Software
Retraction
Also known as: retraccion · retracción · retraction · retraer filamento
Short definition
Retraction is the movement in which the extruder pulls filament back before a non-printing travel move, so the nozzle does not ooze and leave strings.
Full definition
Inside the nozzle the molten plastic is under pressure and tends to come out on its own. When the head has to jump from one area to another without printing, the extruder pulls back a few millimetres of filament to relieve that pressure. The two parameters you tune are distance and speed: a direct extruder needs short retractions, on the order of 0.5 to 2 mm, whereas a bowden system may need 4 to 6 mm because the filament compresses along the tube. Retracting too much causes clogs and gaps on resume; retracting too little leaves strings. It is the setting behind most stringing cases.
Related terms
- StringingStringing is the fine threads of material left between parts of a print when the nozzle oozes during non-printing travel moves.
- Direct drive extruderIn a direct drive extruder the motor that pushes the filament is mounted on the print head itself, a few centimetres from the nozzle.
- Bowden extruderIn a bowden system the extruder motor is fixed to the frame and pushes filament to the head through a PTFE tube.
- HotendThe hotend is the assembly that melts filament: heater block, cartridge, thermistor, heatbreak and nozzle.
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