When there are flat walls on a model the wall quality is affected by features in other locations on the same layer. The effect is along the X and Y axis for the entire outer wall at the same Z height as features like holes or protrusions elsewhere in the model. I’ve noticed this on many different models but this is the most pronounced. Any idea why this happens?
The reason is quite simple:
On the heights with the features the layertime is shorter than on the others and the printer prints therefore slower. So the reason is the printing speed difference.
Two ways to solve this:
You can increase or decrease the layertime in the filament settings - so all layers will be printed with the same speed
Reduce perimeter speeds in the speed settings so that all layers will be printed with the same speed
You can check the speeds of the layers when you click on slice and change in the dropdown of the feature type to speed.
Actually measured the layer shift this morning, 0.1mm on each wall every time there is a hole on any part of the wall, then back to the original layer position when there’s not a hole.
The speed of a flat wall section is between 124 and 150 with a layer time of 9.8-9.6 depending on the width of the diamond shaped hole at that height. The speed of a wall with no feature is 146 to 155 with a layer time of 8.7. If it was simply a function of the slight difference in speed and layer time then the walls should have a gradient effect to them, not an immediate and consistent change as soon as a layer with a feature starts. I will try printing the same model with perimeter speeds set to 124 so there is no difference in wall speed with or without a feature.
The layertime in cooling has direct influence on the printspeed, if the layertime cannot be respected the printer starts to slow down the speed. What you can see in your screenshot.
It also might be possible that the print direction of the perimeter changed on these layers. This would also cause some inconsistency as the printer slows/accelerates and the influence of pressure/linear advance will look different because of the print direction, especially at the corners.
Still does the same thing with inner and outer wall speeds consistent at 124.
My layer time was already longer than the minimum so that is doing nothing, but you’re right in one respect; if I increase the “max fan speed threshold, layer time” it does slow the print speed down to make the the layers take longer, as long as “slow printing down for better layer cooling” is checked.
On the walls with no features all perimeters are printed counter clockwise. On the walls with a hole it alternates direction of each perimeter line, but the outer perimeter is still printed counter clockwise. I see what you’re getting at, how that could cause visual differences, but it shouldn’t. It most definitely shouldn’t be causing a layer shift, especially a 25% layer shift.
Printing direction changes will always be visible on the wall, even if just done in the inner perimeter. Even Infill-Ankers are visible through 3 perimeters and there is no option yet to change the infill anker.
I also noticed with the Bambu/SoftFever slicer that the printing direction is often changed, and this should whenever possible, be prevented.
Unfortunately, I don’t know a solution for the Bambu compatible slicers… I would report it on GitHub.
@kammmolch
Sure, I have tried it with the auto calibration via lidar, as well as via orca slicer all manual calibrations. No difference, unfortunately.
I have created a test object that highlights exactly the phenomenon that the thread creator has. Would you be so kind and print this object with your Bambu? I would like to know if it only affects certain printers or all of them.
I have the same issue on mine. It’s really strange because small recess causes this issue on two sides of large rectangle part in both X an Y direction, about 10cm long on Y direction and 25cm in X direction. I guess you could rotate the part a little bit do it’s not aligned with axis to see if it helps. Cannot investigate it further right now as I torn down the banana bed to fix flatness issue and now waiting for new magnetic sticker + Bambu promised a new bed in a few weeks as they have no stock right now.
I’ve already thought about that. I’ll try it out right away. So rotate the object at 45°, right?
Fortunately, my bed is flat. The v3 beds seem to be a little better.
sorry I can nolonger post images. I always get „access denied“, from multiple devices. this forum is programmed so badly it’s very frustrating…
i just printed it with eSUN PLA+. it took around 20min. 8s layer time which is also for PETG in my generic profiles. it came out… well… short of absolutely perfect on my enclosed P1P. good luck troubleshooting! please post the soulution when you find it, i’m geniunely courious.
edit: i also printed it with 3s layer time to test, this print took only 10min10sek, so half the time. the result is the same. i don’t have any layer shifts and the artefacts are not visible on my prints.
I think it’s more of a slicer issue rather than printer hardware. I re-tensioned the belts, re-run self-test and nothing changed. The issue did not go away regardless of how slow or fast I printed. Then I looked on a tool path in Bambu studio and got suspicious. So I tried Arachne slicer and it made the problem go away by 99%.
