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The Complete Guide to Laser Powder Bed Fusion in 3D Printing

Laser powder bed fusion (LPBF) is a group of metal additive manufacturing methods that use a powder bed and a laser to fuse metal powder together, layer by layer, into a solid part. The best-known example is direct metal laser…

laser powder bed fusion
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History and Development of Laser Powder Bed Fusion

The origins of laser powder bed fusion date back to the 1990s, when EOS patented its process under the name direct metal laser sintering (DMLS). Meanwhile, in 1995, the Fraunhofer Institute introduced the term SLM (Selective Laser Melting) to designate a very similar technology. Although DMLS and SLM have different origins, and different companies still use one term or the other as a brand distinction, the underlying processes are functionally the same.

To avoid confusion, the industry now generally refers to this category of technologies as laser powder bed fusion, or LPBF, noting that contrary to what the term “DMLS” might suggest, none of these processes actually involve sintering. They involve the melting of metal particles.

fusion laser sur lit de poudre

Photo Credits: Fraunhofer ILT, Aachen, Germany

The difference between sintering and melting is quite simple: melting involves the transition from a solid to a liquid state thanks to a high temperature. Sintering, on the other hand, does not allow the metal to melt, as the temperature used is not high enough. As a result, the powder particles are agglomerated together rather than fully merged, which can leave voids and porosity in the finished part.