ProtoCAM: Additive Manufacturing, 3D Printing and Rapid Prototyping.

Selective Laser Sintering: A Featured Technique

Selective laser sintering (SLS) was one of the first additive manufacturing technologies on the scene; it essentially established the industry and set a course that has made innovative parts and prototypes both possible and accessible.

sls featured SLS is the durable workhorse of the rapid prototyping world. If you want impressive aesthetics for show and tell, either stereolithography/SLA or PolyJet 3D printing is probably going to be your choice. If, however, you want to put a part through its paces, SLS performs admirably (and relatively inexpensively).

Presentation and Performance

SLS is known for creating tough end products and prototypes; the technology is often used when functional testing is required of a part or prototype. Although fused deposition modeling also creates a durable part, it may be strong in one direction and brittle in another – like a piece of wood, FDM has a grain. SLS, on the other hand, has a more homogenous material construction and is, therefore, strong in every direction. Even though SLS is still built in layers, each layer is sintered, creating more uniform strength across the entire part.

The sintering process results in a slightly grainy texture, leaving the surface finish rougher than techniques like SLA or PolyJet. However, the range of thermoplastic materials available with SLS allows it to create products with mechanical properties similar to injection molded pieces.

ProtoCAM’s engineers have used SLS to deliver projects such as snowboard bindings; a complex, functional allen wrench; and gears all for pre-production equipment testing. ProtoCAM has also completed production parts, including a project for a telecom company creating enclosures for use out in the field. SLS was the ideal choice for creating a box that would be rugged and durable enough to stand up to all kinds of weather.

Specifications

The maximum build envelope for an SLS project is 29” x 15” x 23” with an X&Y tolerance of +/- 0.005″ for all features smaller than 2″, and +/- 0.003″ per inch for all features larger 2″, +/- 0.010″ in the first inch of Z then +/- 0.003″ per inch thereafter.

Laser sintered nylon is heat- and chemical-resistant, and certified for surgical testing or autoclave exposure. Laser sintered glass-filled nylon delivers increased stiffness that stands up to testing extremes.

Nylon FR-106 is a fire-retardant polyamide that meets the strict Federal Aviation Regulations, and the Duraform EX elastomer has a flexible tear strength that far exceeds that of PolyJet materials. Finally, metal SLS allows customers to capture all the benefits of the technology in an A6 tool steel part.

Typical Results

For durable final parts or resilient prototypes that will stand up to functional testing, SLS is an excellent technique. The range of materials available with SLS, including metal, makes it a widely applicable technology.

SLS is …

• Strong: Available materials have mechanical integrity and heat resistance, with some able to withstand temperatures up to 100°C and an electrical charge of 460 amps.
• Test ready: Tear resistant and resilient materials stand up to the rigors of functional testing.
• Versatile: Thermoplastics and metal materials mean SLS can meet a wide variety of needs.
• Quick: Turnaround time is as short as a few days.
• Cost-effective: ProtoCAM offers competitive pricing on this technology.