Feeder Issues

[K80Bot 0]

My Ultimaker 2 was working perfectly for a year and suddenly developed a habit of slipping when changing the filament. It will load the filament and forward it to the extruder but when the other end gets to the extruder it will only slip and not forward the material any more.

I have taken apart and tested the extruder and can verify that it isn't that.

I replaced the Bowden Tube because I was having some issues with material getting caught.

I've tried the full range of tension settings on the feeder.

I've cleaned the feeder/knurled thingy.

The filament isn't having any trouble unspooling.

Any thoughts on what else I can try?

Other note: When I try and reverse the filament out of the feeder it won't go, but just grinds on the filament in the lowest tension setting. I have to manually pull the filament back out.

All of this is new, and I'm using the same ultimaker branded filament I've been using all along.

[fbrc8-erin 272]

Have you replaced the Teflon coupler? How many hours of print time do you have on the machine?

When you replaced the bowden tube: can you confirm that the widened out end is in your feeder and the flat end is the printhead?

Is your knurled sleeve still tight on the motor shaft?

[gr5 2,172]

Examine the tiny pyramids in the gnurled sleeve in the feeder. They can go from pointy to rounded after years of printing. Or after only hours of printing CF filament.

You want the feeder tight. Tight enough that you can see a pattern in the filament. One of these is a little too tight and the other too loose. You want the tension more like the one on the right but not necessarily quite that tight.

Are you certain the bowden is all the way in? It can get caught up on the edge of the teflon part. If you have that stupid aluminum spacer I recommend you get rid of it and print one instead or drill a hole in it so you can see what's inside.

https://www.youmagine.com/designs/um2-spring-replacement

Also experiment a little - cut off the end of the filament so you don't keep grinding the same exact spot in the feeder. Then insert it and when it gets to the end stop it right away and use "move material". Move the material down until it stops. If it's not coming out of the nozzle move it up and push the bowden every which way as you move it back down to get over the various sharp rims it can hang up on.