Selective Laser Sintering (SLS)

DTM Corporation introduced Selective Laser Sintering (SLS) to the commercial world in 1992.  SLS uses a laser to sinter powder based materials together, layer-by-layer, to form a solid model. The system consists of a laser, part chamber, and control system. The part chamber consists of a build platform, powder cartridge, and leveling roller.

A thin layer of build material is spread across the platform where the laser traces a two-dimensional cross section of the part sintering the material together. The platform then descends a layer thickness and the leveling roller pushes material from the powder cartridge across the build platform, where the next cross section is sintered to the previous. This continues until the part is completed.

Once the model is complete, it is removed from the part chamber and finished by removing any loose material and smoothing the visible surfaces

Materials
NECO Inc. is capable of providing a variety of materials, each having a unique set of properties to fulfill a wide range of applications. The materials offered by NECO Inc. currently include Duraform, DuraformGF, and Somos 201.

Duraform
This material is a hard plastic that provides fine detail, good strength, durability and flexibility while being resistant to solvents, chemicals and fuels. It is ideal for form, fit, and function testing especially on parts with snap fits and living hinges, as well as for other visual aids and as patterns for tooling. In its finished form it is white in color with standard tolerances of ± 0.005″ on small features and +/-0.3% overall. Duraform is also capable of high temperatures with a heat deflection temperature around 350ºF@66psi.

DuraformGF
This material is a hard plastic that provides good detail, strength, durability, and detail while being resistant to solvents, chemicals, and fuels. It is ideal for form, fit, and function testing. It is also good for other visual aids and as patterns for tooling. In its finished form it is Grey in color with standard tolerances are ± 0.005″ on most parts and features. DuraformGF is also capable of high temperatures with a heat deflection temperature around 340ºF.

Somos 201
This material is a rubber like elastomeric polymer that is comparable to a Shore 75A material and offers high flexibility and ductility while being resistant to some solvents. It is excellent for simulating parts that such as hoses, seals, grommets, etc. It is off-white in color with standard tolerances of ± 0.010″ on small features and +/- 0.1% overall on most parts and features. Somos 201 is also capable of high temperatures with a melting temperature around 300ºF.

SLS Material Properties

Mechanical Properties Test
Method
Units Duraform Duraform
GF
Somos
201
Tensile Strength ASTM D638 psi 6,380 5,500  
Tensile Modulus ASTM D638 psi 230,000 855,000 2902
Tensile Elongation at Break ASTM D638   9% 2% 130%
Flexural Modulus ASTM D790 psi 186,000 478,600 2040
Izod Impact – Notched ASTM D256 (ft-lb)/in 4 1.8  
Heat Deflection Temp ASTM D648 degF 350 345  
Hardness ASTM D2240 Shore A     75
Initial Tear Resistance ASTM D624 lb/in     132
Melting Point DSC degF     310