Are you wondering about the advantages and disadvantages of Multi Jet Fusion (MJF) and Selective Laser Sintering (SLS)? You’re not alone, as the reasons for using one over the other aren’t always obvious.
Both additive manufacturing technologies create highly complex and reliable components from polymers. They’re affordable and reliable methods for making everything from functional prototypes to end-use parts. However, critical differences in each technology’s capabilities can significantly impact your 3D printing project.
This guide will show you which technologies are best suited for your project. If you want fast answers fast, scroll to the bottom of the article for a helpful cheat sheet.
How the MJF and SLS Technologies Work
SLS and MJF are powder bed fusion technologies that build up parts layer-by-layer. As the name suggests, SLS uses a laser to heat the powder and fuse the layers. MJF is newer technology developed by HP. It uses heating lamps, fusing lamps, and chemical agents to fuse and detail the layers.
Between these technologies, there are differences in what’s possible regarding the size, powders, finishes, and, most importantly, the best use cases.
The SLS Printing Process
The MJF Printing Process
MJF and SLS Powders
One of the main differences between SLS and MJF is the range of powders available.
Both can make parts with the standard thermoplastic polymers – PA 11 and PA 12. These polymers are popular for a good reason, as they’re strong, ductile, and biocompatible. They’re also relatively affordable.
However, SLS offers a greater variety of powders that aren’t available in MJF. Some of these include:
PA 12 Aluminum Filled: The aluminum filling leads to a metallic-looking appearance. The aluminum also provides excellent dimensional stability at high temperatures while maintaining the light weight of a polymer. It’s ideal for components operating in high temperatures or under great stress.
PA 12 Flame Retardant: This is suitable for parts requiring flame retardancy for safety or regulatory reasons (such as in the aerospace and rail industries).
PEEK: Polyetheretherketone is a high-performance polymer capable of withstanding high temperatures and harsh environments.
So how do the parts look when printing is finished? SLS parts are printed in white, making them easier to color, or sometimes gray. MJF prints in dark gray.
A white part printed by SLS vs. the dark gray of a part created with MJF.
Due to the printed components’ limited colors and grainy finish, the following post-processing options are popular for both SLS and MJF.
Media Blasting: An abrasive medium (such as sand or glass beads) is applied at high pressure. This process removes the remaining powder. It also helps achieve the desired surface roughness and polishes the surface.
Painting: Additional colors can be added via a professional spray-painting system. Various colors are available, but painting can be difficult with complex geometries.
Dyeing: Submerging the part in water mixed with dye changes the color. This process is ideal for parts with complex geometries, as the dye can easily reach the entire surface area.
Smoothing: A chemical reaction results in a very smooth surface.
Tumbling: The parts are placed in a rotating container. They’re then deburred, finely ground, and polished.
For more about SLS post-processing options, read this guide.
When to Use MJF vs. SLS
MJF and SLS are useful additive manufacturing technologies that can help you create everything from functional prototypes to end-use parts. Depending on your use case or needs, it makes sense to choose one technology over the other in the following cases.
More Economical Parts: MJF
For larger batches, MJF usually has a price advantage. The printing process is fast and unused powders are easily recycled, so costs are typically lower than SLS. However, SLS systems are open to a wider variety of powders, resulting in potential cost savings depending on which powder is used.
Voluminous Parts: SLS
Selective Laser Sintering can produce thicker parts compared to MJF. If this is essential to the form and functionality of your part, then SLS has the advantage.
Higher Detail: MJF
Multi Jet Fusion can produce parts with higher levels of detail and higher resolution (1200 dpi). However, SLS offers slightly higher dimensional accuracy. Using PA 12, SLS provides a dimensional accuracy of .03% for parts above 100 mm. MJF offers .05% in comparison.
Larger Parts: SLS
SLS printers can build parts larger than 400 cm. With SLS, the maximum height can reach 605 mm compared to 380 for MJF.
For Advanced Materials: SLS
If your part requires powders beyond the standard polymers, SLS offers a greater selection – including powders that are flame retardant and provide higher performance.
For Colors: SLS
SLS prints in white compared to dark gray. This blank slate makes SLS ideal for the dyeing post-production process, with more color options.
MJF vs. SLS Cheat Sheet
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