Materials
PLA
Polylactic acid (PLA) is the most popular and user-friendly FDM filament. As a renewable, biodegradable, and low-toxicity thermoplastic, it is relatively eco-friendly and highly popular, with hundreds of colours and varieties widely available for consumer purchase. Various composites of PLA exist, each providing some desirable functional or aesthetic improvement over the base product. Through various online vendors, an interested buyer can easily obtain rolls of PLA infused with metal powder, carbon fiber, phosphors, coffee, beer, and much more. However, PLA and PLA composites generally have suboptimal strength and a low glass transition temperature (~60°C for unadulterated PLA) which make them non-ideal for rugged applications as they may fail under loading or deform under moderate heat.
PETG
Polyethylene terephthalate glycol (PETG) is a stronger and more flexible filament than PLA, with an accordingly higher glass transition temperature (~80°C). It is somewhat less common, biodegradable, and user-friendly than PLA, but its material properties often make it more suitable for practical applications. It has impressive durability and chemical resistance, and it is odorless when printing. Due to these qualities, it is considered by some to be the de facto “successor” to ABS filament.
ABS
Acrylonitrile butadiene styrene (ABS) is relatively comparable to PETG in terms of strength, but its high glass transition temperature (~105°C) makes it more well-suited to many rugged applications. ABS is a very common plastic in automotive and household applications, being the material of choice for many OEM automotive trim components. It also has a unique relationship with acetone that differentiates it from other FDM thermoplastics. One can effectively "weld" ABS parts together through direct application of acetone, or give them an aesthetically pleasing smoothed appearance by subjecting them to acetone "vapour baths." However, ABS toxicity, its non-biodegradable nature, and its proclivity to warping during prints have all contributed to its gradual decline in popularity among the non-industrial 3D printing community.
ASA
Acrylonitrile styrene acrylate (ASA) is much less well-known than ABS among 3D printing hobbyists, but boasts superior performance on several fronts. While chemically similar to ABS and with a slightly lower glass transition temperature (~100°C), it is stronger, more durable, and less prone to warping during prints. It also sports impressive UV resistance, making it an ideal choice for practical long-term outdoor applications that would cause most other materials to degrade and fail. Despite these benefits, ASA’s higher price point and lower market availability have prevented it from becoming a staple in the arsenal of most 3D printing enthusiasts.
TPE / TPU
Thermoplastic elastomers (TPE) such as thermoplastic polyurethane (TPU) are distinct from the prior three materials in that they are flexible. Various blends and Shore hardnesses are available, with consistencies ranging from that of a pencil eraser to that of a shopping chart wheel. TPU parts are durable and resistant to moderately high temperatures (~80°C), and their rubber-like property makes them the material of choice for a variety of niche applications such as phone cases, shoe insoles, RC car tires, and more.
Nylon
Polyamide (Nylon) is a thermoplastic known for being both tough and pliable. It has a moderately high glass transition temperature of ~82°C. Nylon is less commonly used than the materials listed above, in part because its tendency to absorb moisture from the air makes it difficult to print with and unreliable for dimensional accuracy. However, it is highly resistant to both impact and abrasion, and its tough and absorbent nature allow it to be easily drilled, tapped, or dyed after printing.
PC
Polycarbonate (PC) is another very strong material, stiffer than nylon and thus superior in resisting deformation under prolonged loading. It is again less common than the materials listed above, in part due to an extremely high printing temperature and a tendency to warp during prints. However, it has fantastic thermal and impact resistance, with a remarkably high glass transition temperature of ~145°C.
Resin
Resin monomers are used in SLA printers to create remarkably detailed prints, with a maximum resolution approximately four times finer than that of most standard FDM printers. The chemical bonding that occurs during the curing of resin also gives it several advantages over thermoplastic filaments. For one, the formed molecular bonds eliminate one of the biggest inherent drawbacks of FDM prints: the structural weakness between layers. In addition, resin prints are watertight, a quality which is not wholly attainable in FDM printing. Resin also does not melt, but has a heat deformation temperature of ~73°C at 66psi. Many types of resin have been created throughout the years to optimize various properties, including strength, heat resistance, flexibility, transparency, and more. Resin's greatest strength, however, lies in its applications in proof-of-concept prototypes and its unparalleled capacity for fine detail.