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Selective laser sintering

Selective laser sintering (SLS) is an additive manufacturing (AM) technique that uses a laser as the power and heat source to sinter powdered material (typically nylon or polyamide), aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure.[1][2][3] It is similar to selective laser melting; the two are instantiations of the same concept but differ in technical details. SLS (as well as the other mentioned AM techniques) is a relatively new technology that so far has mainly been used for rapid prototyping and for low-volume production of component parts. Production roles are expanding as the commercialization of AM technology improves.

For metal 3D printing, see Selective laser melting.

History[edit]

Selective laser sintering (SLS) was developed and patented by Dr. Carl Deckard and academic adviser, Dr. Joe Beaman at the University of Texas at Austin in the mid-1980s, under sponsorship of DARPA.[4] Deckard and Beaman were involved in the resulting start up company Desk Top Manufacturing (DTM) Corp, established to design and build the SLS machines. In 2001, 3D Systems, the biggest competitor to DTM Corp. and SLS technology, acquired DTM Corp..[5] The most recent patent regarding Deckard's SLS technology was issued January 28, 1997 and expired January 28, 2014.[6]


A similar process was patented without being commercialized by R. F. Housholder in 1979.[7]


As SLS requires the use of high-powered lasers it is often too expensive, not to mention possibly too dangerous, to use in the home. The associated expense and potential danger of SLS printing due to lack of commercially available laser systems with Class-1 safety enclosures means that the home market for SLS printing is not as large as the market for other additive manufacturing technologies, such as Fused Deposition Modeling (FDM).

Applications[edit]

SLS technology is in wide use at many industries around the world due to its ability to easily make complex geometries with little to no added manufacturing effort. Its most common application is in prototype parts early in the design cycle such as for investment casting patterns, automotive hardware, and wind tunnel models. SLS is also increasingly being used in limited-run manufacturing to produce end-use parts for aerospace, military,[17] medical, pharmaceutical,[18] and electronics hardware. On a shop floor, SLS can be used for rapid manufacturing of tooling, jigs, and fixtures.[19]

conformal cooling channels

Parts possess high strength and stiffness

Good chemical resistance

Various finishing possibilities (e.g., metallization, stove enameling, vibratory grinding, tub coloring, bonding, powder, coating, flocking)

Bio compatible according to EN ISO 10993-1 and USP/level VI/121 °C

[20]

Complex parts with interior components can be built without trapping the material inside and altering the surface from support removal.

Fastest additive manufacturing process for printing functional, durable, prototypes or end user parts

Wide variety of materials with characteristics of strength, durability, and functionality

Due to the reliable mechanical properties, parts can often substitute typical injection molding plastics

parts have porous surfaces; these can be sealed by several different post-processing methods such as cyanoacrylate coatings, or by hot isostatic pressing.

[21]

3D printing

Desktop manufacturing

Digital fabricator

Direct digital manufacturing

Fab lab

Fused deposition modeling (FDM)

also known as direct manufacturing or on-demand manufacturing

Instant manufacturing

Rapid manufacturing

Rapid prototyping

RepRap Project

Solid freeform fabrication

Stereolithography (SLA)

Von Neumann universal constructor

DMLS – DEVELOPMENT HISTORY AND STATE OF THE ART

Selective Laser Sintering, Birth of an Industry

Laser sintering, melting and others – SLS, SLM, DMLS, DMP, EBM, SHS