PET

Also known as Polyethylene Terephthalate

PET for 3D Printing: Balancing Clarity, Strength, and Sustainability

Polyethylene Terephthalate (PET) is a widely recognized thermoplastic, best known for its use in water bottles and food packaging. In 3D printing, PET offers a unique blend of transparency, chemical resistance, and recyclability, making it an eco-friendly alternative to traditional filaments like PLA and ABS. While not as common as its glycol-modified counterpart PETG, PET is gaining traction for specialized applications where rigidity and sustainability are priorities.

What Is PET?

PET is a lightweight, semi-rigid thermoplastic prized for its clarity, strength, and recyclability. Unlike PETG, which incorporates glycol to improve flexibility, pure PET retains a higher density and rigidity, resulting in parts with enhanced mechanical properties. Its amorphous structure minimizes warping, while its low moisture absorption (compared to PETG) reduces the need for extensive drying.

Printing with PET: Key Considerations

PET’s printing behavior balances accessibility and technical nuance. While easier to handle than ABS, it demands careful temperature control to optimize results.

Optimal Settings

• Nozzle Temperature: 230–245°C (higher than PLA but lower than PETG).

• Bed Temperature: 80–90°C (heated bed required for adhesion).

• Cooling Fan: 10–25% to maintain detail without compromising layer bonding.

• Retraction: 1–2 mm at 20–30 mm/s to minimize stringing.

Adhesion Tips

PET adheres well to PEI sheets, glass beds, or painter’s tape. Glue sticks or adhesives can further enhance bed grip.

Challenges

• Warping: Though less prone than ABS, PET may warp on large prints without a heated bed.

• Stringing: PET’s viscosity requires precise retraction tuning to avoid oozing.

• Moisture Sensitivity: While less hygroscopic than PETG, PET still benefits from dry storage to prevent print defects.

Advantages of PET

1. Strength and Rigidity: PET is denser and harder than PETG, offering superior mechanical strength for functional parts like gears or enclosures.

2. Transparency: Maintains glass-like clarity when printed slowly, ideal for display models or light diffusers.

3. Chemical Resistance: Withstands exposure to oils, acids, and alkalis, suitable for industrial or automotive components.

4. Sustainability: Recyclable and often available in recycled variants, reducing environmental impact.

5. Low Warping: Amorphous structure minimizes shrinkage, enabling large, detailed prints without an enclosure.

Limitations of PET

1. Brittleness: Pure PET is more brittle than PETG, limiting its use in high-impact applications.

2. Heat Resistance: Moderate heat tolerance (~70–80°C) makes it unsuitable for high-temperature environments.

3. Post-Processing: Cannot be smoothed with acetone, limiting aesthetic customization.

4. Printing Nuance: Requires precise temperature control to balance adhesion and surface quality.

PET vs. PETG: A Comparative Overview

Property	PET	PETG
Rigidity	Higher	Moderate
Toughness	Lower	Higher
Transparency	Excellent	Good
Moisture Resistance	Better	Lower
Print Ease	Moderate	Easier
Applications	Structural parts, transparent models	Flexible components, outdoor use

Applications of PET in 3D Printing

• Industrial Components: Durable housings, jigs, and fixtures requiring chemical resistance.

• Consumer Goods: Transparent containers, display stands, or household appliances.

• Electronics: Insulating casings for devices exposed to oils or solvents.

• Sustainable Manufacturing: Recycled PET filaments for eco-conscious prototyping.

Requirements to Print PETG

There should be no specific requirements to print PETG outside of a heated build plate unless using a special blend of it which should be noted by the manufacturer. If you want to print PEG above 240°C - then you will need an all-metal hotend.