

6. In order to easy the cover i use an intermediate connector for the fan where i have soldered also the protection diode

7. Drill the holes for the fan fixation on the cover, i took care to position these holes in such way that the fan center will be positioned on the middle heat sink. 4 holes on a square of 50mm

8. Drill/cut the hole for the air - hole diameter about 55mm

9. On the vertical wall i have drilled 3 10mm diameter holes to allow the hot air exhaust

10. Fix the fan on the cover

11. Connect the fan to the board power circuit

12. Remove the rubber foots from the printer

13. Remove the M3x8 

14. Place the M3x16 in the spacer and assemble it - repeat for each corner

15. Place the Board assembly on the printer

 

The 3D model in stp format used to made the changes can be downloaded from here Mooz 2 Electronics, this is an approximate model.