Tells you: The smallest retraction that prevents strings.
Calibration menu › Retraction test · It works the same on any FDM printer. The menu is Bambu Studio's; Orca Slicer has a very similar one, and in other slicers you print the same test with a downloadable model. Can't see the menu?
How
- Print the test tower. Retraction increases with height: by default, from 0 to 2 mm, 0.1 mm for every millimeter of tower (on top of a 1.4 mm base).
- Look at the height where strings stop appearing.
How to read it
Keep the lowest value that comes out clean: more retraction isn't better, it grinds the filament and can cause jams. On direct-drive printers, like Bambu Lab's, about 2 mm is already a lot.
If there are still strings at 2 mm, retraction isn't the problem: dry the filament and check temperature, flow and pressure advance.
Calculator: enter what you read on the piece
The tower starts raising retraction above a 1.4 mm base: 0 + (9.5 − 1.4) × 0.1 = 0.81 mm.
Where the value goes: Printer › Extruder › Retraction.
Helps with:Strings or cobwebs between partsNo plastic comes out, or only now and then
Avoid crossing walls