Binder Jetting or Powder Binding

• Initially developed at the Massachusetts Institute of Technology in the early 1990s, ExOne obtained the exclusive license to this inkjet-in-powder-bed method of 3D printing in 1996. Two years later, ExOne launched the market's first commercial binder jet 3D printer for metals.

• Binder jetting is a 3D printing process that uses a liquid binding agent deposited onto a build platform to bond layers of powder material and form a part. Binder jetting can be used to print a variety of materials including metals, sands and ceramics. Markets for this process include industrial applications, dental and medical devices, aerospace components, part casting, luxury applications, and more.

• The printing process with this technology consists of spraying a liquid binder onto a bed of powder, solidifying the cross section of the piece, layer by layer. The materials that solidify thanks to the binder are usually gypsum, sand, ceramics, metals or polymers in granular forms.

• Binder jetting 3D printing systems include machines from Desktop Metal, Digital Metal, ExOne, GE Additive, HP (known as Metal Jet Fusion), Viridis3D, and Voxeljet. Binder jetting services are also available from 3DEO, creator of a proprietary binder jetting technology (known as Intelligent Layering), as well as many of the suppliers mentioned.

• Binder Jetting is an additive manufacturing process in which an industrial printhead selectively deposits a liquid binding agent onto a thin layer of powder particles — either metal, sand, ceramics or composites — to build high-value and one-of-a-kind parts and tooling. The process is repeated layer by layer, using a map from a digital design file, until the object is complete.

• Binder Jetting technology has been widely used for ceramic 3D printing because it can work with all materials belonging to this family. Moreover, this technology even enables 3D printing with sand, the only material that does not require additional post-processing. As far as metals are concerned, the Binder Jetting technology allows the production of various types of metal alloys

Difference between Binder jetting and other additive manufacturing processes

• Other forms of 3D printing build parts with a single point — often a laser or nozzle — that extrudes, melts or welds material together. For many of these metal printing processes, a build plate and supports may be required for part stability throughout the build process. Such processes require significantly more material and time to draw out each part with a single point, layer by layer.
• To combat the slow speed of drawing out a part with a single point with head, additional lasers may be added, which intensifies the cost of such systems.
• The heating and cooling that takes place during these longer builds for metal creates residual stresses in the part which must be relieved in a secondary post-processing operation.

Applications

• Binder Jetting is used in a variety of applications including the manufacturing of full-color prototypes, large sand-casting cores and molds on the plastic/ceramic side and small, functional parts on the metal side. Binder Jetting plastics is a well-developed, mature technology; the same process used for metal parts is in an earlier stage of development.

Advantages

• Binder Jetting is faster and more cost-effective than many 3D printing technologies.
• Binder Jetting machines can print quickly by using multiple heads to jet binding material in several places simultaneously, turning out tens or even hundreds of parts in a single build.

Disadvantages

• Metal parts produced by Binder Jetting have inferior mechanical properties than DMLS/SLM parts.
• Delicate parts may be brittle and may be damaged during post processing.
• The choice of materials used in Binder Jetting is narrow.