Blobs in print, Likely from high res STL/Gcode?

General Discussion
1

Describe your issue:

Hello, I printed out this model once using Prusaslicer and another attempt with Cura. The Prusaslicer was mostly good, but I had some support issues and wanted to try using Cure instead (what I am more familiar with), but it appears Cura may be overloading my MCU/KlipperHost connection. I’m getting a lot of blobs on Cura-Sliced print, but it doesn’t appear to be correlated to the seams. I noticed on the outer extusions, its like the nozzle does not move smoothly but instead is kind of pausing at certain points causing the blobs.

Is there a way for me to confirm this is the problem or if this is some slicer settings causing problem?

Basic Information:

Printer Model: Ender 3 S1
MCU / Printerboard: STM32F401 mainboard, connected through USB to Host
System: RPi 4
STL: Printables at 35% scale
Klippy.zip (1.1 MB)

2

Klipper never pauses on high resolution G-code. It either prints or fails with a timing error. (Unless octoprint or other buffering software is used)

You could be hitting this bug in Cura 5.3: 5.3.0 strange artifacts in skin (jagged paths on curved surfaces) · Issue #14811 · Ultimaker/Cura · GitHub
It affects Cura’s toolpath simplifier and leaves very short gcode segments that are considered unremovable as they end up perpendicular to the toolpath’s overall direction. With klipper, this causes surface artefacts as the toolhead slows down to square_corner_velocity when trying to accurately print these short segments.

3

Wow, that does look exactly like what I am seeing, and I am running cura 5.3. Looks like I will be updating or just switching to PrusaSlicer exclusively.