Now that we have power to our RAMPS board – lets take care of it a little, and add in some active cooling to the RAMPS board with the use of a RAMPS Cooling Fan.
Why Have Active Cooling on a RAMPS 1.4 Board?
You can install your RAMPS board and leave it as that – but all those components, especially the poly fuses, stepper driver chips and the power mosfets get warm – very warm! With any electronics – you need to keep them in their operating temperature range for them to function correctly. If the stepper drivers overheat – they can cause the motors to skip a step, which will essentially ruin any print you are currently doing as the x, y or z-axis will be skewed for the remaining print. If the extruder or heated bed mosfet overheats and fails – no more printing for you until you replace it.
To keep these components within their operating temperatures and maintain their functionality with repeatable predictability – i.e. you simply trust your printer will work and not glitch as soon as you turn your back(!) – we can cool the RAMPS board. With added cooling, or active cooling, we increase the reliability of the components and decrease the likelihood of thermal failure. Cool it how you like, blow on it, or place a room fan near it?! But for a more permanent solution Toolson has gone with a known design by using two small (40mm) 12V fans installed just above the board and powered with the spare 12V connection. This gives constant cooling air across the whole RAMPS board. You can also go with a single larger fan, but this will take up more room.
Building the RAMPS Cooling Fan
For the RAMPS cooling fan you will need to print out the two spacer parts, and two ends. One end is “full” and there to mount a step down converter if you need it. It is a simple process of mounting the two fans to the spacers and ends with eight M3 bolts and hex nuts. You should have something like the below:
Double check the air flow of the fans by connecting them to a temporary 12V supply – they usually blow “towards the logo” on a fan. The “logo side” needs to face the RAMPS board so we get a cool airflow blowing over the components – we’re not trying to suck anything away! Tighten up the hex nuts, you don’t need any nyloc nuts for this part – standard hex nuts will do.
Splice the Power Lines
With two 40mm fans you need them to run together, so you will need to splice their power lines together IN PARALLEL, which means join positive to positive, negative to negative – so they both get 12V rather than splitting it. Once spliced together you need to create a new power cable from the spliced connection to a dupont connection to connect the fans to the 12V rail on the RAMPS board. Follow the images below to see how to create a neat and isolated joint.
You can carefully route the cable and secure it with some hot glue or some cable ties to keep it out the way. It’s going to get busy around the RAMPS board – so the neater and cleaner you do things – the better!
Mounting the RAMPS Cooling Fan Mount
The fan mount clips onto the RAMPS board with the little notches cut into its “feet” and holds on just with their own grip and the parts own stiffness. This allows you to easily slip it on and off if you need access to the electronics, to adjust stepper current, remove jumper pins etc. It’s a really elegant design and allows for good air flow and access to all parts.
You can see the wire in the final shot below which will get a dupoint connector crimped onto it to be connected to a 12V supply rail on the RAMPS board. There are several solutions to this to power these fans. You can attach it to the 12V Aux pin which are just between the x-axis stepper driver and the polly fuses, attach it directly to the power in cables, or find other 12V rails on the RAMPS board and attache there. You can even attach it to the green power connectors if you like – but best leave them as the are.
I however have another setup and would like to control these cooling fans – so if the printer is sat idle, they are not required to be spinning. Even though they are very quiet, reducing their use will improve the power consumption of the printer and extend their life. Thankfully controlling these fans is possible with the Marlin firmware and the use of an external controller board (called the Reprap Ramps1.4 RRD Fan Extender). You can get a hint of it in the first image below… see those six pins sticking out the bottom of the RAMPS board below the left fan – that’s the board. But more on that board in a later post!
If you hook up the power to the 12V jumper on the RAMPS board and turn on your 3D printer – the fans should wizz round! Cool… 🤓