ASA vs ABS: Finding the right 3D printing filament

Choosing the right filament for 3D printing can seem like a daunting task, especially when it comes to picking the type of material, let alone the brand. The truth is, there is no single right material for fused filament fabrication (FFF) 3D printing: choosing the right filament depends entirely on the application at hand. In this article we’ll look at two 3D printing materials with fairly similar profiles, ASA and ABS, to understand what their differences are and when using them makes the most sense.

What is ABS filament?

Acrylonitrile butadiene styrene (ABS) is one of the most broadly used thermoplastic filaments in extrusion-based 3D printing. There is no surprise why: the material is easy to process and demonstrates good material properties for printed parts. It is also readily accessible to both professional and hobbyist 3D printing users due to its affordable cost.

As a plastic, ABS was first launched commercially in the 1950s by Borg-Warner Corporation. Before being used as a 3D printing filament, it was predominantly processed using injection molding to create robust and lightweight parts for automotive interiors, appliances, pipe fittings, toys (such as LEGO), and more.[3] Today, the material is still used with injection molding, but it also has a growing share of 3D printing applications.

ABS filament is known for a range of mechanical properties, including good impact strength, abrasion resistance, and chemical resistance. ABS is also characterized by a low melting point compared to other engineering thermoplastics (about 200°C) which, while precluding it from certain high-temperature applications, makes it easy to process on most FDM/FFF 3D printers.[4] Critically, ABS is also known for its low density, which leads to lightweight parts. The material’s combination of good impact resistance and light weight have made it especially popular in the automotive sector, where reductions in vehicle weight lead to better fuel efficiency. Other applications include functional prototypes, tooling, and end-use parts in a range of consumer and industrial sectors.

Recommended reading: ABS print temperature considerations: Nozzle, bed, enclosure

ASA is well suited to outdoor applications due to its UV resistance.

What is ASA filament?

Acrylonitrile styrene acrylate (ASA) filament is a thermoplastic material for FFF 3D printing. Though not as prevalent a material compared to ABS, ASA has many potential applications due to its beneficial material and mechanical properties. In fact, the material bears many similarities to ABS, but offers superior properties, especially when it comes to UV resistance. 

As a material, ASA was first launched by BASF in the early 1970s under the material name Luran S. [1] Its creation was driven by the need—especially by the automotive industry—for a material with similar properties to ABS but with better resistance to weather and harsh environments. Chemically speaking, ASA is similar to ABS but adds a grafted acrylic ester elastomer as the styrene and acrylonitrile undergo copolymerization. This has imparted the material with superior UV stability, improving the thermoplastic’s overall weather resistance.

In filament form, ASA is also characterized by its good toughness, chemical stability, and aesthetic quality. In combination with excellent UV resistance, these properties make ASA filaments well suited for robust use cases and outdoor applications.[2] Common applications for ASA filament are tooling, functional prototypes, and end use components like outdoor electrical enclosures and fixtures, and automotive housings.

Though ASA is not as widely available as ABS, there are today a number of filament suppliers that offer the material—often in a variety of colors. ASA filament suppliers include Stratasys, PolyMaker, ColorFabb, Raise3D, Zortrax, Fillamentum, and 3DXTech, among others. 

ASA vs ABS

ASA and ABS filaments share a number of characteristics, but also have important differences. These differences should influence which of the two 3D printing materials you choose to work with. But let’s start with the things they have in common.

ASA and ABS Similarities

As thermoplastics, ASA and ABS both share some basic properties. In other words, all thermoplastics are characterized by their ability to be melted into liquid form and harden when cooled. This capability is imperative when it comes to FFF 3D printing, as solid plastic filaments are passed through a heated print nozzle (also called hotend), which extrudes the melted material onto a build platform. As layers of the material are extruded, they solidify into an object as the plastic cools.

In addition to their basic thermoplastic makeup, ASA and ABS have a few mechanical properties in common, including high impact resistance and toughness. This means both 3D printing filaments are well suited for functional prototypes, jigs and fixtures, as well as production-grade parts. Both materials also have high glass transition temperatures (105°C for ABS and 100°C for ASA), especially when compared to other filaments like PLA, Nylon, and PETG. Glass transition temperature is the temperature at which the filament changes from a hard solid to an amorphous, rubber-like solid.[5] When it comes to post-processing, both ASA and ABS 3D printed parts can be easily sanded down and smoothed using acetone. 

ASA and ABS do share a couple less desirable features, including their risk of warping and shrinking on the 3D printer print bed. Warping and shrinking occur if the printed materials cool too quickly. This causes the material to contract and solidify, which can lead to poor adhesion and ultimately failed prints. Fortunately, there are steps that can be taken to mitigate these risks, such as temperature control for printing and cooling, and better first layer adhesion with the use of a heated bed, kapton tape, or special adhesives. That being said, some brands of ASA filament do boast better layer adhesion and less shrinkage than their ABS counterparts.

Both ASA and ABS come with a risk of warping, which can be mitigated by temperature control and other settings.

A final thing to note about both ASA and ABS is that the materials should be used within well-ventilated spaces. When 3D printed, ASA releases strong-smelling and toxic fumes, so ventilation is vital. ABS also emits a toxic chemical when it is melted, which can lead to headaches and drowsiness with overexposure.[6] In both materials, the toxicity is related to the thermoplastic's styrene component. All this means is that the 3D printing filaments should be used with proper filtration systems or in a well ventilated space.

In summary, the key similarities between ASA and ABS are:

• Both materials are thermoplastics

• They have good impact resistance and toughness

• They can be post-processed using sanding and acetone

• Warping on the build platform is a risk

• Should be used in a well-ventilated environment due to fumes

ASA and ABS Differences

When it comes to the differences between ASA and ABS filaments, the most important to mention is ultraviolet (UV) resistance. ABS, while tough, is known to degrade quickly when exposed to UV light. This means that the material has limited benefits when used for outdoor applications, where sun exposure is inevitable. When left out, 3D printed parts made from ABS lose their original color (often yellowing) and can lose some of their original strength and integrity.

ASA, by contrast, was specifically engineered for UV resistance. The 3D printing filament is therefore ideally suited to outdoor applications and more rugged use. Additionally, ASA filaments are more resistant to moisture than ABS, a feature which further protects them from the elements and severe weather conditions.[7]

ASA filament has a higher temperature resistance to traditional ABS filaments, which offers both a distinct advantage and disadvantage. First, ASA is well suited to applications that require better heat resistance, such as heat-stressed components. On the downside, however, ASA requires higher printing temperatures to process, which consumes more energy than ABS filaments, thus driving up operational costs. Both ABS and ASA benefit from enclosed and temperature controlled 3D printing systems. Looking at the specifics of heat resistance for each material, ASA filaments tend to have a heat deflection temperature (HDT) between 85 and 96 °C (at 0.46 MPa). ABS has a wider range (between 68 and 89 °C), but filaments often have a marginally lower HDT value than ASA. ASA is also more resistant to temperature fluctuations than ABS. 

For many 3D printing users, this next difference between ASA and ABS is a crucial one: material cost. As one of the most widely available thermoplastic materials available for FFF 3D printing, ABS is also one of the most cost friendly. As a newer and more niche entry in the filament market, ASA material tends to be more expensive. In some cases, especially for hobbyists, ASA spools can be cost prohibitive, making ABS the better option. In industrial or professional use cases, however, the additional cost may well be worth the added benefits of UV resistance.  

In summary, the key differences between ASA and ABS are:

• ASA is more UV resistant than ABS

• ASA is more water resistant than ABS

• ASA has higher temperature resistance than ABS

• ABS is cheaper than ASA filament

Recommended reading: Comparison of PLA, ABS, and PETG Filaments for 3D Printing

Print Settings for ASA and ABS

Both ASA and ABS have specific printing requirements that need to be considered to ensure successful prints and minimize issues such as warping, poor layer adhesion, and inconsistent extrusion. Despite the two polymers’ similarities, it is important to follow their distinct print settings.

ASA print settings

When printing ASA, the recommended printing temperature typically ranges from 230°C to 260°C, depending on the specific filament brand. This is notably higher than ABS, though the material can still be printed using standard metal hot ends. A heated bed is essential for printing with ASA, with bed temperatures ranging between 90°C and 110°C. It is also important to use a high-quality adhesive or build surface to ensure proper bed adhesion and minimize warping. ASA can also benefit from an enclosed print chamber, which helps maintain a stable printing environment and reduce the risk of temperature fluctuations affecting the print quality. The material does not require a cooling fan. When it comes to speed, it’s a good idea to print the first layers at a slower rate (25 mm/s) to ensure first layer bed adhesion. From there, ASA prints well at moderate speeds of up to 50 mm/s. 

ASA and ABS have specific printing parameters that should be followed for the best results.

ABS print settings

ABS requires a printing temperature between 220°C and 250°C, which is slightly lower than ASA. A heated bed is also necessary for printing with ABS, with optimal bed temperatures typically set between 95°C and 110°C. Like ASA, ABS benefits from the use of a bed adhesive, such as glue stick or ABS slurry, which ensures that the first layers of the print do not peel up from the print bed and warp. Enclosed print chambers are highly recommended for ABS printing, as they help maintain a stable temperature and reduce the risk of warping due to drafts or temperature fluctuations. A print enclosure also helps to improve other aspects like adhesion between layers, for stronger parts. For 3D printers with a heated print enclosure, ABS works well at temperatures between 60 and 70 °C. In terms of print speed, it’s also a good idea to print the first layers at a slower rate, but ABS generally prints well at speeds between 40 and 60 mm/s.

Ultimately, we recommend following the recommendations from your filament supplier, as optimal temperature settings and print speeds vary depending on the filament formulation.

Recommended reading: ABS printing speed limits and other considerations

Post-Processing ASA and ABS

Post-processing techniques play a significant role in enhancing the appearance and functionality of 3D printed parts. Both ASA and ABS can benefit from various post-processing methods to improve their surface finish, dimensional accuracy, and mechanical properties. 

In comparing ASA and ABS, ASA prints generally have a smoother finish than ABS parts straight off the build platform, with less distinguishable layer lines. This means that ASA parts do not require as much post-processing, particularly when surface aesthetics are the priority. Both materials are compatible with different forms of post-processing that can be done safely at home, including:

• Sanding: Sanding is a popular method for smoothing the surface of FFF 3D prints and removing layer lines. When sanding ASA or ABS, start with a coarse grit sandpaper and gradually progress to finer grits to achieve a smooth finish. It is essential to sand the part evenly to avoid creating uneven surfaces or altering the part's dimensions.

• Priming and Painting: Priming and painting ASA and ABS parts can improve their appearance and even provide additional protection. It’s important to use a primer specifically designed for plastics to ensure proper adhesion, and to follow up with acrylic or enamel-based paints that are compatible with thermoplastics. Apply multiple thin coats of paint for a smooth, even finish. It is also possible to use a varnish to seal the paint.

• Vapor Smoothing: Vapor smoothing is a technique that involves exposing printed part to a solvent vapor, such as acetone, which softens the surface and smooths out layer lines. Acetone vapor smoothing is compatible with both ASA and ABS and results in a glossy, professional-looking finish. This method does require careful handling and proper ventilation due to the potentially hazardous nature of the solvents used.

Environmental Impact of ASA and ABS

Both ASA and ABS are derived from non-renewable resources. Unlike bio-based plastics like PLA, these filaments are therefore not biodegradable. This inevitably raises some concerns about the materials’ environmental impact.  

ASA and ABS are both petroleum-based plastics and can take hundreds of years to even start to break down.[8] This means that any ABS or ASA that is disposed of contributes to landfill waste and pollution. 

That said, ASA and ABS materials are recyclable, which extends their life cycle. When recycling these thermoplastics, it’s not simply a matter of tossing ABS or ASA into your recycling bin: the process requires specialized facilities with high-temperature capabilities to separate and process the materials effectively. 

It is also possible to recycle ABS at home using a shredder to break up failed or unused prints and then an extrusion machine to transform the shredded plastic into filament. This is a good option for makers that want to save money and help the environment by reusing plastic, however it’s important to remember that recycled ABS may not be as durable as new material.

Conclusion

Ultimately, ASA and ABS are 3D printing filaments that each have their own benefits. ASA offers high impact resistance, toughness, and weather resistance. ABS offers high impact resistance, toughness, and ease of use. ASA typically comes with a higher price point, while ABS filament spools are generally more affordable. 

As we said earlier, what it comes down to is what you are using the material for. If you are setting out to 3D print a prototype or enclosure for indoor use, ABS is probably a good bet. If, on the other hand, you are undertaking a project to produce a functional prototype or end-use part that will be used in an outdoor environment and which can benefit from UV stability, ASA is by far the better option. It is also a good idea to ensure that the material in question is compatible with the 3D printer you are using. If your chosen brand of ASA filament requires an enclosed build chamber, it won’t work well with an open extrusion system. So, while this article provides a helpful overview of ABS and ASA filaments, it is still a good idea to look at filament specifications to find the right material and brand for your needs.

Frequently Asked Questions (FAQ)

Q: What are the main differences between ASA and ABS?

A: The main differences between ASA and ABS are UV resistance, chemical resistance, and temperature resistance. ASA has better UV resistance, chemical resistance, and temperature resistance compared to ABS. Another difference is availability: ABS filaments are more widely available than ASA and tend to be cheaper.

Q: Can ASA and ABS be used interchangeably?

A: While ASA and ABS share many similarities, they have distinct properties that make them suitable for specific applications. For example, unlike ABS, ASA has excellent UV resistance, which makes it a better option for outdoor applications.

Q: Are ASA and ABS safe for the environment?

A: Since both ASA and ABS are made from petroleum-based materials, neither material is biodegradable, which means they do not break down naturally in the environment. However, the materials can be recycled and reused, mitigating their environmental impact. When 3D printing, both ABS and ASA should be processed in a well-ventilated space to minimize the effects of vapors generated in the printing process.

Q: Which material is more expensive, ASA or ABS?

A: ASA is generally more expensive than ABS, as it is a more advanced material. However, prices can vary depending on market trends and availability.

Q: What are some common applications for ASA and ABS?

A: ASA is commonly used in outdoor applications, such as automotive parts, siding, signage, and outdoor furniture, due to its excellent UV resistance. ABS is widely used in consumer products, automotive interiors, and electronic enclosures, thanks to its good mechanical strength and ease of processing.

References

[1] UL Prospector. “Acrylonitrile Styrene Acrylate (ASA)”. [online] https://www.ulprospector.com/plastics/en/generics/8 [Accessed January 3, 2022]

[2] Stratasys, 2022. “ASA”. [online] https://www.stratasys.com/materials/search/asa [Accessed January 3, 2022]

[3] Britannica, 2019. “Acrylonitrile-butadiene-styrene copolymer”. [online] https://www.britannica.com/science/acrylonitrile-butadiene-styrene-copolymer [Accessed January 3, 2022]

[4] Adreco Plastics. “ABS Plastic Properties”. [online] https://adrecoplastics.co.uk/abs-plastic-properties/ [Accessed January 3, 2022]

[5] 3D Solved. “3D Filament Glass Transition Temperatures” [online] https://3dsolved.com/3d-filament-glass-transition-temperatures/  [Accessed January 3, 2022]

[6] AMFG, 2018. “3D Printing with ABS Plastic: All You Need to Know”. [online] https://amfg.ai/2018/06/29/abs-plastic-3d-printing-all-you-need-to-know/ [Accessed January 4, 2022]

[7] Filament2Print. “ASA Natural”. [online]  https://filament2print.com/gb/asa/679-asa-natural.html [Accessed January 3, 2022]

[8] Conserve Energy Future. “Is ABS Plastic Recyclable?” [online] https://www.conserve-energy-future.com/is-abs-plastic-recyclable.php [Accessed September 11, 2023]