Under Extruding?

[denormalize 0]

My UM2+ (UM2 w/ Extrusion Upgrade Kit) recently started having print quality problems especially on the first layer.

 

After first thinking it was a leveling / distance issue and re-leveling the ben many times with no success, I started to look for other answers.

Reading through posts here and other articles, I believe it is under extruding but looking for confirmation and ideas for fixes.

 

After a failed print, it looks like the feeder is grinding the filament so assumed that the problem was on the hot end.

I've tried everything recommended, cleaned head using the atomic method, removing the head and soaking in acetone, I'm getting clean pulls from the atomic method at this point (it wasn't bad to begin with).  I've even opened up and cleaned the feeder.

 

Went back into CURA and deleted the app configurations folder to ensure that there weren't modifications to the default profile.

 

Adjusted nozzle temps to see if that impacted flow (195-210)

 

Still having the problem...

 

Currently printing using CURA's generic PLA profile, .4mm nozzle, with Amazon Basics 2.85mm Dark Gray PLA.

I've had many successful prints with this combo (same spool) before this started happening

 

I've attached a couple of pictures of the first layer issues.

 

 

 

Thanks in advance for your insights and suggestions!

 

 

[Torgeir 243]

Hi denormalize,

 

Welcome in here!

When I look at your pictures, I think this is not a very much squeezed first layer. Say so because first layer always give high pressure at the nozzle. In your case, the pressure is very lo..

So this one probably is the coupler, the withe device just above the heat block in the extruder. This coupler will over time shrink and have less diameter due to temperature and compression.

So first question; during normal print, how much does the nozzle temperature variate in Celsius? Normally, if your printer is good not more than plus minus 1 deg. Celsius. If this is normal on your printer or just close to this, just continue to next point..

Since you say your filaments is grinded the "only" place to look is at the coupler for reduced diameter that will (most often) stop the filament moving further.

This coupler is a known issue for this problem.

 

Thanks

 

Good luck

 

Torgeir

 

 

Edited May 20, 2020 by Torgeir
Txt error.

[denormalize 0]

Thank you for the response.  I took a look at the coupler.  It looks good and isn’t binding or tight when passing filament through it.

 

took a picture of the grinding on the filament.  Strangely, it looks pretty evenly spaced out.

 

[IRobertI 520]

How is your third fan doing? The one on the backside of the printhead. It should be spinning as soon as you power on your printer or when the nozzle reaches ~40C (depends on the age of your mainboard).

[denormalize 0]

Fan appears to be fine

[Torgeir 243]

Hi,

 

I'll think you have a coupler that's collect filament (as a ring) in between the bottom flat of the coupler and the upper flange of the heat block. I have had only one grinding of filament at the feeder, and this was the cause of my problem!

This ring will build up, and become a solid barrier for the filament feeding system.

 

As I see some black colored remains at the bottom of the coupler flange, this tells a story.

 

Here's a magnified picture of your coupler:

 

Good luck

 

Thanks

 

Torgeir