I have a bambu H2S. I did open a support ticket, but it seems outside the expertise of my agent.
When I print between speeds of 160-250, I get very bad walls. Undulating scars that climb in the direction of travel. Converted to volumetric flow rate, it’s at flows between 22-30. I have tried different brands of PLA+ and PETG, the issue presents in both filaments. It presents with hotter, standard and colder nozzle adjustments. I’ve tried slowing down accelerations to 3500 and 2500, regardless, the scars occur if the aforementioned speeds are hit. I’ve tested this at stock volumetric flow rate model orientation. 90°, 180°, 45° and 135°, so it doesn’t seem to be a single motor to blame unless something in the combined motor system is severe enough to affect both motors.
Other things I have attempted.
1.) Ruled out AMS by doing direct external spool.
2.) Followed the wiki on belt tension.
3.) Cleaned pulley with WD40, rubbing alcohol, lubricated pulley.
4.) Cleaned and lubricated all linear guide rods.
5.) Cold pulls
6.) Drying filaments. Different plastic types. Different temps.
7.) Removed hotend, tightened the screws on the back of hotend, reinstalled.
8.) Same as 7, but tried tightening down 3 screws with pressure towards build plate as hotend was reinstalled.
9.) Same as 8 and 7, but tried pressure away from build plate as hotend was reinstalled.
10.) Tried other build plates.
11.) I have had motion calibration plate from the beginning. Mentioning in case there is a known issue with that.
12.) Factory reset. No dice.
I suspect the extruder or the entire XY motor system is resonating unexpectedly bad at those specific speeds due to a flaw. I have been getting “Extruder overloaded” errors with PLA, but on physical observation, it is having absolutely no issues extruding filament. Filament comes out, but it still says it’s overloaded. One click of “Fixed, resume” and it’ll work just fine. Doesn’t occur with petg.
