PETG

PETG stands for polyethylene terephthalate glycol-modified, a thermoplastic polyester derived from PET by incorporating glycol into the polymer chain. This modification increases toughness and processability while preserving the clarity and chemical resistance characteristic of PET.

PETG is known for its clarity and impact resistance. It is generally more transparent and tougher than PET and offers good chemical resistance to water, many solvents, and mild acids and bases. It also exhibits a favorable balance of stiffness and ductility, with a glass transition around 80 C, allowing use in a range of consumer applications.

In manufacturing, PETG is produced as sheet and film for packaging and thermoforming. It is also widely used as a filament for fused deposition modeling (FDM) 3D printing. Compared with ABS, PETG typically prints with easier bed adhesion and less warping, though it can be stringy and requires moisture control.

Printing guidelines and handling: nozzle temperatures commonly 230–250 C, bed temperatures 70–90 C, and minimal cooling on the first layers. Drying the material before printing is advisable to prevent steam and bubbles. PETG benefits from good print bed surfaces and adhesion methods such as glue stick or specialized builders plates. It is hygroscopic, so storage in a sealed container is recommended.

Applications and limitations: PETG is used for packaging, display components, consumer electronics housings, medical devices, and 3D-printed parts. While resistant to many chemicals, it can be attacked by strong solvents and UV light over long periods. It is generally recyclable within PET streams, and some grades are approved for food contact.