Loading...
3D-Druck Bauteil MJF Technologie

MJF or SLS - Which additive manufacturing technology is suitable for what?

In 3D printing, Selective Laser Sintering (SLS) and Multi Jet Fusion (MJF) are probably the most widely used additive manufacturing processes for polymers and elastomers. With common materials, such as PA12, 3D-printed components can be produced using both SLS and MJF. The differences and specific advantages or disadvantages of the processes cannot be identified at first glance. To help you choose the optimal 3D printing process for your parts, we are dedicating this blog text entirely to Selective Laser Sintering versus Multi Jet Fusion.

 

Image: Component from MJF 3D printing

The similarities of additive manufacturing with SLS and MJF

Both Selective Laser Sintering and Multi Jet Fusion use thermoplastic materials, usually nylon, which is fused or sintered in powder form layer by layer. The powdered starting material is thus turned into a solid component in a powder bed. Both processes also require a heat source. In SLS printing, a laser is used for this purpose, scanning and sintering layer by layer, while in MJF printing the fusing agent, a heat-conducting liquid, is applied to the powder layer and then fused with the underlying layer using infrared light. The layered structure of the 3D-printed component is another common feature of the two additive manufacturing processes. And SLS and MJF printing also share a major advantage: no support structures are required for 3D printing. This means that even complex designs with the most demanding geometries can be produced effortlessly. And that includes moving, interlocking components, which can be printed in a single pass with both technologies.

 

View into an SLS and an MJF printer during the manufacturing process

Printprozess SLS additive Fertigungstechnologie

In SLS 3D printing, the batueiles are sintered individually per layer.

Printprozess MJF additive Fertigungstechnologie

In MJF printing, a fusing agent is used to fuse all the layers of the components in the powder bed using an infrared layer.

The differences between SLS and MJF 3D printing

With so many similarities, there are of course differences between the two processes due to technical reasons. The most important differences between Multi Jet Fusion and Selective Laser Sintering are:

 

Material selection

SLS is the much older 3D printing process. Accordingly, the selection of available materials that can be used for printing is large. Polyamides, fiber-reinforced or glass-filled composites, polypropylene or thermoplastic polyurethane (TPU): there are countless materials with very specific technological properties for additive manufacturing with SLS printers.

The situation is different with MJF printing. The process has not been in use for all that long, and the selection of materials available for printing is correspondingly small. Currently, mainly polyamide PA12 is used.

The selection of available materials can be found under the respective technology: MJF andSLS (scroll down on the respective page).

 

Surface finish

In additive manufacturing with MJF printing, the melting of the powder can be controlled very finely. As a result, very smooth surfaces can be achieved even without post-processing, despite the layer-by-layer structure. SLS-printed components are somewhat rough on the surface. Here there is the option of chemical smoothing, but it must be checked in each individual case whether technical properties are affected by the form of post-treatment. Post-processing also increases the price of the printed component.

Jellypipe 3D-Druck Bauteil SLS PA12 Standard und chemisch gegl├Ąttet

A 3D-printed component from SLS, on the left in the picture PA 12 standard, on the right in the picture PA 12 chemically smoothed. The surface of the chemically smoothed component is very smooth. (Macro image, the component is approx. 6 cm wide).

Resolution and minimum wall thicknesses

SLS offers material-dependent printing of features between 0.75 mm and 1 mm, while MJF printing can produce the smallest features down to 0.3 mm. I.e. small details can still be reliably imaged at this size. However, it must be said here that although smaller details can be printed via MJF printing, selective laser sintering has a slight advantage in terms of accuracy.

The minimum wall thicknesses are 1 mm for SLS technology and 0.5 mm for MJF. These must be considered for each part.

 

Strength

Both processes allow the production of components for use in technical environments. If near-isotropic components, where the strength is the same in each tensile direction, are required, MJF 3D printing is the right choice. Consistent manufacturing produces components with high mechanical properties. However, selective laser sintering offers a much wider choice of materials, each with specific mechanical properties that may be more suitable depending on the application. If you are unsure, please contact our Solution Partners to define the optimal process for your component!

Coloring

SLS-printed components can be easily colored in a wide variety of colors, making components in virtually any color possible. For MJF-printed parts there is a technical limitation. Here, the fusing agent used is black, since dark materials absorb infrared radiation much better. Thus, the parts are grayish when they come out of the printer, but black throughout on the inside.

Important to know: MJF can also be printed in full color. This makes the process particularly interesting for illustrative models, model making applications or for the advertising and marketing sector.

 

Production time

The printing process is faster with MJF additive manufacturing technology because all parts in the print space are processed simultaneously with each powder layer. With SLS 3D printing, all shapes must be "traced" with the laser beam per layer. Multi Jet Fusion is also ahead in series production, because this process allows multiple parts to be printed in parallel.

In addition to the production speed, the utilization of the printers is also relevant for the delivery time. The delivery times of a component are displayed in the stores immediately after a 3D print file is uploaded.

 

Sustainability

An important issue in additive manufacturing is the recycling rate of the leftover powder after a 3D print. Since plastics are made from fossil fuels, recycling is relevant to making manufacturing as sustainable as possible. In SLS printing, around 30-50% of the powdered material can be reused after a print, whereas in the MJF process, up to 80% of the powder can be recycled. This also results in lower material costs.

 

Part size and installation space

In terms of the size of the parts to be produced, Selective Laser Sintering, with a maximum size of 680 x 380 (or larger) x 560 millimeters, is well ahead of Multi Jet Fusion, which is at its limit at 380 x 284 x 380 millimeters. However, MJF is ahead when it comes to small components. MJF prints can be produced with minimum dimensions starting at 0.5 millimeters, while SLS prints "only" start at 0.8 millimeters.

 

Prices

When it comes to additive manufacturing of individual parts, similar costs per part can be expected with both processes. In general, MJF printing can also bring a cost advantage due to its time advantage and better mixing ratio of old and fresh powder. However, this cannot be answered in a general way. For a quick cost comparison, we recommend uploading your print file to our calculator in the store and comparing the results.

Conclusion Comparison of additive manufacturing technologies

Selective laser sintering has already been used for 3D printing since the mid-1980s and can be described without exaggeration as one of the veterans of additive manufacturing. Much younger is the Multi Jet process developed by Hewlett-Packard, which has only been used in the industrial sector since 2016. The fact that both processes coexist on an equal footing is due to the sometimes significant differences. For despite all the similarities - printing of powdered materials, use of heat sources, layer-by-layer structure of the printed parts - both processes also have very specific advantages. Choose MJF 3D printing if - Components with a higher surface quality are required - Solid-colored components are needed for marketing applications or model making - Production is to be more cost-effective - Isotropic strength of technical components is required Choose SLS 3D printing if - Precision of the components is the focus - Technical properties are to be ensured through a wide range of materials - Larger components are to be printed

The Jellypipe 3D printing service is looking forward to your project. If you have any questions, please do not hesitate to contact our Solution Partners.

Your Jellypipe

 

PS: Video how a component is created in Selective Laser Sintering can be found here: Video SLS Print Process

Autor

Markus Grimm
Chief Virtual Printfactory

Further informations

Read more about technologies or 3D printing:

Newsletter subscription

Stay up to date with our newsletter.