Materials & technology

Polymer laser sintering: process, platform and materials

How we manufacture: selective laser sintering (SLS), an industrial 3D printing process that fuses polyamide powder layer by layer, on a dual-laser EOS P 770. This page covers the process, the platform and the materials, plus the design rules and process limits that matter for your part.

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Process

How polymer SLS works

Inside a heated build chamber, a laser fuses thin layers of polyamide powder, one cross-section at a time. The powder that is not fused stays loose and supports the parts until the build is finished.

Conceptual illustration

Components

  1. Laser scanners Two CO₂ lasers, steered by scanner mirrors, trace the cross-sections of each layer in parallel.

  2. Heaters Radiant heaters hold the powder surface just below its melting point, so the laser only adds the final energy needed to fuse it.

  3. Heated build chamber A closed, temperature-controlled chamber keeps process conditions stable for the whole build.

  4. Recoater Spreads a fresh, thin layer of powder over the entire build area before each layer is scanned.

  5. Build plane The current layer, magnified in detail A. The laser fuses the powder only where the parts’ cross-sections lie.

  6. Sintered parts Built from fused layers. Channels, cavities and lattices are possible, provided the loose powder can be removed.

  7. Unsintered powder Surrounds and supports the parts throughout the build, so no support structures are needed.

  8. Build platform Lowers by one layer thickness after each layer, until the build is complete.

The layer cycle

  1. Recoat A thin layer of powder is spread across the build area.

  2. Heat The fresh powder is brought up to process temperature.

  3. Sinter The lasers fuse the cross-sections of all parts in that layer.

  4. Lower The platform moves down by one layer thickness. The first four steps repeat until the last layer.

  5. Cool down The finished build cools slowly inside its powder cake, which limits distortion.

  6. Unpack Parts are taken out of the powder, depowdered and bead blasted.

Platform

EOS P 770: two lasers, one large build volume

Our production platform is the EOS P 770, an industrial polymer laser sintering system. Its two 70 W CO₂ lasers work in parallel over a 700 × 380 × 580 mm build volume, which suits large single parts as well as efficient batches of smaller ones.

Manufacturer
EOS GmbH
Process
Polymer laser sintering (SLS)
Laser type
CO₂
Status
Commissioning Installed and being commissioned. Requests are reviewed now; production slots are confirmed per project.
Explore the EOS P 770

EOS GmbH · EOS P 770

Build X
700 mm
Build Y
380 mm
Build Z
580 mm
Lasers
2 × 70 W

Manufacturer machine specifications (EOS GmbH). Usable part dimensions, material suitability and achievable tolerances require engineering review.

Materials

Engineering polymers for SLS

We start with PA 12, the established workhorse of polymer laser sintering. Further materials are added once they are qualified on our platform, and each one shows its status.

  • PA 12

    Commissioning

    Primary material

    Balanced strength, stiffness and chemical resistance. The default choice for functional prototypes and end-use parts.

    Typical uses Housings, brackets, ducts, fixtures

  • PA 11

    Planned

    Bio-based polyamide with higher ductility and impact resistance than PA 12.

    Typical uses Snap-fits, hinges, impact-loaded parts

  • PA 12 GB

    Planned

    Glass-bead-filled PA 12 for higher stiffness and better dimensional stability.

    Typical uses Housings, jigs and fixtures

  • PA 12 FR

    Planned

    Flame-retardant PA 12. Compliance with a specific fire standard is confirmed per application.

    Typical uses Enclosures and interior parts with fire-behavior requirements

  • TPU

    Planned

    Thermoplastic polyurethane: flexible and rubber-like.

    Typical uses Seals, bellows, dampers, grips

Specific powder grades are confirmed per project. We publish numeric properties only from verified datasheets.

Compare materials

Design guidelines

Six rules that make SLS parts better

Most problems with laser-sintered parts can be avoided at the design stage. These are the rules we check first; the values for your part are confirmed in the engineering review.

  1. Respect minimum wall thickness

    Walls that are too thin may not build reliably or may distort. Keep load-bearing walls generous and as uniform as possible.

  2. Let the powder out

    Hollow parts need escape holes so that unsintered powder can be removed. A fully enclosed cavity stays full of powder.

  3. Leave clearance between parts

    Moving or mating features need a gap, or loose powder can fuse them together. This matters most for assemblies built in one piece.

  4. Size holes and channels for cleaning

    Small holes and long, narrow channels are hard to clear of powder. Plan to ream or drill critical holes after the build.

  5. Avoid large flat areas

    Large flat or thick sections are prone to warping as the part cools. Ribs, curvature and uniform walls reduce the risk.

  6. Discuss orientation early

    Build orientation affects surface quality, accuracy and strength. Tell us which surfaces and dimensions are critical.

Read the design guidelines

Characteristics and limits

Process characteristics and limitations

Every process has limits, and knowing them early avoids surprises. This is what to expect from laser-sintered polyamide parts.

  • As-sintered surface texture

    Parts have a matte, slightly grainy surface. Bead blasting evens it out; smoother surfaces need additional finishing.

  • Natural color

    Parts come out in the light, natural color of the powder. Any other color requires dyeing or coating.

  • Orientation effects

    Sloped and curved surfaces show fine layer steps, and properties along the build direction can differ from those within a layer. We choose the orientation for each part.

  • Thermal effects on large flat areas

    Large flat or thick sections can warp or sink as the build cools. Design changes and orientation reduce the risk, and we flag it in the review.

  • Minimum feature sizes

    Very thin walls, small pins, narrow gaps and fine text have practical limits. They depend on geometry and orientation, so we confirm them for each part.

  • Tolerances are confirmed in review

    We do not publish general tolerance figures. Achievable accuracy depends on part size, geometry, orientation and material, and is confirmed for your part in the engineering review.

    Request an engineering review

See finishing options and their status

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Check your design with an engineer

Send CAD files or drawings. We review manufacturability, orientation and material choice before we quote, and your files stay confidential.

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