PETG-CF · reinforced grade · default condition
PETG-CF-CF20
Properties of the CF20 condition, compared with the other PETG-CF grades.
Default commercial PETG-CF filament: best balance of stiffness, matte finish and printability on a hardened 0.4–0.6 mm nozzle.
What is PETG-CF-CF20?
PETG-CF-CF20 is PETG-CF in the CF20 grade — default commercial PETG-CF filament: best balance of stiffness, matte finish and printability on a hardened 0.4–0.6 mm nozzle. PETG-CF-CF20 has a yield strength of 50 MPa (7.25 ksi) and a tensile strength of 52 MPa (7.54 ksi) — weaker than 52% of polymer grades. Elongation at break is 4.5% and the elastic modulus is 4.2 GPa (0.609 Msi). PETG-CF-CF20 has a density of 1.32 g/cm³ (0.0477 lb/in³), heavier than 72% of polymer grades. Its glass-transition temperature is 79°C (174 °F).
Advantages
- Low, predictable mold shrinkage — 0.3%, better than 91% of polymer grades
- Stiff — 4.2 GPa (0.609 Msi), better than 86% of polymer grades
- Conducts heat well — 0.3 W/m·K (0.173 BTU/hr·ft·°F), better than 82% of polymer grades
Limitations
- Limited service temperature — 68°C (154 °F), worse than 80% of polymer grades
- Hard to polish — 30/100, worse than 80% of polymer grades
- High embodied carbon — 7 kg CO₂/kg, worse than 77% of polymer grades
- Limited ductility — 4.5%, worse than 75% of polymer grades
PETG-CF-CF20 properties
Typical room-temperature values for PETG-CF-CF20 — 11 properties are specific to this condition; the rest are grade-level values shared by every PETG-CF grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical4
PETG-CF-CF20 has a density of 1.32 g/cm³ (0.0477 lb/in³), heavier than 72% of polymer grades. Its glass-transition temperature is 79°C (174 °F).
Mechanical13
PETG-CF-CF20 has a yield strength of 50 MPa (7.25 ksi) and a tensile strength of 52 MPa (7.54 ksi) — weaker than 52% of polymer grades. Elongation at break is 4.5% and the elastic modulus is 4.2 GPa (0.609 Msi).
Thermal11
PETG-CF-CF20 is rated for continuous service to 68°C (154 °F). It conducts heat at 0.3 W/m·K (0.173 BTU/hr·ft·°F), better than 82% of polymer grades. Thermal expansion is 40 µm/m·K (22.2 µin/in·°F).
Electrical2
Chemical & Environmental3
Corrosion resistance is very good (78/100), worse than 64% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PETG-CF-CF20 takes about 110 MJ of energy and emits 7 kg of CO₂ — more than 64% of polymer grades. Typical recycled content is 5%.
Manufacturability8
PETG-CF-CF20's machinability is good (62/100, better than 59% of polymer grades); weldability fair (45/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other PETG-CF grades and fills
PETG-CF is also supplied in 4 other conditions. The full side-by-side table is on the PETG-CF overview.
- CF20DefaultDefault commercial PETG-CF filament: best balance of stiffness, matte finish and printability on a hardened 0.4–0.6 mm nozzle.52 MPa tensile
- CF30Choose for maximum stiffness and dimensional stability in jigs, fixtures and drone/RC frames; accept brittle behaviour and fast nozzle wear.56 MPa tensile
- CF10Pick when you want the matte CF look and reduced warping but need more ductility and gentler nozzle wear.48 MPa tensile
Working with PETG-CF-CF20
Is PETG-CF easy to machine?
Drills, mills and taps easily at high speed with sharp carbide and light feeds; carbon fiber is abrasive and dust should be extracted, and keep tools cool to avoid smearing near Tg.
Can PETG-CF be welded?
Hot-plate, hot-gas and ultrasonic welding work on the matrix but fiber at the joint cuts strength; solvent/adhesive bonding needs sanding plus cyanoacrylate or epoxy since PETG resists most solvents.
Can PETG-CF be formed, bent or molded?
Print at 240–260 °C nozzle / 70–85 °C bed with a hardened steel or ruby nozzle ≥0.4 mm, dry the filament 4–6 h at 65 °C, and use slow first layers and generous cooling; injection molding requires drying and low shear to preserve fiber length.
What surface finishes work on PETG-CF?
Comes out matte black and hides layer lines well; sand or bead-blast for uniformity, avoid solvent vapor smoothing (PETG does not respond), and paint only after abrasion plus adhesion primer.
PETG-CF chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| carbon fiber (chopped/milled PAN-based)primary reinforcement; sets stiffness and abrasiveness | 5 – 30 | 18 |
| processing aids / lubricants / pigmentdispersants, chain extenders, carbon black for colour | 0.5 – 3 | 1.5 |
| PETG (glycol-modified PET copolyester, Camorphous copolyester matrix | ≥ 70 (balance) | — |
PETG-CF-CF20 — frequently asked
What is PETG-CF-CF20 used for?
PETG-CF-CF20 is typically used for functional brackets, enclosures and tooling. In short: stiff carbon-filled PETG.
What is the yield strength of PETG-CF-CF20?
PETG-CF-CF20 has a typical yield strength of 50 MPa (7.25 ksi) and a tensile strength of 52 MPa (7.54 ksi) — weaker than 52% of polymer grades. Strength varies by condition: see the 5 listed tempers.
Is PETG-CF-CF20 easy to machine?
Reasonably — machinability is rated good (62/100, better than 59% of polymer grades). Drills, mills and taps easily at high speed with sharp carbide and light feeds; carbon fiber is abrasive and dust should be extracted, and keep tools cool to avoid smearing near Tg.
Can PETG-CF-CF20 be welded?
With care — weldability is rated fair (45/100). Hot-plate, hot-gas and ultrasonic welding work on the matrix but fiber at the joint cuts strength; solvent/adhesive bonding needs sanding plus cyanoacrylate or epoxy since PETG resists most solvents.
What surface finishes work on PETG-CF-CF20?
Comes out matte black and hides layer lines well; sand or bead-blast for uniformity, avoid solvent vapor smoothing (PETG does not respond), and paint only after abrasion plus adhesion primer.
Can PETG-CF-CF20 be formed, bent or molded?
Print at 240–260 °C nozzle / 70–85 °C bed with a hardened steel or ruby nozzle ≥0.4 mm, dry the filament 4–6 h at 65 °C, and use slow first layers and generous cooling; injection molding requires drying and low shear to preserve fiber length.
What is the maximum service temperature of PETG-CF-CF20?
PETG-CF-CF20 is rated for continuous use to about 68°C (154 °F), and briefly to 85°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PETG-CF-CF20?
Yes — PETG-CF-CF20 is available for 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- PETG-CF filament technical data sheet — Bambu Lab (2024)
- CarbonX PETG+CF carbon fiber PETG filament TDS — 3DXTech (2023)
- PETG-CF / PolyLite PETG technical data — Polymaker (2024)
- Eastar / Eastman copolyester (PETG) product data — Eastman Chemical (2022)
- Copolyester and short-fiber compound property records — CAMPUS Plastics (2024)
- ASTM D638 / D790 / D256 test methods for plastics — ASTM International (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.