PETG-CF

PETG-CF is PETG with carbon fiber added. Compared to plain PETG it is noticeably stiffer, more dimensionally stable, and has a nice matte surface with no glare or stringing. It is essentially "engineering PETG": it keeps the base material's water and heat resistance but becomes stiffer and finishes better.

What it is good for

• Functional parts needing stiffness and stability
• Brackets, housings, frames with a premium matte finish
• Parts under moderate heat (PETG-level resistance, ~70 °C)
• Items where plain PETG is too flexible and glossy

Where NOT to use it

• A brass nozzle with no swap — carbon fiber is abrasive
• Impact loads — CF lowers toughness
• High temperature (>75 °C) — use PA-CF or ABS instead
• Transparent items — CF makes PETG matte and opaque

How to print

• Nozzle temperature: 240–270 °C
• Bed temperature: 70–90 °C
• Nozzle: hardened steel, ideally 0.5–0.6 mm
• Cooling: 30–50%
• Speed: 40–70 mm/s
• Adhesion: glue stick as a release layer (the PETG base sticks hard)

Drying and storage

PETG-CF is hygroscopic like regular PETG, plus the filler holds moisture. Drying is mandatory for good results.

• Drying: 60–70 °C for 6–8 hours
• Storage: airtight box with silica gel
• Signs of moisture: stringing, hissing, rough matte surface

Pros and cons

• Stiffer and more stable than plain PETG
• Nice matte, glare-free surface
• Keeps PETG water and heat resistance
• Strings less than plain PETG

• Needs a hardened nozzle
• Lower toughness than PETG
• Hygroscopic — needs drying
• Sticks hard to the bed