(506) 2240-6804
Sls sla 3d printing
FDM vs. SLA vs. SLS
Additive manufacturing, or 3D printing, lowers costs, saves time, and transcends the limits of fabrication processes for product development. From concept models and functional prototypes in rapid prototyping to jigs, fixtures, or even end-use parts in manufacturing, 3D printing technologies offer versatile solutions in a wide variety of applications.
Over the last few years, high-resolution 3D printers have become more affordable, easier to use, and more reliable. As a result, 3D printing technology is now accessible to more businesses, but choosing between the various competing 3D printing solutions can be difficult.
Which technology is suitable for your particular application? What materials are available? What equipment and training do you need to get started? How about costs and return on investment?
In this article, we’ll take a closer look at the three most established plastic 3D printing processes today: fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS).
Trying to decide between FDM and SLA 3D printers? Check out our in-depth FDM vs. SLA comparison.
Video Guide
Having trouble finding the best 3D printing technology for your needs? In this video guide, we compare FDM, SLA, and SLS technologies across popular buying considerations.
Watch the Videos
Download the high-resolution version of this infographic here.
Fused deposition modeling (FDM), also known as fused filament fabrication (FFF), is the most widely used form of 3D printing at the consumer level, fueled by the emergence of hobbyist 3D printers. FDM 3D printers build parts by melting and extruding thermoplastic filament, which a printer nozzle deposits layer by layer in the build area.
FDM works with a range of standard thermoplastics, such as ABS, PLA, and their various blends. The technique is well-suited for basic proof-of-concept models, as well as quick and low-cost prototyping of simple parts, such as parts that might typically be machined.
FDM parts tend to have visible layer lines and might show inaccuracies around complex features. This example was printed on a Stratasys uPrint industrial FDM 3D printer with soluble supports (machine starting at $15,900).
FDM has the lowest resolution and accuracy when compared to SLA or SLS and is not the best option for printing complex designs or parts with intricate features. Higher-quality finishes may be obtained through chemical and mechanical polishing processes. Industrial FDM 3D printers use soluble supports to mitigate some of these issues and offer a wider range of engineering thermoplastics, but they also come at a steep price.
FDM printers struggle with complex designs or parts with intricate features (left), compared to SLA printers (right).
Stereolithography was the world’s first 3D printing technology, invented in the 1980s, and is still one of the most popular technologies for professionals. SLA resin 3D printers use a laser to cure liquid resin into hardened plastic in a process called photopolymerization.
See how stereolithography works.
SLA parts have the highest resolution and accuracy, the clearest details, and the smoothest surface finish of all plastic 3D printing technologies, but the main benefit of SLA lies in its versatility. Material manufacturers have created innovative SLA photopolymer resin formulations with a wide range of optical, mechanical, and thermal properties to match those of standard, engineering, and industrial thermoplastics.
SLA parts have sharp edges, a smooth surface finish, and minimal visible layer lines. This example part was printed on a Formlabs Form 3 desktop SLA 3D printer (machine starting at $3,750).
SLA is a great option for highly detailed prototypes requiring tight tolerances and smooth surfaces, such as molds, patterns, and functional parts. SLA is widely used in a range of industries from engineering and product design to manufacturing, dentistry, jewelry, model making, and education.
White Paper
Looking for a 3D printer to realize your 3D models in high resolution? Download our white paper to learn how SLA printing works and why it's the most popular 3D printing process for creating models with incredible details.
Download the White Paper
Sample part
See and feel Formlabs quality firsthand. We’ll ship a free sample part to your office.
Request a Free Sample Part
Selective laser sintering is the most common additive manufacturing technology for industrial applications, trusted by engineers and manufacturers across different industries for its ability to produce strong, functional parts.
See how selective laser sintering works.
SLS 3D printers use a high-powered laser to fuse small particles of polymer powder. The unfused powder supports the part during printing and eliminates the need for dedicated support structures. This makes SLS ideal for complex geometries, including interior features, undercuts, thin walls, and negative features. Parts produced with SLS printing have excellent mechanical characteristics, with strength resembling that of injection-molded parts.
SLS parts have a slightly rough surface finish, but almost no visible layer lines. This example part was printed on a Formlabs Fuse 1 benchtop SLS 3D printer (machine starting at $18,500).
The most common material for selective laser sintering is nylon, a popular engineering thermoplastic with excellent mechanical properties. Nylon is lightweight, strong, and flexible, as well as stable against impact, chemicals, heat, UV light, water, and dirt.
The combination of low cost per part, high productivity, and established materials make SLS a popular choice among engineers for functional prototyping, and a cost-effective alternative to injection molding for limited-run or bridge manufacturing.
White Paper
Looking for a 3D printer to create strong, functional parts? Download our white paper to learn how SLS printing works and why it's a popular 3D printing process for functional prototyping and end-use production.
Download the White Paper
Sample part
See and feel Formlabs SLS quality firsthand.
We’ll ship a free sample part to your office.
Request a Free Sample Part
Each 3D printing technology has its own strengths, weaknesses, and requirements, and is suitable for different applications and businesses. The following table summarizes some key characteristics and considerations.
| Fused Deposition Modeling (FDM) | Stereolithography (SLA) | Selective Laser Sintering (SLS) | |
|---|---|---|---|
| Resolution | ★★☆☆☆ | ★★★★★ | ★★★★☆ |
| Accuracy | ★★★★☆ | ★★★★★ | ★★★★★ |
| Surface Finish | ★★☆☆☆ | ★★★★★ | ★★★★☆ |
| Throughput | ★★★☆☆ | ★★★★☆ | ★★★★★ |
| Complex Designs | ★★★☆☆ | ★★★★☆ | ★★★★★ |
| Ease of Use | ★★★★★ | ★★★★★ | ★★★★☆ |
| Pros | Low-cost consumer machines and materials Fast and easy for simple, small parts | Great value High accuracy Smooth surface finish Fast printing speeds Range of functional applications | Strong functional parts Design freedom No need for support structures |
| Cons | Low accuracy Low details Limited design compatibility | Sensitive to long exposure to UV light | Rough surface finish Limited material options |
| Applications | Low-cost rapid prototyping Basic proof-of-concept models | Functional prototyping Patterns, molds, and tooling Dental applications Jewelry prototyping and casting Modelmaking | Functional prototyping Short-run, bridge, or custom manufacturing |
| Print Volume | Up to 300 x 300 x 600 mm (desktop and benchtop 3D printers) | Up to 300 x 335 x 200 mm (desktop and benchtop 3D printers) | Up to 165 x 165 x 300 mm (benchtop industrial 3D printers) |
| Materials | Standard thermoplastics, such as ABS, PLA, and their various blends. | Varieties of resin (thermosetting plastics). Standard, engineering (ABS-like, PP-like, flexible, heat-resistant), castable, dental, and medical (biocompatible). | Engineering thermoplastics. Nylon 11, Nylon 12, and their composites. |
| Training | Minor training on build setup, machine operation, and finishing; moderate training on maintenance. | Plug and play. Minor training on build setup, maintenance, machine operation, and finishing. | Moderate training on build setup, maintenance, machine operation, and finishing. |
| Facility Requirements | Air-conditioned environment or preferably custom ventilation for desktop machines. | Desktop machines are suitable for an office environment. | Workshop environment with moderate space requirements for benchtop systems. |
| Ancillary Equipment | Support removal system for machines with soluble supports (optionally automated), finishing tools. | Washing station and post-curing station (both can be automated), finishing tools. | Post-processing station for part cleaning and material recovery. |
Ultimately, you should choose the technology that makes the most sense for your business. Prices have dropped significantly in recent years, and today, all three technologies are available in compact, affordable systems.
Calculating 3D printing costs does not end with upfront equipment costs. 3D printing material and labor costs have a significant influence on cost per part, depending on the application and your production needs.
Here’s a detailed breakdown by technology:
| Fused Deposition Modeling (FDM) | Stereolithography (SLA) | Selective Laser Sintering (SLS) | |
|---|---|---|---|
| Equipment Costs | Budget printers and 3D printer kits start at a few hundred dollars. Higher quality mid-range desktop printers start around $2,000, and industrial systems are available from $15,000. | Professional desktop printers start at $3,750, large-format benchtop printers at $11,000, and large-scale industrial machines are available from $80,000. | Benchtop industrial systems start at $18,500, and traditional industrial printers are available from $100,000. |
| Material Costs | $50-$150/kg for most standard and engineering filaments, and $100-200/kg for support materials. | $149-$200/L for most standard and engineering resins. | $100/kg for nylon. SLS requires no support structures, and unfused powder can be reused, which lowers material costs. |
| Labor Needs | Manual support removal (can be mostly automated for industrial systems with soluble supports). Lengthy post-processing is required for a high-quality finish. | Washing and post-curing (both can be mostly automated). Simple post-processing to remove support marks. | Simple cleaning to remove excess powder. |
Interactive
Try our interactive ROI tool to see how much time and cost you can save when 3D printing on Formlabs 3D printers.
Calculate Your Savings
Prototypes of a ski goggles' frame printed with FDM, SLA and SLS technology (from left to right).
We hope this article has helped you focus your search for the best 3D printing technology for your application.
Explore our additional resources to master the intricacies of 3D printing, and dive deeper into each technology to learn more about specific 3D printing systems.
Learn More About 3D Printing
SLS vs. SLA: Differences and Comparison
SLS (selective laser sintering) is a 3D printing technique that uses a laser to fuse together small particles of plastic, metal, glass, or ceramic powder into a solid object. SLA (stereolithography) uses an ultraviolet (UV) laser to cure (harden) photosensitive resin into the desired shape. Both technologies employ a laser as part of their build process, but they differ in terms of build speed, precision, price, and processing. A full understanding of the choice between SLS vs.
SLA requires more background information.
A major advantage SLS has over SLA is in the time it takes to manufacture a part. It has a shorter lead time. Therefore, more such parts can be produced per day. However, if precision details are important, SLS becomes the best choice because it produces parts with tighter tolerances.
In this article, we will compare and contrast these two types of 3D printers. We will also take a cursory look at other alternatives that can serve as replacements for either one of them.
SLS Definition and Comparison to SLA
SLS was created in the 1980s at the University of Texas in Austin by Dr. Carl Deckard and Dr. Joe Beaman. SLS is a 3D printing technology that uses a powerful laser to selectively fuse layers of powdered particles. Most such machines use nylon-based or polymer-based build materials, though more advanced versions have been created to fuse materials with higher melting temperatures.
Each print begins with a digital version of the part, built into a computer.
The SLS machine turns that into a physical object by tracing out the geometry of each successive 2D slice of the object, fusing powder at the necessary points. After one layer is finished, another fine layer of powder is applied and the process repeats. SLS produces parts with good mechanical properties making them suitable for end-users. This is not the case for SLA, the products of which are not as tough as those of SLS. The image below shows how an SLS printer works:
SLA Definition and Comparison to SLS
Chuck Hull, the founder of 3D Systems, invented the SLA process and coined its name in 1986. In 1992, an upgraded version was produced that made the fabrication of complex parts possible — and it did so quicker than old machines as well. Among 3D printing technologies, SLA is the oldest.
SLA is an additive manufacturing process that uses an ultraviolet (UV) laser to cure a photopolymer or a light-sensitive resin. It builds parts upside-down, with the build plate in contact with the reservoir of resin.
The laser is directed at specific points on the plate until the desired sections solidify. The plate then raises up out of the reservoir so the next layer can be cured, fusing with the previous layer of hardened resin. The part appears to rise out of the liquid pool. Critically, and unlike SLS, SLA can print to extremely tight tolerances. The image below shows how an SLA 3D printer works:
Comparison of SLS and SLA
The table below highlights some key attributes when comparing SLS vs. SLA:
The polymer resin used in SLA is sensitive to UV light. As such, it should be kept away from sunlight or any other source of light that contains UV radiation. SLS products do not have this shortcoming, and nor do they need supporting structures during manufacturing. The unfused powder particles are sufficient to provide support.
SLS vs. SLA: Technology Comparison
The high-powered laser in SLS is completely enclosed, giving operators no view of the print. SLA laser output is significantly lower in power and requires only tinted glass or a plastic enclosure to prevent the UV light from escaping.
SLS vs. SLA: Material Comparison
The polymer powder in SLS is easy to handle but users must wear gloves while handling SLA parts. The resin used in the production process is slightly harmful. Some commercially available production materials used in SLS include: polyaryletherketones, thermoplastic elastomers, polystyrenes, and nylon. SLA materials include but are not limited to: epoxy photopolymer, acrylic photopolymer, and some others with polypropylene-like and ABS-like properties.
SLS vs. SLA: Product Applications Comparison
SLS produces parts that are tougher than those of SLA. This makes them better options for mechanical or end-use applications.
SLS vs. SLA: Print Volume Comparison
Thanks to its size and the sintering time, SLS prints faster than SLA both on large- and small-scale models. In addition to this, SLS requires no supporting structures during the building process.
SLS vs. SLA: Cost Comparison
SLS devices are generally more expensive than SLA devices.
In both cases, the cost is compounded over time since materials such as resin or powder have to be purchased regularly. SLS machines can be purchased for as little as $10,000 or as much as $650,000. The cost depends on the maximum build volume, minimum layer thickness, print speed, laser type, and the build materials it can accept. SLA machines, on the other hand, usually fall in the range of $3,750 to $5,000, depending on the size. They can be classified into four different types: DIY, advanced hobbyist, professional and performance, and business and industrial.
What Are the Mutual Alternatives to the SLS and SLA?
A mutual alternative to SLS and SLA is:
- MJF: MJF (Multi-Jet Fusion) bears some similarities to both SLS and SLA. It can be used to produce end-use parts like its SLS counterpart. But like SLA, it does not require a high-powered laser and is a good option for functional prototypes or proofs of concept.
What Are the Similarities Between SLS and SLA?
SLS and SLA share some basic similarities:
- Both technologies employ lasers to fuse material.
- Both require post-processing. SLS parts have to be cleaned to remove excess powder and may need extra work to match surface-quality specifications. Similarly, SLA parts have to be cleaned to get rid of uncured resin.
What Are the Other Comparisons for SLS Besides SLA?
Listed below are the 3D printing technologies that can also be compared to SLS:
- SLS vs. SLM: SLM (selective laser melting) is a similar powder-bed technique but fuses metallic powder rather than polymers. For more information, see our article on SLS vs. SLM.
- SLS vs. EBM: EBM (electron beam melting) is similar to SLM in that it melts and prints metal parts. However, it is done under a vacuum and uses an electron beam rather than a laser. It can achieve higher temperatures, resulting in better melting and a stronger bond between particles.
- SLS vs. FDM: In SLS, the polymer powder is heated to a temperature below the melting point before a high-power laser is applied to specific spots to actually melt it.
FDM, or fused deposition modeling, utilizes a heated nozzle to melt and extrude layers of filament material. The resulting liquid is fused to previous layers to create the required shape. Both designs require heat before fusion takes place. For more information, see our article on SLS vs. FDM.
What Are the Other Comparisons for SLA Besides SLS?
Listed below are the 3D printing technologies that can also be compared to SLA:
- SLA vs. MJ: MJ (material jetting) machines feature an inkjet-like print head that sprays liquid photopolymer in the pattern of a part’s cross-section. That spray is then followed by a UV light that cures the polymer.
- SLA vs. DLP: Like SLA, DLP (digital light processing) printers subject select portions of photopolymer resin to ultraviolet light in order to cure them. While SLA uses a laser beam to selectively cure the resin, DLP utilizes a projector light and thousands of microscopic mirrors to direct it to or away from the build surface.
For more information, see our article on SLA vs. DLP.
Summary
This article summarized the differences between SLS and SLA 3D printing technologies.
To learn more about SLS vs. SLA and to help select the perfect technology for your products, contact a Xometry representative.
Xometry offers a full range of 3D printing services for your project needs. Visit our Instant Quote Engine to get a free, no-obligation quote in minutes.
Disclaimer
The content appearing on this webpage is for informational purposes only. Xometry makes no representation or warranty of any kind, be it expressed or implied, as to the accuracy, completeness, or validity of the information. Any performance parameters, geometric tolerances, specific design features, quality and types of materials, or processes should not be inferred to represent what will be delivered by third-party suppliers or manufacturers through Xometry’s network. Buyers seeking quotes for parts are responsible for defining the specific requirements for those parts.
Please refer to our terms and conditions for more information.
Team Xometry
This article was written by various Xometry contributors. Xometry is a leading resource on manufacturing with CNC machining, sheet metal fabrication, 3D printing, injection molding, urethane casting, and more.
Comparison of 3D printing technologies: FDM, SLA and SLS
Additive manufacturing or 3D printing reduces costs, saves time and expands the technological possibilities in product development. 3D printing technologies offer versatile solutions for applications ranging from rapid concept and functional prototypes in the field of prototyping to fixtures and clamps or even final parts in manufacturing.
Over the past few years, high resolution 3D printers have become more affordable, more reliable and easier to use. As a result, more companies have been able to use 3D printing technology, but choosing between different competing 3D printing solutions can be difficult.
Which technology is right for your needs? What materials are available for her? What equipment and training is needed to get started? What are the costs and payback?
In this article, we take a closer look at three of today's most well-known plastic 3D printing technologies: Fused Deposition Modeling (FDM), Stereolithography (SLA), and Selective Laser Sintering (SLS).
Choosing between FDM and SLA 3D printer? Check out our detailed comparison of FDM and SLA technologies.
Download this high resolution infographic here.
VIDEO MANUAL
Can't find the 3D printing technology that best suits your needs? In this video tutorial, we compare Fused Deposition Modeling (FDM), Stereolithography (SLA), and Selective Laser Sintering (SLS) technologies in terms of the top factors to consider when purchasing.
Watch Video
Fused Deposition Modeling (FDM), also known as Fused Filament Manufacturing (FFF), is the most widely used form of 3D printing at the consumer level, fueled by the rise of consumer 3D printers. On FDM printers, models are made by melting and extruding a thermoplastic filament, which the printer's nozzle applies layer by layer to the model being built.
The FDM method uses a range of standard plastics such as ABS, PLA and their various blends.
It is well suited for making basic experimental models, as well as for quickly and inexpensively prototyping simple parts, such as parts that are usually machined.
FDM models often show layer lines and may have inaccuracies around complex features. This sample was printed on a Stratasys uPrint FDM industrial 3D printer with soluble support structures (printer price starting at $15,900).
FDM printers have the lowest resolution and accuracy of SLA or SLS and are not the best option for printing complex designs or parts with complex features. Surface quality can be improved by chemical and mechanical polishing processes. To address these issues, industrial FDM 3D printers use soluble support structures and offer a wider range of engineering thermoplastics, but they are also expensive.
FDM printers do not handle complex designs or parts with complex features well (left) compared to SLA printers (right).
Invented in the 1980s, stereolithography is the world's first 3D printing technology and is still one of the most popular technologies among professionals today.
SLA printers use a process called photopolymerization, which is the conversion of liquid polymers into hardened plastic using a laser.
See stereolithography in action.
Models printed on SLA printers have the highest resolution and accuracy, the sharpest detail and the smoothest surface of all plastic 3D printing technologies, but the main advantage of the SLA method is its versatility. Materials manufacturers have developed innovative formulas for SLA polymers with a wide range of optical, mechanical and thermal properties that match those of standard, engineering and industrial thermoplastics.
Models created using SLA technology have sharp edges, a smooth surface and almost invisible layer lines. This sample was printed on a Formlabs Form 3 Desktop Stereolithographic 3D Printer (price starting at $3499).
SLA is an excellent option for making highly detailed prototypes that require tight tolerances and smooth surfaces such as molds, templates and functional parts.
SLA technology is widely used in industries ranging from engineering and design to manufacturing, dentistry, jewelry, modeling, and education.
White Paper
Download our in-depth white paper to learn how SLA printing works, why thousands of professionals use it today, and how this 3D printing technology can be useful in your work.
Download white paper
free sample
Experience Formlabs print quality firsthand. We will send a free 3D printing sample directly to your office.
Request a free sample
Selective laser sintering is the most common additive manufacturing technology used in industry.
Selective Laser Sintering (SLS) 3D printers use a high power laser to sinter fine polymer powder particles. The unsprayed powder supports the model during printing and eliminates the need for special support structures.
This makes SLS ideal for complex geometries, including internal features, grooves, thin walls, and negative taper. Models produced using SLS printing have excellent mechanical characteristics: their strength can be compared with the strength of injection molded parts.
Models created with SLS technology have a slightly rough surface, but almost no visible layer lines. This sample was printed on the Formlabs Fuse 1 SLS workshop 3D printer (price starting at $18,500).
The most common selective laser sintering material is nylon, a popular engineering thermoplastic with excellent mechanical properties. Nylon is light, strong and flexible, resistant to impact, heat, chemicals, UV radiation, water and dirt.
The combination of low part cost, high productivity, and widely used materials makes SLS a popular method for engineering functional prototyping and a cost-effective alternative to injection molding in cases where production runs are limited.
White Paper
Looking for a 3D printer to create durable, functional models? Download our white paper to learn how selective laser sintering (SLS) technology works and why it is popular in 3D printing for functional prototypes and end-use products.
Download white paper
Each 3D printing technology has its strengths, weaknesses, limitations and applications. The following table summarizes the key characteristics and factors.
| Modeling method (FDM) | Stereolithography (SLA) | Selective laser sintering (SLS) | |
|---|---|---|---|
| ★★★★☆ | |||
| accuracy | ★cle ★cle \ ★★★★★ | ||
| Easy to use | ★★★★★ | ★★★★★ | ★★★★★★★★★★★★★0104 |
| Benefits | Speed Inexpensive custom machines and materials | High cost efficiency High accuracy Smooth surface Wide range of functional applications | Robust functional parts Design flexibility No need for supporting structures |
| Disadvantages | Poor accuracy low detail Limited Compliance with Design Design | Susceptibility to prolonged UV exposure | Uneven surface Material Limitations |
| Applications | Inexpensive Rapid Prototyping Basic experimental models | Functional prototyping Templates, forms and tools Dental products Prototyping jewelry and molds Model building | Functional prototyping Small-scale and custom manufacturing |
| Print volume | Up to ~300 x 300 x 600 mm (desktop 3D printers) | Up to ~300 x 335 x 200 mm (Desktop and Workshop 3D printers) | Up to 165 x 165 x 300 mm (Workshop 3D printers) |
| Materials | ABS plastic, PLA and their various mixtures. | Various polymers (thermosets). Standard, engineering (with properties of ABS plastic, polypropylene, flexible, heat-resistant), molding, dental and medical (biocompatible). | Engineering thermoplastics. Nylon 11, Nylon 12 and their composites. |
| Training | Minimum training in equipment setup, machine operation and surface treatment; short maintenance training. | Plug and play concept. Minimal training in equipment setup, maintenance, machine operation and surface treatment. | Short training in equipment setup, maintenance, machine operation and surface treatment. |
| Room requirements | Air-conditioned environment or preferably individual ventilation for desktop machines. | Desktop machines suitable for office use. | Workshop systems have moderate space requirements and can be installed in a production environment. |
| Accessories | Support removal system for machines with soluble support structures (optionally automated), finishing tools. | Finishing station, washing station (optionally automated), finishing tools. | Post-processing station for cleaning models and restoring materials. |
Either way, you should choose the technology that best suits your business. Prices have dropped significantly in recent years, and today all three technologies are offered in compact and affordable systems.
3D printing costing doesn't end with initial equipment costs. Material and labor costs have a significant impact on the cost of each part, depending on the application and production needs.
Below is a detailed breakdown by technology.
| Modeling method (FDM) | Stereolithography (SLA) | Selective laser sintering (SLS) | Equipment costs and sets for 3D-dimensions for 3Ds and sets several hundred dollars. Offering higher quality, mid-range desktop printers start at $2,000, while industrial systems start at $15,000. | Professional desktop printers start at $3,500, large-format workshop printers start at $10,000, industrial systems for large-scale production start at $80,000. |
|---|---|---|---|
| Material cost | $50-$150/kg for most standard and engineering yarns and $100-$200/kg for auxiliary materials. | $50-$150/L for most standard and engineering polymers. | $100/kg for nylon. SLS does not require supporting structures and unused powder can be reused, reducing material costs. |
| Labor | Manual removal of support structures (may be automated for industrial systems with dissolvable supports). Long post-processing is required to obtain a high quality surface. | Washing and final polymerization (both can be automated). Simple post-processing to remove supporting structures. | Easy cleaning to remove excess powder. |
INTERACTIVE MATERIAL
Try our interactive ROI tool to see how much time and money you can save by printing with Formlabs 3D printers.
Calculate savings
FDM, SLA and SLS printed prototype ski goggle frames (left to right).
We hope this article has helped you narrow down your search for the 3D printing technology best suited to your needs.
Take advantage of our additional resources to learn the ins and outs of 3D printing, learn more about each technology and learn more about specific 3D printing systems.
Learn more about 3D printing technologies
Selective Laser Sintering (SLS) 3D Printing Guide
Selective Laser Sintering (SLS) 3D printing is a technology trusted by engineers and manufacturers across industries because it allows you to create durable and functional models.
In this detailed guide, we'll explain selective laser sintering technology, the different systems and materials on the market, the workflow and different applications of SLS printers, and when to choose 3D printing with this technology over others.
additive and traditional manufacturing methods.
White Paper
Looking for a 3D printer to create durable, functional models? Download our white paper to learn how selective laser sintering (SLS) technology works and why it is popular in 3D printing for functional prototypes and end-use products.
Download white paper
Selective laser sintering (SLS) is an additive manufacturing technology that uses a powerful laser to sinter fine polymer powder particles into a solid structure based on a 3D model.
SLS 3D printing has been popular with engineers and manufacturers for decades. With its low model cost, high productivity, and common materials, this technology is well suited for a wide range of applications, from rapid prototyping to low-volume production, limited trial runs, or custom-made products.
Recent advances in technology, materials and software have opened up the possibility of SLS printing to a wider range of companies.
Previously, such tools were used only in a few high-tech industries.
Introducing the Fuse 1 high performance SLS 3D printer, finally available.
Webinar
Watch our product demo to learn about Fuse 1 and SLS 3D printing from Formlabs.
Watch webinar
Schematic representation of the selective laser sintering process. The SLS method uses a powerful laser to sinter small particles of polymer powder into a solid structure based on a 3D model.
-
Print: A thin layer of powder is applied to the top of the platform inside the cooking chamber. The printer preheats the powder to just below the melting point of the feedstock. This allows the laser to more easily raise the temperature of certain areas of the powder bed and monitor the solidification of the model. The laser scans the cross section of the 3D model, heating the powder to the material's melting temperature or just below.
Particles are mechanically joined together to form a single solid object. The unsprayed powder supports the model during printing and eliminates the need for special support structures. The platform is then lowered into the working chamber one layer, typically 50-200 µm thick, and the process is repeated for each layer until the models are complete. -
Cooling down: After printing and before post-processing, the build chamber should cool down a little in the printer body and then outside the body to ensure optimal mechanical properties of the models and avoid their deformation.
-
Post-processing: finished models must be removed from the working chamber, separated from each other and cleaned of excess powder. The powder can be recycled and printed models can be blasted or tumbled.
To learn more about the workflow, see the SLS 3D Printing Workflow section below.
SLS models have a slightly grainy surface, but the layer lines are almost invisible.
To achieve a smooth surface, SLS models are recommended to be blasted or tumbled. This sample was printed on a Fuse 1 industrial 3D printer with SLS technology for workshops from Formlabs.
The green powder supports the model during printing and eliminates the need for special support structures. This makes SLS ideal for complex geometries, including internal features, undercuts, thin walls, and negative draft features.
Models created using SLS 3D printing have excellent mechanical properties: their strength is comparable to that of injection molded models.
Compare Selective Laser Sintering (SLS) 3D printing with other common plastic modeling technologies: Fused Deposition Modeling (FDM) and Stereolithography (SLA).
Selective Laser Sintering (SLS) is one of the first additive manufacturing technologies developed in the mid-1980s by Dr. Carl Deckard and Dr. Joe Beeman at the University of Texas at Austin. Since then, the method has been adapted to work with a variety of materials, including plastics, metals, glass, ceramics, and various powdered composite materials.
Today, all of these technologies are classified as wafer synthesis, additive manufacturing processes that selectively sinter regions of a powder layer under the influence of thermal energy.
The two most common substrate synthesis systems currently available are a plastic based method commonly referred to as Selective Laser Sintering (SLS) and a metal based method known as Direct Metal Laser Sintering (DMLS) or Selective Laser Melting (SLM). ). Until recently, both systems were very expensive and complex, which limited their use to the production of small batches of expensive models or custom-made products, such as aerospace components or medical devices.
Innovation in this area will make plastic-based SLS as affordable as other 3D printing technologies such as stereolithography (SLA) and Fused Deposition Modeling (FDM) and become widely available in affordable, compact systems.
All selective laser sintering 3D printers use the process described in the previous section.
Basically, such printers differ in the type of laser, the volume of printing and the complexity of the system. Different solutions are used for temperature control, powder dosing and layering in different devices.
Selective laser sintering technology requires high precision and strict control during the printing process. The temperature of the powder and (incomplete) models must be controlled within 2°C during the three stages of production: preheating, sintering and storage before extraction, in order to minimize warping, stress and thermal deformation.
For decades, selective laser sintering has been one of the most popular professional 3D printing technologies, but due to its complexity, strict requirements and high price, only service bureaus and large enterprises could use it.
Conventional industrial SLS 3D printing systems have one or more powerful lasers. An inert atmosphere (nitrogen or other gases) is needed to prevent the powder from oxidizing and breaking down during the printing process, which requires specialized air handling equipment.
These installations also require special heating, ventilation and air conditioning (HVAC) systems and industrial power supplies. In addition, even the smallest industrial installations occupy an area of at least 10 square meters. m.
Due to the high initial cost of approximately $100,000 (and much more for complete solutions), traditional industrial systems with SLS technology were out of reach for many enterprises.
As with other 3D printing technologies such as Fused Deposition Modeling (FDM) and Stereolithography (SLA), more affordable, compact systems with SLS technology have recently begun to appear on the market. However, these solutions had significant drawbacks. These include low quality models and complex manual workflows due to a lack of post-processing solutions. This severely limited their use in industrial production.
The Formlabs Fuse 1 printer is in a new category with these deficiencies fixed . It is the first industrial SLS 3D printer for the workshop, delivering high quality, compact size, streamlined workflow, and cost far less than traditional industrial systems of the same type.
The Fuse 1 printer does not require any special infrastructure and will easily fit into your workplace.
The Fuse 1 uses a single laser and has a smaller working chamber that requires less heat. The powder is exposed to elevated temperatures for a shorter period of time, so there is no need for inert gases and specialized ventilation equipment. Thanks to its lower power consumption, it can run on a standard AC power supply without requiring special infrastructure.
The Fuse 1 features patent pending Surface Armor technology. This creates a semi-baked shell that heats evenly around the models as they are printed. This results in excellent surface quality, stable mechanical properties, high reliability and a high material renewal rate.
In addition to providing a compact, self-sustaining ecosystem and complete powder handling capability, Fuse 1 is complemented by the Fuse Sift Station, a stand-alone stand-alone device for model retrieval, recovery, storage and powder mixing.
Overall, the Fuse 1 industrial 3D printer with SLS for workshops has slightly less print volume than traditional entry-level SLS systems, but is smaller, easier to work with and less expensive.
| Fuse 1 Industrial SLS Workshop Printer | Traditional Industrial SLS 3D Printers | from 18,500 US dollars | 100 000 - 500,000 US dollars and more than | |||
|---|---|---|---|---|---|---|
| Print volume | to 165 x 165 x 300 mm | to 550 x 550 x 750 mm 9010 Benefits | Availability High quality models High performance Simplified workflow Compact dimensions Low maintenance | High print volume High quality models High performance Many material options | ||
| Disadvantages | Less print volume Limited material options | Expensive equipment Big sizes Infrastructure requirements Large amount of maintenance Special Operator Required |
The most common selective laser sintering (SLS) material is nylon.
It is a high performance engineering thermoplastic for both functional prototyping and end-use fabrication. Nylon is ideal for the production of complex knots and strong models with high environmental resistance.
3D printed SLS nylon for strength, rigidity and durability. The final models are impact-resistant and highly wear-resistant. Nylon is resistant to UV, light, heat, moisture, solvents, temperature and water. Nylon models printed on a 3D printer are also biocompatible and do not cause allergic reactions. This means that they can be worn and used safely in many situations.
Nylon is ideal for a range of functional applications, from consumer product design to healthcare applications.
Nylon is a synthetic thermoplastic polymer from the polyamide family. It is available in several versions, each designed to print different products. Nylon 12 Powder has a wide range of applications and is a general purpose, general purpose SLS 3D printing powder. Nylon 12 GF Powder is a composite material with a high fiber content, increased stiffness and heat resistance for difficult industrial conditions.
Nylon 11 Powder helps fill a gap in prototyping and end-use applications where increased ductility, impact resistance and the ability to withstand wear without brittle fracture are required.
- Impact Prototypes, Clamps and Fixtures
- Thin-walled pipes and bodies
- Rivets, fasteners and latches
- Orthopedic products and prostheses*
- High Performance Prototyping
- Small batch production
- One-piece clamping and holding fixtures and tooling
- Conventional SLS models
- Heavy-duty clamping and fastening fixtures and spare parts
- Continuous models
- Threads and sockets
- High temperature models
* Material properties may vary depending on model design and manufacturing method. It is the manufacturer's responsibility to confirm the suitability of printed models for their intended use.
| 40% | ||||||
| Extension when rupture, Z (%) | 6% | 3% | ACCOUSE | |||
|---|---|---|---|---|---|---|
| shock strength for | 36 J/m | 36 J/m | 71 J/m | |||
Bending temperature under load at 1. 8 MPa (°C) | 87 °C | 113 °C | 46 °C | 170°C | 171°C | 182 °C |
Nylon 12 Powder and Nylon 11 Powder are one-component powders, but some SLS 3D printers can also use two-component powders, such as coated powders or powder blends.
Nylon 12 GF Powder is a composite material with a high fiberglass content, while other nylon composites with aluminide, carbon or glass are designed to increase the strength, stiffness or flexibility of models. In such two-component powders, only the component with the lower glass transition point is sintered, which binds both components.
SLS 3D printing accelerates innovation and helps businesses in a wide range of industries such as engineering, manufacturing and healthcare.
Manage the entire product development process, from iteration of first concept design to production of ready-to-use products:
- Rapid Prototyping
- Product mockups for user feedback
- Functional Prototyping
- Functional testing of products under severe conditions (e.
g. piping, brackets)
Manage your supply chain and respond quickly to changing needs:
- End-use manufacturing
- Small batch production
- Mass production of new customized consumer products
- Spare parts manufacturing, supply chain sustainability
- Durable, durable clamping and fastening devices (such as clamps and clamps) and accessories
- Custom manufacturing of automotive, motorcycle and marine equipment parts and restocking of military items on demand
Self-manufacturing of ready-to-use medical devices, taking into account the individual characteristics of patients:
- Prototyping of medical devices
- Prostheses and orthotics (e.g. prosthetic limbs and orthoses)
- Surgical models and instruments
- End-Use Products (Nylon 12 is biocompatible and can be sterilized*)
* Material properties may vary depending on model design and production method.
It is the manufacturer's responsibility to confirm the suitability of printed models for their intended use.
Use any CAD software or 3D scan data to design the model and export it to a 3D printable format (STL or OBJ) file. All printers with SLS technology use software that allows you to adjust settings, position models, estimate print times, and layer your digital model. Once set up, the model preparation software sends commands to the printer via a wireless or cable connection.
The Fuse 1 uses PreForm print preparation software (free to download). It allows you to easily duplicate and place multiple models on a 3D grid to maximize your print volume. PreForm automatically suggests the optimal orientation and position of models with the ability to make manual changes.
The workflow for preparing the printer varies from system to system. Most traditional SLS systems require extensive training, tools, and physical actions to prepare and maintain them.
Fuse 1 redefines the SLS workflow, making it simple and efficient, as well as providing trouble-free printing and complete powder handling thanks to modular components.
The Fuse 1 can be easily loaded with powder using a special cartridge.
The Fuse 1 uses a detachable build chamber so you can start a new print while the previous build chamber is still cooling.
Once all pre-checks have been completed, the machine is ready to print. Depending on the size and complexity of the 3D models, as well as their density, printing using SLS technology can take from several hours to several days.
When printing is complete, the build chamber in the housing should cool down a bit before proceeding with the next steps. To start the next print, you can remove the build chamber and insert a new one. Before post-processing, the working chamber must cool down to ensure optimal mechanical properties of the models and avoid their deformation. This can take up to half of the total print time.
Fuse 1 is equipped with a touch screen that allows you to see in real time how each new layer is formed during the printing process. This camera image can also be transferred to a computer using PreForm to monitor the print without leaving the workplace.
Compared to other 3D printing processes, post-processing of SLS-printed models requires a minimum of time and labor. With no supporting structures, it is easy to scale and provides consistent results across batches of models.
After printing is completed, remove the finished models from the build chamber, separate them and clean them of excess powder. As a rule, this is done manually at the cleaning station using compressed air or a jet apparatus.
The excess powder left after the creation of the model is filtered to remove large particles from it. After that, it can be recycled. Under the influence of high temperature, the properties of green powder deteriorate slightly, so for subsequent printing it must be mixed with new material.
Due to the possibility of reusing materials, SLS technology produces a minimum amount of waste.
SLS technology typically uses separate devices for powder recovery, storage and mixing. The Fuse 1 workflow uses a single Fuse Sift to retrieve patterns and greens, store, dispense, and mix material streams.
Fuse Sift completes the Fuse 1 SLS print workflow. This system is used for safe and efficient model retrieval and powder recycling.
Fuse Sift automatically doses and mixes used and new powder, reducing waste and controlling powder delivery.
After the powder has been sieved, the 3D models printed using selective laser sintering technology are ready for use. However, there are a few more post-processing steps you can perform on these models.
By default, the surface of 3D models created using SLS technology remains grainy. To achieve a smooth surface, Formlabs recommends blasting or tumbling models made using this method. Models can be spray painted, lacquered, electroplated or otherwise to achieve the desired color, surface quality and properties such as water resistance (special coating) and electrical conductivity (electrolytic coating).
Models created with SLS Formlabs are dark in color and therefore not well suited for staining.
Immersion printed SLS model from Partial Hand Solutions.
SLS models can be electroplated for a metal-like surface.
Selective laser sintering is preferred by engineers and manufacturers for its wide design options, high productivity, low model cost and proven end use materials.
Most additive manufacturing processes such as stereolithography (SLA) and Fused Deposition Modeling (FDM) require specialized support structures to fabricate overhang structures.
Selective laser sintering does not require support structures because the unsintered powder surrounds the model during printing. SLS printing makes it easy to create overhangs, intricate geometries, interconnecting parts, internal channels and other intricate details.
Intricately patterned arm splint for weight reduction.
Engineers typically design models in terms of the capabilities of the final manufacturing process, also known as design-for-technology (DFM).
When additive manufacturing is only used for prototyping, it comes down to creating models and designs that can be replicated in the manufacturing process using traditional tools.
Selective laser sintering is emerging as a viable rapid production method and its application area continues to expand, so it can open up new possibilities in design and construction. 3D printers with SLS technology can create complex geometries that are impossible or incredibly expensive to manufacture using traditional processes. SLS technology also allows design professionals to combine complex assemblies into a single model that would normally require multiple models to be created. This helps avoid the problem of loose connections and saves assembly time.
Selective laser sintering can unleash the potential of generative design, as it allows the creation of lightweight models that use complex lattice structures that cannot be fabricated by traditional methods.
Selective laser sintering is the fastest additive manufacturing technology for making functional, durable prototypes and end-use products.
Lasers used for powder sintering have much faster scanning speeds and are more accurate than the layering methods used in other processes such as Industrial Fused Deposition Modeling (FDM).
To maximize the available print volume in each printer, multiple models can be placed side by side. Operators can use the software to optimize print volume and maximize productivity by leaving only minimal clearance between models.
SLS technology allows operators to fill the build chamber with as many models as possible, as it allows them to be printed without supporting structures, saving time in post-processing.
SLS 3D printing requires the right materials for functionality and versatility. Nylon and its composites are proven, high quality thermoplastic materials. Laser-sintered nylon models have close to 100% density and mechanical properties that are comparable to products made using traditional manufacturing methods such as injection molding.
Screwdriver printed in Nylon 12 Powder.
After a simple post-processing, nylon models have a smooth, professional quality surface.
SLS Printable Nylon is an excellent replacement for conventional injection molded plastics. The latches and other mechanical connections produced from it are superior to products created using any other additive manufacturing technology. It is ideal for making functional plastic parts that will work and not break down over time like products created through other additive manufacturing methods.
When calculating the cost of one model, it is usually necessary to take into account the cost of ownership of equipment, material costs and labor costs:
-
Equipment cost of ownership: The more models a printer can produce over its lifetime, the lower the cost per model. Therefore, higher performance results in a lower cost of ownership per model. With high laser scanning speeds, the ability to produce multiple models at once to maximize the working volume, and a simple post-processing process, SLS 3D printing guarantees the highest productivity of any additive manufacturing method.
-
Material: Most 3D printing technologies use proprietary materials, while nylon is a common thermoplastic that is produced in large quantities for industrial applications. This makes it one of the most inexpensive raw materials for additive manufacturing. SLS 3D printing requires no support structures and allows you to print with recycled powder with minimal waste.
-
Labor: Labor is a disadvantage of many 3D printing solutions. Work processes in most technologies are quite laborious and difficult to automate, which can significantly affect the cost of one model. Easy post-processing with SLS printing reduces manual labor and allows for easy scalability.
A 3D printer with SLS technology is a significant investment initially, but it often pays off even faster than buying smaller devices. SLS for workshop technology significantly reduces initial acquisition costs and also reduces model costs in most applications.
If 3D printing is rarely used in your business, it is recommended to use the services of third-party service bureaus. But in this case, the cash costs will be higher and you will have to wait longer for the order to be completed. One of the main advantages of 3D printing is its speed compared to traditional production methods. But this advantage loses its value when it takes up to several weeks for a third-party company to deliver a model.
REEKON Tools
