Knurled Wheel pushing out of the Gear Shaft.

[Sabby 0]

Hi guys,

The knurled wheel is just slipping out from the gear shaft when it is loading or unloading a filament. Even when I am going to print a pre - set file from the UM2 SD card, I am facing this issue. And I have figured it out that whether a file has been set at higher retraction or at lower retraction, the knurled wheel is slipping from the gear shaft.

This is a problem which I am facing with my Ultimaker 2 for a couple of weeks. I thought that it is an issue of the knurled wheel so I bought a spare. But that did not work out either. I am really in a mess. Can't figure out what can be the main issue. Is it a problem with the gear shaft or is it the grub screw or is it the knurled wheel?

Guys, if any one has a clue about this then please help me out.

[gr5 2,173]

Are you sure the knurled wheel is slipping? it is common for the extruder stepper motor to suddenly slip backwards about 1/3 of a turn followed by no extrusion until it catches back up to where it left off. If this happens you usually want to increase temperatuer (to lower viscosity as PLA is like honey at 240C and like toothpaste at 190C) or slow down the printer. The force that this feeder can put out before skipping is impressive -about 5kg or 10 pounds - enough to lift the printer off a table if you tried to do it yourself by pushing up on the filament.

What temperature, layer height, and print speed are you printing at?

it could be you just need some cold pulls to get all the gunk out of the nozzle - particularly off the inner walls of the nozzle.

[Sabby 0]

Are you sure the knurled wheel is slipping?  it is common for the extruder stepper motor to suddenly slip backwards about 1/3 of a turn followed by no extrusion until it catches back up to where it left off.  If this happens you usually want to increase temperatuer (to lower viscosity as PLA is like honey at 240C and like toothpaste at 190C) or slow down the printer.  The force that this feeder can put out before skipping is impressive -about 5kg or 10 pounds - enough to lift the printer off a table if you tried to do it yourself by pushing up on the filament.

What temperature, layer height, and print speed are you printing at?

it could be you just need some cold pulls to get all the gunk out of the nozzle - particularly off the inner walls of the nozzle.

As much as I have observed the knurled wheel is coming out of the gear shaft at time of printing. I guess it does not depend upon the settings as because it is happening also when I am trying to print a pre-set file from the SD card provided by Ultimaker. I guess it is just a mechanical issue.

Still if you have any more ideas please do provide.

[gr5 2,173]

Can't you just tighten the set screw ("wheel screw" in photo)? You have to tighten the hell out of these - it should be so tight that the tool twists a bit.

I don't know if that's a photo of your personal feeder but a year or two they changed the feeder design slightly to make it easier to get a tool into that set screw - the is a circular (mostly - or G shaped?) ridge around the hole - they removed the ridge in one spot for tightening the set screw with a straight tool.