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

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.

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.

Melting, by contrast, allows the liquid metal to fill those gaps, which is why LPBF processes are generally capable of producing denser, higher-strength parts than sintering-based methods, without additional densification steps. So while “DMLS” remains the common name for EOS-style LPBF systems, the parts it produces are, technically speaking, melted rather than sintered, which is part of why LPBF parts can achieve mechanical properties competitive with wrought or machined metal.

How Laser Powder Bed Fusion Works

The LPBF 3D printing process (including DMLS) works as follows:

• Material preparation: A fine metal powder, often a specific alloy, is stored in a hopper and fed into the printer, which first creates an inert atmosphere in its build chamber.
• Preheating: The chamber and the powder are heated to a temperature just below the material’s melting point, so the metal solidifies rapidly once the laser passes over it.
• Powder deposition: A thin layer of powder, typically 20 to 60 microns thick, is spread across the build platen using a roller.
• Laser fusion: A fiber-optic laser scans the cross-section of the part, melting the powder according to the 3D model. As it cools, the material solidifies immediately.
• Layering: Once a layer is complete, the platen descends, a new layer of powder is applied, and the process repeats until the part is fully formed.

LPBF Materials

Laser powder bed fusion requires powdered metals, including aluminum, titanium, inconel, steel and cobalt-chromium.

Post-Processing

After printing, the chamber is cooled and unfused powder, known as “cake,” is removed from the tray, typically by suction, compressed air, or sandblasting. Parts remain attached to the build plate by print supports throughout this process. Unlike SLS technology, which is largely self-supporting, LPBF processes like DMLS commonly require these supports to minimize warping and distortion caused by high build temperatures. Once the part has cooled, supports are removed by cutting, machining, or wire EDM.

After support removal and cleaning, LPBF parts typically undergo further post-treatment, which may include heat treatment to relieve residual stress, CNC machining, or polishing to improve surface finish.

Key Benefits of Laser Powder Bed Fusion

Laser powder bed fusion processes, including DMLS, offer a number of advantages:

• Geometric complexity: It enables the design of geometrically complex parts, impossible to obtain with conventional metal fabrication methods such as milling.
• Reduced weight and number of components: Thanks to topological optimization techniques, LPBF can reduce the final weight of parts and the number of components to be assembled.
• Mechanical strength: Parts produced using DMLS have a mechanical strength comparable to those manufactured using traditional subtractive manufacturing techniques.

LPBF Applications

Due to its benefits outlined above, LPBF is an attractive technology for diverse sectors. Aerospace and defense companies are adopting it to create lightweight and complex components. Automotive companies like BMW Group and Volkswagen are using it for EV lightweighting and tooling. Healthcare providers utilize LPBF for patient-specific implants and surgical tools. Tech companies are using it for hardware innovation.

Prominent Market Players

Several key players, including EOS, 3D Systems, Additive Industries, AddUp, Colibrium Additive, Nikon SLM Solutions, Sisma, Velo3D, and Renishaw, offer solutions in this fast-growing market. According to Dataintelo, the global LPBF market reached $4.8 billion in 2025, with strong momentum across multiple end-use verticals. And it’s growing, projected to reach $21.6 billion by 2034 at a CAGR of 17.7%.

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*Cover Photo Credits: DMG Mori