• Metal Powder Bed Fusion is a process where solid objects are produced inside a build area, using some kind of thermal energy source to induce fusion between "metal powder" particles one layer at a time.

• Most of Powder Bed Fusion technologies employ mechanisms for adding powder as the object is being generated, resulting in the final component being encased in the metal powder. The main variations in the Metal Powder Bed Fusion technologies come from the use of different energy sources; high powered lasers or electron beams.

• Both "Direct Metal Laser Sintering" (DMLS) and "Selective Laser Melting" (SLM) produce objects in a similar fashion to "Selective Laser Sintering" (SLS). The main difference is that these types are applied to the production of metal parts.

  • DMLS does not melt the powdered metal but instead heats it to a point so that it can fuse on a molecular level.

  • SLM uses the laser to achieve a full melt of the metal powder forming a homogeneous part. This results in a metal part that has a single melting temperature.

  • SLM does not use sintering for the fusion of powder granules but will completely melt the powder using a high energy laser to create fully dense materials in a layer-wise method that has mechanical properties similar to those of metal parts manufactured in conventional ways.

• Another main difference between DMLS and SLM is that; the DMLS produces parts from metal alloys, while the SLM form single element materials, such as titanium.

• Unlike SLS, the DMLS & SLM processes require structural support, to limit the possibility of any distortion that may occur despite the fact that the surrounding powder provides physical support.

• Just like conventional processes, there's a risk of warping due to the residual stresses produced during printing, because of the high temperatures. Parts are also typically heat-treated after printing, while still attached to the build plate, to relieve any residual stresses in the parts after printing.

  • In comparison with other Metal Powder Bed Fusion techniques, "Electron Beam Melting" (EBM) uses a high energy beam, or electrons to induce fusion between the particles of metal powder.

  • A focused electron beam scans across a thin layer of powder, causing localised melting and solidification over a specific cross-sectional area.

• When compared with DMLS & SLM, EBM generally has a superior build speed because of its higher energy density. However, things like minimum feature size, powder particle size, layer thickness, and surface finish are typically larger.

  • Also, EBM parts are fabricated in a vacuum, and the process can only be used with conductive materials.

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• Materials: Metal Powder of Aluminium, Stainless Steel, Titanium

• Dimensional Accuracy: ±0.1 mm

• Common Applications: Functional metal parts used for aerospace, automotive, medical fields

• Strengths: Strongest functional parts, Complex geometries

• Weaknesses: Small build sizes, Highest price point of all technologies