Complex Geometry, No Supports, Real Nylon

Selective Laser Sintering (SLS) uses a high-powered laser to fuse nylon powder particles into solid parts — layer by layer, inside a heated powder bed. Because the surrounding powder supports the part during the build, SLS can produce geometries that would be impossible with any other process.

Internal channels. Interlocking assemblies printed as one piece. Lattice structures. Nested parts. If you can model it, SLS can probably build it.

How SLS Works

  • A thin layer of nylon powder (typically PA 12) is spread across the build platform
  • A CO₂ laser selectively fuses the powder according to the cross-section of your part
  • The platform lowers by one layer thickness (~0.1mm), new powder is spread
  • The process repeats — unfused powder supports overhangs and internal features
  • After the build, the part cools slowly in the powder bed before being excavated and cleaned

The key advantage: no support structures. The unfused powder bed acts as a natural support, which means:

  • No support removal marks
  • No wasted material on supports
  • No design compromises to accommodate support access

When to Choose SLS

SLS is the right choice when:

  • Geometry is complex — internal channels, undercuts, nested components, lattice/infill structures
  • You need functional nylon parts — PA 12 and PA 11 are tough, chemically resistant, and fatigue-friendly
  • Batch production — SLS packs parts efficiently in the powder bed, driving down per-unit cost at 20–500+ quantities
  • Moving assemblies — hinges, ball joints, and interlocking mechanisms can be printed assembled
  • No support marks allowed — every surface is a “show surface”

Common applications:

  • Automotive intake manifolds and complex ducting
  • Functional prototypes for fit and assembly testing
  • Small-batch production parts replacing injection molding
  • Medical device housings and surgical guides
  • Drone and UAV structural components
  • Custom orthotics and wearables

SLS Materials

Material Key Properties Typical Use
PA 12 (Nylon 12) Strong, stiff, good detail, chemical resistant General-purpose prototyping and production
PA 11 (Nylon 11) Higher ductility and impact resistance than PA 12 Parts needing flexibility or impact toughness
PA 12 Glass-Filled ~30-40% glass bead fill. Higher stiffness, heat resistance Structural parts, under-hood automotive
PA 12 Mineral-Filled Improved stiffness and thermal stability Connectors, housing with tight tolerances
TPU / Flex Rubber-like, various durometers Gaskets, soft-touch grips, shock absorption
PA 12 Flame Retardant UL 94 V-0 rated Aerospace, electronics, transportation

SLS vs. Other Processes

SLS vs. FDM

  • SLS wins on: Geometric freedom, no support marks, isotropic strength, batch efficiency
  • FDM wins on: Larger individual parts, wider material range (PC-ISO, ULTEM), lower cost for simple geometries
  • Choose SLS when: The geometry is complex or you need consistent properties in all directions

SLS vs. MJF

  • SLS wins on: Wider material selection (flame-retardant, mineral-filled), larger max part size, established track record
  • MJF wins on: Surface finish, build speed, cost per part at moderate volumes
  • Choose SLS when: You need specialty nylon variants or the part exceeds MJF build volume

SLS vs. SLA

  • SLS wins on: Material strength and durability, UV stability, no post-curing, batch production economics
  • SLA wins on: Surface finish, dimensional accuracy, transparent materials, very fine features
  • Choose SLS when: The part needs to perform mechanically, not just look good

Design Tips for SLS

  • Minimum wall thickness: 0.7mm (1mm+ recommended for structural parts)
  • Escape holes: Include holes for removing trapped powder from enclosed volumes (min 4mm diameter)
  • Clearance: 0.5mm minimum between moving parts printed in assembly
  • Surface texture: SLS has a slightly grainy, matte finish — excellent for gripping, not ideal if you need gloss (requires post-processing)
  • Accuracy: Typical ±0.3% with a ±0.3mm floor

How PartSnap Delivers SLS

SLS is available through our production network. We handle:

  • Design review — optimizing your part for SLS-specific considerations (powder evacuation, wall thickness, orientation)
  • Process recommendation — honest guidance on whether SLS, MJF, FDM, or SLA is the best fit
  • Quality management — first article review, dimensional inspection, and delivery coordination

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info@partsnap.com · 214.449.1455