As you probably already know, Fused Deposition Modeling or FDM (A.K.A. Fused Filament Fabrication) is one of the most common, not to mention affordable 3D Printing technologies out there. It relies on the use of a computer controlled heated extruder that pushes the melted thermoplastic filament through a nozzle. The computer controlled nozzle deposits the molten plastic in thin layers to form the 3D object from the bottom up.
The filament is to a 3D printer what ink cartridges are to your standard ink-jet home printer: neither can exists without the other. There aren’t too many types of inks for you to choose from, but in the world of 3D printing, there is a wide range of filament types, each made of different kinds of materials (different thermoplastics and blends) which will have an immense impact on the overall properties and characteristics of the final printed object.
Choosing between so many options can be a bit overwhelming at first, and you may find yourself thinking:
“Ok, I’ve got my 3D printer set up, which filament should I use for my project?”
In this article, I’ll show you the different thermoplastic filament types most commonly used in 3D printing, along with the most relevant properties and characteristics of each different material to help you decide which one is right for you.
PLA stands for Poly(Lactic Acid), which is a very special type of thermoplastic that has received a lot of attention lately. Besides its popularity in the 3D printing industry, PLA is also famous for being “green”, and we’re not talking about color. Why? For two important reasons:
1st - It’s biodegradable:
It’s a well-known fact that most plastics can take hundreds and even thousands of years to decompose naturally. PLA naturally breaks down into harmless lactic acid due to the action of sunlight, water or bacteria.
2nd - PLA production uses natural, renewable resources
Unlike most plastics, which are produced by the petrochemical industry from oil and natural gas, PLA is made from renewable sources like cornstarch, sugars, and similar compounds, which are readily available from food crops as well as from some food industry by-products.
Disclosure: This page contains affiliate links. However, clicking an affiliate link doesn’t affect the price you pay and I only link to products I fully stand behind for the stated purpose.
Properties of PLA
One of the lowest melting points (around 160ºC) means that you’ll require the lowest printing temperature (190-220ºC at the extruder). This saves energy and money.
- Very hygroscopic. (absorbs moisture from the air)
- Not water-resistant.
- Low chemical resistance.
Better if stored in a dry, sealed container in dark and cool place like a fridge, away from direct sunlight or other UV light sources.
By far the easiest material to print with, giving the least amount of issues in the process. A great choice for noobies, as most FDM printers, even the cheapest ones, are well equipped to print with this type of filament.
PET stands for Polyethylene Terephthalate, and it is almost sure you’ve heard of it before: it’s what most plastic water bottles and food containers are made of. PETG is a type of PET that has been modified with glycol, a very water-attracting alcohol. This makes for an immense difference in properties, which are specifically tailored for 3D printing.
Along with PLA and ABS filaments, PETG filaments are among the most widely used in FDM 3D printing.
Properties of PETG Filaments
- Less brittle than both ABS and PLA.
- Not as scratch resistant as ABS.
- Tensile strength is middle ground between PLA and ABS.
- It’s more durable than PLA.
- Requires moderate extruder temperatures of around 220-250ºC
- It’ll warp less than both PLA and ABS
- Printed pieces can be used at up to around 75ºC which is higher than for PLA.
- It requires a heated bed for printing
- Not biodegradable.
- Depending on formulation, may be food safe.
- Unlike PLA, it’s water resistant.
- It’s resistant to some organic solvents and acids.
- Very hygroscopic (absorbs moisture from the air).
Like PLA, it’s better to store it in a dry, dark and cool place like a fridge, away from direct sunlight or UV light sources.
Very easy to print with, comparable to PLA
ABS is short for Acrylonitrile Butadiene Styrene copolymer. It actually represents a whole family of thermoplastics with a very wide range of properties that depend on the proportions of its three components. ABS is, along with PLA, one of the most commonly used 3D printing filament materials, available in many different colors and textures.
Properties of ABS Filaments
High impact resistance and toughness are the most prominent mechanical properties. It’s also more durable than PLA.
Withstands higher temperatures than PLA (printed pieces can be used at up to around 100ºC).
Doesn’t have a defined melting point like other thermoplastics, but extruder temperatures normally need to go from 220-250ºC
- Not biodegradable
- Degrades and loses properties under direct sunlight.
- It’s water resistant (hot or cold)
- Resistant to some diluted and even concentrated acids and bases.
The only consideration needed is to keep it in a dark shelf, away from direct sunlight and any UV light source.
Can be difficult to print. It’s prone to warping and requires not only a heated bed, but an enclosed and heated chamber. Also off-gases harmful vapors so an exhaust/air cleaner is recommended.
TPE (TPU/TPEE) Filaments
TPE stands for Thermoplastic Elastomer. However technical it may seem, the name is actually a bit of a giveaway: it refers to a thermoplastic (any material that becomes plastic when hot) that has elastic properties and is therefore flexible. TPEs are the material of choice whenever you’re seeking to print flexible, durable, rubber-like functional parts such as seals, bushings, shoe-soles, insoles, toy tires, etc. They are great for building functional parts to be used for vibration dampening, or whenever you’re looking for a part that will fit tightly around, and/or adjust to the shape of another one, like in the case of and anti-slip linings and phone cases.
The term TPE doesn’t refer to a single type of resin or polymer, like in the case of PLA. As with ABS, TPE is actually an umbrella term that refers to any material with the said qualities of flexibility and durability, which is the reason why many refer to TPEs simply as Flexible Filaments. TPEs could be made of one polymer, co-polymers, polymer and/or co-polymer blends, and so on. Furthermore, any one of those polymers could be of a different type, such as polyesters, polyurethanes, etc.
Such a diverse set of materials will obviously not have identical properties among all its members (other than being a thermoplastic and being flexible, of course), so I won’t give you a list of common properties for all TPE filaments. Having said that, TPEs can be divided into families (or types) that do share common properties. The two most commonly available types or families of TPEs are TPU and TPEE (also called TPC).
What are TPU Filaments?
As I mentioned above, TPU is a type of TPE. In this case, the U stands for Urethane. In other words, TPU stands for Thermoplastic Polyurethane, a special sort of low-density flexible plastic used very frequently in foams for shoe linings, upholstery and automotive seating; for flexible straps and bands; flexible parts for footwear and a whole lot more.
- Highly resistant to impact and abrasion, which makes it very durable.
- It has flexural memory (when deformed by a force and then released, it will return to its original shape)
- Highly flexible and elastic (very low tensile strength)
- In general, you could say that the mechanical properties of TPU are middle ground between a hard plastic like ABS and rubber or soft silicone.
- Works better than other materials at low temperatures.
- Extruder temperature range 200-245ºC (depending on composition)
- High coefficients of thermal expansion, which implies shrinkage as it cools downs.
- Resistant to grease, oil and some organic solvents.
- Not resistant to acids and bases.
- Most TPU filaments are water-resistant, although some aren’t (check with the manufacturer when buying)
- Not food safe.
- TPU discolors rapidly on the surface with UV exposure, but the bulk properties of the material aren’t usually affected.
Preferably in a dark, airtight container or bag with a desiccant at room temperature. No refrigeration needed.
It can be rather difficult to print, especially with Bowden extruders, but it’s the easiest to print among PTE filaments.
The main printing issues are stringing, clogging, coiling and blobbing.
On the other hand, layer-to-layer adhesion is excellent.
What are TPEE/TPC Filaments?
TPEE and TPC are terms used interchangeably to refer to a sort of TPE called Thermoplastic Copolyester. Polymers are usually made by polymerizing, or linking, the same repetitive unit, called a monomer, one after the other. TPC is a block copolymer, which means that different monomers are first polymerized into blocks of different sizes (like sticking Legos of the same color together), and then, the different blocks are polymerized or linked together.
TPC offers different properties depending on the monomers used in the blocks, the size of the blocks, and the proportions in which those blocks are combined. The type of linkage between the monomers is more chemically resistant than in the case of polyurethane. The addition of blocks made from harder polymers gives most TPCs higher structural strength than TPU as well.
Properties of TPEE/TPC Filaments
TPU is still a thermoplastic and it’s still an elastomer, but, because of its different composition, some of its properties will tend to be a bit different from other TPEs. In the following table, you’ll find the general properties of TPC, and I’ll mention the key differences from other types of TPEs.
- More resistant and durable than TPU
- It’s harder than TPU, but still flexible and elastic.
- It has flexural memory (when deformed by a force and then released, it will return to its original shape)
- Melting point: around 180ºC
- Extruder temperature: 220-260ºC
- Virtually no warping
- Withstands higher working temperatures than TPU
- Resistant to grease, oils and some organic solvents.
- It has better water resistance than TPU
- Better UV resistance compared to TPU
The same as TPU: Preferably in a dry, dark, airtight container or bag with a desiccant at room temperature. No refrigeration needed.
Its printability is better than TPU’s, since TPC is slightly stiffer, which reduces stringing, coiling and clogging. Nevertheless, it’s still a difficult material to print with.
Layer-to-layer adhesion is also excellent.
Nylon is one of those plastics you constantly hear about in your everyday life. It’s extensively used in the synthetic fabrics industry (as parts of our everyday garments), in kitchenware (in spatulas, spoons, turners, thongs, etc.) and in plastic fasteners and different plastic parts in machinery (plastic gears, bushings, etc.). It’s slightly flexible but, unlike TPE filament, it’s not elastic and doesn’t show flexural memory.
Excluding flexible and elastic parts, Nylon is the one-size-fits-all solution for printing functional, strong and durable parts and pieces. It can be easily dyed with standard fabric dyes, which will give you liberty to experiment with colors before or after printing.
Properties of Nylon Filaments
- Durable, strong and slightly flexible material.
- Not elastic.
- High impact resistance.
- High resistance to abrasion.
- Can withstand high pressures.
- Melting point: 180ªC
- Extruder temperature 230-260ºC
- Prone to warping, requires a heated bed at around 90ºC or a heated enclosure at around 45ºC.
- Withstands both high and low temperatures without losing properties.
- Great chemical resistance to oils and solvents.
- Very hygroscopic.
- Can be dyed before or after printing.
Since it is hygroscopic, Nylon is especially prone to absorb moisture, which makes for horrible printing defects. Nylon filaments should be stored in airtight containers along with desiccants to avoid humidity.
It’s not the easiest filament to print because it’s prone to warping and, therefore, requires a heated bet and an all-metal extruder. Other than that, it’s as easy to work with as ABS filaments.
Nylon shows very good layer-to-layer adhesion.