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Process › Strength› Top/bottom shellsbottom_shell_layers

Bottom shell layers

In Bambu Studio, the profile 0.20mm Standard @BBL A1 sets it to3

It changes with the Bambu Lab A1 factory profile:0.08mm Extra Fine70.08mm High Quality70.12mm Fine50.12mm High Quality50.16mm High Quality40.16mm Optimal40.20mm Standard30.20mm Strength30.24mm Draft30.28mm Extra Draft3Why does it change?

How many solid layers make up the base of the part. With too few, the infill shows from below and the base is weak; with a lot, it takes longer and gains almost nothing.

How it works

The base rests on the plate, so it doesn't have the top's problem of stretching across the air over the infill. That's why it needs fewer layers: 3 layers of 0.2 mm add up to 0.6 mm, enough for a smooth base that supports the infill above.

This setting counts layers, not millimeters: with 0.12 mm layers you need more for the same thickness. To guarantee a thickness in millimeters there's “Bottom shell thickness”.

When to change it

  • A miniature with very thin layers (0.08–0.12 mm): 4 or 5.
  • The bottom of a planter that mustn't leak, or a base you plan to sand: 4 or 5.
  • A drawer organizer nobody will see from below: 2, and you save a little time.

Typical values

ValueWhat for
20.28 mm layers; base that won't be seen
3Defaultdefault
5Thin layers or solid bases

Watch out for

  • With 0 layers, the infill prints straight onto the plate: the base ends up full of holes and comes loose.
  • “Elephant's foot” (when the base bulges out slightly) shows up in the first few millimeters of the part: adding solid layers won't fix it.

Goes well with

What Bambu Studio says

This is the number of solid layers of bottom shell, including the bottom surface layer. When the thickness calculated by this value is thinner than bottom shell thickness, the bottom shell layers will be increased

Bambu Studio tooltip for this setting · AGPL-3.0

Read more at the official source