MJF vs. SLS | Beginners Guide

MJF vs. SLS | Beginners Guide

Navigating the additive manufacturing (AM) technology landscape can be challenging.  It’s our job to be informative and provide guidance to determine the right option for your next project. Multi-Jet Fusion (MJF) and Selective Laser Sintering (SLS) are two of the most prominent additive technologies within the marketplace today. Each offers strong material options, excellent surface finish qualities and are considered highly repeatable. While similar in many ways, there are several key differences between the two technologies that we want to address. In this article, we will explore each technology and help uncover the right one for your next project. 

Multi-Jet Fusion

Multi-Jet Fusion is a powder-bed fusion process that selectively applies fusing and detailing agents to layers of powder to form parts. The process repeats and the layers build until the 3D model is complete. Once the build is finished, the parts are removed from the powder bed and post-processed. MJF utilizes engineering-grade nylon powder, thus parts are durable for prototyping or production purposes. Nylon PA 12 is one of the most commonly used materials across a variety of industries due to its high dimensional accuracy, toughness, and excellent chemical resistance properties. Learn more about Nylon PA 12.

MJF Characteristics

  • Highly accurate features for complex parts
  • Better isotropic properties in the Z direction
  • No support required, allowing more design freedom
  • High throughout and excellent mechanical properties

Nylon PA 12 Mechanical Properties

Selective Laser Sintering

Selective Laser Sintering (SLS) uses powder materials but instead of a fusing agent, SLS uses a high-powered laser to melt the particles before moving onto the next layer. The laser selectively fused the powdered material by applying heat and pressure, otherwise known as sintering. Once a layer is complete, the build platform moves downwards and the re-coating blade spreads a thin layer of powder on the build platform. The process repeats until the part is complete. Once finished, the parts are completely immersed in powder which takes time to cool, remove, and post-process (~10+ hours).

SLS Characteristics

  • Wide range of thermoplastic and elastomeric materials
  • Good resolution for concept and rapid prototyping 
  • Wide range of color dye options 
  • Good isotropic mechanical properties

MJF vs. SLS Comparative Data

What's the right option for my next project?

Now that we understand the fundamental differences between the two technologies, we can down-click to determine the right option per application. MJF and SLS are suitable options for general prototyping, short-run production, spares and repairs because of the excellent mechanical properties afforded by engineering-grade nylon materials. However, several slight differences need to be accounted for. Here are some beginner questions to get you started:

Is this a one-off prototype or a short-run production project?

Both technologies build parts with consistent isotropic properties, indicating that your parts will have identical mechanical properties regardless of orientation. This is not always true with other 3D-printing processes. Because of that important factor, MJF or SLS should align with your part strength requirements. However, when it comes to production orders, MJF build nesting and optimization tends to be more cost-effective compared to SLS. Both technologies can produce parts within a single work shift but MJF has better speed and throughput capacity, resulting in lower cost per part. Get a sample part today.

What is the part environment?

How and where will your part function daily? Understanding the environment will help determine which process and material choice is right for you. Does UV stability matter? Does chemical resistance make a difference? For most general applications, MJF or SLS can be interchangeable. However, there are some notable differences. For example, MJF Nylon PA 12 is medical device certified (USP Class I-IV) and approved for skin contact. Furthermore, Nylon PA 12 has better UV resistance properties for outdoor applications. Alternatively, there is a wider selection of SLS Polyamides (12, 11, GC, CF) that perform better for lightweighting, chemical and heat resistance.

How important is resolution?

As you can see from the table above, MJF parts have a finer resolution of 0.020 in (0.51mm) compared to 0.030 in (0.762mm) for SLS. Relative to injection molding, if a smooth surface finish is a requirement then MJF is the ideal choice. However, it’s important to note that post-processing is an important consideration for all additive manufacturing technologies, including MJF and SLS. At Endeavor 3D, we offer a range of post-processing techniques, color dyeing, and vapor smoothing to help get you the best surface quality possible. Learn about AM Post Processing.
There are more similarities between the two technologies than differences. However, if you take a deep dive into your product development process and part lifecycle then it becomes much more clear which option is the best for you. 

Contact us and get a free quote for your next 3D printing project.

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