What types of 3D printing and additive manufacturing are there?

What types of 3D printing and additive manufacturing are there?

An overview of the different 3D printing and additive manufacturing processes available.

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What types of 3D printing technologies are there?

Additive manufacturing technologies transform a digital 3D model into a physical object by building up the material layer by layer. The processes can be classified in several ways, but probably the most useful is by material type and the energy source. 

There are seven major categories based on the 3D printing process type, defined by the American Society for Testing and Materials (ASTM). Each category varies in the way it forms plastic and metal parts, and each can offer different choices that range from material selection, surface finish, durability, and speed/price.

The seven main types of 3D printing are:

If you’d like more detail on any one of these, please continue reading below.

The seven types of additive manufacturing technologies explained

1. Sheet Lamination

Sheet Lamination involves fusing or laminating layers of plastic or paper together using heat and pressure. These layers can then be cut into the desired shape with a computer-controlled laser or blade. This category includes Laminated Object Manufacturing (LOM).

2. Direct Energy Deposition (DED)

Direct Energy Deposition involves melting powder material as it is deposited. Direct Energy Deposition mainly uses metal in the form of powders or wire. There are two key technologies in this category: Laser Engineered Net Shaping (LENS) and Electron Beam Additive Manufacturing (EBAM). The difference between the two is the heat source used to melt the material. LENS uses a laser head, while EBAM uses an electron beam.

3. Material Extrusion

Material Extrusion involves squeezing a material through a nozzle and onto a build plate.

Included in the category of Material Extrusion is Fused Deposition Modelling (FDM – which is trademarked) – and Fused Filament Fabrication (FFF - which is not trademarked).

FDM and FFF use strings of solid thermoplastic material, which are pushed through a heated nozzle that melts the material. The printer then moves the nozzle, extruding the material at precise locations. 

At the same time, another nozzle extrudes a dissolvable secondary material that is used to support the part as it cools. As the part is printed, the platform moves down, which allows the material to cool and solidify and builds up the part layer by layer.

4. Material Jetting

In Material Jetting, inkjet printheads are used to apply the melted build and support material directly onto the build platform. The materials used in this process can be plastic, metal, or wax. 

Once the materials have cooled and solidified, the build platform is lowered, and new layers are added until the part is complete. Material is deposited in droplets in lines as opposed to points.

Material Jetting requires support for the part, which is printed simultaneously during building from a dissolvable material that is removed afterward. Apart from Material Jetting itself, there are two other technologies included in this category: Nano Particle Jetting (NPJ) and Drop-on-demand (DOD).

5. Binder Jetting

With Binder Jetting, an adhesive binding agent is dispensed into a thin layer of powder material to build the part layer by layer. These layers bind together to form a solid component.

After printing, the parts require additional post-processing before they can be used. The most common materials used in the post-processing stage are sand and metal.

HP METAL JET TECHNOLOGY is a relatively new binder jetting metal 3D printing process. It uses HP Thermal Inkjet nozzles to precisely deliver HP Binding Agent to a powder metal bed, using industry-standard metal injection molding (MIM) metal powders. This technology can produce multiple metal parts at the same time, with isotropic properties and density similar to MIM (>96% after sintering).

6. Vat Photopolymerization

Vat Photopolymerization involves exposing a light-activated polymer resin to a specific wavelength so that it undergoes a chemical reaction and becomes a solid.

Three different heat sources are available when using this technique:

  • STEREOLITHOGRAPHY (SLA) uses a laser to selectively melt and cure the liquid plastic, tracing the cross-section progressively and building up the part layer by layer.

  • DIRECT LIGHT PROCESSING (DLP) uses a DLP projector to flash all voxels of the layer at the same time.

  • CONTINUOUS DIRECT LIGHT PROCESSING (CDLP), also known as Continuous Liquid Interface Production (CLIP – which is trademarked), leverages the continuous motion of the build plate in the Z-direction to flash melt the layer.

7. Powder Bed Fusion (PBF)

Powder Bed Fusion (PBF) produces parts using a heat source that causes plastic or metal powder particles to fuse, sinter, or melt together one layer at a time. The manufacturing techniques in this category vary according to the energy source used and the base material.

The Powder Bed Fusion category includes:

  • SELECTIVE LASER SINTERING (SLS) is perhaps the most widely known of additive manufacturing technologies and uses a laser to sinter thin layers of powder material.

  • SELECTIVE LASER MELTING (SLM) fully melts and Direct Metal Laser Sintering (DMLS) near-melts the powder material, meaning it is used with metals and alloys. Since the material is melted, SLM requires a support structure.

  • ELECTRON BEAM MELTING (EBM) uses a high-energy electron beam rather than a laser to fuse particles. It requires a vacuum build environment and can only be used with conductive materials.

  • HP MULTI JET FUSION (MJF) is a combination of Powder Bed Fusion and Binder Jetting technologies. Unlike SLS or FDM, which use a point-by-point printing approach, HP MJF technology can print a complete layer at the same time. A layer of powder material is spread on the print bed. Then, the fusing and detailing agents are deposited at voxel-level on top of the powder, defining the regions of the layer that need to be fused or protected from fusion, respectively. Heat is applied to the bed, and the areas where the fusing agent was deposited are fused. Once these fused layers cool down, they solidify and build the designed 3D printed part.

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