What is PETG?
PETG filament
PETG filament is one of the most popular 3D printing materials because it combines the ease of printing of PLA with the enhanced durability of ABS in one package. When a material is needed that can withstand mechanical stress, moisture, and moderate heat without a complex printing environment, PETG is often the most practical solution. It is suitable for both hobbyists and professionals, and its balanced properties make it a very versatile option for functional parts.
PETG is based on PETG polymer, which is a glycol-modified version of PET plastic. The addition of glycol improves the material's impact resistance and reduces brittleness, making it suitable for 3D printing. PETG is particularly known for its good layer adhesion, chemical resistance, and the fact that it does not shrink as much as ABS. This makes the printing process more predictable and reduces the risk of cracking or warping of the part.
PETG properties and technical values
The table below presents typical technical properties of PETG filament. Values vary depending on the manufacturer, but the table gives a realistic picture of the material's practical performance.
|
Property |
Typical Value |
Practical Significance |
|
Tensile Strength |
45–55 MPa |
Good mechanical strength |
|
Modulus of Elasticity |
1.8–2.2 GPa |
Balanced stiffness |
|
Heat Deflection Temperature (HDT) |
70–85 °C |
More heat resistant than PLA |
|
Impact Resistance |
Very good |
Does not crack easily |
|
UV Resistance |
Moderate |
Suitable for moderate outdoor use |
|
Shrinkage |
Low |
Minimal warping |
|
Density |
approx. 1.27 g/cm³ |
Slightly heavier than PLA |
PETG's strength lies in its balance. It is not as rigid as fiberglass-reinforced technical filaments, but it offers sufficient mechanical performance for most functional applications. Compared to PLA, PETG is more resistant to impact and heat, and it doesn't break as easily. Compared to ABS, it prints more easily and requires a less controlled thermal environment.
What is PETG filament used for in practice?
PETG is excellent for enclosures, fixtures, containers, protective covers, and mechanical parts where durability and some flexibility are required. The material's good chemical resistance also makes it suitable for moist environments and parts exposed to, for example, cleaning agents or mild chemicals. PETG is also often used for outdoor parts when better weather resistance than PLA offers is needed.
Because PETG is not brittle, it is well suited for parts that are subject to impact or vibration. However, it is not the best option for very hot environments where the temperature rises close to 100 degrees Celsius. For such applications, more technical materials should be considered.
PETG printing and hardware requirements
PETG typically prints at a nozzle temperature of 220–250 °C and on a heated bed, usually at 70–90 °C. The material does not shrink significantly, so an enclosed print chamber is not essential, but it can improve layer adhesion for large parts. PETG adheres well to the print bed, sometimes even too well, so using a removable bed or a release agent can facilitate part removal.
Unlike fiber-reinforced filaments, PETG does not significantly wear down the nozzle, so a standard brass nozzle is well-suited for normal use. However, the material is somewhat prone to thin stringing during printing, which requires careful optimization of retraction settings. When properly adjusted, PETG offers a clean surface and excellent inter-layer strength.
Frequently asked questions about PETG filament
Is PETG better than PLA?
PETG is better when impact resistance, flexibility, and higher heat tolerance are needed. PLA is easier to print, but it is more brittle and softens at lower temperatures.
Is PETG difficult to print?
PETG is slightly more demanding than PLA, but significantly easier than ABS. With the correct temperature and retraction settings, it prints reliably.
Is PETG suitable for outdoor use?
Yes, PETG withstands moisture and moderate UV exposure better than PLA, making it suitable for many outdoor applications.
Does PETG withstand heat?
PETG withstands more heat than PLA, but not as much as ABS or ASA. It is not the best choice for continuous heat exposure above 90 °C.
Can PETG be used for food contact?
Raw PETG material may be food-safe, but the layered structure of a 3D-printed part can harbor bacteria. Suitability for food contact depends on the filament manufacturer and the intended use.
Does PETG require a special nozzle?
No. PETG is not an abrasive material, so a standard brass nozzle works well.
Summary
PETG filament is a versatile and durable 3D printing material that offers an excellent balance between printability and mechanical performance. It is widely suitable for functional parts exposed to mechanical stress, moisture, or moderate heat. When a reliable and versatile filament is needed without the printing challenges of ABS, PETG is often one of the best choices.