Table 3. Three-dimensional techniques, materials, and resolution.
| 3D printing techniques | Description | Materials | Layer thickness & X/Y resolution* |
|---|---|---|---|
| Selective laser sintering (SLS) | Uses a CO2 laser to fuse, or sinter, a fine thermoplastic powder (such as polycarbonate or nylon) in layers to form the model | Thermoplastics, ceramic, metals | Layer thickness: 0.004–0.006 mm; X/Y resolution: 0.030–0.050 |
| Direct metal laser sintering (DMLS) | An SLS-like technique developed by EOS GmBH (Plannegg, Germany), which uses a laser to sinter metal powder) | Bronze alloy, steel, stainless steel, titanium, aluminum, cobalt, nickel alloy | Layer thickness: 0.0008–0.0012; X/Y resolution: 0.012–0.016 |
| Stereolithography (SLA) | Uses an ultraviolet laser and a mobile platform sitting inside a vat of resin, the laser polymerizes the resin in layers as the platform descends deeper into the vat | Epoxy resin, acrylate photopolymer | Layer thickness: 0.002; X/Y resolution: 0.004 |
| Fused deposition modeling (FDM)—also referred to as free form fabrication (FFF) or extrusion | Developed by Stratasys Inc. (Eden Prairie, MN, USA). FDM deposits a heated thermoplastic material layer by layer to produce a model | Acrylonitrile butadine styrene (ABS), wax, polycarbonate, polypropylene, various polyesters | Layer thickness: 0.007; X/Y resolution: 0.0028 |
| Multi-Jet modeling | Developed at MIT. Ink-jet nozzles are used to spray a liquid binding agent onto a ceramic or metallic powder creating a thin solid layer. After the model is complete, it must be sintered in a furnace and subsequently infiltrated with metal to yield a full-density model. Two different jets can be used to create a composite part. The composite material can be printed with functional components or one material may serve as support structure for more complex models. The supports are usually removed during the post-processing phase of production. The post-processing can be performed manually or by a variety of chemical methods | Plastics | Layer thickness: 0.016**; X/Y resolution: N/A |
| Polyjet printing | Similar to multi-jet modeling, however, can use a greater variety of materials and has a more simple post-processing stage | Photopolymers | Layer thickness: 0.00063; X/Y resolution: 0.0017 |
*, accuracy information listed is the highest resolutions available as listed by Stratasys Inc. (Eden Prairie, MN, USA); **, specifications for the ProJet3500 HDMax (3DSystems).