Cooling in 3D printing: how much air helps a part

What cooling is for

Plastic has to set quickly after being printed, otherwise it deforms or sags. The fan on the head cools it, which helps above all with overhangs, bridges and small details. With small parts the slicer also slows printing so each layer has time to cool. The settings are described in the OrcaSlicer wiki.

PLA and PETG are cooled differently

• PLA tolerates strong cooling, often close to full power. It sets quickly and holds even fine detail.
• PETG needs less cooling. With a strong stream the layers bond to each other less well and the part can be brittle, so it is cooled moderately.
• The first layers are usually not cooled so they stick, see first layer.

Cooling and strength

The faster plastic sets, the less time it has to bond with the layer beneath. Stronger cooling therefore gives a nice surface and overhangs, but a weaker part. For strong parts cooling is limited, and for decorative ones it is increased. The nozzle temperature is related too, and with an enclosed printer the chamber, which keeps the heat inside.

Cooling and small parts. With small parts a layer is finished in a few seconds and the next is laid on still warm plastic. The slicer therefore slows printing so the plastic has time to cool. With several pieces on the plate the nozzle moves between parts and each has time to cool, see full plate.

Cooling in your order

We set the cooling ourselves for PLA and PETG, and you do not choose it in the calculator. If you need a stronger part, choose 40% strength and consider PETG. If you need clean overhangs and fine detail, PLA suits better. The differences are also explained in the comparison of PLA and PETG.