What is PETG?
PETG is a thermoplastic polyester that takes its name from the chemical structure of polyethylene terephthalate, a commonly used plastic in industry. The addition of glycol to PET makes it more flexible and better suited for 3D printing. PETG offers an excellent balance of strength, durability, and impact resistance, making it one of the most versatile materials for 3D printing projects.
Characteristics of PETG:
- Strong and Tough: PETG is known for its combination of strength and flexibility. It is more durable than PLA and less fragile than ABS.
- Easy to print: PETG has good adhesion to the print bed and is less prone to warping than ABS, while still being stronger than PLA.
- Moisture Resistant: Unlike some other filaments, PETG is more resistant to moisture and chemicals, making it suitable for outdoor use and humid environments.
Applications of PETG
PETG is a versatile material suitable for many applications ranging from functional prototypes to consumer goods. Here are some of the most common uses of PETG:
1. Functional Prototypes
The combination of strength and flexibility makes PETG ideal for creating functional prototypes that need to be tested in real-world situations. It offers durability and abrasion resistance, while being easy to print.
2. Housings for Electronics
Due to its chemical and moisture resistance, PETG is often used for printing housings for electronic devices. It protects against environmental factors such as moisture and chemicals and provides a sturdy covering for sensitive components.
3. Parts for Machine Construction
The durability of PETG makes it an excellent choice for printing machine parts, tools and fixtures. It can tolerate mechanical stress and impact well, making it suitable for industrial applications.
4. Outdoor applications
PETG is UV and weather resistant, making it suitable for outdoor applications such as garden accessories, outdoor enclosures and parts exposed to the elements.
5. Food-related applications
PETG is biologically inert and can be used in contact with food, provided it is correctly printed and post-treated. This makes it ideal for making food-related products such as storage containers, but it is important to check that the specific filament is food-safe certified.
Advantages of PETG
PETG offers a number of attractive advantages that make it a favorite choice for many 3D printers, both hobbyists and professionals. Here are the main benefits:
- Strong and Flexible: PETG provides an excellent balance between strength and flexibility. It is less brittle than PLA and offers more impact resistance than ABS, making it suitable for functional parts that must withstand mechanical stress.
- Weather and UV Resistant: PETG is resistant to UV light and moisture, making it a perfect choice for outdoor applications and parts exposed to the elements.
- Less Susceptible to Warping: Compared to ABS, PETG is less prone to warping and tearing during printing, making it easier to print even without a fully enclosed print chamber.
- Smooth Surface: PETG provides a smooth finish with good interlayer adhesion, resulting in strong prints with a professional appearance.
- Moisture and Chemical Resistant: PETG has good resistance to water, chemicals and oils, making it ideal for parts exposed to such environments.
Disadvantages of PETG
Although PETG has many advantages, there are also some disadvantages that are important to consider before choosing this material:
- Less heat resistant than ABS: Although PETG is stronger and more durable than PLA, it is not as heat resistant as ABS. When exposed to higher temperatures, PETG can deform.
- Stringing and oozing: PETG is known to cause stringing (wires between print parts) and oozing (filament leakage from the nozzle) during printing. This can be reduced by using the correct print settings and temperature settings.
- Slightly sticky: PETG can be slightly sticky during printing, meaning the filament can stick to the nozzle or other parts of the printer, which can cause problems if not managed properly.
- Post-processing can be more difficult: Due to the strong film adhesion of PETG, it can be more difficult to sand or machine compared to PLA or ABS.
3D printing with PETG
Successfully printing with PETG requires a few specific adjustments to your printer settings to get the best results. Here are some tips for printing with PETG:
1. Temperature settings
PETG requires higher printing temperatures than PLA, usually between 220°C and 250°C. A temperature of 70°C to 90°C is recommended for the print bed to ensure good adhesion. Make sure to experiment with the settings to see what temperature works best with your specific filament and printer.
2. Use a print bed with good adhesion
PETG tends to adhere strongly to the print bed, which can lead to damage to the print surface when removing the print. Therefore, use a flexible printing surface, blue painter's tape or a lubricant such as a thin layer of glue stick to ensure that the print comes off easily without damaging the print bed.
3. Minimize stringing
Stringing is a common problem when printing with PETG. It's important to optimize the retraction settings in your slicer to minimize this. Increase the retraction speed and distance to reduce stringing, and experiment with the temperature to find the right balance.
4. Storage of PETG
Although PETG is more resistant to moisture than PLA, it must still be stored dry to avoid printing problems. PETG can absorb moisture from the air, which can reduce print quality. Therefore, store the filament in a sealed container with silica gel bags to keep it dry.
5. Post-processing of the prints
Post-processing of PETG prints can be somewhat more difficult due to the strong layer adhesion. It can be difficult to sand the surface smooth, but it is possible to polish or paint the print for a professional finish.
Frequently asked questions about PETG
1. How does PETG compare to PLA?
PETG is stronger, more flexible and more durable than PLA. It is also more resistant to high temperatures and moisture. However, PLA is easier to print and is more environmentally friendly due to its biodegradable properties.
2. Is PETG safe for food contact?
PETG is in theory food safe, but it depends on the purity of the filament and the dyes used. It is important to check that the PETG filament you are using is specifically certified as food safe.
3. Should I use a heated print bed for PETG?
Yes, a heated print bed is essential for printing with PETG. A bed temperature of 70°C to 90°C helps improve the adhesion of the filament to the print bed and prevents warping.
4. Is PETG suitable for outdoor applications?
Yes, PETG has good resistance to UV light and moisture, making it very suitable for outdoor applications and parts exposed to the elements.
5. How do I prevent stringing when printing with PETG?
To reduce stringing, optimize your printer's retraction settings and experiment with lower printing temperatures. A higher retraction speed and distance can also help prevent unwanted filament threads.
6. Is PETG recyclable?
Yes, PETG is recyclable, although the process may differ depending on the facilities in your region. Always check local guidelines for recycling thermoplastics.
