Retraction Tuning Calculator — Retraction Settings by Material

Retraction pulls filament back from the nozzle during travel moves to prevent oozing and stringing. Direct drive printers typically need 0.5-2mm of retraction, while Bowden tube printers need around 4-6mm due to the longer filament path — and more again (up to 8mm) with a very long tube or a large 0.6-0.8mm nozzle.

PETG has a higher viscosity when melted and tends to leave thin strings between travel moves. It benefits from slightly higher retraction distances, lower temperatures and enabling z-hop. Wiping features in your slicer also help.

Z-hop lifts the nozzle slightly during travel moves to clear printed features and reduce the chance of the nozzle dragging through stringing. It adds a small amount of print time. Use 0.2-0.4mm for most materials, higher for stringy materials.

Start with the recommended values and print a retraction test tower. Per Ellis’ Print Tuning Guide, change distance in 0.1mm steps on a direct-drive printer and 0.5mm steps on a Bowden printer, adjusting speed in roughly 5mm/s increments. Too much retraction causes clogs and under-extrusion; too little leaves stringing and blobs.