A Comprehensive Guide to PETG Filament Temperature

PETG (Polyethylene Terephthalate Glycol) filament has become a favorite among 3D printing enthusiasts and professionals for its unique balance of strength, flexibility, and ease of use. Offering durability comparable to ABS and printability similar to PLA, PETG is a versatile material suitable for a wide range of applications, from functional prototypes to outdoor items. However, achieving perfect PETG prints requires precise temperature control for both the hotend and the heated bed. In this comprehensive guide, we’ll explore key printing tips for PETG and provide recommended temperature settings for popular PETG filament brands to help you optimize your 3D printing experience.

Hotend Temperature Management

The hotend temperature is crucial for PETG because it directly affects filament flow, layer adhesion, and print quality. PETG generally requires a nozzle temperature between 220°C and 260°C, depending on the brand and your printer’s setup. Here’s how to optimize hotend temperature:

Start with Manufacturer Recommendations: Always check the filament manufacturer’s suggested temperature range, typically printed on the spool or packaging. This provides a reliable starting point.

Print a Temperature Tower: Since optimal temperatures vary by brand and printer, print a temperature tower (available on platforms like Thingiverse) to test a range of temperatures in 5°C increments. Look for signs of under-extrusion (gaps, weak layer adhesion) or over-extrusion (stringing, oozing, blobbing) to dial in the ideal setting.

Avoid Excessive Heat: Printing too hot (above 260°C) can lead to stringing, oozing, or even filament degradation due to hydrolysis, especially if the filament is moist. Hydrolysis occurs when moisture in the filament turns to steam at high temperatures, weakening the material.

Consider Your Hotend Type: PETG can often be printed with PTFE-lined hotends (up to 240°C), but an all-metal hotend is recommended for temperatures above 240°C to avoid degrading the PTFE liner and releasing toxic fumes.

Adjust for Stringing: PETG is prone to stringing due to its low viscosity when melted. If stringing occurs, lower the hotend temperature by 5°C increments and increase retraction settings in your slicer. 

Heated Bed Temperature

A heated bed is highly recommended for PETG to ensure proper first-layer adhesion and minimize warping. The ideal bed temperature typically ranges between 60°C and 90°C, though some brands may require slightly higher settings. Key tips for bed temperature include:

Use a Heated Bed for Best Results: While PETG can technically be printed without a heated bed using adhesives like glue stick or blue painter’s tape, a heated bed set to 60–90°C significantly improves adhesion and reduces warping, especially for larger prints.

Start with an Initial Higher Bed Temperature: For the first layer, consider setting the bed temperature 5–10°C higher (e.g., 85–90°C) to enhance adhesion, then lower it to the standard range (e.g., 75–80°C) for subsequent layers to prevent over-adhesion or “elephant’s foot” (a bulging first layer).

Choose the Right Build Surface: PETG adheres strongly to most surfaces, which can be both an advantage and a challenge. Avoid smooth PEI sheets, as PETG may bond too tightly and damage the surface upon removal. Textured PEI, glass with glue stick, or blue painter’s tape are excellent choices. Apply a thin layer of glue stick or hairspray to glass beds to act as a release agent.

Clean the Bed: Before printing, clean the build surface with isopropyl alcohol or warm water with dish soap to remove grease and debris, ensuring optimal adhesion.

How to Find The Perfect Temp

Even if you have the recommended 3D printing temperatures from both the filament and printer manufacturers, you may still encounter issues. The most reliable way to determine the optimal PETG filament temperature is through trial and error.

We can conduct multiple tests and compare the results. It's best to keep the 3D print speed low. If you notice stringing on the printed model or clumping around the nozzle, the nozzle temperature may be too high. Conversely, if you see an "elephant's foot" on the print due to excessive adhesion to the hot bed, the bed temperature may be too high.

A quick way to test different 3D printing temperatures is by using a temperature tower. You can modify the G-code file to set different temperatures for each layer of the tower.

Key Printing Tips for PETG

To achieve high-quality PETG prints, proper setup and fine-tuning are essential. PETG’s unique properties, such as its low shrinkage, excellent layer adhesion, and tendency to stick well to print surfaces, make it forgiving in some ways but challenging in others. Below are critical tips to ensure successful PETG printing.

1. Cooling and Fan Settings

Cooling is critical for PETG to balance detail and strength: 

Moderate Cooling: Unlike PLA, PETG doesn’t require aggressive cooling. Set the cooling fan to 30–60% speed to prevent stringing and improve surface detail without compromising layer adhesion. For maximum strength, consider turning the fan off entirely after the first few layers, though this may increase stringing. 

First Layers Without Cooling: Disable the cooling fan for the first 2–3 layers to promote better bed adhesion and prevent warping. After that, gradually increase fan speed to 50% for optimal results.

2. Print Speed and Retraction

Print Speed: PETG prints best at speeds of 40–60 mm/s for standard printers. Faster speeds (up to 80 mm/s) are possible with well-tuned printers, but slower speeds reduce stringing and improve layer adhesion. For intricate first layers, reduce speed to 15–20 mm/s.

Retraction Settings: PETG’s low viscosity makes it prone to stringing. Increase retraction distance (e.g., 0.5–2 mm) and speed (e.g., 30–50 mm/s) in your slicer to minimize oozing. Test and adjust based on your printer’s performance.

3. Environmental Considerations

Use an Enclosure for Large Prints: PETG is less prone to warping than ABS, but an enclosure helps maintain a stable ambient temperature (20–40°C) for large or complex prints, reducing thermal stress.

Keep Filament Dry: PETG is hygroscopic and absorbs moisture, which can cause bubbling, poor layer adhesion, and brittleness. Store filament in an airtight container with desiccant, and dry it (e.g., at 65°C for 8 hours) before printing if it’s been exposed to humidity.

4. Post-Processing and Adhesion Challenges

Prevent Over-Adhesion: PETG’s strong bed adhesion can make print removal difficult. Use a glue stick or hairspray as a release agent, and allow the bed to cool completely before removing prints to avoid damaging the build surface or print.

Sanding and Finishing: PETG is softer than ABS and doesn’t sand as easily. Wet or dry sanding is possible, but avoid chemical smoothing (e.g., acetone), as it doesn’t work with PETG. Choose the correct filament color, as PETG doesn’t bond well with paints.

3D Print Temperatures for Popular PETG Filament Brands

Different PETG filament brands have unique formulations, affecting their optimal printing temperatures. Below are recommended hotend and bed temperature ranges for some of the most popular PETG filament brands, based on manufacturer guidelines and user feedback. Always start with the manufacturer’s recommendations and fine-tune with test prints like temperature towers.

Prusament PETG:

Hotend Temperature: 230–250°C (default 250°C for Prusa printers)

Bed Temperature: 80–90°C (85°C for the first layer, 80°C for subsequent layers)

Notes: Prusament PETG is known for low stringing when using PrusaSlicer’s optimized profiles. Avoid smooth PEI sheets to prevent over-adhesion.

Hatchbox PETG:

Hotend Temperature: 230–260°C (optimal around 235–245°C)

Bed Temperature: 70–85°C (80°C is a common starting point)

Notes: Hatchbox offers a wide range of colors, including transparent and glow-in-the-dark options. Its higher temperature range may require an all-metal hotend for best results.

Overture PETG:

Hotend Temperature: 230–250°C (optimal around 235–245°C)

Bed Temperature: 70–85°C

Notes: Overture is a budget-friendly option with consistent quality. It includes a resealable bag and a BuildTak-style surface for convenience. Test retraction settings to minimize stringing.

Polymaker PolyLite/PolyMax PETG:

Hotend Temperature: 230–240°C (PolyLite), 230–250°C (PolyMax)

Bed Temperature: 70–80°C

Notes: Polymaker’s PETG uses Pantone color shading for consistency, ideal for prints where color matters. PolyMax is slightly stronger but has fewer color options. Suitable for PTFE-lined hotends at lower temperatures.

SUNLU PETG:

Hotend Temperature: 235–245°C

Bed Temperature: 70–85°C

Notes: SUNLU PETG is a cost-effective choice with reliable performance. It’s sensitive to moisture, so drying is critical for consistent extrusion.

Filamatrix PETG:

Hotend Temperature: 220–260°C (varies by specific copolymer formulation)

Bed Temperature: 70–90°C

Notes: Filamatrix emphasizes high-quality adhesion and extrusion. Start at the lower end of the temperature range for smaller prints and increase for larger or complex models.

Kingroon PETG:

Hotend Temperature: 230–250°C

Bed Temperature: 70–90°C

Notes: Optimized for high-speed printing, reduces oozing and clumping. Dry thoroughly before use (65°C for 8 hours) to maintain quality, especially for long prints.

General Guidelines for Temperature Tuning

Start in the Middle: Begin with the midpoint of the recommended temperature range (e.g., 240°C for hotend, 80°C for bed) and adjust in 5°C increments based on print quality.

Test with Calibration Prints: Use temperature towers and calibration cubes to identify the best settings for your specific filament and printer. Look for smooth extrusion, minimal stringing, and strong layer adhesion.

Environmental Adjustments: In cooler environments (below 20°C), slightly increase hotend and bed temperatures. In warmer settings (above 30°C), reduce temperatures to avoid overheating and stringing.

Conclusion

PETG filament offers an excellent balance of strength, flexibility, and printability, making it a go-to material for both hobbyists and professionals. By carefully managing hotend and bed temperatures, along with cooling, print speed, and retraction settings, you can unlock PETG’s full potential for high-quality, durable prints. Always refer to the manufacturer’s recommended temperature ranges for your specific filament brand and fine-tune with test prints to account for your printer’s unique characteristics. With the tips and temperature guidelines provided in this article, you’re well-equipped to achieve perfect PETG prints for a wide range of applications, from functional parts to outdoor projects. Happy printing!