UM3 Problem with the feeder

[BJC 0]

I did a 3d print last night and near the end, the print became loose and what seems to be under extruding. This morning a new print and I can see barely any filament is coming out. I finally realize the feeder has chewed the filament and is not pushing filament out. I tried consulting the manual and pulling the filament hard but it just don't move. I can see the feeder gear spinning when I try to 'unload' the materials, but no matter how hard I pull, it just won't move. Here are my questions:

 

1. How do I unload the feeder now? Do I just have to pull hard enough to yank the filament out?

2. How do I adjust the feeder so that chewing on the filament won't happened, the manual indicates how to do it physically, but no where does it let you know at what level is an appropriate setting on the gear?

 

Thanks

[gr5 2,099]

In the near future, print this thing out:

https://www.youmagine.com/designs/wedgebot-for-ultimaker2

 

That should be your very next print.

 

Well I assume you held the lever up and pulled and couldn't get the filament out.  Did you try while the core was hot?  You need to do this with the core at 150C (or hotter but 150 is safer).

 

If that still doesn't work you have to remove the bowden at either end.  Best to do it at the head.  Push the head towards the front of the machine.  Remove the small white clip around the collet.  Push down and hold down the collet firmly (use pliers if you have to) and at the same time lift up on the Bowden tube.  While doing all this someone needs to hold that lever on the feeder so you need a second person or you need some kind of wedge like the one above (a screw driver might work - make sure the filament slides up and down a few mm before deciding your temporary wedge is working).

 

If it's really really stuck in the core even when the core is at 150C for a few minutes then get a hot flame and an exacto knife - (first practice) heat the blade up until water is boiling and keep going another 5 seconds then use it to slice the pla just above the metal tube at the top of the core.  Now you can slide it out and disassemble.  Don't disassemble without watching my video!  You can damage the core with almost zero force when taking it apart so watch my vid first.

[gr5 2,099]

@BJC contacted me privately and says he removed bowden both ends and remove material.

 

You should be good to go.  If you really want to proceed cautiously (not necessary) you can heat the core up manually through the menu system to 180C (a good temp for pla testing) and then just slide some new filament in while holding the feeder lever.  Then keep pushing and some should come out the nozzle.  You have to push very hard - hard enough to lift the printer - if you want to push as hard as the feeder does but at 180C you should be able to get it to come out slowly without that much force.

 

This also gives you an idea of the forces involved.

 

Your next print should be the wedgebot I linked to above to save your fingers from feeder-lever-pain.

[BJC 0]

On 1/21/2018 at 9:13 PM, gr5 said:

@BJC contacted me privately and says he removed bowden both ends and remove material.

 

You should be good to go.  If you really want to proceed cautiously (not necessary) you can heat the core up manually through the menu system to 180C (a good temp for pla testing) and then just slide some new filament in while holding the feeder lever.  Then keep pushing and some should come out the nozzle.  You have to push very hard - hard enough to lift the printer - if you want to push as hard as the feeder does but at 180C you should be able to get it to come out slowly without that much force.

 

This also gives you an idea of the forces involved.

 

Your next print should be the wedgebot I linked to above to save your fingers from feeder-lever-pain.

 

So I fixed it, started printing and everything is running smooth until the print near the end again where the print is all messed up. So the feeder is grinding the filament again. I cleaned everything according to the manual (taking the feeder apart), the feeder doesn't seem to have any broken parts or wear. The bowen tube seems to be fine and unbroken. The filament I'm currently using is Ultimaker White PLA, and feeder tension setting is set at the recommended (right at the middle mark). I've printed a few items after I got the printer and everything was fine. Until this new print....

 

The print I'm trying to print is a scaled down park, with very very small details and very compact features. Lines and features are around 0.4mm to 0.8mm. Biggest features are 1-3mm walls and blocks. I've printed a first version of the park with less details and less compact features and it was fine. After I added all the extremely fine details and features that's when the feeder is jamming, twice, with the same print. Some features are so fine it shows up on my 3d software (Rhino) and cura, but doesn't actually get printed (0.3-0.35mm). Again, the print twice has always been fine from start to near finish, it is only near the top with all the fine features when it starts to under extrude and jam.

 

So my observation leads me to believe my revision to my model is causing the printer feeder to jam. Is that even possible?

[kmanstudios 1,120]

Try tightening the feeder tension. Recommended is not set in stone. Some filaments are just different enough to require a bit more tension. It can also vary by batches on certain factors such as slipperiness or widths, etc.

[gr5 2,099]

I'm not sure what you are printing but it sounds like it's doing a lot of retractions?  That can cause grinding issues.  You don't want the same spot of filament going back and forth more than 20 times through the feeder.  In fact to test out my theory let's limit it to 10 times so set this:

"maximum retraction count" to 10

and set "minimum extrusion distance window" to 4.5mm (that's typical retraction distance)

 

Reslice and there will probably be a lot fewer retractions and your filament should be less likely to grind.  This is assuming you have a lot of retractions.  It should also speed up your predicted print time.

[BJC 0]

Yea I'm sure now it's the retraction, because when I pull the filament out, there is not just one grind point, but like 4 severe grind points.

 

Thank you so much for your help.

5 hours ago, gr5 said:

I'm not sure what you are printing but it sounds like it's doing a lot of retractions?  That can cause grinding issues.  You don't want the same spot of filament going back and forth more than 20 times through the feeder.  In fact to test out my theory let's limit it to 10 times so set this:

"maximum retraction count" to 10

and set "minimum extrusion distance window" to 4.5mm (that's typical retraction distance)

 

Reslice and there will probably be a lot fewer retractions and your filament should be less likely to grind.  This is assuming you have a lot of retractions.  It should also speed up your predicted print time.