How to 3d Print with Nylon
Nylon has proven to be one of the most popular materials where 3d printing is concerned. This can be viewed as a result of its popularity outside 3d printing. The application of nylon is vast owing to its unique properties, and the benefits of 3d printing imply that its parts can be made easily and cheaply.
Desktop fused deposition modeling (FDM) 3d printing technology which is well recognized as a well-known type of 3d printing, can often encounter issues as it involves trial and error. While some materials are easy to print, others have a bigger learning curve. This article will discuss all there is to know about nylon 3d printing.
The synthesis of nylon was first carried out by Dupont, an American chemical company, in 1935. He developed the material for commercial purposes, and since then, nylon has become a common feature in numerous industries. Nylon generally stands for a group of plastics otherwise known as polyamides. These plastics are mostly semi-crystalline and hard materials. They come in many variants, with the most common ones being nylon 6, nylon 6-6, and nylon 12. It is a thermoplastic material that means it becomes soft or turns to liquid when heated beyond its melting point and solidifies on cooling. The heating process can be continuously carried out without having any significant effect on its chemical and mechanical properties.
Nylon can easily be mixed with other plastics to form composites, thereby boosting their performance parameters. This is mainly carried out in automobile industries and the common composites in 3d printing are glass-filled nylon and carbon-fiber-filled nylon. Owing to its versatility, nylon remains a suitable material for almost all types of manufacturing operations like injection molding, extrusion, and additive manufacturing (in FDM, SLS, and MSF).
Nylon remains quite popular in traditional and additive manufacturing industries. Nylon's first major application was in the manufacture of a toothbrush, but it's use rapidly spread to other sectors due to its unique material properties. Some of the popular application of nylon material includes:
- Nylon is used in the textile industry for manufacturing fishing lines and food packaging
- Nylon is used in the textile industry to manufacture various products like lingeries, hosiery, raincoats, windbreakers, and athletic wear for sports.
- Nylon is used in the automobile industry to produce parts like intake manifolds, door handles, and radiator grills.
- Nylon is used in consumer products to manufacture sporting goods such as ski bindings and skateboard wheels.
- Nylon is used in manufacturing machinery for moving parts like gears and rollers.
Just as nylon has become a go-to material in traditional manufacturing, it has also become a popular material to use with 3D printers. With 3D printers come the extra benefits of unlimited geometrics, iteration, customization, and low-volume affordability.
Nylon's flexibility and durability account for it's 3d printing parts with thin walls. In addition, it's low frictional coefficient with a high melting point makes it exceptionally resistant to abrasion and enables it to be used in printing for parts like a functional interlocking gear. The mechanical properties of nylon can be compared to ABS (another widely used material in traditional and additive manufacturing). ABS is well known for its strength, but nylon's resistance to wear and fatigue accounts for its superiority for applications requiring such properties.
Amid its advantages, nylon has a major drawback that often hampers its printing performance. That is its hygroscopicity (it's moisture absorption property). This property is detrimental to nylon delivering predictable performance. But, even at that, it also helps nylon in easy post-processing with fabrics and spray paint, thereby making it suitable for printing aesthetic (display) models.
Successful cases of a patient receiving a titanium pelvis implant, another getting a titanium lower jaw, a motorcyclist patient with an injured face from an accident had it rebuilt with 3d printing parts have been recorded.
With bioprinting, 3d printing of artificial organs, helping solve organ failure issues in patients faster, is important to both patients and their families and the healthcare system. 3D printed tissues have been developed for pharmaceutical testing as a cost-effective and ethical method of identifying the side effects of drug and validating safe dosages.
The 3D printing process of binder jetting can be used to produce pills. The process allows the produced pills to be very porous, thereby allowing high dosages in a single pill that can quickly be dissolved and easily be digested. These are useful in treating serious conditions like epilepsy.
Nylon 3D printing can be achieved with fused deposition modeling (FDM) using nylon filament or with selective laser sintering (SLS) or multi-jet fusion (MLF) using nylon Powder. The difference between these technologies, their pros, and cons, and how they can be used to create nylon parts will be fully discussed.
Fused deposition modeling (FDM)
3D printing with nylon can often be expensive to get into as MJF and SLS printers and their powders are expensive to acquire. However, possibilities abound in 3D printing nylon using an FDM printer paired with a special nylon filament.
FDM 3d printers use filaments, melted, and then extracted into a build platform in layers through a nozzle until the part is complete. Although 3D printing nylon on an FDM printer is easily accessible compared to SLS or MLF, the FDM printed nylon part is not that impressive in quality.
Not all FDM printers can easily handle nylon filament with ease. Therefore, having a quality (all metal) hot end that can handle temperatures above 250°c is important. In addition, nylon is prone to warping. Hence, bed adhesion is an issue of its own.
Nylon filament has variations, with the most common being PA6 and PA66. Both have the standard nylon properties of abrasion resistance, strength, and low frictional coefficient but come with a flaw: high moisture absorption.
- Storage and printing:
High moisture absorption can negatively impact a filament in the form of degradation. Degraded filament loses its properties, and nylon filament can degrade as early as an hour. Therefore, to avoid degradation, proper storage of nylon filament is essential. When the filament is not being used, a simple plastic airtight container can come in handy, but what to do when printing? The ideal storage method is placing it in a storage unit with humidity control which allows the filament to get into the extruder.
Once the storage method has been figured out, printing with nylon filament should come next. Although the exact printer, material being used, and the manufacturers recommended setting play a huge role, an overview of the nylon printing settings is outlined below:
- Nozzle temperature: 240-290°c
- Bed temperature: up to 65°c
- Bed surface: PVA glue stick, magigoo, garolite, 3D lac
- Print speed: 25:50 mm/s
- Fan speed: 0-50%
- Enclosure: recommended but not necessary.
Selective laser sintering (SLS)
SLS makes use of a laser to sinter a powder layer by layer until the part is complete. Various types of laser sintering technology abound. Although adaptation for metal and glass is available, most SLS 3D printers are oriented towards polymers.
One of the major materials used with SLS is nylon, specifically the PA11 and PA12 powder types. PA11 is applied in parts that require UV and impact resistance, while PA12 is more suitable for enhanced part strength and stiffness. As a result, reinforced PA powders also known as nylon composite powders abound. They usually contain either glass, aluminum, or carbon fiber particles in addition to nylon.
With SLS, it is possible to reuse up to 50-70% of uninsured powder for future prints.
This characteristic is a major advantage over FDM as the material extruded as support won't be converted back into filament for reuse. SLS is more suitable for 3D printing with nylon when compared to FDM. Nylon is useful in making functional parts, and SLS has the required ability to produce complex functional parts and gain strength from using powder rather than filament. The major disadvantage of SLS is its expensive industrial SLS 3D printers which often come with a high cost.
Multi-jet Fusion (MJF)
MJF is a unique powder sintering technology. It was developed by Hewlett Packard and launched in 2016. MJF bears certain similarities to SLS and also shares a thing or two with binder jetting.
Both MLF and SLS carry out the printing process in a similar manner. There is a distribution of a layer of powder into the build platform before sintering. However, whereas in SLS, the laser would start sintering, MLF takes an extra step in the printing process in the form of chemical agents.
The spraying of a fusing agent on top of each fresh layer of powder precisely where the future layer will be sintered. The fusing agent helps to absorb the energy from the printer's heat source. While SLS uses a high-powered laser, MJF depends on a high-powered Infrared light paired with the fusing agent to speed up the sintering process, thereby making MJF faster than SLS.
Nylon is considered the most popular material for printing 3D. It was first synthesized in 1935 by Dupont, an American chemical company. Nylon stands for a group of plastics called polymers. In 3D printing with nylon, three technologies are involved. They include fused deposition modeling (FDM), selective laser sintering (SLS), and multi-jet fusion (MJF), with each technology having insidious methods of 3D printing. Nylon, apart from its usefulness in 3D printing, also has a range of applications like its application in the textile industry, automobile industry, to mention a few.