Glossary · Filament

PETG

A robust printing material, stronger and more heat-resistant than PLA. Good for brackets and parts that need to withstand some stress.

Explained in more detail

Glycol-modified polyethylene terephthalate, related to the material of PET bottles. Printing temperature 230 to 250 °C, bed 70 to 85 °C, moderate cooling. Tougher and more impact-resistant than PLA, dimensionally stable up to around 70 to 80 °C, with good resistance to many chemicals. Prone to stringing and sometimes sticks too strongly to smooth PEI, so use a release agent such as glue stick. Slightly hygroscopic, store dry.

Where does the term come from?

PET stands for polyethylene terephthalate, the G for glycol. In PETG a different glycol replaces part of the ethylene glycol, so the material hardly crystallises and stays clear and tough during processing.

In practice

Do not press the first layer too hard: PETG likes slightly more distance than PLA, otherwise material collects as a blob on the nozzle.
Keep part cooling at 30 to 60%, slightly more for overhangs.
Dry at 60 to 65 °C for 4 to 6 hours before printing, which clearly reduces stringing.
Remove parts from smooth PEI only after cooling, otherwise PETG can tear pieces out of the coating.
A silicone sock on the heater block prevents PETG from sticking to the nozzle and heater block.

Not to be confused

PETG is not the same as the PET of drinks bottles: without the glycol modification, PET crystallises and is much harder to process on home printers.

Frequently asked questions

What temperature does PETG need?

230 to 250 °C at the nozzle and 70 to 85 °C at the bed. The figure on the spool takes priority.

Why does PETG stick so strongly to the print bed?

On smooth PEI, PETG sometimes adheres too well. A thin film of glue stick acts as a separating layer, or you can use a textured plate.

Printers that can process PETG

According to manufacturer specifications, from the 58 printers in the wiki: