I'm facing weird "pillars" of underextrusion on outer walls of my XYZ test cube.
On the pictures below I`ve printed PLA test cubes with a 0.4 mm nozzle, 0.2 mm height and 210/50 °C hotends/bed temperature.
Gaps are appearing in walls parallel to both X and Y sides. The pictured side is parallel to Y face.
I'm slicing with Cura, my printer is a homebuilt around Anycubic Kossel with Marlin 2.0 onboard.
What have I tried already:
1. Temperature from 190 to 210 °C
2. Retraction from none to 6 mm 60 mm/sec
3. Tuning down Jerk in Marlin from [10,10,0.3] to [5,5,0.3]
4. Tuning down acceleration from 3000 to 1000
5. Tuning print speed from 60 to 30 mm/sec 6. Checking belts, nozzle and extruder.
UPD1: tried removing combing - it did not help. But I noticed that my printer accelerates strangely at this parts
UPD2: could it be stuttering? I have 320 segments per second with block buffer size of 8 bytes(?)
UPD3: lowering segments count to 120 and raising block size to 32