Annealing PET-CF

Annealing means heating a finished part below its melting point and letting it cool slowly. For PET-CF, it raises stiffness, strength, and heat resistance substantially.

A proven method

In independent testing, Edge of 3D used this cycle:

1. Heat the oven to 105°C.
2. Hold at 105°C for 90 minutes.
3. Cool slowly to 50°C over about 3 hours.

Every part annealed this way reached about 240–250°C in his oven heat test, no matter what temperature it was printed at. He also printed and annealed a new probe mount for one of his printers from PET-CF.

A gentler starting point

If your oven or dryer can't reach 105°C, anneal at 85°C for about 5 hours. Adjust between 80–100°C and 4–8 hours based on wall thickness and part size. A filament dryer that reaches these temperatures, such as the SUNLU FilaDryer E2, also works.

Tips

• Use an oven thermometer. Many ovens run hotter or cooler than their dial says.
• Support parts on a flat tray. Thin, unsupported features can sag slightly.
• Expect a small amount of dimensional change. Test-anneal a sample before annealing a precision part.
• Annealed parts are stiffer but more brittle. See How print temperature affects strength.