Five classics. Walls under 0.8 mm (deform during print). Solid volumes >=10 cm³ without shelling (warping + high cost). Sharp internal corners (stress concentrations -> cracks). Closed cavities without outflow (powder stays inside). Thread holes thinner than the screw diameter (can crack). Our DfAM check flags these on upload.
The five classics
Walls under 0.8 mm. Our machines can print 0.4-0.6 mm, but the part is not reliable. Recommended: 1 mm minimum, 1.5-2 mm under load.
Solid volumes without shelling. Any volume above ~10 cm³ that stays solid costs material and increases warp risk.
Sharp internal corners. R = 0 mm is a stress concentration where cracks begin. R >=0.5 mm is a cheap fix.
Closed cavities. A hollow part without an opening of at least 5 mm still holds loose powder after printing that you cannot get out.
Thread holes with too thin a wall. Tapped threading directly in polymer works a few cycles. After that it weakens fast. Consider heat-set inserts.
Mistakes only visible after production
Orientation effects. Your 20 mm critical dimension horizontal is more dimensionally stable printed vertically (or vice versa). Without CAD input our slicer picks the most build-time efficient orientation, not necessarily optimal for your critical dimension.
Assembly tolerance stack-up. Two parts individually ±0.2 mm can pair to ±0.6 mm. Tell our engineers which fit dimensions are critical.
How to prevent mistakes before production
Auto-analysis in CAD. SolidWorks, Fusion 360, Inventor, NX have wall thickness and draft analysis. Run it before upload.
Our DfAM check. Free, within one working day, concrete pointers per zone.
Prototype test. If it is your first part for SLS, print one or two before you place a series.
For recurring design patterns (multiple brackets for the same application): DfAM consult to build structural learning for your team.