What Binder Jetting is

A binder jetting print head selectively sprays adhesive onto a layer of powder [2].

Binder Jetting uses two materials. The two materials are a powder base for its build material and a liquid binder agent. The manufacturing process starts with a leveling roller that spreads a thin layer of the powder material over the build platform [1].  Then the printhead moves horizontally while spraying the binder agent on the specified area of the powder layer.

The binder agent acts as an adhesive between the powder layers. This is due to the chemical reaction the liquid binder creates. The build platform lowers as subsequent layers are added until the piece is finished. The curing process will be highlighted in the following.

 


Process

 

  1. The material is spread over the build platform using a roller.
  2. The binder adhesive is deposited by the printhead on locations where it is needed.
  3. The build platform is lowered as the model is being built.
  4. Layers of powder are spread over the existing layer, and the model is formed where the powder contacts liquid.
  5. The unbound powder still surrounds the object.
  6. The process is repeated until the entire model is complete.

Curing Process

There are four post-processing steps that all objects are required to go through:

  • Curing and sintering involve the application of heat. This usually happens in a controlled environment like a furnace, to effectively fuse the particles together.
  • Sintering is when the binder agent is burned away in this process, leaving the part porous.
  • Infiltration is done to reduce porosity and increase density. Different materials infiltrate and fill these voids.
  • Finishing is the final step. At the end of the post-processing, parts display much higher resistance and better mechanical properties [1].

Materials

Materials include ceramic, metallic, and sand products. All objects require post-processing.


Equipment Used Today

  • Digital Metal’s DM P2500
  • ExOne’s M-Flex
  • Voxeljet’s VX1000
  • 3D Systems’ Projet CJP 860pro
  • The ComeTrue T10 3D printer by MicroJet Technology

More information can be found at:

A Guide to the Top 5 Industrial Binder Jetting Machines


Applications

The binder jetting process produces metal parts at a lower cost than other technologies like powder bed fusion. Issues related to residual stress are eliminated since the metal powder is not melted during this process. Binder jetting is a faster process relative to other metal additive manufacturing processes.

Non-metallic parts can be produced in a wide range of colors, making this process especially suitable for high-fidelity prototyping [1]. These materials are also widely used for producing sand molds and cast patterns.


Pros and Cons

Pros:

  • Cheaper metal fabrication [1]
  • The process is generally faster than others [1, 2]
  • The two material method allows for a large number of different binder-powder combinations and various mechanical properties [2]

Cons:

  • Not always suitable for structural parts, due to the use of binder material [2]
  • High process time and costs [1]
  • Additional post-processing can add significant time to the overall process [2]

Video Demonstration of the Binder Jetting Process

Proxima 3D. (2016). Binder Jetting 3D Printing Process. Available at: https://www.youtube.com/watch?v=97doBH9jSXY. (12/20/20).



References

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

[2] https://www.lboro.ac.uk/research/amrg/about/the7categoriesofadditivemanufacturing/binderjetting/

[3] https://make.3dexperience.3ds.com/processes/binder-jetting

 

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