Selective laser sintering (SLS) was developed and patented by Dr. Carl Deckard and Dr. Joe Beaman at the University of Texas at Austin in the mid-1980s. Deckard and Beaman were involved in the resulting start up company DTM, established to design and build the SLS machines. In 2001, 3D Systems, the biggest competitor to DTM and SLS technology, acquired DTM. This page discusses in detail the advantages of using SLS technology to 3D print parts. It explains the most common SLS materials, offers rules for designers to follow when printing with SLS, and also shows a gallery of various parts that were produced using SLS 3D Printing equipment.
Selective laser sintering (SLS) is an additive manufacturing (AM) technique that uses a laser as the power and heat source to sinter a powdered material (typically nylon or other plastic). At the start of a new layer the print bed is dropped by 0.004”- 0.006” depending on the material being printed. The recoater picks up a load of freshly heated raw powder from the material storage bin and moves across the build platform filling in the thickness that the build platform has been dropped with the fresh hot powder. At this point the laser comes on and begins tracing and hatching that slice of the parts being printed. The part slice is defined by a 3D model that has been loaded into the machines build management software. As the laser sweeps across the areas being sintered it is binding the material together to create a solid structure. After the powder is sintered, the parts must be allowed time to cool. Depending on the size of the parts, cooling time usually takes equally as long as the time it took to print the job in the first place. For that reason SLS jobs usually have longer lead times (at least 1 day for production and 1 day for cooling) when compared to other printing technology like SLA, PolyJet, or FDM. For extremely large SLS parts (something larger than 20″ x 20″ X 10″), printing can span several days followed by several days of cool down time.
Selective Laser Sintering uses high-powered lasers to sinter powdered material, binding it together to create a solid structure. This printing process is considered to be a support free process. The parts are supported by unsintered powder that is left over after that layer has been sintered. Once the printing of that build is complete, the part(s) are removed from the block of loose unsintered powder they are trapped inside of and cleaned by hand and using air jets and a bead blaster to remove all the excess powder that is still clinging to the surface of the part.
SLS is known for having a relatively good level of accuracy, cheap raw material costs, the ability to easily make complex geometries without supports, parts that are very strong, and producing parts that can handle high temperatures (300F+). This makes it an incredibly useful technology for a broad range of applications in things like prototype parts, investment casting patterns, automotive parts, and wind tunnel models. It is also commonly used for low volume manufacturing of end use parts for aerospace, military, medical, pharmaceutical, and electronics hardware. On a shop floor, SLS can be used for rapid manufacturing of tooling, nesting, and fixtures.
Common applications for SLS parts:
Laser-sintered parts made from PA 2200 possess excellent material properties:
Typical applications of this material are things like high quality fully functional plastic parts. Due to the excellent mechanical properties of this material it is often used as a substitute for Nylon injection moulding plastics. The biocompatibility of this material allows for its use on prostheses and the high abrasion resistance it possesses allows for part with movable connections.
PA 3200 GF is a whitish, glass-filled polyamide 12 powder, which is characterised by an excellent stiffness in combination with good elongation at break. Laser-sintered parts made from PA 3200 GF possess excellent material properties:
A typical application for PA 3200 GF is for end use parts within the engine bay of cars, for deep-drawing dies or any other application which requires particular stiffness, high heat distortion temperature and low abrasive wear.
DuraForm PAx Natural is a nylon copolymer that offers properties similar to injection molded plastic and features high impact resistance with high elongation at break in any direction, including Z. Engineered for easy processing and high recyclability, DuraForm PAx Natural is ideal for functional prototypes and end-use parts with good mechanical properties and long-term stability.
Advantages of having parts 3D Printed using SLS equipment:
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