To build parts one layer at a time, you need to convert various materials into a form that can fit a layer by layer build process. For the additive process of Powder Bed Fusion (PBF), polymers or metals need to be converted into a fine powder. Then, you need some way to bind layers of powder into specific shapes and geometries. Powder Bed Fusion systems typically use a light source, either lasers or electron beams, to melt or sinter the powder layer-by-layer.
A review of the layer-by-layer process: The laser or electron beam moves over the powder in the powder bed, turning the powder into liquid or into a sufficiently liquid state so that when the affected powder cools it solidifies and adheres to the previous layer of powder. The light source affects a specific depth of powder, depending on the 3D printer’s specifications. After that, a new thin layer of powder is spread over that earlier layer, and sintered or melted to the previous layer to bond the layers, and the process repeats until a part is built. Most laser based PBF systems use an enclosed build chamber that is filled with an inert gas to prevent the potential of explosions, particular with metal powders.
Users will find a number of brand names to describe PBF. These include Direct Metal Laser Sintering (DMLS), Selective Laser Melting (SLM), Laser Powder Bed Fusion (LPBF), and Selective Laser Sintering (SLS). In some cases, the vendors’ processes vary a bit so a new label describes that. For example, you can’t melt plastic, but you can sinter it.
Here’s a look at which additive vendors offer PBF systems.
3D Systems metal 3D printers use Direct Metal Printing (DMP) to build parts. A high-precision laser solidifies metal powder.
The FormUp 350, from AddUp, is a metal 3D printer that uses what the company calls Laser Beam Melting (LBM). It works with stainless steel, nickel, titanium alloys and aluminium alloys.
DMG Mori has two printers that use Direct Metal Laser Sintering (DMLS).
EOS operates in the polymer 3D printing market with Selective Laser Sintering(SLS) 3D printers, and in the metal industry with a range of Direct Metal Laser Sintering (DMLS) 3D printers.
GE Additive offers 3D printers originally from Arcam and Concept Laser. The Arcam printers use Electron Beam Melting (EBM). The Concept Laser systems operate with LaserCUSING technology, based on laser sintering of metals.
Renishaw offers four metal PBF systems. Its PBF is a form of laser melting.
SLM Solutions uses DMLS patented as Selective Laser Melting (SLM) on its range of additive systems. The 3D printers use multiple lasers for faster operation.
Trumpf has three printers with Laser Metal Fusion (LMF) technology (a process similar to DMLS). The company also offers two printers based on Laser Metal Deposition technologies.
The following vendors offer variations of powder bed fusion.
Australian manufacturer Aurora Labs uses an additive build method that can be categorized between powder bed fusion and direct energy deposition (DED) that it calls Multi-layer Concurrent Printing. It claims this technique speeds up the build process.
ExOne also offers a powder-based 3D printer, primarily working with sand for castings. It uses binders to build parts one layer at a time.
HP’s Metal Jet additive system includes a bed of powder, but it uses special chemical binders to build parts a layer at a time. It offers systems that work with polymers and metal materials.
After beginning with AM software, Velo3D recently launched its 3D printer Sapphire System that uses patented Intelligent Fusion technology, based on a powder bed.