PETG
Also known as Polyethylene Terephthalate Glycol
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Also known as Polyethylene Terephthalate Glycol
Last updated
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This glycol-modified version of PET plastic combines the best traits of its counterparts, offering ease of use and versatility. Whether you’re crafting functional prototypes or parts requiring chemical resistance, PETG is a filament worth mastering. Let’s explore what makes it a favorite among makers and professionals alike.
PETG is a thermoplastic derived from PET (the same plastic used in water bottles), modified with glycol to enhance flexibility and reduce brittleness. This adjustment makes it more suitable for 3D printing, as it improves layer adhesion and reduces shrinkage during cooling. PETG’s unique blend of properties bridges the gap between PLA’s user-friendliness and ABS’s higher heat resistance, making it ideal for projects that demand both slightly higher heat resistance, chemical resistance, and practicality.
Printing with PETG is straightforward but requires attention to detail. Unlike PLA, which thrives with minimal setup, PETG benefits from precise temperature control. A nozzle temperature between 220–260°C and a heated bed at 70–85°C ensure optimal layer bonding. While PETG doesn’t warp as aggressively as ABS, a heated bed is still recommended to prevent lifting.
Adhesion can be tricky: too little, and prints detach; too much, and they fuse to the bed. Solutions like glue sticks, painter’s tape, or PEI sheets strike the right balance. PETG’s tendency to ooze and string demands careful retraction settings—1–2 mm at 20–30 mm/s—to keep surfaces clean. Faster travel times to prevent oozing is recommended. A silicone nozzle sock helps prevent filament buildup, while slower first-layer speeds (20–30 mm/s) improve bed adhesion.
PETG’s popularity stems from its well-rounded strengths.
Chemical resistance is a standout feature. PETG withstands exposure to acids, alkalis, oils, and UV light, making it ideal for outdoor applications like garden tools, automotive components, or UV-exposed signage. Some variants are even FDA-approved for food contact, though certifications should always be verified for safety.
Transparency adds to PETG’s appeal. Unlike many opaque filaments, it retains a glass-like clarity when printed slowly, perfect for light diffusers, vases, or display models. Combined with low warping and excellent layer adhesion, PETG is a forgiving material for both beginners and experts.
No material is perfect, and PETG has its quirks. Stringing and oozing are common challenges, requiring meticulous retraction tuning and travel speed adjustments. Post-processing options are limited compared to ABS, as PETG can’t be smoothed with acetone.
PETG is also generally not impact resistant - meaning it can shatter when dropped - depending on the manufacturer's formula.
PETG occupies a unique niche in the 3D printing ecosystem. It outperforms PLA in heat resistance (withstanding up to 80°C) but lacks ABS’s higher temperature tolerance (100–110°C) and lacks high impact resistance. Unlike TPU, PETG isn’t flexible but offers greater rigidity for structural parts. Its chemical resistance surpasses both PLA and ABS, while its transparency rivals specialized filaments like clear ABS.
PETG’s versatility shines across industries. Hobbyists use it for durable phone cases, tool handles, and cosplay props. Engineers rely on it for functional prototypes, mechanical parts, and robotics components. In food-related applications, PETG’s potential for food safety (when final print is certified) suits it for kitchen utensils or storage containers.
