Process › Support› Advancedraft_first_layer_expansion
Initial layer expansion
How far the first layer of the support or raft sticks out to the sides, like a small rim that helps it grip the plate. At −1 the slicer decides.
How it works
A thin support column has very little footing and can tip over or come loose. Widening just its first layer gives it a “foot” that grips better, using almost no plastic.
At −1 (auto), the slicer uses about 2 mm. A fixed number forces that margin; 0 removes the foot.
When to change it
- Most parts: −1 (the default).
- Several parts packed close together on the plate, where one part's support foot runs into the next: 0 or 1 mm.
- Very tall supports that come loose from the plate (under an airplane wing): 3 mm.
Typical values
| Value | What for |
|---|---|
| −1 | Auto (≈ 2 mm); defaultdefault |
| 0 | No foot |
| 3 mm | Supports that come loose |
Watch out for
- The foot can creep under the part if the part has a base nearby; then it's hard to pull off.
- On a raft, what widens is its whole first layer: useful if the raft lifts at the corners.
Goes well with
What Bambu Studio saysits help card, quoted
What Bambu Studio says
Expand the first raft or support layer to improve bed plate adhesion, -1 means auto
Bambu Studio tooltip for this setting · AGPL-3.0
Read more at the official source
In your profile0.20mm Standard @BBL A1 · -1 mm
In Bambu Studio, the profile 0.20mm Standard @BBL A1 sets it to-1 mm
In other slicers
- Orca Slicer
- First layer expansionSupport
- PrusaSlicer
- First layer expansionSupport material
- Cura
- No clear equivalent.
Names taken from each program's code (Orca Slicer 2.4.2, PrusaSlicer 2.9.6, Cura 5.13.0). Credits