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Detailed explanation of material jetting (MJ) technology

  • Time:2021-07-01

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Material jetting is a relatively new 3D printing technology that utilizes liquid photopolymers and ultraviolet light for 3D printing. Today, let's learn about the working principle, advantages and disadvantages and application fields of this rapid manufacturing technology.

 

1What does material jetting mean?

 

Material jetting (MJ) is one of the fastest and most accurate 3D printing techniques. Its basic principle is to use jets of liquid photopolymer droplets, which solidify under the irradiation of ultraviolet light, thereby manufacturing parts.

 

Because the photopolymer resin is ejected in droplets before curing, MJ is often likened to a 2D inkjet process. The difference between the two is that inkjet printers only deposit a single layer of ink droplets, whereas MJ builds layer by layer until the part is complete.


MJ is also very similar to SLA in that they both use a UV light source to cure the resin. But the difference is that the MJ 3D printer fires hundreds of tiny droplets at a time, while the SLA 3D printer is in a full vat of resin, selectively cured point by point with a laser.


 

2Linear deposition

 

Another aspect that makes MJ unique is how the material is deposited (and thus cured). Basically, the MJ printer jets resin from multiple printheads along an X-axis carrier that travels back and forth across the changing print. To help visualize the movement of the device, refer to the light source in a 2D scanner or the wiper of a car.

 


In contrast, the three most popular 3D printing technologies, FDM, SLA and SLS, all print objects in a point-by-point manner by depositing, curing and sintering material, and MJ is considered the fastest and most accurate based on the above working principles. One of the best 3D printing technologies is no lie.


Multiple print heads deposit droplets on the X axis


The X axis moves back and forth along the Y axis


 

How MJ Works

 

 

 

 

Various components of the MJ 3D printer

 

  

The main components of the MJ 3D printer are the print head, UV light source, build platform and material container. The printhead and light source hang along the same X-axis carriage.


The printing process begins by pouring resin into the material container. Just like SLA, MJ uses a thermoset photopolymer resin, which means it has to be heated to between 30-60°C to achieve the right viscosity.


As the X-axis carriage begins to travel across the build platform, the printhead begins to selectively fire hundreds of tiny droplets of resin. After the print head is a UV light source, which immediately cures the sprayed resin. When the entire layer is complete, the build platform drops one layer in height and repeats the process until the part is complete.


In addition to allowing material deposition across the entire X-axis, multiple printheads provide another benefit: multi-material printing. Similar to other multi-material 3D printers, this allows for dissolvable support materials or multi-variety or full-color functional materials.


MJ has a lot of material to choose from. Standard resins are used to make prototypes and end-use parts, but there are also flexible, castable clear and temperature-resistant materials.


 

3Advantages and disadvantages of MJ

 

Like any other 3D printing technology, MJ 3D printing has its pros and cons.


advantage


As mentioned above, build speed and dimensional accuracy are the two parameters that really make the MJ stand out.

Due to the nature of this technology, multiple parts can be produced without compromising build speed, which is already very fast even for a single part. This is very convenient for sharing or small-scale production.

Parts manufactured through MJ have a very smooth surface, ideal for prototyping aesthetics. As a result, material-injected parts are comparable to injection-molded parts (in terms of appearance).

Full-color and multi-material 3D printing is another amazing feature of MJ, further adding to the aesthetic quality of prototypes and end-use parts.


shortcoming

High performance printing and extremely smooth surface finish at a great price. MJ is one of the most expensive 3D printing technologies. This is due to the cost of machines and materials.

Another limitation of MJ is the strength of the printed parts. The weak construction of MJ parts means they are not suitable for making parts that are subjected to certain loads.

In fact, MJ has the same limitations as SLA. Parts printed with both techniques are fragile due to the nature of the resin.



 

                                                      Resin prints are very fragile

 

  There's also the downside that MJ isn't without scrap. Like FDM and SLA, MJ printing parts with overhangs also requires support. Given the high cost of resins, and even dissolvable support materials, any amount of waste would not be ideal for users.

 


4Application field

 

 

 

 

                                                   Models made with material jetting

 

  

As you might have guessed, MJ is mostly used to make beautiful, realistic prototypes.


For example, MJ might appeal to doctors and students who need accurate models of body parts. Likewise, architects, designers and artists can benefit from the accuracy and aesthetic quality of material jetted models.


Due to the high detail and temperature stability of the material, MJ can also be used to make low-speed injection molds.


Regardless, the cost of using MJ's 3D-printed parts has been the limiting factor for the technology's use in professional applications in most cases.