What Is MultiJet (MJP) 3D Printing?

Get to know the basics of MultiJet Printing, also known as MJP 3D printing. Find out why this new printing technique is gaining popularity for producing high speed and accurate to CAD precision parts and prototypes. Learn about MJP printing works, discover materials and surface finishing options and explore its benefits and drawbacks in this article.

If you are interested in HLH’s MJP services, discover our MJP capabilities here.

What is MJP 3D printing?

MultiJet printing or MJP is an additive manufacturing process comparable to Stereolithography (SLA 3D printing) — capable of producing visually aesthetic prints with complex shapes and a high level of detail. MJP can print in Ultra High-Definition mode, making it possible to print even smaller features, down to 300 microns or finer.

MJP 3D-printed objects have a wide range of applicability. MJP can print parts with superior finish and high fidelity, hence it is often used to make concept models for industries such as marketing and communications, as well as functional parts for the automotive, aerospace, medical, and consumer electronics industries.

How does MJP printing work?

Most additive manufacturing processes like SLS and DMLS, melt plastics or metals and fuse them together in layers to form the desired product. But MJP 3D printing works differently.

During the MJP printing process, the multi-jet printer deposits droplets of a photoreactive material which solidifies when it is exposed to UV light. UV light is shone on the droplets until they solidify. Then, the printer deposits more droplets on top of the first ones, followed by layer after layer of solidified MG2-CL. These layers eventually achieve the desired shape that is the 3D printed object.

MJP uses a dissolvable or meltable support material that can be completely removed in a hands-free process, allowing for delicate, complex features and internal cavities to be easily cleaned without damaging the final product.

What materials are used for MJP printing?

MJP uses different classes of VisiJet® materials. At HLH, we use VisiJet Armor M2G-CL, an ABS-like engineering class material developed to replicate and even enhance most of the properties of ABS plastic. ABS is used commonly in 3D printing, and you’ll find it in many household items like electrical outlet covers and LEGO bricks.

MG2-CL, when solidified, is tough and strong, which means it will hold its shape and not easily deform or break while in use. This makes it great for functional parts, such as snap-fits, jigs, fixtures, and tools. The material has a transparent clear appearance and is smooth by nature — seen as aesthetically pleasing and modern — making it ideal for aesthetic models and prototypes.

What are the options for MJP post-processing?

Oftentimes, MJP printed parts and prototypes are left ‘as printed.’ They’re not sanded, polished, painted or changed in any ways. This is because they are naturally visually appealing with their transparent color and smooth surfaces. However, if your project requires further post processing, you have a few options:

Painting

If you desire your MJP printed part to be coloured, this can be achieved by painting it. At HLH, achievable colors include black and Pantone/RAL colors.

Dyeing

One way to infuse a uniform color throughout the entire MJP print is by dyeing it. Dyeing is fast, cost-effective, and brings vivid life into the part or model.

What are the advantages of MJP printing?

• Functional Parts: MJP uses materials with good mechanical properties (comparable to PC and ABS), making it excellent for functional parts.
• Requires little post-processing: As the support material can be removed cleanly through a dissolving process and MJP parts are naturally smooth, they often require little-to-no post-processing.
• Complex Geometries: MJP allows for greater design freedom due to the easy removal of the support material.
• High Resolution Prints: The unique 3D printing process that ProJet MJP 2500 use results in exceptionally high-resolution prints, making it great for creating detailed prototypes and concept models.

What are the disadvantages of MJP printing?

• Size: Compared with other 3D printing technologies, such as SLA and FDM, MJP prints are limited in size (294 x 211 x 144 mm). This is less of a disadvantage for those who want to print small jigs and fixtures and concept ideas and models, as these are often smaller than the final iteration.
• Range of Materials: Compared with 3D printing techniques, such as SLA and FDM, MJP is limited in material choice. VisiJet MG2-CL is transparent and doesn’t come in a solid color. This could be seen as a drawback, however, if desired, colour can always be added in post processing via dye or paint.

When to use MJP printing?

MJP is the perfect solution if you’re looking to print a highly detailed, high resolution end-use part or concept model. Even though you’re limited on the range of materials you can use for this process, the one material that is available is strong, tough, and prints transparent and smooth. If you want to add some color to the result, that is easily done through painting or dyeing.

MJP 3D printing is applicable to several different types of industries, including automotive, aerospace, medical, consumer electronics, communications, sales, and marketing. This is all due to it being a useful, efficient, and refined form of manufacturing.

Interested in getting your next project MJP 3D printed? Get an instant quote here.