SLS fine detail is a common question from customers printing miniatures and small parts. On 3D Printing Stack Exchange, someone planning to print a 150 mm model for painting asked whether SLS could reproduce small details like the faces of tiny crew figures.
How much SLS fine detail can you expect?
It depends on the powder grain size and the laser spot. Detail in the 100 to 200 µm range is generally achievable. One answer said industrial machines use particles between 20 and 80 µm, mostly 40 to 60 µm. It put a typical nylon laser spot around 50 µm, which it called comparable to resin printers, and estimated miniature details at about 100 to 200 µm. Another answer noted that Sinterit’s desktop printers use 50 µm nylon powder that shrinks somewhat, so features slightly under 50 µm may still show.
What do process guides publish?
- HP’s MJF handbook lists a minimum printable feature width of 0.1 mm, a minimum slit between walls of 0.5 mm, and minimum hole and shaft diameters of 0.5 mm.
- Rapidobject’s SLS/MJF guidelines say embossed and engraved structures can be printed from 0.25 mm. Readable text needs a 0.5 mm minimum line width and at least 2.5 mm total height (about 7 pt), with 4.0 mm (about 11 pt) recommended.
Treat these as limits for the process at its best. Small features still depend on orientation and finishing.
What about the surface?
One answer described an SLS model bought from Shapeways: no visible layers, but individual grains visible under magnification. For painted miniatures, that grain texture can matter as much as the feature size.
How should a bureau handle these requests?
- Ask for the smallest critical feature in millimeters, not “high detail.”
- Offer a test piece with several levels of detail, as one answer suggested, before printing the full job.
- Warn that media blasting or smoothing can soften the finest details.
- Recommend resin printing when the detail is smaller than your powder process can reliably hold.
Related on the Solvi blog: MJF Tolerances: Clearance for Holes and Nut Pockets; MJF vs SLS Parts: What Should a Bureau Tell Customers?; Should You Dye MJF Parts Black or Vapor Smooth Them?.
Sources: 3D Printing Stack Exchange SLS detail question; HP MJF Design Handbook; Rapidobject SLS/MJF design guidelines (German).