What does the term "retraction" refer to in FDM printing?

Retraction in Fused Deposition Modeling (FDM) printing specifically refers to the action of pulling the filament back into the nozzle during the movement from one point to another in order to minimize or prevent the unwanted extrusion of filament. This is particularly important to reduce stringing or oozing that can occur when the nozzle travels across open areas without printing. By retracting the filament, pressure is reduced in the nozzle, preventing excess filament from seeping out and causing stringing, which leads to a cleaner finish and more precise print.

In contrast, the other options address different aspects of the printing process. For example, removing supports is related to post-processing of completed prints, while adjusting speed settings pertains to the overall operational parameters of the printer rather than the specific action of retraction. The method of adding layers to the object is a fundamental characteristic of how FDM works but does not pertain to the retraction process itself.