underextrusion after brim

[bigmodels 16]

Hoping someone has run into this problem.

 

Ultimaker 3 prints brim fine and then as soon as it goes to print the actual piece underextrusion happens. Photos attached.

 

Just so we can rule out a few things.

-new bowden tubes

-new bondtech extruders as I thought this was the issue, the original ones were getting quite old since the machine has been used a lot.

-new 0.25AA cores, same thing happens on AA0.4 core as well

 

Using standard profiles for different core types, the only thing I really change is infill up to 25%. Played around with temperatures but it doesn't really make a difference.

 

When I pulled out the material it is different from a normal material unload where it gets caught in the printhead and will not unload. There is a bulbous section that travels up 40mm from the end of the material. Photo attached for reference.

 

photo attached with thin lines is with 0.25 core

photo attached with more of a solid look to it 0.4 core

 

I think there must be an issue with the printhead somewhere. Maybe some sort of heating issue.

 

logs attached

 

If anyone can assist it would be greatly appreciated.

 

Peter

 

 

ultimakersystem-ccbdd3000259.5.3.0.boot-7.log.zip

[geert_2 556]

Could it be that the nozzle-cooling fan is not working, and the heat creeps up into and above the nozzles, weakening the filament and thus blocking further feeding? That could produce similar effects. Those fans could suck-up debris and hairs of filament, and get stuck.

 

[libertyhouseplans 2]

The fan was the first thing I thought of, too. I experienced a similar issue in which prints would fail partway through the first layer, because the nozzle temps weren't triggering the front fan.

 

First thing I'd do is this cleaning routine:

https://support.makerbot.com/s/article/1667411590139

 

Then I would run a cleaning routine on the nozzle (hot pull) and start a new print to see if/when the front fan kicks in before the print begins to underextrude.

[bigmodels 16]

thanks for the assistance! I have received some new fans and will get them installed. Will let you know the results once completed.