Filament not coming out of nozzle, while extruder still pushes

[yinjiang 0]

Hello all,

 

I've encountered an annoying problem on my brand new S5. It happened to all my first 3 large prints (ran a small test and it worked fine) - the extruder motor keeps pushing the material but the hot end decides to stop spitting filament mid print, resulting in this huge mess of entangled filament on the back. The pushing force is so strong that it dislodges the feeder tube. Please see attached images - (sorry for the sideway pics)... Everythiing was set properly. AA for PLA, no BB in use.

 

The printer doesn't even send an error message, shows it was done printing - faulty flow sensor too?

 

Did I get a lemon?

 

Your help is appreciated!

[IRobertI 520]

This is a problem with your coupling collet for the bowden tube (the little round piece that holds the bowden in place in the feeder). Get in contact with your reseller to get a new one and you should be good to go.

 

Your flow sensor is fine, the filament is still moving through the feeder normally so the sensor is seeing normal movement.

[yinjiang 0]

14 minutes ago, IRobertI said:

This is a problem with your coupling collet for the bowden tube (the little round piece that holds the bowden in place in the feeder). Get in contact with your reseller to get a new one and you should be good to go.

 

Your flow sensor is fine, the filament is still moving through the feeder normally so the sensor is seeing normal movement.

Thanks for your reply - but how could this coupler dislodge randomly middle print? If this is true then that is a serious design flaw that the whole printer relies on this one tiny plastic clip. 

[IRobertI 520]

Normally it doesn't happen and there are thousands upon thousands of Ultimaker printers using these collets without issue. However, a while back a few bad collets snuck into production. The problem with these is that the tiny little metal teeth inside don't stick out far enough so they don't properly bite into the bowden tube which can cause this issue. Since these collets aren't individually tracked it's very difficult to know which printers _may_ be affected by this issue. Thankfully it's an easy fix if and when the problem shows up.

[yinjiang 0]

12 minutes ago, IRobertI said:

Normally it doesn't happen and there are thousands upon thousands of Ultimaker printers using these collets without issue. However, a while back a few bad collets snuck into production. The problem with these is that the tiny little metal teeth inside don't stick out far enough so they don't properly bite into the bowden tube which can cause this issue. Since these collets aren't individually tracked it's very difficult to know which printers _may_ be affected by this issue. Thankfully it's an easy fix if and when the problem shows up.

Thank you Robert. I will contact them. I'll report back if this problem has been resolved.

[yinjiang 0]

On 7/26/2021 at 11:38 AM, yinjiang said:

Thank you Robert. I will contact them. I'll report back if this problem has been resolved.

Robert,

 

Yesterday I tried to swap the collet with the second feeder with no luck - the same thing happened again. I even cut off the bowden tube by 1/2", where it's damaged buy forcing out of the metal teeth. How likely is it that all collets are defective on the printer? Or could it be caused by some other issues? Thanks.

[IRobertI 520]

Hmm, sorry to hear that. I think the most likely culprit is the collet. Theoretically it could be an issue with the bowden tube being too thin but it's very unlikely I would say. I know there were a few cases of that in the past but that was several years ago, haven't seen any issues with the bowdens like that lately.

I don't know how likely it is that all collets are affected. What you could do as a test is to swap one of the collets from the head with the collet from the feeder. I think in all cases I've seen, the bowden tube has come loose at the feeder end, never at the head, so it should be safe to try.