PETG stands for polyethylene terephthalate glycol(or poly(ethylene terephthalate)), which is a thermoplastic polyester material. It is derived from PET (Polyethylene Terephthalate) by adding glycol, which is what the "G" in PETG stands for. This modification lowers PETG’s crystallinity, making its molecular structure less orderly. Low crystallinity means PETG is less likely to warp or shrink out of shape during 3D printing, improving layer adhesion and increasing printing success rates.
Advantages Of PETG
PETG is widely used in many fields due to its many advantages. First PETG has good impact resistance and is more resilient than materials such as PLA. It can withstand large external forces without breaking easily and is suitable for printing parts that require high strength. Secondly, PETG's low shrinkage and low deformation characteristics reduce the risk of warping and deformation during the printing process, thereby ensuring higher printing accuracy, and is particularly suitable for printing large-size or complex structure models.
Recommended reading: PETG vs PLA: Differences And Comparisons You Need To Know
PETG also has excellent transparency chemical resistance, and strong tolerance to many chemicals, solvents, and oils. Therefore, it is suitable for making transparent or translucent parts, such as display models or lamp covers.
In addition, although PETG is not as resistant to high temperatures as ABS, it still has good hesitance. Overall, PETG has become an ideal choice of 3D printing materials due to its high cost performance, toughness, and printing stability
Disadvantages Of PETG
Low surface hardness and easy-to-damage
Although PETG has excellent toughness and is not easy to break, its surface Mohs hardness is only 2-3 (ordinary glass is 5.5), and it is easily scratched by sharp objects or hard objects during daily use. For transparent/translucent parts (such as lampshades and display screen protective layers), scratches not only reduce light transmittance and aesthetics, but also reduce functionality.
Recycling feasibility is questionable
Although PETG is theoretically a recyclable material, the actual recycling conditions are relatively complicated. In addition, most recycled materials have reduced mechanical properties due to thermal degradation (such as a 30% reduction in tensile strength), and can only be downgraded for low-end products.
3D printing process defects
Wiredrawing problem: The high viscosity of PETG filament causes material residue when the print head moves, forming spider web-like silk threads in complex structures or fine parts (such as support points and suspended details), affecting molding accuracy;
Hygroscopic interference: When exposed to a humid environment, 3d printing filament PETG can absorb more than 0.3% moisture in 24 hours. When the PETG filament is not fully dried and printed directly, the vaporization of water will produce bubbles and interlayer cracking and aggravate the wiredrawing phenomenon. To maintain stable performance, it needs to be dried at 60-80℃ for 4-6 hours in advance.
Recommended reading: How to Dry Filament
PETG Applications
PETG is widely used in food and beverage packaging, including bottles and containers. It meets FDA and EU food contact standards, making it safe for storing food. Its high transparency allows for easy visibility of contents, while its durability and chemical resistance ensure that it can withstand daily use and various storage conditions.
Beyond packaging, PETG plays a crucial role in industrial applications. Its toughness and impact resistance make it ideal for mechanical parts and industrial equipment components. It can endure harsh working environments without cracking or breaking, making it a preferred material for demanding applications.
In the medical field, PETG is commonly used for devices such as syringes, culture dishes, and centrifuge tubes. These applications require strong chemical resistance, durability, and sterilization. PETG meets these requirements and can be effectively sterilized using gamma rays, hydrogen peroxide gas, or other standard methods, ensuring safety and hygiene in medical environments.
PETG is also used in automotive interiors, such as dashboard trim and storage compartments. However, its suitability for this application is debated. While PETG has a higher heat resistance than PLA, its heat deformation temperature is around 69.4°C. This makes it unsuitable for prolonged exposure to high temperatures, which are common in vehicle interiors during hot weather.
Overall, PETG is a versatile material with applications in packaging, industry, healthcare, and even automotive design. Its combination of transparency, durability, and chemical resistance makes it a reliable choice in many fields. However, its heat resistance limitations should be considered when selecting it for high-temperature environments.
Comparing PETG With Other Materials
PETG vs PLA
PETG outperforms PLA in mechanical properties, including toughness, tensile strength, and heat resistance. Due to these advantages, PETG is more suitable for functional parts that require durability and flexibility. In contrast, PLA is known for its low cost and ease of printing, making it ideal for decorative models and rapid prototyping. While PLA is biodegradable and widely used in hobbyist projects, its brittleness and lower heat resistance limit its use in demanding applications.
PETG vs ABS
ABS generally has higher tensile strength than PETG, making it a strong material for load-bearing applications. However, PETG has better impact resistance and flexibility, which helps prevent cracking under stress. ABS also has a higher heat deformation temperature (90-100°C), making it more suitable for high-temperature environments. However, ABS is typically opaque and emits fumes when printed, requiring proper ventilation. PETG, on the other hand, is easier to print and has better chemical resistance, making it a preferred choice for parts exposed to chemicals or requiring transparency.
PETG vs PC (Polycarbonate)
Both PETG and PC share characteristics such as high transparency and recyclability. However, PC is one of the strongest and most impact-resistant thermoplastics available. It is widely used in bulletproof glass, safety helmets, and protective gear due to its superior physical properties. PC filaments are significantly more expensive, typically ranging from $30 to $60 per spool, and require professional-grade 3D printers with high-temperature capabilities. As a result, PC is not beginner-friendly, and those on a budget should carefully consider whether its advantages justify the added cost and printing difficulty.
PETG vs PET
PET and PETG have similar chemical structures, but PET is not commonly used in FDM 3D printing due to its high shrinkage and difficulty in processing. PETG is a modified version of PET, with glycol added to alter its molecular structure. This modification enhances PETG’s transparency, flexibility, and impact resistance, making it more suitable for 3D printing and applications that require durability and slight flexibility.
How To Print PETG Filament
PETG Print Setting
The following guidelines provide general recommendations for 3D printing with PETG filament. However, different brands may have specific optimal settings. Always refer to the manufacturer’s instructions for the best results.
| Parameter | Recommended Settings | Notes/Explanation |
|---|---|---|
| Nozzle Temperature | 220–250°C | Use lower temps (220–230°C) for simple models; higher temps (240–250°C) for complex prints. Calibrate with a temperature tower. |
| Print Bed Temperature | 70–90°C | Glass bed: 85–90°C (use glue stick); PEI sheet: 70–80°C. Disable fan for the first layer. |
| Fan Speed | 30%–50% | Turn off fan for the first 2–3 layers; increase to 60% for overhangs/bridging. |
| Print Speed | 40–60 mm/s | Reduce to 20–30 mm/s for outer walls/details; set first layer speed to 50% of total. |
| Retraction Distance | 4–6 mm (Direct Drive) | Pair with retraction speed of 35–45 mm/s; enable "Coasting" to reduce stringing. |
| 5–8 mm (Bowden) | ||
| Z-Hop Height | 0.2–0.5 mm | Minimizes stringing during travel moves. |
| Moisture Control | Store in sealed dry box (<30% RH) | Dry filament at 60°C for 4–6 hours if brittle or bubbly. |
PETG Print Common Problems and Solutions
If you encounter common issues while 3D printing with PETG filament, you can refer to the corresponding solutions below to troubleshoot and resolve them effectively.
| Issue | Root Cause | Solution |
|---|---|---|
| Warping (Corner Lift) | Low bed temp / Fast cooling | Increase bed temp to 80°C, disable first-layer fan, use an enclosure or adhesive. |
| Poor Layer Adhesion | Low nozzle temp / High speed | Increase nozzle temp by 10°C, reduce speed by 20%, check under-extrusion. |
| Over-Extrusion (Rough Surface) | High flow / Incorrect filament diameter | Calibrate filament diameter (measure 5 points), reduce flow by 3%–5%. |
| Stringing | Insufficient retraction / High temp | Increase retraction by 1 mm, lower temp by 5°C, enable Coasting and Z-Hop. |
| First Layer Detachment | Dirty bed / Nozzle too high | Clean bed (isopropyl alcohol), adjust Z-offset for slight squish (~0.1 mm). |
PETG’s future development
With the increasing global focus on environmental protection and sustainable materials, the PETG market is expected to experience steady growth in the coming years. Its recyclability and low environmental impact make it a popular choice in various industries. Market forecasts indicate that the PETG industry will expand from $2.748 billion in 2023 to $3.819 billion by 2033, driven by rising demand for eco-friendly materials.
Technological advancements are also expanding PETG’s range of applications. Researchers and manufacturers continuously develop new formulations to enhance its properties, making it suitable for more demanding environments. In the future, PETG could be compounded with other materials to improve its strength, heat resistance, and durability. These innovations may enable PETG to be used in advanced fields such as aerospace, automotive lightweight components, and high-performance industrial applications.
Frequently Asked Questions
Q: Is PETG food safe?
A: Yes, PETG is generally considered food safe and is certified by the FDA and the EU for food contact. However, not all PETG products are automatically safe for food use. Some 3D printing PETG filaments may contain additives or colorants that are not certified for food contact.
Additionally, 3D printed PETG objects have layer lines where bacteria can accumulate, making them harder to clean thoroughly. Over time, this can lead to hygiene concerns, especially with repeated use. To improve food safety, consider post-processing methods such as sealing the surface with a food-safe coating.
It is also important to use a clean, food-safe nozzle and avoid printing with materials that could leave contaminants in the printer. If you plan to use PETG for food-related applications, always check the filament specifications and ensure proper handling to minimize risks.
Q: Is petg stronger than pla?
A: Yes, PETG is stronger, more impact-resistant, and heat-resistant than PLA but slightly harder to print.
Q: What is the petg glass transition temperature?
A:The glass transition temperature (Tg) of PETG is typically 80–85°C (176–185°F). Below this temperature, PETG retains its structural integrity, while above it, the material becomes more flexible and prone to deformation under stress.