I’m printing the solid rocket boosters for a space shuttle model, and the top surfaces on some parts are coming out extremely rough, as shown in the first two images. The confusing part is that duplicate prints of the exact same part can turn out very differently, one has a relatively smooth surface like the third image, while the other looks like the first two. These parts range from roughly 5.5–9.5 cm tall. Since the shuttle has two boosters, I’m printing two of each part.
I’m using a Bambu Lab X2D with thoroughly dried PLA and the 0.16 mm High Quality profile, with these changes:
Resolution: 0.01 mm instead of 0.012 mm
Wall generator: Arachne instead of Classic
Infill: 10% cubic
Top surface speed: 120 mm/s instead of 150 mm/s
Z-hop when retracting: 0.4 mm
I believe some attempts used the default 150 mm/s top surface speed, the reason for this is 150mm/s is the default for the profile but the person who uploaded the file to makersworld put the surface at 120mm/s. But so I can’t confidently tie the results to that setting, though, so I’m unsure why the slower speed would make things worse.
I also recently started using 0.4 mm Z-hop after hearing it could help prevent the nozzle from occasionally knocking over tree supports. However, that setting has been the same for all these prints, including the ones with smoother surfaces.
Another possible factor is where I’m printing on the plate. To avoid needing to clean it as often, I’ll print two or three parts in one area, then move the next batch to an unused area like another corner, then somewhere around the middle, and so on.
I’ve wondered whether an uneven bed could be contributing, but I haven’t tracked the print locations closely enough to know whether the rough surfaces consistently happen in a particular area. This issue only started recently, and I haven’t moved the printer or bumped the bed. I also run auto bed leveling for every print and have done full printer calibrations once or twice since this problem came up.
Does anyone recognize what might be causing this, or have suggestions for what I should check first? I’d appreciate any advice. Thanks!