SLS 3D Printing — Save Time, Money and Space

Selective Laser Sintering (SLS) is opening new doors for manufacturers and engineers in a great variety of industries. Manufacturing operations both large and small are realizing the benefits of SLS 3D printing in prototyping and small-batch production of functional parts.

SLS printing hit the scene in the early ‘90s, but it has historically suffered from availability issues. For a long time, SLS printers were prohibitively expensive machines that required potentially dozens of square metres of factory floor space.

But the technology has developed rapidly in the past years. Today, with compact and affordable benchtop-scale machines — like the Formlabs Fuse 1 — even small-scale manufacturers can harness the productivity and cost-saving advantages of SLS.

In this blog, we’ll explore the basics of SLS 3D printing, the benefits it offers, and which applications SLS is most suitable for. Let’s learn how you can optimise your manufacturing operation — with lasers.

How SLS 3D Printing Works

Like SLA, SLS 3D printing uses a strong laser to solidify the material feedstock. But while SLA works with liquid resin, SLS is a powder-based technology.

The generic term for the process SLS 3D printing uses is powder-bed fusion. It’s suitable for printing with both metals and plastics. However, when used with metal, the technology is known by various other names, such as Laser Powder Bed Fusion (L-PBF), Direct Metal Laser Melting (DMLM), or Selective Laser Melting (SLM).

But whatever the name, the operating principle of the 3D printers remains the same. The powder material is stored in a compartment next to the heated print bed. A roller or a blade swipes across the print bed, distributing a thin layer of powder over it.

The printer’s laser will then trace the shape of the object layer over the powder, fusing and solidifying the material. After the laser has finished its job, the print bed lowers by the height of one layer. This process repeats over and over until the print run is finished.

Once the printer is done, the object inside will require post-processing as it’s still covered in powder. Typically, you’ll remove the entire print chamber and move it to a post-processing station, where you can de-powder, polish, and coat the part if necessary.

Benefits of SLS 3D Printing

SLS 3D printing makes it possible to quickly print highly complex, end-use ready parts at a competitive price. Let’s take a closer look at the advantage of introducing an SLS 3D printer at your workshop.

Design Freedom

Unlike many other 3D printing technologies, SLS-printed parts don’t require support structures, since the surrounding powder in the print chamber supports them. This allows you to print complex geometries — like overhangs and interlocking parts — that are impossible for traditional manufacturing. Additionally, you can consolidate multi-part components into a single printed part, saving time and money in assembly.

Fast Production

SLS is one of the fastest 3D printing technologies that can produce end-use ready parts. The lasers of SLS printers scan the print bed very quickly, and the lack of support structures makes post-processing operations simpler.

High Productivity

SLS printers can achieve high productivity by printing multiple parts at once. In fact, the technology encourages you to maximise your throughput. The more parts you can fit in the print chamber, the better they support each other while also minimising material waste.

Competitive Per-Part Cost

SLS printers offer one of the highest ROI rates out of any 3D printing technology. Granted, the initial cost is higher with SLS printers, but the productivity, short lead times, and lower price point of benchtop-sized machines allow you to quickly recover your investment.

End-Use Materials

Some 3D printing technologies are only suitable for prototyping. Although SLS 3D printing can absolutely create prototypes, it also supports materials that are ready for end users after cleaning. SLS makes it easy for you to shorten your time-to-market and lead times, and to grow your business.

Material Recycling

With SLS 3D printers, you can reuse up to 70% of unfused powder. This makes SLS one of the least wasteful manufacturing methods. Not only will powder recycling lower your material costs, you’ll also do a favour for the planet.

SLS 3D Printing Materials

As we already mentioned, SLS 3D printing uses powdered plastic materials as feedstock. The most common SLS materials are:

• Nylon 11
• Nylon 12
• TPU
• Speciality materials

Different types of Nylon are the most popular material options for SLS 3D printing. Nylon 12 is a versatile general-purpose material that makes it possible to print parts with a high level of detail and dimensional accuracy.

Nylon 11, on the other hand, is more ductile and flexible. It doesn’t produce details quite as sharp as Nylon 12, but it’s an excellent choice for performance parts that are resistant to impacts and general wear and tear.

Some SLS 3D printers are able to print with TPU, or thermoplastic urethane. Like Nylon 11, it provides high flexibility, together with abrasion and impact resistance, making it a good option for both prototyping and functional parts.

There are also many speciality materials, which are often proprietary and formulated to work with specific printers. These include glass- and carbon-filled nylons, castable polystyrene, and other materials intended for specific applications.

SLS 3D Printing Applications

The toughness and impact resistance of parts produced through SLS 3D printing make the technology suitable for a wide range of different applications. From small workshops to large aerospace companies, SLS has something to offer for everyone.

Prototyping and Product Development

SLS 3D printing is a great option for quickly creating durable product prototypes, thanks to its high print speed. In this general application, SLS suits all manufacturing operations, no matter their field.

Small Businesses

Small and medium-sized businesses can benefit from SLS’ speed and high throughput to deliver functional and customizable parts with short lead times. The technology is highly suitable for low-volume production of — for example — packaging materials or cases for electronics. It enables small businesses to produce parts on demand, eliminating the need to maintain an extensive inventory.

Tooling and Patterns

With SLS, you can easily produce large quantities of permanent jigs, fixtures, tools, or casting patterns. If you require snaps, clips, or hinged parts, simply use Nylon 11 to print durable parts.

Automotive

Many automotive manufacturers have adopted SLS 3D printing. The technology can produce both prototypes and test models for automotive design and wind-tunnels tests, and functional car parts, such as gaskets, seals, and hoses.

Aerospace

SLS 3D printing can create parts with highly durability and fire resistance, which are requirement for aerospace hardware. Several aerospace companies use SLS to create components for airplanes and even satellites.

Medical

SLS printers are a popular option in medical fields, as Nylon 12 is biocompatible and can be safely sanitized. Hospitals and doctors use SLS 3D printing to create both prototype and functional medical devices, surgical models and tools, and durable prosthetics and orthotics.

Considerations When Choosing SLS 3D Printing

As we’ve learned, SLS is a versatile technology that suits many different applications. However, you should be aware of couple of considerations before you purchase your first SLS printer.

Although it’s not as post-processing intensive as some other 3D printing technologies, SLS printed parts will require a certain level of post-processing. You will have to at least de-powder the parts, and they often also need sanding, coating, or dyeing.

However, you can make post-processing easier with a multi-purpose post-processing station, like AM Efficiency. Not only will these machines carry out several post-processing steps, they will save valuable workshop space.

SLS 3D printing also doesn’t support such an extensive range of material options as some other technologies. This isn’t usually an issue, though, as the available thermoplastic materials will get the job done for the purposes SLS is suitable for. Additionally, manufacturers are constantly researching and developing new material options.

Finally, as we already mentioned briefly, industrial-grade SLS machines can be very expensive. They are professional-grade 3D printers, and the price tags often reflect that.

But, with the introduction of benchtop-sized SLS printers, like Formlabs Fuse 1, SLS 3D printing has become much more affordable. Additionally, you’re likely to see quick ROI due to the excellent productivity and part quality SLS 3D printing provides.

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Want to learn more about how SLS 3D printing can help your manufacturing operation? The helpful SolidPrint3D team is ready to answer your questions. Call us on 01926 333 777 or email us at info@solidprint3d.co.uk.