What Powder Bed Fusion is

Powder Bed Fusion [1].

Powder Bed Fusion is a process that occurs in a near-vacuum chamber with an inert gas [1]. The chamber is heated and the process starts by spreading a thin layer of powder material onto a build platform [1]. A thermal energy source, usually a laser, searches regions of the bed that will be used to bond the powder together, and this forms a thin layer of combined material [1]. Once a layer is complete, the build platform lowers and another layer of powder is spread on top. The layers are fused together, and when the process is complete, the unbound powder is removed from the part [1].

There are several Powder Bed Fusion methods. These methods include Selective Laser Sintering (SLS), Selective Laser Melting (SLM) or Direct Metal Laser Sintering (DMLS), Electron Beam Melting (EBM), and Multi Jet Fusion (MJF) by HP [2].

 

 

 

 

 


Process

 

  1. A layer of material is spread over the build platform and then a laser fuses the first later.
  2. A roller spreads a new layer of powder across the previous.
  3. The preceding layers are fused and the process repeats until the model is created.
  4. The loose, unfused powder remains in the build bed, but it is removed during post-processing.

Curing Process

There are no additional curing processes that the model undergoes before post-processing.


Materials

Materials include plastics, metals, and ceramics. Nylon is one of the plastics used in this process. Metals include Stainless Steel, Titanium, Aluminium, Cobalt Chrome [1].


Equipment Used Today


Applications

Powder bed fusion is used for production parts. The mechanical properties of metal parts produced by SLM and EBM methods are similar to machining and casting [1]. The medical and aerospace industries are already making use of these technologies [1]. In the aerospace industry, the new Boeing 777X engines contain around 300 additively-manufactured components each, and all of them are made by powder bed fusion methods [1].


Pros and Cons

Pros:

  • Unused material can sometimes be recycled [1]
  • Suitable for visual models and prototypes [2]
  • The powder acts as an integrated support structure [2]

Cons:

  • Lack of structural properties in materials [2]
  • Size of models are limited to the powder bed size
  • Costly material and post-processing steps [1]

Video Demonstration of the Powder Bed Fusion: Direct Metal Laser Sintering Method Process

Stratasys Direct Manufacturing. (2019). How it Works: Direct Metal Laser Sintering (DMLS)Available at: https://www.youtube.com/watch?v=yiUUZxp7bLQ&feature=emb_title. (12/29/20).



References

[1] https://all3dp.com/2/main-types-additive-manufacturing/

[2] https://make.3dexperience.3ds.com/processes/powder-bed-fusion

[3] https://www.lboro.ac.uk/research/amrg/about/the7categoriesofadditivemanufacturing/powderbedfusion/

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