If you’re new to PLA 3D printing, then you probably know how important good cooling is in order to reduce the warping and to produce an appealing surface finish. There are various different cooling setups and fans, and all of them will produce different results. Controlling the layer temperature is one of the trickiest parts when printing, so once you get that right, you should be able to produce quality prints every single time.
If you’re printing small parts that have small layer surface areas, or turn objects at extremely high speeds so that each layer is finished within a matter of seconds, the layer of plastic that has been just laid down will not have enough time to cool down, so it will be still a bit molten when the next layer is placed. With hot plastic being extruded and the radiated heat from the nozzle, the finished product can end up being a messy blob instead of the product you had in mind.
One way to combat that is to slow down the speed, but that still won’t fix your problem. This is where a controlled 3D printer fan can make a huge difference. When you fit a 3D printer fan, you can still run your printer at full speed, even when you’re printing finer details. Without it, the printer may instruct the G-code to slow down to allow for more natural cooling before adding more.
Cooling fans can bridge extruded material, which is an essential part of many 3D printed products. Bridging is the process when a product has to span a gap, basically making it bridge in thin air. If you extrude plastic without having anything beneath it, the extruded material will sag down and will oftentimes break. Even though bridging filament without a fan is possible, you’ll typically have some strings of snapped extruded filament hanging, and some sagging.
However, it’s not just about buying the cooling fan, you should also mount it properly, so that it cools the top layer of the part that’s being printed. If you cool the heated-bed, the part may pop off in the middle of the printing process. On the other hand, if you cool the hot-end, the extruder may jam. With that said, it’s not uncommon for cooling fans to have a 3D printed duct, which helps direct the stream of cool air across the object when it’s being printed.
Remember, using a cooling fan is fine with PLA, but not with ABS material. The fan can make the ABS part’s edges curl up by cooling them too quickly, and the next layer will probably be even worse. Eventually, it will get too warped and deformed that the print head can completely knock it off the building platform.