Feeder slipping / Filament chewed

[glennwelker 0]

Sounds like a common issue but I haven't found a solution.

Short prints offer no issue.

Longer prints... more than 40 minutes result in the feeder slipping.

Filament becomes quite chewed at this point.

Tension on feeder is at its mimimum. Raising tension resulted in immediate chewing of filament.

Using default settings on the printer itself. Cura file shows speed at 50mm/s, travel speed at 150mm/s.

Any help would be appreciated.

Printer is new as of a week ago and has 14.9 firmware.

 

[gr5 1,345]

Probably because the stepper motor is hotter on longer prints. Especially problematic on some of the newer UM2 printers and with lots of retraction and after 30 minutes of warmup by the stepper motor.

One solution is to print ABS which doesn't melt at such a low temperature (or XT or "high temp PLA" or nylon).

A better solution might be to just put a small desk fan behind your printer and have it blow into the feeder to cool the stepper. Or remove the cover in the back left corner (only 2 screws) and put a fan blowing onto that feeder stepper.

Another simple solution is to lower the current to the feeder stepper. Stepper motors use the same amount of current when they are stopped as when they are moving. You can set the current to any axis with M907 gcode. Just insert this line towards the top of any gcode file. I'd put it after the homing code (G28 I think).

Default current is 1250ma (1.25 Amps):

M907 E1250

Try 1 amp (although your stepper may now start slipping a lot):

M907 E1000

Also consider raising your nozzle temp - perhaps to 240C? wamer PLA means more like honey and less like toothpaste which means less force on the filament so less grinding.

 

[gr5 1,345]

By the way most UM2 printers don't have this problem. Mine doesn't have this problem. But I think some steppers are slightly hotter than others. Just 5C hotter is probably all it takes.

 

[IRobertI 448]

Softer filaments like Colorfabb's PLA/PHA blend can be a bit more sensitive to long, intensive retraction prints. A harder filament like pure PLA or something like XT can help in that case.