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Christian Rice By Christian Rice • January 21, 2018

Electron Beam Melting vs. Direct Metal Laser Sintering

What about an aeronautics company producing a fuel nozzle? This question is mega important to the engineering process. At Link3D, we're addicted to diving into the hard questions and providing insight on everything related to this fast-growing industry. The following high-level overview outlines what rocks about both EBM and DMLS:

Let's begin with describing the Electron Beam Melting (EBM) process: EBM process builds functional metal parts layer by layer using metal powder. What differentiates this process from all other AM processes is the powder melted by a powerful electron beam (typically around 3,500 watts) to produce precise, often complex, geometric shapes. Due to the use of the electron beam as the heat source, parts are necessarily built under vacuum conditions and at elevated temperatures.

Why choose EBM?

  • Low level of internal defects
  • Good material properties, in particular fatigue properties
  • No limitations in chemical composition
  • Minimal residual stresses due to high process temperature
  • Little waste material: virtually all excess powder can be recycled

Now let's look at the Direct Metal Laser Sintering (DMLS) process: DMLS uses a precise, high-wattage laser to "sinter" powdered metals and alloys to form accurate, complex and fully-functional metal parts. Today, the sintering terminology lingers due to it being the historical proprietary process name given by EOS rather than it being an accurate description of the current process, which actually involves almost complete melting of the metal powder to produce fully dense parts. It's important to note that the DMLS process is very similar to the laser melting processes of SLM Solutions, Concept Laser and other AM hardware companies.

Why choose DMLS?

  • A broad range of metal materials.
  • Finer layer thickness (typically 20–40 μm, compared with 50–70 μm for EBM).
  • Better accuracy as a result – typically DMLS produces a smoother surface finish than EBM
  • Raw DMLS parts have a surface finish comparable to fine investment cast parts.

Adoption of either EBM or DMLS technology really depends on one's specific vertical and application. At Link3D. we have been privy to a vast number of RFQs in the aerospace industry lean towards EBM vs. medical applications leaning towards the DMLS process for fine resolutions.