Filament

From Maker Trainer, the online makerspace

3D printing filament is the thermoplastic feedstock for FDM 3D printers. There are many types of filament available with different properties such as colour, texture, weight, strength, heat resistance, chemical resistance etc., requiring different temperatures to print. The most common sizes (diameter) of filament is 1.75 mm and 2.85 mm.

To read more about how filament is turned into a 3D print, see Material extrusion.

Types of filament

(Note: The characteristics and temperatures given in the list below are only representative of industry defaults. Individual products can vary greatly, and their respective data sheets will always hold the most accurate information about them. Many filaments also contain additives to achieve different desired properties.)

General use materials

PLA (180 - 230°C)

PLA (Polylactic Acid) is the most popular filament used in desktop material extrusion. Due to its low cost and easy of use, it is the choice of filament of most people starting out in 3D printing, and many users stick with it, since it yields great looking parts with a wide variety of colours available. Derived from natural resources such as corn, PLA is renewable and biodegradable.

PROS CONS
Inexpensive Brittle
Easy to print Plastic feel
Strong and stiff Low heat resistance
Good dimensional accuracy Low chemical resistance
Little warping May require cooling fan
No bad odour Degrades outdoor
Long product shelf life
ABS (210 - 250°C)

ABS (Acrylonitrile Butadiene Styrene) is a popular material due to its low cost and good mechanical properties. ABS is known for its toughness and impact resistance. ABS has a higher heat resistance than PLA, but because of this it also needs to be printed at higher temperatures. It is prone to warping, and because of this a heated bed (and ideally a heated chamber) is recommended to print it. It gives off a strong odour while printing which can also be potentially noxious, so the print area should be well-ventilated. Can be treated in post-processing to an acetone vapor bath to smooth out visible layer lines.

PROS CONS
Inexpensive Heavy warping
Tough and impact resistant Shrinkage
Heat resistant Bad odour
Chemical resistant Potentially noxious fumes
Scratch resistant High temperature
Easy to post-process
PET and PETG (220 - 235°C)

PET (Polyethylene Terephthalate) is one of the most widely produced thermoplastics in the world, used in manufacturing and in the textile industry (where it's referred to as polyester). Due to its lack of flexibility, pure PET is less commonly used in 3D printing, but popular derivatives have been created through the use of additives.

PETG is PET with glycol added to it for better flexibility and impact resistance. Having great layer adhesion, the material tends to bend rather than break, making it a popular choice for 3D printed parts. PETG is also commonly used to manufacture water bottles.

PROS CONS
Very strong More difficult to print
Little warping Poor bridging
No bad smell Post-processing limited
Water resistance Stringing
Chemical resistance Prone to scratching
Good clear options
Heat resistance
Nylon (220 - 260°C)

Nylon (also Polyamide or PA) is one of the most popular materials in the plastics industry, used for making durable parts. Different variations are commonly named by the number of carbons in their chemical structure such as PA6, PA12 etc. For 3D printing, nylon filaments require high extruder temperatures between 220-260 ºC. The material is very hygroscopic (it absorbs moisture easily) which can lead to printing issues. It is recommended that spools are kept in an airtight container or that they are dried before printing.

PROS CONS
Very strong and tough High temperature
Highly impact and abrasion resistance Prone to warping
Heat resistance Special attention to dryness
Flexibility
No bad smell
TPE and TPU (225 - 235°C)

TPE (Thermoplastic Elastomer) is an umbrella term for a range of rubbery plastic blends, their main characteristic being elasticity and flexibility. The one most commonly used in 3D printing is TPU (Thermoplastic polyurethane), a relatively hard and rigid variation. TPEs are challenging to print due to their elasticity, and getting a good surface finish without stringing is even more difficult. Post-processing is usually required for aesthetic parts.

PROS CONS
Flexibility and elasticity Difficult to print (especially on Bowden extruders)
Soft Stringing
Impact resistance Poor bridging
Vibration dampening
Long shelf life
ASA (240 - 260°C)

ASA (Acrylic Styrene Acrylonitrile) is a plastic that has a similar composition and characteristics to ABS, but is more weather resistant, and is somewhat less prone to warping and cracking. Can be treated in post-processing to an acetone vapor bath to smooth out visible layer lines.

PROS CONS
Strong UV resistance Expensive
Heat and cold resistance Warping and cracking
Tough and durable Shrinkage
Water resistance Bad odour
Chemical resistance Potentially noxious fumes
Anti-static High temperature
PC (270 - 310°C)

PC (Polycarbonate) is a high-strength, tough and impact resistant engineering material with extremely high heat deflection, traditionally used to make bulletproof glass, DVDs and sunglasses lenses. In its pure form it requires very high extrusion temperatures (260-300°C), so many Polycarbonate filaments contain additives that allow them to be printed at lower temperatures. PC is best printed inside an enclosed chamber on a heated bed. Layer separation and warping can occur due to lack of heat.

PROS CONS
Strength and impact resistance Very hygroscopic
Heat resistance up to 150°C Very high printing temperature
Flexibility Oozing
Transparent Warping
PP (210 - 230°C)

PP (Polypropylene) is a semi-rigid and lightweight material that is commonly used in storage and packaging applications. Polypropylene is tough and has a good fatigue resistance making it ideal for low strength applications like living hinges, straps, leashes, etc. The semi-crystalline structure of the material causes the 3D printed parts to heavily warp upon cooling, making it challenging to 3D print.

PROS CONS
Impact and fatigue resistance Heavy warping
Softness Expensive
Flexibility Low strength
Heat resistance
Acrylic (235 - 250°C)

Acrylic is the common name for PMMA (Polymethylmethacrylate), a semi-transparent 3D printable thermoplastic.

PMMA filament is mainly transparent, which makes it great for printing semi-clear parts where light has to pass through. You can use this filament to print items like lampshades, window panes, and other objects that are fully or semi-transparent.

PROS CONS
Strength Warping
Durability Toxicity
Impact resistnce
Translucent / Transparent

Support materials

HIPS (210 - 250°C)

HIPS (High Impact Polystyrene) is a thermoplastic most often used as a support material for ABS on dual extrusion printers. This is because HIPS can be dissolved in d-Limonene, making the support-removal process easy and precise. HIPS has many of the same printing properties as ABS, including printing temperature. HIPS can also be used for regular 3D printing, being a lightweight and durable polymer.

PROS CONS
Soluble support material High temperature
Inexpensive Heated bed required
Lightweight Heated chamber recommended
Strength and toughness
Impact resistance
Heat resistance
Water resistance
PVA (180 - 230°C)

PVA (Polyvinyl Alcohol) is a soft biodegradable thermoplastic that dissolves when exposed to water. In 3D printing, it is most commonly used as a soluble support material. Soluble supports are especially helpful where these would be difficult to remove normally by hand, such as inside complex shapes or hollow cavities.

PROS CONS
No special chemicals Expensive
Very hygroscopic
Extra dry storage
Can clog the extruder
Breakaway (215 - 230°C)

Breakaway filament is used to create supports that are quick and easy to remove, and also leave less marks after removal. A dual extruder machine is necessary for breakaway supports to be printed in conjunction with the filament of choice for the desired part.

PROS CONS
Great support material Dual extruder needed
Less visible support marks Prints take longer due to dual extruding
Long shelf-life Only useful as support
Can be used with many filaments
No sanding needed
Quicker than soluble materials

Special use materials

Composite: wood, metal etc. (190 - 220°C)

Composite filaments are created by adding powdered materials to a thermoplastic base to give printed parts the aesthetic of the powdered material (such as wood, copper, bronze etc.), and sometimes also to add weight. Due to the abrasive added particles, these filaments generate a lot of wear on nozzles.

PROS CONS
Unique aesthetic High nozzle wear
Less plastic feel Clogging
Heavier parts Can require wider or stronger nozzles
Fiber-filled: carbon, glass etc. (190 - 220°C)

Fiber-filled filaments are created by adding 'chopped' short pieces of a fiber material to a thermoplastic base. These strands highly increase the strength and stiffness of the resulting filament. At the same time they prevent shrinking of printed parts as they cool down. Due to the abrasive nature of the infill material, these filaments generate a lot of wear on nozzles.

Fiber-filled filaments can be printed on most FDM 3D printers, and should not be confused with continuous fiber filaments, which are much stronger (especially along the direction of the fibers), but more expensive and require specialist 3D printers to be extruded.

PROS CONS
High strength High nozzle wear
Stiffness Clogging
Requires steel nozzle
Expensive
High-temperature: PAEK, PEI etc. (340 - 450°C)

High-temperature filaments are engineering-grade materials (sometimes referred to as advanced materials) used for their extremely high strength-to-weight ratio, toughness and durability. The two families of plastics commonly used are PAEK (Polyaryle Ether Ketones, consisting of PEEK, PEKK etc.) and PEI (Polyetherimide, often referred to by its brand name, ULTEM). The most common of these materials is PEEK, which is often used in specialist applications of traditional manufacturing.

These thermoplastics require very high extrusion temperatures (over 300°C), and can only be printed in dedicated high-temperature machines. The polymers can take on three forms: amorphous semi-crystalline and crystalline. Generally after extrusion, the materials will be in an amorphous state, and while they already have great mechanical properties in this state, their strength and stiffness can be increased further through annealing, a process which crystallises the polymer's structures.

Some of these thermoplastics are used as medical implants due to their biocompatibility.

PROS CONS
Strength Very expensive
Durability and toughness Very high printing temperature
Heat resistance Requires annealing to achieve full strength
Chemical resistance
Biocompatibility