Blobs produced at end of long straight lines on every layer when doing spiral mode

[davidjdixon]

Bambu Studio Version

1.8.2.56

Where is the application from?

Bambu Lab github releases

OS version

macOS 14.2

Additional system information

No response

Printer

Bambu Lab X1 Carbon

How to reproduce

In my example:

1. Use a 0.8mm nozzle, set line-height to 0.8mm, outer wall width to 2mm (this is an extreme setting, but works in the right circumstances).
2. An an object with a straight edge of around 13mm followed by a curved corner (a simple curved rectangle would be fine)
3. Set print to work in spiralised (vase) mode with zero bottom layers
4. Start print and watch results at the junction of the long straight line and the curve.

Actual results

At each layer, the print head will pause for a fraction of a second and purge excess material at the exact same position. This is not a traditional seam line as the print head isnt jumping to a new layer, but instead it seems to pause to finish an extrusion is believes hasnt fully completed.

Note, this only happens at the end of long straight lines, by adding a tiny curve along the long line, it stops this purging behavior.

Expected results

The print head should not be pausing or creating such excessive extrusion.

Note: within Bambu Studio, there is no indication that this pause is occuring, and no visible seem is shown in the rendered output in any of the visualisation modes.

Project file & Debug log uploads

n/a. common issue

Checklist of files to include

• [ ] Log file
• [ ] Project file

[QingZhangBambu]

if you don't mind, could you provide the 3mf file you used?

[davidjdixon]

example-blobs.3mf.zip Apologies. I didnt see the notification for this. I have attached the 3MF for review

[davidjdixon]

For reference, I'm also attaching a small video that shows how the printer is behaving during the print that creates the issue (ie the pausing/purging)

https://github.com/bambulab/BambuStudio/assets/452007/1691f6dc-2b85-4956-b2a4-160568680ed2

[davidjdixon]

For additional comparison, I've added a new plate to the 3MF which has the exact same model with small negative cylinders added to create a tiny "bump" in the long lines. This "hack" stops all blobbing for a reason I cant fathom.

example-blobs.3mf.zip

[QingZhangBambu]

I slice the 3mf file there is no abnormal E in gcode cmd. Could you provid the gcode file for us to print in machine to reproduce it?

[QingZhangBambu]

And The version shows 1.9, Bambu Studio does not generate the 3mf.

[davidjdixon]

You're quite right, that specific output was from OrcaSlicer. I have partially replicated the issue on Bambu Slicer. Since that slicer has hard limits on line-height (which is not the same on Orca Slicer), for all layers (bar the first) I am unable to push the line height above 0.64mm on a 0.8mm hotend. With this line height, I am unable to replicate the issue. However on the bottom layer, a 0.8mm line height is possible, and on THAT layer, I do see exactly the same issue. This leads me to believe it's a problem somewhere in the extrusion calculation that breaks down after enforced line height.

3MF and GCODE is attached which provides this behaviour. example-blobs-bambu-studio.3mf.zip example-blobs-bambu-studio.gcode.3mf.zip

Note, I would be looking to have the oozing prevented while allowing the extra line heights instead of an arbitrary limit on line heights being applied to hide the issue (as that just pushes the resolution downstream to Orca Slicer who do not have the arbitrary enforcement).

[QingZhangBambu]

thanks for the files. i will check this and talk to concerned staff. and if you don't mind you can post the PR link you push to orca, concerned staff will check, if they merge the code, we will thanks you in release note.

[davidjdixon]

Thanks and not a problem. The link for the Orca Slicer issue has been reported here: https://github.com/SoftFever/OrcaSlicer/issues/3461

[mxbng]

Hello everyone,

Is there a solution to this problem? I have the same

[QingZhangBambu]

@davidjdixon Holle, this issue has been fixed, please update to the newest firmware

[LJorissen-1]

@QingZhangBambu Hi,

I've noticed a similar issue on my P1S, but it seems there is only a firmware update available for the X1c. Will a fix for the P1S printers follow?

Additional info related to P1S: while printing wider objects with the same settings as davidjdixon (nozzle: 0.8mm, layer-height: 0,8-1mm, line width: 1mm - I was using these settings because I'm interested in the shape of the lines on the first layer. I'm not planning to use these settings on multi-layer prints), printing is fine over short distances (e.g. about 5cm). However, at the end of longer lines (20cm) the print head stops moving and keeps extruding material for a few seconds, resulting in a huge blob at the end of the line.

I think I have a timelapse video of this on my printer. I will upload it later if necessary.

[mxbng]

@LJorissen-1 @QingZhangBambu Hi, i also have a P1S. Is the update related to the printer or the slicer?

[LJorissen-1]

I assume that it is an update related to the printer, considering that QingZhangBambu asks to update to the newest firmware.

According to this page there is a new firmware update for the X1c released on the 8th of April.

The last firmware update for the P1S was released on the 22nd of January according to this page.

[QingZhangBambu]

@LJorissen-1 Relevant staff stated that p1s was repaired, please update and check. If you still have problems, please open a new issue and upload the 3mf and gcode files and I'll talk to the concerned staff.

[mxbng]

@QingZhangBambu Hello, I updated everything yesterday, but unfortunately I still have the problem. I open later a new issue and upload the desired files.

[MBLine]

@QingZhangBambu I opened a new issue #4987

[QingZhangBambu]

@mxbng @LJorissen-1 OK, I‘ve talked to them and the concerned staff said that it will fixed in the next P1S firmware version.