Pinpoint Cura setting that causes under extrusion

[Foxyproxy 0]

Hopfully someone here can help me. My walls seems to constantly under extrude. I know the cause... when the printer moves from infill to the walls, it sits still at the start of a wall and retracts (6mm) and primes (6mm) again. Then it starts printing the wall. But this retraction and priming results in underextrusion at the start of the walls. At first I thought it was pressure advance but its not as I tested with that off. Anyone has any ideas?

[GregValiant 1,287]

With your model loaded and Cura set up to slice - Under the "File" menu is "Save Project".  Use that and post the 3mf file here and someone will take a look.

Off the top of my head and from far away it could be a couple of things like Retract at Layer Change, Retract before Outer Wall, or it could be that your retract speed is slow and so the retract and prime are taking too long.

 

The 3mf file is the best to troubleshoot with as it will have your printer, settings, and the model in it.

[Foxyproxy 0]

Here's the requested file

CE3PRO_testprint.3mf

[GregValiant 1,287]

From what I see in the gcode from your 3mf file that shouldn't print at all.  Your starting gcode is just enough to keep Cura from adding the temperatures.  The results are this:

 

;Generated with Cura_SteamEngine 4.12.1
M82 ;absolute extrusion mode
START_PRINT BED_TEMP=80 EXTRUDER_TEMP=235
G92 E0
G92 E0
G1 F2400 E-6.5
;LAYER_COUNT:25
;LAYER:0
M107
G0 F12000 X95.924 Y95.614 Z0.2
;TYPE:SKIRT
G1 F2400 E0
G1 F1500 X96.458 Y95.173 E0.0254

 

That says the first extrusion is happening with a cold nozzle and cold bed and no homing.  How are you handling all of that?  Are you printing via Octoprint or something?

 

When you vary the line width like you are then the flow rate through the nozzle varies.  That causes varying pressure in the nozzle.  On a personal note - I never use Retract Before Outer Wall or Retract at Layer Change as I have found them to cause under-extrusion at the start of a layer.  On a small part like you have there it may not be the issue, but on large parts that can have a lot of travel before the start of a layer I have found it can have negative effects.

For reference my printer is an Ender 3 Pro and my StartUp Gcode is vastly different than yours.

Edited November 26, 2021 by GregValiant

[Foxyproxy 0]

I use Klipper and Fluidd. The start gcode calls on a macro in klipper and passes through the temps. The macro handles the rest. Good point on line width, I'll make sure to change it. Already disabled retract before outer wall and layer change. That said, I've found my issue. After checking e-steps calibration, I found that it extuded only 18mm instead of 50mm and was squeaking a lot. Turned out the extruder arm has a crack in it. Time for an upgrade.

[GregValiant 1,287]

The winner of the "Worst Extruder Arm from Creality" contest is over on Reddit.  It was broken right out of the box.  That's an incredible "Mean Time Between Failure" rate of 0.00000.

[Foxyproxy 0]

How can they not have updated their design yet... XD

[GregValiant 1,287]

C'mon Man...  They sell the aluminum replacements at a premium.  Everybody who buys any Ender model or a CR10 ends up paying more because they must replace the arm and that replacement is always sooner and never later.

[Foxyproxy 0]

hahaha yeah i suppose thats right