if you have modified the filament profile, for example, to push the flow rate up, I have seen this produce exactly the same results you show above even running the same gcode on two identical P1S
so the questions are:
non-bambu filament?
did you modify the flow rate or other tweak/speedup?
Canāt say for sure itāll help. But get in the habit of doing that whenever you change something in the mechanics, like belt tension and/or cleaning/lubricating the XY gantry.
I meant āvolumetric flow rateā max value. if you increase this to get faster prints, it can push filament beyond what the printer can maintain.
in bambuās slicer, generic filaments default to very low values like 7 mm^3 when they can probably do 12. bambu filaments default to 15 or higher (depending) so they seem like they perform better with the default slicer profiles. not sure if this is bambu steering you to their filaments or based on their real experience with 3rd party filament.
I see! Flow Rate is 11.5.
Iām testing FLOW now, and for Flow 120% it seems a lot better. But dimensional accuracy is way offā¦
Question is why on my first P1S everything is perfect, second one, on same identical settings, the results are awful.
I know no machine is identical to another, some differences are acceptable but this is quite a puzzleā¦
Even two āidenticalā printers can have slight mechanical differences, like friction, free play, mechanics.
Means that what works just fine on one printer might not work out the same on the other.
You said you checked different flow ratios - by playing with the values but not by doing a filament calibration
Do yourself a huge favour and run the calibration on both machines.
For the ābadā one also run the hardware calibration.
No need at this point to change the flow ratio unless the calibration patches indicate you should - it is just a confirmation here.
Letās say the first printer needs a flow ratio of 0.97 while the other needs 1.02 - well within specs and a totally normal difference.
Calibrate both to their correct values and you should get matching results.
If there is a huge difference of lets say 0.25 or more in the flow ratio calibration values it could indicate troubles with the extruder, hotend or transport system.
Best option with two printers would be to just swap the hotends to see if the problem swapps as well.
All filament related troubles checked/eliminated but still no 100% joy ?
Assuming you did the hardware rattle calibration I would now go and check the movement of the belt system.
Do the x and y belts run freely in those rear pulleys or are they rubbing stuck at the top/bottom?
Do all the axis move smooth when moved by hand and without any binding/jumping?
If that is also all fine or got adjusted to no avail it might mean that you have to compensate for the issues by adjusting the print settings.
The filament is calibrated for both machines.
A flow ratio between 90-110% is completely acceptable, but definitely not 120%. This causes very large deviations from the nominal dimensions of the models.
I donāt see the point of doing mechanical calibration on a good printer (#1), everything is as it should be there. The prints are perfect.
As for the pulleys, everything is fine, the belt moves freely, it doesnāt rub against the pulleys.
I donāt like the idea of āā"adjusting" the print settings to be more or less satisfactory. At the moment Iām looking for the reason for this printer behavior, especially since a month ago everything was perfect.
Something happened. Iām trying to figure out what it could be.
Although recently one of the pulleys has been making noise (nothing bad, itās just louder than the others), unfortunately I have no idea which one it could be - the sound carries through the casing and itās hard to tell exactly which one it is.
Iām trying to narrow down the suspects so I can do more thorough testing and possibly use parts from a āgoodā printer.
Thanks for your help and I look forward to your further suggestions!
Iām very curious about whatās going on.
I managed to find the fault!
The PTFE tube inside the printer was very worn and while the filament moved very smoothly towards the printer, there was considerable resistance in the opposite direction (when retracting).
After replacing the PTFE tube, the problem disappeared completely!
Thank you very much for your help and best regards!
uki
