"Move material" grinding filament

[JohnK 30]

Hi all,

I recently upgraded the feeder on my Ultimaker 2 to Roberts alternate feeder V2, mainly to print flexible filaments. I'm very happy with the way it performs, prints no problems with every material I've tried, for long periods of time.

The only small issue I have is when loading filament, I normally go to push the filament through manually, then go to "'move material" and feed some through the nozzle.

The thing with doing this is, it grinds the filament unless I go extremely slowly, I have to be ever so careful, regardless of tension on the feeder. But then when printing, regardless of speed, there are no problems whatsoever.

Does the "move material" function have a different amount of torque or something like that ?

[gr5 2,094]

with "move material" it's easy to go much faster than the printer can normally print. I don't get grinding material though - your tension is probably too loose. The forces in there are impressively high - about 10 pounds or 5kg force is being pushed on that filament before the feeder skips backwards (which you want to happen during move material versus grinding).

Here are some photos giving you an indication of the desired tension - the filament on the left had not enough tension. The one on the right might be a little too much.

[JohnK 30]

Thanks for the quick reply..

The markings on mine are kind of in between the two examples you posted. I'll take a picture later on and post it up.

I might try and go tighter, just a little scared of putting too much tension on the feeder. I'm using the default yoke on Roberts feeder and my tensioned spring length is around 12.5mm.

Thanks

[Labern 774]

The feeder has a built in safety feature where it reverses (kicks) back a few mm if the pressure build up becomes to high. This stops the feeder grinding the material. To don't be scared to add more tension. By memory my spring length is between 11 - 12 mm

[JohnK 30]

Thanks so much guys. It seems when I thought I was putting a lot of tension on things, I was actually not putting anywhere near enough.

I've dialed in a fair bit more tension on the feeder, spring length (when compressed) is now down to 10.5mm. Now during "move material" I can go a lot faster than before and it continues to extrude without grinding. When I really crank things up fast, it skips back as it's supposed to do.