Although the profiles in Ultimaker Cura are completely optimized for Ultimaker printers and materials, they may need some adjustment in specific cases. Sometimes, warping and delamination can occur despite the use of the default profiles, because of the shape and size of the model and material choice. In these cases, and when changing the design and/or material is not possible, it is recommended to take a look at the fan speed and print speed. Adjusting these settings according to the instructions below can help to improve print quality.
The fans on the sides of the print head cool the material after it has been laid down. This is important as the layer has to solidify before the next layer is printed on it. However, excessive cooling can cause materials to contract too much, as they tend to shrink when cooling down fast. Especially engineering materials such as ABS, CPE+, PC, and PP are prone to this. Although the print head fan speed has been optimized for these materials in the profiles, there is a small chance that for some specific models warping or delamination still shows up.
In this case, it can help to further decrease the fan speed, to 0 or 1%. You can do this in Ultimaker Cura by going to the Custom settings in the Sidebar, then search for the setting Fan speed and change it. Some of the materials are already printed with the fans off, but for others it is possible to decrease it. Especially for mechanical prototypes this can help to improve the layer bonding and build plate adhesion.
Another way of improving the layer bonding and reducing the chance of delamination is lowering the print speed. Although the default profiles, in general, enhance good interlayer adhesion, it can in some specific cases help print a bit slower, so that the layer bond even better. If you decide to change this, it is recommended to lower the print speed by 20%. This can be done in the Custom settings in Ultimaker Cura. Look for the setting Print speed, and then change it to a value that is 20% lower than the original value.