Nylon, otherwise known as polyamide (PA), is a collection of thermoplastic polymers often employed in 3D printing. Nylon is applauded for its endurance under high mechanical stress, along with its resistance to heat, tearing, and abrasion. Consequently, this material is often seen being used in the production of heavy-duty parts, such as those needed in the automotive and aerospace sectors or within the medical industry.
In 3D printing, an array of nylon types is utilized, which are named based on the number of carbon atoms they possess. PA6 is typically used in FDM printing, whereas PA11 and PA12 are employed in powder-based methods. Despite the overlaps in applications of PA11 and PA12, they do vary significantly. Thus, we decided to compare these two materials, looking into their properties, origins, printing requirements, applications, and price range.
Where They Come From and Their Properties
Polyamides are differentiated by the number following the common PA code, which indicates the amount of carbon atoms. Therefore, PA11 and PA12 may appear very similar at first glance. However, these two types of nylon are different in many ways, starting with their origin and manufacturing process.
PA12 is a thermoplastic, semi-crystalline and linear, obtained from natural gas or petroleum. Chemical processes are used to obtain laurin lactam, which is the starting molecule for the manufacture of PA12. In 1963, Chemische Werke Hüls AG first presented PA12 in collaboration with Emser Werke in Domat. Since then, the homopolymer, which consists of a single monomer component, has been used for many applications. Despite this, PA12 is increasingly at the heart of debates about its origin and environmental impact.
In search of greater durability and “greener” production, companies are turning to alternative materials with similar properties. This has contributed to the rise of PA11, as the origin of this polyamide is biological. PA11 is made from renewable raw materials, obtained from plant derivatives.
In most cases, castor oil is used, which in turn is obtained by pressing the seeds of the African miracle tree “Ricinus communis”. Castor oil is then converted into the amino acid 11-aminoundecanoic acid by synthesizing monomers. Subsequent polymerization of the monomers then gives rise to PA11.
The origin of PA11 thus resembles that of PA6, and is far removed from PA12. Although PA11 is considered a more sustainable alternative due to its biosourced origin, it is not biodegradable. Like other polyamides, it must be sorted in a specialized collection system before being processed for recycling.
Although the origins of PA11 and PA12 are very different, their mechanical properties are very similar, which is why they are often used in industry for similar purposes. PA11 and PA12 are considered to be extremely robust, strong and resistant, with convincing frictional-, wear- and chemical-resistance. PA12 is considered the lightest of all polyamide plastics, and is distinguished by its low concentration of amide groups. In addition, PA12 outperforms other polyamides in terms of low water absorption and density.
Although PA11 also absorbs relatively little water for a polyamide, it cannot compete with PA12 in this respect. Its advantages lie in its mechanical properties, which surpass those of PA12. PA11 is highly ductile and has excellent impact resistance. It is highly resistant to abrasion and fatigue, and PA11 parts boast higher isotropy. It withstands temperatures of up to 190°C, even though permanent temperatures range from -40°C to 125°C. Finished PA11 parts are both strong and flexible, durable and have an opaque matte surface. The same is true of PA12 parts. In both cases, the parts can be colored.
PA 12 (white) is the lightest type of nylon, while PA 11 (grey) has better mechanical properties. (photo credits: Jellypipe)
When discussing operating temperature, PA 12 doesn’t perform as well as PA 11. It can endure from -50°C up to 150°C, but a continuous operating temperature is limited to 50-80°C. Much like PA 11, it stands up well to abrasion and fatigue. PA 12 resists fats, oils, solvent, alkalis, and salt solutions, so parts made from it show high wear resistance and are easy to weld and bond. Furthermore, PA 12 is not only the lightest polyamide, but it’s also the best at resisting stress cracking.
The impact resistance of PA12 is substantial, but it doesn’t match that of PA11. When compared directly, PA 12 falls a bit short in strength and hardness compared to PA11. To make up for this, PA12 is often strengthened with additives like glass or carbon fibers.
Parts made from both materials usually work well with fabrics and are safe for human skin contact. It’s important to note that certain manufacturers’ PA12 can be utilized for parts that will come into contact with food, a feature not always found with PA11. There are some PA11 powders that are FDA-cleared for food contact.
3D Printing with PA11 and PA12
In 3D printing, PA is largely utilized in filament and powder form. There’s also PA resin that’s available for the SLA process replicating the attributes of PA thermoplastics. The most utilized filament for nylon is PA6 and it’s seen to a restricted measure in powder form.
The powder-based operations mainly implement PA11 and PA12 because of the thermoplastic attributes of the substance, as nylon can be molded or particularly well joined using heat. These operations include Selective Laser Sintering (SLS), Multi Jet Fusion, Selective Absorption Fusion (SAF) and High Speed Sintering (HSS). They carry the attribute of high productivity, and the powder not utilized for parts could be reused to some extent.
PA12 is inclined to be used more regularly in additive manufacturing than PA11, primarily due to its prior availability and lower melting point. PA12 melts at about 175-180° (subject to the maker), as opposed to PA11, which only liquefies around 200°. These melting temperature disparities also clarify why powders can’t be combined for the same print. The powder handling is a challenge for these 3D printing processes, even though most makers offer specific Build Unit solutions for each substance.
Post-Processing
Whichever process you opt for when printing with PA11 and PA12, post-processing is a vital phase that is applicable to both PA11 and PA12 components. In this regard, there aren’t any differences between the materials as some post-processing stages are obligatory for both, whilst others are discretionary for both.
Irrespective of whether the parts are constructed from PA11 or PA12, the primary step is depowdering. This is where the components are extracted from the powder cake and powder is detached from all sides. This powder can then be recycled somewhat in a fresh printing procedure. Assorted processes then facilitate the extended cleaning of these parts, as some amount of residual powder continues to stick to them, enabling enhanced surface finishing.
Water jet, air jet and bead blasting, along with chemical smoothening and drum polishing, are some among the post-processing methods that can be implemented. Furthermore, it is viable to paint or color the PA11 and PA12 components in the final steps.
An important step in all powder-based processes is post-processing (photo credits: Protiq)
PA11 and PA12 Applications
Both materials belong to the same group of plastics and can be found in a multitude of applications in the 3D printing process. This understandably leads to some overlap when it comes to the fields where they are used.
In the medical field, PA11 and PA12 powders are used as long as they have been determined to be biocompatible by the manufacturer. They are used in the manufacture of prostheses, orthoses, medical devices and medical appliances. In the medical field, however, PA11 is more appreciated for its biocompatibility and flexibility than PA12, which is generally stronger.
PA11 and PA12 are often used for prosthetics and orthotics (photo credits: EOS)
Both materials are also used in the automotive industry. PA11 is popular for vehicle prototyping parts, but also for serial production. Due to its resistance to impact and chemicals, it is also used for the manufacture of vehicle parts in the event of a collision, both internally (PA11 does not crack) and externally, for gaskets, engine components and coatings, for example. PA12 is also used in automotive 3D printing, i.e. for vehicle construction, particularly for precision hoses and tubes, including pressure- and impact-resistant fuel lines.
In aeronautics, PA11 is used in 3D printing because of its impact resistance and lightness, such as fairings and internal structural parts for aircraft. PA12 is also ideal for the manufacture of precision hoses and tubes – particularly for pressure- and impact-resistant fuel lines. Furthermore, in both the automotive and aerospace sectors, PA11 is appreciated, unlike PA12, for the lighter parts it produces and its contribution to energy efficiency, while PA12’s advantages lie in its rigidity and hardness for parts requiring greater strength.
The sports industry also uses both materials: PA11 for its abrasion-resistance, e.g. for ski linings and cleat soles, and for its superior flexibility. PA12 is used for winter sports equipment, such as alpine and cross-country ski boots and ski bindings, thanks to its particular mechanical resistance at low temperatures.
PA11 and PA12 are also used in sports (photo credits: Prodways/Salomon)
Both materials are used in mechanical engineering, electrical engineering and electronics, as well as in the packaging industry. Here, PA11 is particularly appreciated for its longevity and PA12 for its high toughness.
PA12 is used in the manufacture of precision hoses and tubes, particularly for pressure- and impact-resistant fuel lines, as well as for drive elements in wet environments or underwater transmission parts – where high dimensional accuracy is required – and for mechanical engineering components such as hinges and gears, as well as insulating films.
Meanwhile, in electrical engineering and electronics, PA11 is used as an insulating and protective material for cables, connectors and the housings of electronic devices. Furthermore, due to its particularly long service life, it is generally well-suited for highly technical applications.
A nylon connector (photo credits: EOS)
PA11 and PA12 Manufacturers and Prices
Generally speaking, PA12 is typically more costly than PA11, due to the lower current demand for PA11. PA11 can be sourced from some manufacturers for as little as $50/kg, but elsewhere for as much as $200/kg. Differences in price for the same powder type can hinge on whether it’s standard or reinforced. When comparing prices of completed pieces created from these two materials, it is obvious that mass-produced components fashioned from PA11 are considerably less expensive than those made from PA12, by about 30% depending on the quantity generated. Notably, for single part manufacture, utilizing PA12 proves to be cost-effective.
These materials can be purchased from a plethora of manufacturers. Prominent PA11 makers include EMS-Grivory and the French Arkema group, who sell PA11 under the RILSAN® PA11 brand. Arkema also provides PA12, which was formerly sold under the same name as PA11, but now under the RILSAMID® name for clear differentiation. PA12 is often available in the market under the VESTAMID® or VESTOSINT® names. Furthermore, BASF offers both PA12 and PA11 in powder form. PA12 can also be procured from manufacturers involved in 3D printing like Evonik, and 3DSystems and Farsoon, who supply powders developed in collaboration with chemical firms, but do not disclose these material development partnerships.
Manufacturers are increasingly striving to produce greener and more organic PA12 alongside the environmentally-friendly PA11 material. EOS, a German supplier of equipment and materials, provides PA12 as a superior option to ABS or PA6 plastics commonly used in injection molding. They have consistently enhanced the production efficiency of this material, for instance, by lessening its carbon footprint through renewable energy utilization.
Polyamide powders infused with Kevlar, carbon fibers, or even glass beads are also available on the market. HP offers a 40% glass bead-infused thermoplastic with a high recycling rate, known as HP 3D High Reusability PA12 Glass Beads. HP recently introduced a new PA12 powder developed in partnership with Arkema. Named HP 3D HR PA 12 S, this material boasts a high reusability rate of up to 85%, aiding in waste reduction.
Read More: Comparing PA11 and PA12: Selecting the Best Nylon for Your 3D Printing Needs - 3D Printing News