Hello everyone, I have a small problem with my prints that I can’t figure out. When I have a change in geometry in the parts (e.g., holes or bulges - see pictures), there is always something that I would describe as a z-offset across the entire part at one level, but then it seems like the printer recovers? Or is it just over-extrusion? Does anyone know this problem and how to get it under control?
Thanks in advance for any hints. The parts are printed with Bambu PLA Matte (new from the box and stored dry in the AMS). Layer and thickness settings are with the default parameters (0.2mm strength, 0.12mm high quality and 0.16mm „normal“).
This is not unusual and there is a simple explanation. When you add some kind of geometry to a print, the internal preassure inner walls are also different as one changes levels. As filament shrinks, one will see this expressed as horizontal layers lines.
One way to visualize this is by printing a benchy with only one outer wall. You will likely see a line on the wall where the deck meets.
There are some workarounds but the quickest way to test this is to increase the number of walls and also change the print order from the default of inner/outer to outer/inner which will force the outer walls to print first thus allowing the filament to cool and harden faster.
Increase wall loops to create thicker walls.
Other Options
- Another option is to slow down the print. Through the silent mode feature which can only take affect after printing starts. It cuts all movements down to 50%.
- You can try to increase the part cooling fan but that may introduce other artifacts such as poor layer adhesion if it’s turned up too high.
- Increase the layer height either globally or using the variable layer height tool.
- Change the infill pattern to something like Gyroid or 3D triangle. This will vary the internal filament placement and also influence outer wall smoothness.
3 Likes
Thanks a lot for the really great explanation and the approaches to solutions 
I’ll try them out on my next print. What surprises me is that it only occurs on the upper sides; according to the theory, it should also occur on the bottom and only in the area of the change, not across the whole layer, or?
Anyway, I’m very grateful for the suggested solutions and will report back as soon as I have an update!
Best regards.