For SLS you do not design like you would for CNC or injection moulding. No draft restrictions, no tool reach, no demoulding angles. What does count: wall thickness min 1 mm (1.5-2 mm under load), rounded internal corners, and where possible print assemblies as one piece. Shell solid volumes for cost savings. Our DfAM check flags what you miss.
Five design principles for SLS
Forget manufacturing restrictions from CNC or injection moulding. Internal channels, overhangs, undercuts: all welcome.
Integrate where possible. A three-piece assembly can be one print. Saves tolerance stack-up, assembly and part numbers.
Shell solid volume. Solid part = expensive material. Hollow with 1.5-2 mm walls and internal ribs for stiffness.
Think about heat management. Large solid zones give warpage risk. Avoid or split them.
Wall thickness within material norms. 1 mm non-loaded, 1.5-2 mm loaded, 2 mm fibre-reinforced.
What to keep from classic CAD
Rounded internal corners stay important. R >=0.5 mm at inside edges reduces stress concentrations and crack risk.
Uniform wall thickness helps. Strong variations can warp during cool-down. Thread holes: model with a drill diameter for tap finishing, or use heat-set inserts. Hinge pins: 0.3-0.5 mm clearance; SLS typically hits ±0.2 mm tolerance.
Press-fits and other post-processing zones: mark reference surfaces, our engineers help with surface treatment or CNC finishing.
What you do differently than CNC or injection moulding
No rotational symmetry restrictions. Your part does not need to run from a single fixture. No demoulding angles needed, SLS has no mould. No tool reach limit, internal pockets are welcome.
Orientation pays off: lay long thin brackets horizontal for better dimensional accuracy. For critical dimensions: mark those zones or tell our engineers which ones cannot lose tolerance.
Ask for a DfAM check whenever you design for SLS for the first time. Small tweaks save time and cost.