PET-CF filament
Engineering composite for loaded, heat-resistant parts: brackets, gears, housings, jigs. Stiffer and more heat-resistant than PETG.
Nozzle 270–300 °C · Bed 70–90 °C
Material passport
- Enclosure
- Recommended
- Hardened nozzle
- Required
- All-metal hotend
- Required
- Drying before printing
- Recommended
Popular PET-CF lines
How to print PET-CF
PET-CF is PET (polyethylene terephthalate) reinforced with chopped carbon fiber (around 15%). Unlike familiar PETG, the base here is pure, more crystalline PET, so the material holds a higher working temperature and keeps its shape better under heat. The carbon sharply raises stiffness and dimensional stability and almost eliminates warping, but makes the filament abrasive. It is an engineering composite for loaded parts, not a beginner material.
What it is good for
- Functional loaded parts: brackets, gears, jigs
- Parts that run warm: electronics housings, under-the-hood components
- Rigid structures where dimensional stability matters
- Parts that must hold high temperature after annealing
Where NOT to use it
- Decorative and thin models — the matte carbon surface hides fine detail
- First projects on an open budget printer with no prep
- Parts that need to flex and spring back — carbon makes it stiff and brittle on bending
- Printing with a brass nozzle — carbon fiber grinds it down within a couple of spools
How to print
- Nozzle temperature: 270–300 °C
- Bed temperature: 70–90 °C
- Nozzle: hardened only (carbon fiber is abrasive), all-metal hotend
- Enclosure: an enclosure is recommended — it cuts warping and delamination on larger parts
- Cooling: low or off — for better layer adhesion
- Adhesion: glue stick or a dedicated coating on a preheated bed
Drying and storage
PET-CF is hygroscopic — it absorbs moisture from the air. Wet filament crackles while printing, bubbles, and loses strength, and since carbon already weakens the layer bond, wet stock makes it downright crumbly.
- Drying: 70–80 °C for 6–8 hours before printing
- Storage: airtight box with silica gel; ideally print straight from a dryer
- Signs of moisture: crackling and steam while printing, bubbles, a rough surface
Pros and cons
- High stiffness and dimensional stability, barely warps
- Good heat resistance; up to roughly 194 °C after annealing
- Stronger and more heat-resistant than plain PETG thanks to the pure PET base
- Matte surface that hides layer lines
- Abrasive — needs a hardened nozzle and all-metal hotend
- Hygroscopic, needs thorough drying
- Brittle on bending, poor with impact loads
- Harder to print than PETG: high temps, enclosure, not for beginners
FAQ
A hardened steel nozzle and an all-metal hotend only. The carbon fiber is abrasive and will grind down a brass nozzle within a couple of spools, and a PTFE tube won't survive 270–300 °C.