In this article you will learn about the Binder Jetting process. I will discuss the functional principle, the advantages and disadvantages as well as possible areas of application and post-processing options.
What is the Binder Jetting process?
Binder jetting is an additive or generative manufacturing process, also known colloquially as 3D printing. The starting material for the process is always a powder, which is bonded layer by layer with adhesives – the binder that gives the process its name – and thus brought into the desired shape. Binder jetting is a comparatively “old” manufacturing option. In the early 1990s, Binder Jetting was developed and patented at MIT in Massachusetts.
How is a Binder Jetting printer constructed?
In principle, binder jetting printers work similarly to inkjet printers. Using a print head, binder is applied layer by layer to a powder to gradually realize a shape previously defined by CAD. A characteristic feature of BJ printers is a lowerable base plate, which after a successfully bonded layer is lowered down to allow the next layer to be bonded.
In addition to the lowerable platform and the printhead, the printers always have two tanks, one for the adhesive, one for the powder supply. As a rule, the BJ printers are of portal design.
How does Binder Jetting work?
In the additive production process, a powder layer is first applied to a base plate. A binder is then applied with pinpoint accuracy by means of a print head, which ensures that the powder sticks together. In the next step, another layer of powder is applied and bonded again. Little by little, the desired model is thus also created from the various layers.
Where is the Binder Jetting process used?
Binder jetting is an extremely versatile process, as theoretically all materials that are available in powder form can be bonded together. Even sensitive starting materials such as food or pharmaceuticals can be formed into three-dimensional objects. Since no heat sources are required during printing, no stresses are generated within the components, making binder jetting suitable for even the most sensitive materials. Currently, the process is frequently used in rapid prototyping, but also for the production of casting molds or master models. Other examples of applications are the jewelry industry, art academies or medical technology.
Which materials can be printed with Binder Jetting?
Whether metals, ceramics, sand or plastics – in principle, any material that can be processed in powder form can be formed into 3D models using binder jetting. The ability to print stainless steels is particularly interesting – this is not currently possible with many other 3D printing processes. Depending on the printer used, multicolor models are also possible. For this purpose, ink particles are added during printing to give color to the individual layers.
How is post-processing done in binder jetting?
While models made of plastic only need to be freed of excess powder after printing, metal parts require more complex post-processing. After binder jetting, metal workpieces must be freed from adhesive residues and additionally sintered. This is the only way to ensure sufficient strength of the models. During sintering, shrinkage of the models can occur, so that an exact final geometry can only be realized reliably with sufficient experience.
Binder Jetting – What are the advantages and disadvantages?
One of the greatest advantages of binder jetting is the universal applicability of different materials. These can even be combined with each other, so that, for example, models made of stainless steel and plastic are conceivable. Coloring the models can also be counted among the advantages. In addition, Binder Jetting is comparatively inexpensive. A disadvantage is clearly the low stability of the end products. Since they are always parts glued together from powder, no great strength can be expected. In the case of metal parts, however, the strength can be significantly increased by adding further metals (in the case of stainless steels, for example, by adding bronze) and subsequent sintering. Also, the surface of the models is always slightly rough, about the same as after sandblasting.
- Fast manufacturing
- Large models are also possible
- No support structures necessary
- Full color models can be displayed
- Extremely complex shaping possible
- Combination of different materials in one model
- Not much strength
- Mechanically loadable only if the components are post-treated
- No smooth surfaces possible