UM3 issue with extrusion

[mat89 0]

Hello UM colleagues

 

About the machine:

Firmware

Version

5.3.0.0

Latest

5.3.0.20211003

I've a UM3 machine which is roughly 4 1/2 year old, so far it was printig very reliable. The machine has an aftermarket print bed, otherwise the machine is fully original. 

For most of my prints I mainly use a 0.4 AA printcore in 'Printcore 1' slot, in the 'Printcore 2' slot I use sometimes 0.25 AA or 0.4 BB cores, but only very rarely. As print material I use PLA mainly.

Now I got an issue with the 'Printocre 1' slot I think, here is the issue and what I tried.

 

 

Issue: When printing with 0.4 AA printcore in 'Printcore 1', the machine stops extruding material after some hours (after approx 4+ hours I would say). I can see that the extruder is grinding the filament, until it can't push it anymore. 

 

What I did already try to solve the issue:

Changed the filament, but still the same issue

Replaced the AA 0.4 printcore with another AA 0.4 AA printcore, still same issue

Tried a newer Cura version, still same issue

Raised printcore temperature from 210 degrees to 230 for testing, still same issue

Moved the AA 0.4 printcore from 'Printcore 1' slot to the 'Printcore 2' slot, now the core is working as expected again.

 

My conclusion is, that the 'Printcore 1' slot is defective and the printcore in there gets cold after multiple hours of printing. Is this possible or a known issue? The extruder should not be the issue, as it is grinding the filmanet... so it tries to push the material, but it won't move as the printcore can't melt the material. 

 

Any ideas how to confirm this? Maybe I can get the temperature from the printcore through the API and log it to a file on the computer or something like that... 

 

All ideas are appreciated how to identify the root cause and how it can be repaired.

 

BR
Mat

Edited November 19 by mat89

[Dustin 86]

Does not really sound like there is anything at all wrong with the print core.

However it does sound like your front fan is very dirty or dead/about to die.

If the front fan is not properly spinning at expected speeds (and clean) the cooling for the printcore is not optimal and will eventually heat soak and cause jamming like your experiencing