A 3D printing technology which adopts both the principles of SLS as well as material jetting is called Binder jetting 3D Printing technology. Unlike other 3D printers, Binder jetting printers generally contain two tanks, one is empty while the other is filled with a material powder.
Scroll down and continue reading to get more information regarding the overview, working process, post-processings, and at last the advantages and disadvantages of Binder jet 3D printing technology.
An Overview On Binder Jetting 3D Printing Technology:
In contrast to other 3D printing printers, Binder jetting 3D printers manufacture parts without any structural support. They print highly precise parts and hence the process is repeatable. This technology is widely set for eliminating a major issue of disfiguring the desired part, which might lead to the failure of the prototype. The parts printed in this method are composed of a material powder and a liquid agent with binding properties.
This technique needs a wide variety of materials like sands, metals and ceramics to get the desired objects. In marketing fields, it is vastly used for the production of objects like aerospace components, dental medical tools and so on.
What is Binder Jetting 3D Printing Technology?
Binder Jetting is an additive 3D manufacturing technique which combines two agents namely, the material powder and a liquid binder to print a desired part. The liquid binding agent binds the layers of powder material, which is already spread on the print plate with the help of a recoating blade.
Binder jetting helps in printing colourful parts with high compatibility. Besides, large parts can be printed with low cost metals or sands relative to other 3D printing methods.
How Does a Binder Jetting 3D Printer Work?
Before you start up with the working process let us have a look at the components used in this technique along with their functions.
Material Container: The powder material used to print the object will be stored in this container.
Build Plate: This is the actual site for the whole printing process and where the powder material is deposited.
Recoater Blade: It plays an important role in spreading the powder material uniformly on the print plate in a layered format.
Printhead: This extrudes out the liquid binding agent onto the powder material present on the build platform, which leads to fusion between the two agents resulting in the formation of strong bond between them.
Overflow Bin: During the recoating process, it stores the excess amount of powder material.
The process is initiated by spreading the powder material onto the build platform with the help of a recoater. If any excess powder being spread on the first layer is collected by the overflow bin. As soon as the powder is spread on the build platform, the printhead starts its role by spraying the liquid agent onto the powder to bind the first layer. The diameter of a single droplet of liquid binding agent is about 80 microns.
The nozzles used here are similar to those used in 2D printers. Just after the first layer is printed, the print plate moves one layer down in height and the printhead moves away to cleanse the nozzle. The recoater again spreads a new layer of the powder material, but this time on the initially printed layer. The process of recoating and ink jetting is continued till the desired part is completely printed.
Once the part is completely printed, the excess powder is removed from the part with the help of a cleaner and cleaned by applying pressure.
The last state of the process is known as the Green state, where the part is observed to be highly porous with low mechanical properties.
Post-Processings In Binder Jetting:
In order to achieve the lost mechanical properties, post-processings like infiltration, sintering or standard metal post-processing is to be done compulsory.
Infiltration: In this step the printed part is to be kept in a furnace and to be burnt excluding the voids. By now, the part has lost 40% of its porosity. The excluded voids are infiltered with Bronze through capillary action which helps to achieve minimum porosity and provides enough strength.
Sintering: This is an alternative to infiltration. The printed part is kept in a higher temperature furnace than in infiltration, which improves the density and increases its strength too.
Standard Metal Post-Processing: This is to be done only when the part is printed by Metal Binder jetting and not by Sand Binder jetting technique. Before starting this method, the part must undergo either infiltration or sintering.
Pros And Cons:
- Wide variety of colours can be used for manufacturing the desired parts.
- Doesn’t depend on the support structures.
- Printing process is quite faster in contrast to other 3D printing processes.
- Large and colourful parts can be printed.
- Prints low-priced metal parts.
- Since the process occurs at ambient temperature, warping and curling issues are not regarded.
- Use of liquid binding agent is not always befitting to print desired parts.
- Without post-processings parts are incomplete with high porosity and low mechanical properties.
- Minimum materials can be selected for printing, whilst other 3D printing technologies can select a wide range of materials.