Minimum wall thickness for 3D printing
There is no single minimum wall thickness. It depends on the technology, the material and what the wall has to carry. Published values differ between sources, so these are the values Dokimion checks against, with the difference between the smallest wall that can form and a wall you can rely on.
By technology
| Technology | Smallest wall checked | Why it matters |
|---|---|---|
| FDM | 2 nozzle diameters, 0.8 mm with a 0.4 mm nozzle | a thinner wall cannot hold two perimeters and is weak or missing; features thinner than the nozzle or the layer are flagged |
| SLA | 0.6 mm, smallest detail 0.3 mm | a free wall thinner than this tears when the layer peels off the film |
| SLS | 0.8 mm | thinner walls break during cleaning or do not form |
| Metal LPBF | 0.25 to 0.5 mm depending on the alloy, 0.4 mm by default | the wall can form but may be distorted or fragile; see the alloy table |
Metal alloys
| Alloy | Smallest wall (mm) | Reliable wall (mm) |
|---|---|---|
| Ti6Al4V | 0.25 | 1.4 |
| AlSi10Mg | 0.3 | 1.4 |
| 316L | 0.3 | 1.0 |
| 17-4PH | 0.3 | 1.0 |
| IN718 | 0.3 | 1.4 |
| IN625 | 0.3 | 1.4 |
| CoCr | 0.3 | 1.0 |
| CuCrZr | 0.5 | 2.0 |
| Other (default) | 0.4 | 1.5 |
The reliable wall is a working assumption for standard parameters, not a measured limit. Below it the report says "below the reliable threshold for standard parameters", never "impossible".
How the check treats thin walls
The check measures the thickness under each surface and reports the share of the surface that is below the limit. That share is one of the three components of the Kolesar Score. For metal, more than 10 % of the surface below the smallest wall caps the score at 59.
How to fix a thin wall
- Thicken it to the reliable wall, not just to the smallest one.
- Use ribs instead of a thick plate: a thin wall with ribs is stiffer and prints better than a thin wall alone.
- Round internal corners so the wall does not start at a sharp notch.
- Merge a thin feature into a thicker neighbour when it carries no function of its own.
- Change the technology when fine detail is the point: resin resolves features of 0.3 mm that FDM cannot.
Values depend on the machine, parameters and material, and published sources disagree, so confirm them with whoever builds the part.
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