Selective Laser Sintering (SLS) 3D Printing Manufacturing

Engineers and manufacturers from a cross-section of industries use selective laser sintering 3D printing (SLS) to create robustly functioning parts. Rapid PSI is proud to offer expert Selective Laser Sintering (SLS) Services – and many other types of Additive Manufacturing as well.

In this article, we will cover:

• What is selective laser sintering 3D printing (SLS)?
• What materials does selective laser sintering 3D printing (SLS) use?
• How does selective laser sintering 3D printing (SLS) work?
• What is selective laser sintering 3D printing (SLS) used for?
• Why you should choose selective laser sintering 3D printing (SLS)
• The benefits of selective laser sintering 3D printing (SLS)

But first, a brief history of selective laser sintering 3D printing (SLS) and where we are now.

A short history of SLS

SLS was a technique created in the mid-1980s by Dr. Joe Beaman and Dr. Carl Deckard. 

Their original method has been improved and streamline and can now use the following materials: 

• Metals
• Glass
• Ceramics
• Plastics
• Composite material powders

We now collectively categorized these as powder bed fusion. The most common powder bed fusion systems are selective laser melting (SLM) and direct metal laser sintering (DMLS). These are referred to as SLS, selective laser sintering. 

In recent years, these processes’ cost has drastically reduced, allowing more industries to benefit from them.

Beaman and Deckard founded one of the first 3D printing startups, called DTM Corp, nine years after creating the process. 

The process is streamlined enough that you can find Selective Laser Sintering Services readily available nearly everywhere.

Selective Laser Sintering

What is selective laser sintering 3D printing (SLS)?

3D printers or additive manufacturing turns digital designs into 3d, or three-dimensional, objects. 3D printing has become one of the most affordable and efficient ways to create prototypes, finished products, and parts. Today we call the technology selective laser sintering SLS. The new technology allows tiny particles of ceramics, glass, plastics to be fused using a high-powered laser. The fusing creates a solid, three-dimensional object. The objects are built one layer at a time. The most significant benefit of using SLS for your 3D printing is that it is a self-supporting structure. As the object is being built, the hollow spaces are filled with unused powder; this gives it its self-supporting nature.

What materials does selective laser sintering 3D printing (SLS) use?

One of the most sought-after and common materials in SLS is nylon. Nylon is ideal for complex assemblies; it can function for both end-use products and functional prototyping. Parts created using nylon are durable, strong, and impact-resistant. They can withstand a wide range of wear and tear. Nylon is resistant to solvents, moisture, heat, water, temperature, light, and UV. What makes nylon even more impressive is that it is biocompatible and can be used for ready-to-wear parts. Nylon 12 is the most commonly used version for SLS. This material is a single-component powder. However, many SLS printers will use two-component powders. Both coated powders and powder mixtures. Nylon composites with glass, carbon, and aluminide are optimized for higher flexibility, stiffness, and/or higher strength. Aside from Nylon 12, there are some other standard material options.

• Polyamide 11
• Polyamide 12
• Glass-filled nylon
• Carbon-fiber filled nylon
• Aluminum-filled nylon

The functionality of all of these materials can be increased by applying a water-tight coating or metal plating. The parts' appearance can also be upgraded by polishing, spray painting, lacquering, and dyeing.

How does selective laser sintering 3D printing (SLS) work?

The SLS process in 3D printing works in the following steps:

• The build is designed, and the powder bin is heated first. They are heating to just below the melting temperature of the polymer.
• A recoating blade spreads a layer of powder over the built form.
• A C02 laser will scan the contour of the following layer. Selectively sintering will occur between the particles of polymer powder.
• A cross-section of the component is scanned; this ensures that the part is solidly built.
• Once that layer is complete, the build platform moves down, and the blade recoats the surface.
• This process is repeated until the part is completed.
• Once the printing is completed, the parts are coated in unsintered powder, and the powder bin will cool down ahead of any part being unpacked.
• The cooling takes around 12 hours to be completed.
• After the cooling period, the part will be cleaned using blasting media or compressed air.

SLA powder is 50% recyclable so that any remaining unsintered powder may be collected and reused.

What is selective laser sintering 3D printing (SLS) used for?

Selective laser sintering 3D printing (SLS) can be used in several industries for many different items. The durability and cost-effectiveness of selective laser sintering 3D printing (SLS) have been rising in popularity. SLS technology has the unique ability to create complex shapes and geometries with almost manufacturing effort. The use of SLS is commonly found within prototypes. The machine’s ability to create prototypes early in the design cycle has made it invaluable in many industries. You will also see the use of SLS in the following products, parts, or industries:

• Automotive hardware
• Wind tunnel models
• Jigs
• Fixtures
• Tooling
• Limited-run manufacturing
• Medical - prosthetics, medical device prototyping, surgical tools
• Military
• Electronic hardware

Selective laser sintering 3D printing (SLS) applications

Here are some examples of SLS technology in use.

Consumer goods

One of the major characteristics that you can expect from our While SLS might sound like it would only be used for tech items, Chanel actually used the technology to create a mascara brush. It is the first and patented mascara brush to be developed using 3D printing technology.

Aerospace

SLS technology is being used for interior parts of aircraft. Emirates has used SLS 3D printing to produce several cabin components, including air vents.

Motorsports

Motorsports teams are competitive, and using innovative materials is an essential part of being ahead of the competition. SLS is used to create aerodynamic wine tunnels, cores, serial parts, and laminating molds. 

SLS applications have yet to reach their full potential; however, we are likely to see an increase in it with large brands adopting the technology.

Why you should choose selective laser sintering 3D printing (SLS)

Why you should choose selective laser sintering 3D printing (SLS)

Productivity

Since SLS is the fastest AM technology for durable, end-use, functional parts, it makes it unbeatable in terms of productivity. Unlike FDM layer deposition methods, SLS has a faster scanning speed and is more accurate too. To increase productivity, multiple parts can be nested during printing. This tactic will maximize the output and make the most of the build space. To ensure the best use of space, software that maximizes each build can give the perfect layout for optimal output. This method also saves time in post-processing.

End-use materials

The material possibilities allow for completed end-use products to be produced—specifically Nylon composites with their proven high-quality thermoplastics. Using the SLS process, nylon has close to a 100% density. The mechanical properties are also comparable to parts made using injection molding.

Design freedoms

Both FDM and SLA manufacturing processes require support structures to be fabricated, with overhanging features. Since they do not require support structures with SLS, they can produce previously impossible geometries. This includes parts with interior components, channels, highly complex designs, moving parts, and interlocking parts. Parts designed by engineers will have the final manufacturing process in mind; this is known as manufacturing design. Selective laser sintering allows for the full potential to be reached by generative designs and reduces the process's cost.

Development cycles

SLS technology enables engineers to produce prototypes very early in the design process. Streamlining the improvement process and the speed at which an end-use part can be created. Prototypes can be created, tested, modified, and improved over the space of a few days. Reducing the cost and the development time.

Cost per part

When looking at a competitive cost per part, the following is taken into account:

• Labor
• Material
• Equipment ownership

Increased speed, capacity with reduced use of materials means that the cost per part is significantly lower when using selective laser sintering 3D printing (SLS).

The benefits of selective laser sintering 3D printing (SLS)

Even more significant volumes

Laser sintering machines generally have a bigger print size in comparison to FDM printing options.

Finishing

You can achieve an excellent quality finish when using SLS technology. SLS product parts do not need heavy-post processing. Giving a smooth flat surface and reduced layering effects.

Speed

For short to medium runs, SLS offers a speed that FDM cannot match. 

Support parts

You can achieve an excellent quality finish when using SLS

Complex internal cavities, complicated geometric shapes, and overhangs are no issue for SLS printing. Unsintereted powder will act as a support, which saves both money and time. 

Post-processing

Selective laser sintering 3D printing doesn’t require curing, soluble baths, or a lot of heavy post-processing. 

Once the part is complete, it can be air blasted or sandblasted to produce a high-quality finish.

Full volume

To get the most out of the space and a higher ROI, you can nest your parts. As you will not be printing support parts, you can use the entire volume of space available.

Cost

The combination of not needing to print support parts, the possible nesting, and increased printing speed adds up to a reduced cost per part.

Z strength

Something only possible using SLS printing is the Z-axis mechanical properties. 

The evolution of SLS is exciting. Allowing large volume projects with a reduced cost, SLS is regarded as the best option for 3D printing.