Why is filament being retracted on single color prints?

I have noticed that when doing a single color print using the AMS that after a period of time, the print stops and the filament is retracted. While this really isn’t a problem most of the time and just adds additional time to the print, when the spool is low, the retraction causes issues and stops the print. Why is it doing this unneeded retraction during printing?

If the filament spends a longer period inside the PTFE tube, it can lead to moisture being absorbed, and it can also become brittle.

The filament is retracted to avoid such issues which could cause problems in unloading/loading if the printer has not been used for a longer period of time.

This makes no sense since the filament is moving during printing.

So thinking about this. Moisture builds up in the tube as filament is moving forward during printing. It is then retracted leaving moisture in the tube and on the filament. There is no active drying performed so the same moist filament is then pushed back into the moist tube. What has been accomplished that doesn’t already happen during filament movement during normal printing?

1 Like