Active cooling for better results in 3D-printing with Replicator Dual and Replicator-based printers (CTC, WanHao, PrinterBot, FlashForge...)

PLA prints left uncooled, right cooled. A difference like day and night


There are some cheap 3D printers to buy, all based on the original Makerbot Replicator Dual. They all have in common that they have no active cooling. This can be easily and inexpensively retrofitted and brings a huge leap in quality when printing PLA.

Active cooling blows an air stream directly to the point at which the hot plastic is applied and thereby cools it down. This prevents the part from warping during printing and the corners from lifting.

However, active cooling is not suitable for printing ABS because the individual layers do not adhere well to one another and the object becomes cracked.




Print active cooling

To retrofit an active cooling system to a replicator, you only need a strong 40mm fan, a few M4 screws and nuts, two cables, and a few printed parts. There is a very good air duct to download from Thingiverse.com that takes the fan air to where it is needed. You should print this out. It is best to use ABS because it only softens at higher temperatures and print with 100% infill.

Here are the parts

Do not use force to get the nuts into the openings provided in the air duct, otherwise there is a risk that the part will break. I simply heated the nuts with a soldering iron, positioned them with tweezers and then pressed them in with pliers. So the nuts are really tight and the ventilation duct can be assembled.


Now you can mount the active cooling to check whether it is seated correctly. It is important that the channel sits slightly higher than the tips of the printheads

Wire active cooling

Now you need a power supply for the fan. Either take an external power supply for a 12V fan (e.g. a 12V plug-in power supply, an old router, etc.) or you get a 24V fan and tap the voltage directly at the power supply of the 3D printer.

To gain access to the control electronics you have to remove a screw on the right side of your printer and remove the base plate. Attention! Always make sure that the mains plug is pulled when working on the electronics. There you can see the power supply and the mainboard. The easiest way is to connect the fan directly to the power supply: one cable at + 24V, the other at -24V. Simply clamp the cables to the existing cables.

With some devices there is also a suitable connection terminal for active cooling, or this can be retrofitted. However, good soldering skills are required so that I can only recommend this procedure to people who have experience in soldering small components.

See description and photos

Mount the base plate again and connect the fan to the two cables with a luster terminal. If it does not turn, switch off the device, swap the wires on the luster terminal and switch on again. Now the fan should start and you can check which side it is blowing on and which side it is sucking air in. Switch off the device and mount the fan so that it blows the air into the air duct.

You should also integrate a switch in the circuit so that you can switch the active cooling on and off. Place the switch so that you can easily reach it without having to crawl behind the printer.

If you have done everything correctly, you can now switch the active cooling on and off with the printer switched on and start your first test prints with active cooling.

If you don't believe in connecting the cables, you shouldn't try either.



Tip: Only switch on active cooling after the first layer has been printed. With 3D printing it is always important that the first layer adheres well to the print bed and it does this best when it is not cooled. When the first layer is finished, you can confidently switch on the active cooling and leave the pressure to itself.



Attention! If you tinker with your printer and what breaks it is your own fault! We do not guarantee the accuracy of our information.

Nevertheless, I wish you much success and have fun with the greatly improved printing results.