Printing with Formfutura's Flexifil on UM3. Print fails after several hours

[medicalmodeller 5]

Can anyone help me?   I have an UM3 and am trying to print something that takes 6 hours.  I am printing Flexifil.  It says print 220-260C.   The print failed after 4 hours.  I assumed that the nozzle was jammed so removed the filament and I could see that the feeder had been grinding without the filament moving.   I cleared the nozzle using the Atomic technique.  I then opened the feeder to clean it out as I have not done this for ages.  I reassembled and started the print again.  I increased the nozzle temperature to 260.   This time it failed with a jam after about 1 hour.     

Has anyone any advice on how to print reliably with FLexifil???  Should I tighten the feeder to maximum??  SHould I increase the temperature even more?

Thanks

Edited February 15 by medicalmodeller

[Enigma_M4 123]

Hi,

is your front fan clean and running? Your problem sounds like there's heat creep involved.

Regards

 

[medicalmodeller 5]

I wonder if its retraction with this flexible stuff.  I will turn off and try again

 

[medicalmodeller 5]

Ugh!.  Failed again.   The filament bunches up in the feeder.   The nozzle does not seem to be blocked since if I unload and immediately load, material comes out the nozzle

 

I have increased the grip in the feeder

I have increased the hot end temperature

I have slowed down the speed to 20

I put a fan on the feeder to cool the filament

 

I am running out of ideas.