Outer surface of thin part has remnants from backside ribs

[coseng 4]

I have a large (650x650x950) heated chamber CoreXY printer for printing ABS made with a Duet 6HC mainboard and E3D supervolcano hot end and 0.8mm diamond nozzle and am using Cura for slicing.  I have generally very good results with thicker parts that have infill, but on thin wall parts have issues with the main outer surface showing remnants from ribs on the opposite side.  The base of this part is about 400mm long.  The g-code preview shows the printhead paths as smooth, but the resulting part is anything but smooth with the ribs on the opposite side clearly showing through.  I've had this problem since finishing the printer and have been using Cura 4.13 since the early 5 releases with variable line widths were providing weird results.  I thought the 5.2 release with a specific mention of mimicking injection molding could be an improvement, but so far it has not been.  Is there a special mode to activate this feature or do I have some settings wrong?

 

 

 

bad-outer-surface.curaprofile

 

Any suggestions to improve any aspects of print quality are appreciated.

 

Happy holidays to all.

 

 

[MariMakes 192]

Hey @coseng,

Happy holidays 🎄
 

There are settings that you can change to improve the variable linewidht behavior.

You can read more about them here: 

https://support.ultimaker.com/hc/en-us/articles/4792077687068

 

It might also be a case of buffer underrun if you are not seeing any hints of the artifacts in the preview. 🤔
Do you have your Maximum Resolution or Maximum Deviation too Low dramatically increasing the amount of Gcode your printer needs to process?
We also see that in some cases it helps to turn off the interruption recovery feature on your 3D printer.

 

Do you have a project file for us? It contains the printer and settings we need for troubleshooting. 
To save a project file go to File -> Save project.

[coseng 4]

@MariMakes, thanks!  Happy holidays and new year to you too!

 

I can print lots of other thicker geometry without any problems, but these thin wall parts always seem to have these artifacts.  The Cura preview window seesm to show full width wall paths, so not sure where these are coming from.  The same part but thick with infill instead of thin with ribs prints fine.  Those marks on the backside are where I cut off some ribs for printing stability.

 

Here is the project file.   subframe-chain-solid.zip

 

Regards,

 

Chris

 

[MariMakes 192]

Hey @coseng,

 

Thanks for sharing your gcode. But it does not contain the information I'm looking for. 

 

Do you have a project file for us? It contains the printer and settings we need for troubleshooting. 
Can try to follow the following steps:
- Click File in the top right corner
- Click Save project

- Save as a Cura Project 3MF file (*.3mf)

[coseng 4]

@MariMakes Sorry about that, I dropped the wrong file in!  Here is the 3mf file.

 

Hope you had a nice New Year's.

 

subframe-right-3mf.zip

 

Chris

 

[PaulKuiper 8]

Hey @coseng,

 

You currently have the wall ordering set from inside to outside.

It think it will already help a lot to set it to outside to inside: 

 

The harder to print inner wall structures will have less influence on the outerwall in this case.
I also noticed that you use random seam, you might want to try the front left corner instead:

    

 

[coseng 4]

Thanks for the reply.  I tried running outer wall first, but then had issues with the printed bead sometimes falling off the part and the show-through problem still happened.

 

It seems that for the slight overhangs having the inner wall printed first gives the outer wall something more to adhere to and prevents the falling off.  Switching to inner wall first eliminated the falling off problem and the show-through problem remained unchanged.

 

Chris

[GregValiant 1,141]

Welcome back Coseng.  Remember...

There is no replacement for displacement.

Edited January 10 by GregValiant

[coseng 4]

Ha, thanks!  Its actually about displacement per unit time.   😉

 

Chris