Carbon Fibre and Glass-Filled Filament: When You Need It

Carbon Fibre and Glass-Filled Filament: When You Need It

What the fibres actually do

Short chopped carbon or glass fibres added to a polymer base raise stiffness (modulus), reduce shrink and improve dimensional stability. They do not always raise tensile strength; in some materials they reduce impact resistance because the fibres create stress concentration points. The right way to think about CF and GF is 'more rigid, more stable, more brittle in thin features'.

Common CF and GF blends in stock

Material Best for
PLA-CF Stiff display parts, jigs
PETG-CF Functional brackets, tools, semi-outdoor
ABS-CF Higher-temp tooling
ASA-CF Outdoor functional parts
PA-CF (nylon) Engineering brackets, drone frames
PC-GF High-temp, high-rigidity functional

Hardware you need

  • Hardened steel or ruby nozzle (brass wears out in hours on CF)
  • All-metal hotend for the higher-temp blends (PA, PC)
  • Direct drive helps but is not strictly required
  • Enclosure required for PA-CF and PC-GF

Print settings to start with

  • Slightly hotter than the base material (5 to 10 C)
  • Slower speeds (30 to 50 mm/s)
  • Higher line widths help fibre orientation
  • Dry the spool every time, especially for PA-CF

When NOT to use CF or GF

  • Parts that need to flex or absorb impact (use TPU or tough PETG)
  • Miniatures and fine detail (fibres show on the surface)
  • Food contact

Browse the range

Carbon filled, Glass filled, CF Wrapped Filaments, PETG GF, PC GF, ABS GF.

Back to blog