What is retraction in FDM printing?

Retraction in Fused Deposition Modeling (FDM) printing refers specifically to the process of pulling back the filament in order to eliminate the potential for oozing or stringing when the print head moves between different areas of the print. During travel moves, the print head does not extrude material; however, residual molten filament can leak from the nozzle due to gravity and pressure buildup in the hot end. By retracting the filament slightly before the print head moves to a new location, the excess material can be retracted back into the nozzle, reducing the chances of unwanted filament drips or strings across the print.

This process is crucial for achieving clean and detailed prints, especially in intricate designs where precision is important. It enhances the overall print quality by minimizing the artifacts associated with unwanted extrusion during non-printing movements. Understanding and optimizing the retraction settings—such as distance and speed—can significantly improve the results of an FDM print.