Bug Some support lines segments are generated from dozens of microscopic segments with added vibration.

[jessidy 0]

Hello!

The ultimaker cura slicer generates strange supports and code for them, adding extra movements, breaking a regular straight line into a huge (dozens) number of tiny segments in the form of a zigzag (the size of the vibration is a hundredth of a millimeter), so all this is visible in gcode, you can see it in the program by playing back the nozzle movement on the layer (everything above 4-th layer in my example).

 

The problem occurs often but randomly, most often when there are straight inclined surfaces that turned out to be parallel to the support line (in my example, this is a zigzag support connecting line) and almost does not depend on the type of support or the model. I have attached files with the most noticeable example.

 

3D printer print almost twice as slowly in such cases, and when passing through these sections, the motors emit an unpleasant buzzing sound, where each sound oscillation corresponds to the movement along one such microsegment.

 

gif animation of a problem!

 

Linux appimage, cura version 5.6.0 (and older versions)

 

cura-settings.curaprofile

egor-angle-a.stl

gcode.zip

Edited December 16, 2023 by jessidy
bug tested in new cura version, added animation

[Slashee_the_Cow 274]

If you could provide the .3mf file (in Cura go to File > Save Project) for the project, that would really help, as it shows your slicing settings, and also the model is correctly placed on the build plate - I import the STL into Cura and it absolutely dwarfs my printable area so either you have a printer with a build area of over a square metre or the STL isn't in mm. Even if I knew the scale, still doesn't tell me your settings.

 

You can go to Speed > Enable Jerk Control > Support Jerk and lower it. That controls the instant speed change on a corner (you can't slow to a crawl for a corner because then it'll overextrude) so that any vibrations produced by a direction change won't be so violent.

Edited December 16, 2023 by Slashee_the_Cow
fixed typo

[jessidy 0]

2 hours ago, Slashee_the_Cow said:

If you could provide the .3mf file (in Cura go to File > Save Project) for the project, that would really help, as it shows your slicing settings, and also the model is correctly placed on the build plate - I import the STL into Cura and it absolutely dwarfs my printable area so either you have a printer with a build area of over a square metre or the STL isn't in mm. Even if I knew the scale, still doesn't tell me your settings.

 

You can go to Speed > Enable Jerk Control > Support Jerk and lower it. That controls the instant speed change on a corner (you can't slow to a crawl for a corner because then it'll overextrude) so that any vibrations produced by a direction change won't be so violent.

I think you do not understand, the problem are in slicer, generating too many short moves for support line

egor-angle-a.3mf

[GregValiant 1,260]

In the Mesh Fixes section turn up the "Maximum Resolution" to 0.60.  With the setting at 0.25 a lot of short lines make it into the gcode.  I didn't count them but there are lines in the range of .006mm long.  With the Maximum Resolution at 0.6 the shortest line in the file was 0.146mm.  That's a big improvement.  The file length fell by 4000 lines.

[jessidy 0]

53 minutes ago, GregValiant said:

In the Mesh Fixes section turn up the "Maximum Resolution" to 0.60.  With the setting at 0.25 a lot of short lines make it into the gcode.  I didn't count them but there are lines in the range of .006mm long.  With the Maximum Resolution at 0.6 the shortest line in the file was 0.146mm.  That's a big improvement.  The file length fell by 4000 lines.

this option work only with object, but not for generated supports, my settings are 0.6667

[Slashee_the_Cow 274]

Change your Support Line Width to 0.8mm to match your wall width - that way you won't have a small line doing laps to cover the whole area of the big lines.

[jessidy 0]

39 minutes ago, Slashee_the_Cow said:

Change your Support Line Width to 0.8mm to match your wall width - that way you won't have a small line doing laps to cover the whole area of the big lines.

I tried that and it didn't change anything.

[Slashee_the_Cow 274]

3 hours ago, jessidy said:

I tried that and it didn't change anything.

It did for me, in some of the nasty spots anyway.

Example, layer 35, support line width 0.4:

Layer 35, support line width 0.8:

The bit on the left where it goes into a triangle that ends with three practically horizontal lines? Gone. That tiny island below it? Gone. The little loop after the main wall? Gone. The tiny island next to it? Gone. And now the bit in the middle  has joined up with the rest of the support (instead of going back on itself), so it'll be stronger.

 

Example, layer 210, support line width 0.4:

I'm not sure I can even count how many lines it's trying to draw in that little bit at the bottom left. Not to mention it than has to retract so it doesn't have to double back on itself.

Layer 210, support line width 0.8:

Now it just draws a smooth triangle-ish which integrates into the support, again making it stronger, and doesn't require an immediate retraction.

[jessidy 0]

the problem are not here, look at that!

 

here are animation:

[Slashee_the_Cow 274]

Okay, now with the animation I can see what the actual problem is - it's not obvious just based on screenshots. I'll have a look.

[Slashee_the_Cow 274]

Okay still not sure I can 100% why - maybe it's trying too hard to follow lines that are a bit bigger than it is? - but increase Mesh Fixes > Maximum Deviation for extruder 2. Not sure if I have to emphasise that, don't deal with problems where changing a setting for a single extruder is the fix that much. Anyway, my testing shows 0.06 is about the minimum to fix it.

[jessidy 0]

20 minutes ago, Slashee_the_Cow said:

Okay still not sure I can 100% why - maybe it's trying too hard to follow lines that are a bit bigger than it is? - but increase Mesh Fixes > Maximum Deviation for extruder 2. Not sure if I have to emphasise that, don't deal with problems where changing a setting for a single extruder is the fix that much. Anyway, my testing shows 0.06 is about the minimum to fix it.

excellent, thank you! it's fixed a problem.

[wwmotorsports 0]

Hi, 

 

I'm having the same problem on 5.6.0, but changing the maximum resolution settings (or any of the other mesh fix settings for that matter) seems to have no impact on the output. 

 

I threw some test cubes at various rotations and a sphere in for slicing, and saw that the issue only seems to present itself for tessellations of the STL that are not perpendicular to the bed of the printer?  

 

I have attached some photos and the 3mf file for this below. If someone could please help me out on this one I would be forever grateful, I'm losing my mind trying to fix this... 

 

Jitter Test.3mf

 

Sliced STLs and Orientations: 

 

Sliced Results Overview:

 

No rotation cube, no artifact in support structure:

 

Z-axis rotation only, no artifact in support structure:

 

Y-axis rotation only, no artifact in support structure:

 

2-Axis rotation, and you can see that the support walls and connecting lines are actually composed of the same microsegments that OP was complaining about. 

 

And here are the results in G-Code Analyzer for that same support structure. You can clearly see the accelerations and decelerations that the printer is trying to achieve for this, and it is vibrating the printers like crazy... 

 

[GregValiant 1,260]

I've seen this in my own prints.

This is your project.  (I've set the line width to .10 and forced compatibility mode for the view.  I think it's easier to see.)

It's obvious that the behavior extends into the skirt as well as that wall of the support structure.

 

This is snippet of the gcode.  It's as if Cura is stepping the line into a series of orthographic moves instead of a single long "point A to point B" move as would be expected.

G1 X645.935 Y286.278 E153.93243
G1 X645.941 Y286.843 E153.99585
G1 X645.994 Y287.368 E154.05509
G1 X646.105 Y287.925 E154.11884
G1 X646.266 Y288.469 E154.18252
G1 X646.464 Y288.956 E154.24154

I didn't find a way to get rid of it either.

I have not seen a bug report on Github that mentions this.  You can go HERE and click on the "New Issue" button to fill out a bug report.

[wwmotorsports 0]

Thanks for the quick reply! Glad that I am not the only one having this problem. 

 

I have created a new bug report for this, linked below for everyone's reference:

https://github.com/Ultimaker/Cura/issues/18045

 

Hopefully we'll get some feedback on this before too long...