4.5 Firmware Retraction (Deprime)

This allows you to configure the printer with a filament retraction setting (in units of steps) to be used when pauses occur, planned or otherwise. You are able to separately control the right extruder, A, and the left extruder, B. If your printer is only equipped with one extruder, it is considered “A”.

When a deprime setting is non-zero, the printer will deprime the associated extruder by the specified number of steps when it is active and any of the following occurs:

Pausing, whether user initiated or a P-Stop generated pause.
When the printing process is temporarily idle because the queue of processed segments has run out. Depriming the active extruder will help prevent blemishes.
If “Deprime on Travel” is enabled, then, when the printer detects a travel move it will deprime. However, it is difficult for the printer to truly detect this, as the printing of very low layer heights may require many short printing moves which are not accompanied by extrusion. In actuality, the printer can only identify travel moves if the print commands disable the extruder stepper motor before effecting a move. Note that most slicers do not disable the extruders before a travel move, as it may allow the filament to back out of the extruder by an unknown amount.

When printing resumes, the printer then feeds the filament back in by the same number of steps by which it was deprimed.

By default “Deprime on Travel” is disabled, though deprime is set to a non-zero value for each extruder as per Table 4.1.