This is pretty entertaining and useful at the same time. Google Notebook LM deep dive from Bambu Wiki on retractions
https://notebooklm.google.com/notebook/661c9363-1a01-4d97-8fc2-73221e0ef9d3/audio
https://wiki.bambulab.com/en/software/bambu-studio/parameter/retraction
Hey, I had a bunch of issues as well, especially with gaps and under-extrusion after travel moves (A1 mini with hardened 0.6 nozzle) and after a lot of testing I finally fixed everything for me (mostly)
I’ll just share them here, hoping it might help some of you guys with this strangely fickle nozzle
biggest fix was the setting “extra length on restart”, currently unavailable in Bambu studio. I had to get Orcaslicer for this. setting it to around 0.08mm closed all the gaps I had in my walls etc, but causes over extrusion on top layers sometimes, which I mostly fixed by reducing the top surface flow rate to 0.98
“travel distance threshold” (for retraction): 2 mm
retraction length 1mm
wipe after retraction, 1-2 mm length
precise wall: on
outer/inner wall order
Arachne on (set minimum wall width to 50% helped a bit with thin features made for 0.4 nozzles)
keeping travel speed and acceleration high helped with retraction
also set first layer flow rate to 1.02 (for some reason first layer always under extrudes with 0.6 nozzle, regardless of the filament I use)
hope this helps anyone o/
Honestly, I think it makes total sense. The X1/P1 simply can’t flow well enough to give you what you are looking for.
When I played with the profiles, I first thought they were garbage too… then I sat down and did the work to “improve” them, only to find I was back very close to what Bambu offered after 4 or 5 hours of tuning. It was a total waste of time to realize the base profiles are optimized ok, at least for the stock hardware.
Being the A1 has a longer heating zone, I’d bet it has a greater flow rating (and potentially better extrusion system to go along with the higher flow). More flow, allows larger nozzles to realize speed benefits. For the X1/P1, the nozzle is running at max speed around max volumetric flow with a 0.4mm, so moving to a 0.6mm or 0.8mm nozzle you are forced to slow down to the print speed to balance how much filament the system can extrude. So, the only gains are from the higher layer heights. In my testing, I felt like the extrusion system was the biggest limit. I found that, for certain models, it could flow enough to realize a good speed, but for normal models with lots of starts and stops or changes in direction, it just couldn’t keep up. That said, I didn’t do an exhaustive assessment, as it looked like a waste of time to keep drilling down on what the actual problem was. It was clear, the base profile is about all you are going to get.
However, I did find situations and tricks that made the 0.8mm useful. For example, a 0.40mm layer height (opposed to a 0.12mm - 0.20mm) doesn’t need a ton of floors and top surfaces. Those can be lowered or halved in many cases. Same with the walls, a 0.8mm walls from the base 0.8mm profile is normally enough, opposed to two 0.40mm walls. Also, the 0.8mm nozzle prints feel a little more stout, even with equal wall and floor/top thickness (I assuming the gaps in two 0.4mm walls is weaker than no gaps in one 0.8mm wall). So you’ll find a value there. But stay away if you have unsupported overhangs. Taller layer heights perform noticeably worse than short layer heights.