Wall thickness change after Z seam

[stevewhite 0]

This is an anomaly that I'm trying to correct. The pic is a wing section from a 3d printed RC plane. 

At the wing feature the Z seam changed location resulting in a wall thickening for approx. 800mm then gradually returned to correct dimension.

By adjusting the slicer (Cura 5.2.1) Z seam location, I relocated it to a non intrusive place.

I've band aided the problem; however as this has happens on all my single wall prints , I'd like to figure out the root cause.

 

Ender 3V2

Retraction - 4.5

Retraction Speed - 45

Retraction extra prime amount 0.4

 

Not sure what other info to provide

 

Thanks for any insight

Edited February 12 by stevewhite

[Slashee_the_Cow 269]

6 hours ago, stevewhite said:

a wall thickening for approx. 800mm then gradually returned to correct dimension

I'm going to assume that's a typo and that the problem doesn't take nearly a metre to correct itself.

 

If you're printing single wall though: why aren't you using spiralise mode? (Special Modes > Spiralize Outer Contour) - no Z seams whatsoever. Or am I misunderstanding things and it has guts but only one wall around the outside?

 

Also:

• Have you tried using the latest version of Cura? There's been slicing engine upgrades since 5.2.1 which might change things
• Is it happening happening at the start of a Z seam (printer moves there and starts printing) or the end?
• What material are you using? On a Bowden extruder (been a while since I used one) I usually retracted even PLA a bit more than you are.

If it's becoming too thick then the problem is probably overextrusion from something. Have you tried without the extra retraction prime? That will result in overextrusion because it extrudes further than it retracted (to make sure there's sufficient pressure in the nozzle to start printing again).

[stevewhite 0]

Thanks for pointing out the measurement error, very large print ;-}.

 

Plane Print recommends using version 4.13.1, not the newer versions. Probably all the testing was done with this version

The tool path does not change with Spiralized checked

Happens at the z seam start

Normal PLA, due to stringing I'm having to play with the retraction settings, too much then I'm getting holes, too little then more stringing.

I've tried Extra Retraction Prime at different values with no change. Is this setting not the same as normal retraction?

 

thanks for the response, greatly appreciated.

 

Steve 

[Slashee_the_Cow 269]

4 hours ago, stevewhite said:

I've tried Extra Retraction Prime at different values with no change. Is this setting not the same as normal retraction?

At the end of a retraction move, it puts a bit more filament in the nozzle than it retracted to make sure there's enough pressure in there to start printing. This will cause overextrusion because it's using more filament than is needed. You should only need to have this on if you have a problem where when it starts at a Z seam, it doesn't immediately start extruding filament. Generally not a problem with PLA. More of a problem with stringier filaments like PETG and TPU because it's harder for the extruder to grab them and move them as needed.

 

5 hours ago, stevewhite said:

Normal PLA, due to stringing I'm having to play with the retraction settings, too much then I'm getting holes, too little then more stringing.

If you can get an otherwise good print with a bit of stringing, the stringing isn't the end of the world. There's a plugin you can get (just click Marketplace at the top right of Cura) called AutoTowers Generator which will let you print calibration towers where it keeps all the values the same except what you're testing, so you can print a tower for retraction distance and one for retraction speed to see if any of the results are markedly better. Easier than trial and error on regular prints.

 

5 hours ago, stevewhite said:

Plane Print recommends using version 4.13.1, not the newer versions. Probably all the testing was done with this version

Probably, but there have also been major changes in the slicing engine (and by that I mean basically gutting it and replacing it) in the 5.x versions so it could be worth trying. Just remember that unless the problem only comes up when you print it full size, small scale testing is your friend, unless you are either literally made of filament or have enough money that you might as well be.

[stevewhite 0]

Thankyou for the responses, i'll certainly give your suggestions a try.