Issue reproduces with Marlin 1.1.9 and 2.0 builds. Gcode is generated by Cura 4.2.1.
When linear_advance (v1.5) is "off" (M900 K0) - everything is uniform and smooth, only corners are protruding as expected (same gcode, only M900 line is changed).
When linear_advance is on (2), I get these horizontal defects. My calibrated K-value is 2, I am getting same defects with K=1 as well as K=2. Position of defects is repeatable, so it is not random mechanics-caused underextrusion.
My setup uses a BMG Bowden extruder, A4988 drivers for Z and extruder with diode smoothers (X, Y are on TMC2209). I print the PETG with 245 °C, Perimeters at 50 mm/s, Gyroid Infill at 120 mm/s.
3D printer is Ghost4 (extruder is not stock), board is MKS_GEN_L.
I tried the following:
![rHbCY.jpg]( "rHbCY.jpg")
![LCWl3.jpg]( "LCWl3.jpg")
When linear_advance (v1.5) is "off" (M900 K0) - everything is uniform and smooth, only corners are protruding as expected (same gcode, only M900 line is changed).
When linear_advance is on (2), I get these horizontal defects. My calibrated K-value is 2, I am getting same defects with K=1 as well as K=2. Position of defects is repeatable, so it is not random mechanics-caused underextrusion.
My setup uses a BMG Bowden extruder, A4988 drivers for Z and extruder with diode smoothers (X, Y are on TMC2209). I print the PETG with 245 °C, Perimeters at 50 mm/s, Gyroid Infill at 120 mm/s.
3D printer is Ghost4 (extruder is not stock), board is MKS_GEN_L.
I tried the following:
- Removed diode smoothers on extruder and Z - no improvement.
- It seems defect is somewhat connected to infill. Without infill print is nearly perfect. 50x50 box without infill prints perfectly, so it does not look like outer-wall speed-related. Reduced outer wall to 33 mm/s, infill to 100 mm/s (accelerations are also down 750->500, 1000->750), no improvement. Returned to A4988 on all axis - no improvement. Switched to 1/8 step on extruder (maybe it is step speed-related) - no improvement. Disabled infill before walls - no improvement.
- Starting shooting time-lapses, and outer perimeter is extremely weird on some layers (see below), but not all. Position of weird layers is consistent, at the same place on every print.
- Migrated configuration to latest Marlin 2.0. Enabled SQUARE_WAVE_STEPPING - no improvement. Gcode is uploaded here: [s.14.by] Also attached here.
Marlin configuration files also attached in archive. - After inspecting larger parts printed before I enabled linear_advance (on large 100mm circular parts) - I also noticed this defect, more rare though and less pronounced.
