Multi Jet Fusion ( MJF ) and Selective Laser Sintering ( SLS ) are 3D printing processes respectively used in black and white nylon. Both two methods belong to the powder bed-based 3D printing process. The initial materials used are power, tiled on the printing platform, and made into parts by layer-by-layer hot melting or sintering of powder particles. The main difference is hot source. SLS uses laser as the heat source, while MJF uses an ink that absorbs infrared light to spray on the powder bed, and then scans the printing platform through the infrared heat source to fuse the ink area.
SLS: A thin layer of powder if first spread evenly over a platform where it is heated to a temperature close to sintering. Then each cross section is scanned by a laser in a predetermined path to sinter the powder. The platform will move down a layer and repeat it until all is complete. After printing, the entire silo must be cooled before the parts can be removed from the powder.
MJF: A thin layer of powder if first spread evenly over a platform where it is heated to a temperature close to sintering. The slide with an inkjet nozzle is slide through the powder bed and a fusing agent is sprayed on the powder. At the same time, a detailing agent is sprayed near the edge of the part to prevent powder sintering, and then a high-power infrared heat source irradiates the powder bed and sinters the area where the flux is sprayed, while the remaining powder remains unchanged. Repeat the process until all parts are constructed. Similar to SLS, MJF printed parts are encapsulated in powder and need to be cooled down before the can be removed.
Dimensional Accuracy
Both MJF and SLS offer industrial-grade 3D printing with high dimensional accuracy. MJF is slightly outperforming in dimensional accuracy, mainly because the MJF printhead prints at 1200 DPI ( or about 1 dot per 0.022mm ), while the typical laser spot diameter of the SLS system is about 0.3-0.4mm. In addition, the detail agent used in MJF helps print fine features and sharp edges.
Appearance and Surface Quality
As dark materials absorb heat radiation more efficiently, the fusion agent currently used in MJF is black, which give a light grey appearance of MJF parts. A uniform black finish can be achieved by subsequent steps.
SLS parts are usually white and can be dyed in any color. So to some degree, its application range is wider.
The parts printed by both methods have granular surfaces, but both can be post-processed to achieve high standard.
Material Properties
The main material used in both processes is PA 12 ( nylon ). The SLS parts is slightly weaker in the print direction Z, whereas the MJF parts have excellent strength and flexibility and more even mechanical properties.
Cost and Delivery time
Black nylon is slightly superior in performance and slightly more expensive
The delivery time is generally similar. Black nylon may have advantages in delivery time due to higher powder recovery and faster cooling rate.
Tolerances for SLS and MJF in PCBWay
