SLS vs. MJF: Key Differences & How They Compare

Comparisons Between SLS and MJF

When comparing SLS and MJF, there are some common properties that come to mind. Matt Schmidt, a Senior Solutions Engineer here at Xometry, states, "The SLS and MJF platforms are very similar and are capable of processing common materials such as Nylon 11 and 12. However, there are some differences in the way each platform processes the materials that create different results. The SLS system utilizes a laser thermal source to melt powder bed materials, which has greater and more localized heating effects. The higher heat gradiant often resluts in lower mechanical property values for tensile, yield and elongation. On the other hand, MJF utilizes an infrared heat lamp, which is a more broad spectrum and melts materials at a more consistent rate across the powder bed. This increases the mechanical properties slightly over SLS. However, the localized heat source from a SLS laser platform, will provide slightly more accurate dimensional results over the broad spectrum heat lamp of MJF. Material properties and accuracy become factors within the decision-making process. Lastly, the SLS systems traditionally have larger build areas, which provide for larger parts or larger volume throughput with better production costs. The overall low operational costs of MJF favor day-to-day prototype builds and lower-volume production parts."

AttributeSLSMJF

Attribute

Print resolution

SLS

120 microns

MJF

80 microns

Attribute

Can be dyed in multiple colors

SLS

Yes

MJF

Attribute

Minimum recommended feature size

SLS

0.75 mm

MJF

0.75 mm

Attribute

Can recycle more than 80% of unused powder

SLS

MJF

Yes

Attribute

Parts need to be cooled after printing

SLS

Yes

MJF

Attribute

Parts need support structures

SLS

MJF

Attribute

Largest print volume

SLS

660 x 380 x 580 mm

MJF

380 x 280 x 380 mm

Table 1. SLS vs. MJF Comparison

Of the two, MJF can produce higher-resolution parts and its raw material is significantly more isotropic and recyclable. SLS machines are available with larger build volumes, though.

SLS vs. MJF: Technology Comparison

SLS and MJF are both powder-bed fusion technologies. Powder bed fusion (PBF) means that parts are cumulatively built up one layer at a time by fusing powdered thermoplastics. SLS uses a heated chamber and a CO2 laser to sinter the particles. Meanwhile, the MJF process depends on an infrared heat source, preheated powder, and a specialized fusing agent deposited by a printhead, all working together to fuse the particles.

SLS vs. MJF: Material Comparison

SLS and MJF extensively use polyamides like nylon 12 and 11, TPU (thermoplastic polyurethane), TPA (thermoplastic polyamide), and polypropylene. SLS is also able to print with carbon- and aluminum-filled nylon. Overall SLS works with a broader range of nylons, while MJF offers other material options like polypropylene and flexible TPU.

SLS vs. MJF: Product Applications Comparison

SLS and MJF are used to create functional parts such as casting patterns, medical devices, and elastomeric parts. SLS is often used for prototyping components that will eventually be injection molded, as the designs tend to react similarly to the manufacturing process, allowing engineers to hone designs before committing to mold tooling, which can be costly. Regarding aesthetics, MJF products have a dull, uneven gray color and can only accept black dye. However, SLS parts are naturally off-white and can be dyed with many colors, making them more ideal for visual prototypes.

SLS vs. MJF: Print Volume Comparison

SLS machines have larger build volumes than MJF machines, especially for certain material variants, such as glass-filled nylon. With its larger build area, SLS can print more nested parts in a single run. Large 3D-printed parts can often warp, but it’s more of a problem for MJF processes than SLS. With SLS printing, build planners utilize as much of the build volume as possible because unused powder is less recyclable in SLS than with MJF.

SLS vs. MJF: Surface Finish Comparison

SLS and MJF parts both have a characteristic rough/matte surface finish. However, in both cases, technicians can smooth the surfaces via shot blasting or media tumbling. Chemical vapor smoothing has recently allowed both SLS and MJF parts to achieve a sealed, semi-gloss surface at low costs.

SLS vs. MJF: Cost Comparison

SLS and MJF have similar print costs at lower quantities. However, at higher quantities, MJF's economy of scale is better than that of SLS. MJF is more competitive because the printing process is slightly faster, and the unused material is more recyclable.

Quantity ProducedSLSMJF

Quantity Produced

SLS

$ 101.64

MJF

$ 45.13

Quantity Produced

100

SLS

$ 40.93

MJF

$ 37.12

Table 2. SLS vs. MJF Price Difference

What are the Mutual Alternatives to the SLS and MJF?

Despite the benefits of SLS and MJF, below is an alternative technology that can achieve similar results:

Stereolithography (SLA): Stereolithography is not a powder-based printing process but is one of the few technologies that can achieve similar or better print resolution and quality. SLA makes use of a liquid photopolymer and builds parts by curing successive layers of that liquid.

What are the Similarities Between SLS and MJF?

Both technologies make use of powder bed fusion processes to manufacture parts.
Printing cost is comparable when scaled up.
Parts have a rough/matte surface finish.
Both printers most commonly use nylon 12 powder.

What are the Other Comparisons for SLS Besides MJF?

Besides MJF, other 3D printing processes similar to SLS include:

SLS vs. DMLS: DMLS (Direct Laser Metal Sintering) systems produce metal parts in a similar manner to SLS. Instead of plastic powder, a metal powder is used. A more powerful laser enables it to hit higher temperatures and thus sinter the metal. To learn more, see our full guide on SLS vs. DMLS.

What are the Other Comparisons for MJF Besides SLS?

Besides SLS, other 3D printing processes similar to MJF include:

MJF vs. Binder Jetting: Binder jetting is functionally similar to MJF but does not fully sinter the material during the printing process. A similar inkjet-style printing head applies a binding agent to the powder in the shape of each layer. The agent bonds the particles together and also bonds layers to one another. The actual sintering step occurs in a sintering furnace after the whole structure has been built and the unbonded powder removed.

Summary

Xometry offers a full range of 3D printing services for your projects, including SLS and MJF 3D printing services. Visit our Instant Quote Engine for an instant quote in seconds.

Disclaimer

The content appearing on this webpage is for informational purposes only. Xometry makes no representation or warranty of any kind, expressed or implied, as to the information’s accuracy, completeness, or validity. Designers should not infer performance parameters, geometric tolerances, specific design features, quality and types of materials, or processes to represent what will be delivered by third-party suppliers or manufacturers through Xometry’s network. Buyers seeking quotes for parts are responsible for defining the specific requirements for those parts. Please refer to our terms and conditions for more information.

Dean McClements

Dean McClements is a B.Eng Honors graduate in Mechanical Engineering with over two decades of experience in the manufacturing industry. His professional journey includes significant roles at leading companies such as Caterpillar, Autodesk, Collins Aerospace, and Hyster-Yale, where he developed a deep understanding of engineering processes and innovations.