SLS Design-Rule Checker
Updated
Enter a few dimensions for a PA12 gray nylon SLS part and get Pass, Caution or Fail for each design rule, with the threshold and the reason behind it.
Published guidance from Forge Labs' SLS design guide, not Apis test results.
Results
Enter a dimension to see Pass, Caution or Fail for each rule. Empty fields are skipped.
Method
Where every value comes from.
These are published bureau guidelines. Apis has not published its own test results for these rules yet.
Supported wall
- Minimum: 0.8 mm
- Recommended: 1 mm
- Critical: 0.45 mm
Supported walls: minimum 0.8 mm, recommended 0.8 to 1.0 mm.
Forge Labs, SLS Design GuideUnsupported wall
Hole diameter
- Minimum in a 1 mm wall: 0.5 mm
- Minimum in a 3 mm wall: 0.6 mm
- Minimum in a 6 mm wall: 0.7 mm
Minimum hole diameter by wall thickness: 1 mm wall, 0.5 mm; 3 mm wall, 0.6 mm; 6 mm wall, 0.7 mm.
Forge Labs, SLS Design GuideClearance
- Minimum: 0.5 mm
Clearance between moving or assembled parts: minimum 0.5 mm.
Forge Labs, SLS Design GuideHinge clearance
Pin diameter
Engraved or embossed detail
Extruded text
- Flat minimum: 1.5 mm
- Vertical minimum: 2 mm
Extruded text: flat 1.5 mm, vertical 2 mm.
Forge Labs, SLS Design GuideEscape holes
- Single hole minimum: 4 mm
- Large part size: 50 mm
- Large part hole count: 2 holes
- Large part hole minimum: 2 mm
Hollow parts need at least one escape hole of at least 4 mm. Parts over 50 x 50 x 50 mm need at least 2 holes of at least 2 mm each.
Forge Labs, SLS Design GuideExpected tolerance
- Percent of nominal: 0.3%
- Minimum band: 0.3 mm
Tolerance: ±0.3% with a ±0.3 mm minimum.
Forge Labs, SLS Design Guide
Hole interpolation
For walls between the 1, 3 and 6 mm table rows, Apis interpolates the minimum hole diameter linearly. Below 1 mm the 0.5 mm row applies; above 6 mm the 0.7 mm row applies. Results that use a value between rows say "Interpolated by Apis between Forge Labs table rows".
Escape hole reading
We read "over 50 x 50 x 50 mm" as all three bounding box sides over 50 mm. Smaller parts pass with one hole of at least 4 mm. Accepting 2 or more holes of at least 2 mm on a smaller part is our reading of the guide.
Sources: Forge Labs, SLS Design Guide (checked 2026-10-30).
Send your file for an engineering reviewFAQ
SLS design rule questions.
01What is the minimum wall thickness for a PA12 gray nylon SLS part?
Forge Labs' SLS design guide gives 0.8 mm as the minimum for a wall connected on two or more sides, with 0.8 to 1.0 mm recommended. A wall connected on one side or less needs at least 1.5 mm. Walls under 0.45 mm may over-sinter.
02How much clearance should moving or assembled SLS parts have?
The guide gives a minimum of 0.5 mm between moving or assembled parts, 0.6 mm of hinge clearance and a pin diameter of at least 0.8 mm.
03How big should escape holes be on a hollow SLS part?
The guide calls for at least one escape hole of at least 4 mm. Parts over 50 x 50 x 50 mm need at least 2 holes of at least 2 mm each.
04What tolerance should I expect on an SLS part?
The guide gives ±0.3% with a ±0.3 mm minimum, so a 50 mm dimension expects ±0.30 mm and a 200 mm dimension expects ±0.60 mm.