I have been printing on the P1S with Bambu Lab’s white PETG. The model I am working on has a domed top, so I have enabled variable layer height to ensure that it comes out as fine as possible, and when printing a single model, the surface comes out looking pretty good.
However, I have tried to print this model in a batch of four, and both times I have had these artifacts on top of the print (each of the four models in the batch has the artifacts):
It’s really strange because the whole model looks great except for the very top. It seems that the artifacts begin to appear right where the layer height starts decreasing.
Part of me thinks that I need to turn up the nozzle temperature by 10 degrees C, but I figured I would post this to ask if anyone else has run into a similar issue, and how they solved it. Any advice would be appreciated. Thanks!
Maybe it has to do with the printing speed. Take a look at this thread: **Cloning Problem**
If this problem appears with multiple parts, maybe it’s your nozzle collecting some filament around it and sometimes this blob goes off the nozzle and goes in the part.
When you say a batch of four, are you printing four parts simultaneously or by object (i.e. one at a time)?
Four parts simultaneously
I cannot be precise without seeing the model slicer preview, but if I need to guess:
- When printing a single model, the print speed is limited by the filament layer time;
- by increasing the material per layer 4x and further travel movements, the layer time limit is no longer relevant, which results in printing at a higher speed;
- other differences may also influence quality, such as cooling;
- you can easily compare and tune the print settings by comparing the single and 4-piece print previews.
A more uncomplicated and, in my opinion, more practical option is to change the print sequence to “by object”. This option has many advantages and, in your case, is likely to work without any further changes. Nevertheless, you should check the preview windows to identify any issues. The downside is the need for larger clearance between parts.
If you need help tweak the print settings based on the preview windows, please share some print screens.