Binder jetting is one of the seven recognized standard 3D Printing processes. The technique is copyrighted by the name 3DP technology. It was developed at Massachusetts Institute of Technology (MIT) in 1993. Later on, the license of the technology was obtained by Z Corporation in 1995.
This is a powder based 3D printing technique and uses a powder like building material to be joined by liquid binder for 3D printing. In a typical apparatus for binder jetting, there are two chambers where one chamber is filled with powdered building material to feed into the other chamber and the second chamber is used for realizing the 3D model. The 3D model is built by gluing together the powdered building material using the liquid binder. The powder is filled into first chamber and feed to the second chamber by rolling sufficient amount for each layer by a levelling roller. The rolled out powder is filled over the building platform which has been lowered to the depth equal to height of the layer that has to be created in the beginning of the process. The liquid adhesive binder is supplied through an inkjet print head which disposes out the binder liquid at controlled rate while the head moves along the horizontal plane. After a single layer has been laid out, the platform is again lowered to a depth equal to the height of next layer and powder is rolled out from the first chamber to the building chamber. Again next layer is built by jetting the liquid binder from print head in a computer controlled manner. Similarly, all successive layers are built. After the completion of final layer, the 3D model is still glued along the remaining building powder. The 3D model has to be taken out and the extra powdered glued to the model has to be cleaned off. Even before that, the model needs to be left in the binder jetting machine to cool down and get completely solidified for high quality finish of the model.
The advantage of using binder jetting process is that there is no need of using support structures while creating the 3D model. The model created has better mechanical characteristics and robust build. Though, the process is faster than other 3D printing processes, cleaning off the extra glued powder from the model consumes additional time after the generation of the model.
The commonly used building materials for binder jetting process are stainless steel, glass and some polymers like Acrylonitrile Butadiene Styrene (ABS), Polyamide (PA) and Polycarbonate (PC). With wide range of suitable building materials and possibility of many binder and powder combinations, a large range of models having many possible colours and different mechanical properties can be created using the binder jetting process. However, due to use of binder liquid, the process is usually not suitable for making structural parts. Still, Binder jetting can be efficiently used for prototyping.
ExOne M-Flex is one of the binder jetting 3D printer used in the industries. The X1 from AddWii is another affordable binder jetting 3D printer.
In the next article of this series, Power Bed Fusion technique for 3D Printing will be discussed.
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