Design guide
Wall thickness
The single most common reason a part fails to print or breaks in service. Get this right and the rest of the design is much more forgiving.
Why thickness matters
FDM walls are built from extruded lines of plastic, typically 0.42 mm wide on a 0.4 mm nozzle. A wall thinner than two lines (≈ 0.8 mm) is fragile, often translucent, and easy to puncture. Below one line wide, the slicer can't print it at all, it gets skipped or replaced with a wobbly single bead.
Aim for walls that are an integer multiple of the line width. The sweet spot for functional parts is 1.6 mm (4 lines), strong enough for most load paths, fast to print, and clean to finish.
Recommended values per material
These are working numbers for our Bambu printers at 0.2 mm layer height. Thicker walls are always fine; thinner walls are a gamble.
| Material | Minimum (mm) | Recommended (mm) | Notes |
|---|---|---|---|
| PLA | 0.8 | 1.6 | , |
| PETG | 1 | 1.6 | , |
| ABS | 1 | 2 | Thinner walls cup as the part cools. |
| ASA | 1 | 2 | , |
| PA-CF | 1.2 | 2 | Fibre length sets the floor, go thicker on load paths. |
| TPU | 1.2 | 2 | Soft material, thin walls collapse under their own weight. |
Measured for a 0.4 mm nozzle. Larger nozzles raise the minimum proportionally.
Common pitfalls
- Surface details modelled at < 0.4 mm, embossed logos and text either disappear or print as messy blobs. Aim for 0.6 mm minimum stroke width and 0.4 mm minimum emboss depth.
- Knife-edge walls where two surfaces taper to a point. The tip becomes a single bead and breaks off. Add a 0.8 mm flat at the edge.
- Internal ribs thinner than the outer wall, print speed jumps around as the slicer switches modes, leaving visible scars. Match rib thickness to the outer wall.
Send it as a STEP if you can
STEP preserves true CAD geometry, so we can re-thicken walls before slicing if they're borderline. STL mesh is a one-way trip, once it's a triangle soup, we can only flag the issue and ask you to re-export.
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Last reviewed May 2026 · Rigid Prints engineering team