Carbon Fiber Filament Explained: What the Fibers Add and Cost

Who this guide is for

You've seen "CF" on a spool and want to know what it actually changes, whether your printer can handle it, and which base plastic fits the part you have in mind. This guide explains what filament and printer makers publish about carbon fiber: the gains, the costs, how PLA-CF, PETG-CF, PET-CF, and nylon CF differ, and the setup each one needs.

Everything below comes from documentation published by Prusa, Bambu Lab, Polymaker, ELEGOO, Siraya Tech, SUNLU, and Creality. We haven't printed these materials for this page. Where we quote a figure, it describes one maker's product under that maker's test conditions. "CF" isn't a standard grade, so fiber content and behavior differ between brands. For specific spools, see our carbon fiber filament shortlist.

What does carbon fiber add to filament?

Makers mostly agree on the benefits, though each puts it in its own words.

• Stiffness. Prusa's composites guide says fibers are mixed into polymers "to improve their mechanical properties" and that they increase "tensile yield strength". Bambu Lab's PLA-CF page quotes "a stiffness of 3950 MPa" and calls PLA-CF suitable for "functional and load-bearing parts that resist bending." Polymaker says the 17% fiber in Fiberon PET-CF17 "delivers a high modulus for excellent stiffness and dimensional stability."
• Dimensional stability and less warping. Prusa says fibers improve dimensional stability and make the material "less susceptible to warping." Bambu Lab credits PLA-CF's "low shrinkage and excellent warping resistance," ELEGOO says carbon fiber "minimizes warping and shrinkage" in its PLA-CF, and Prusa says its PC Blend Carbon Fiber shrinks less than 1% when annealed.
• A matte finish that hides layer lines. Bambu Lab says the fiber "effectively conceals layer lines," Polymaker describes "a beautiful matte black finish with virtually invisible layer lines" for PolyLite PLA-CF, and ELEGOO says its PETG-CF's "fine matte texture" reduces visible layer lines. Prusa even says Prusament PETG Carbon Fiber is filled with fibers "just for aesthetic purposes."
• Heat resistance, sometimes. Prusa says fibers increase "high-temperature resistance," and lists better heat resistance among the pros of composites. Whether that shows up depends on the base plastic, and in some data it doesn't (see the next section).
• Lighter parts. Prusa says fibers make the material "lightweight," and lists "Lighter than unmodified Prusament PC Blend" as a pro of its PC Blend Carbon Fiber.

What are the downsides of carbon fiber filament?

Prusa's composites guide lists the cons plainly: "A hardened steel nozzle is needed," "Filament more brittle," "Worse layer-to-layer adhesion," and "Higher risk of nozzle clogging." It adds that fibers "usually" decrease "Charpy impact resistance and layer-to-layer adhesion," and that some cheap composites suffer "often nozzle clogging, oozing, and filament breaking."

• Abrasion. Prusa says "carbon, glass and kevlar fibers are highly abrasive." Polymaker's data sheets for Fiberon PETG-rCF08 and its three Fiberon nylons estimate brass nozzle life at "approximately 9h." Bambu Lab says the nozzle and extruder gears "require more frequent maintenance," and that rough or abrasive materials such as carbon fiber "can eventually grind down" the PTFE feed channels inside its AMS units.
• Brittle filament. Polymaker says "carbon fiber and glass fiber filament is more brittle," and that's why it winds Fiberon on a larger spool core. Prusa lists "Breakable filament (unlike Prusament PC Blend)" as a con of its PC Blend Carbon Fiber. Siraya Tech says carbon fiber makes its PET-CF "more brittle," so it can break in an AMS feed path.
• Impact resistance. Bambu Lab's material table rates PA-CF/GF lower than plain PA for impact resistance, even though it rates it higher for heat deflection and tensile strength. PET-CF/GF shares the table's lowest impact rating with PVA. Polymaker says annealing its PET-CF17 "does not enhance impact resistance or layer adhesion. This means the material does not become tougher after annealing."
• Layer adhesion. Polymaker's product pages define the Z direction as "between the layers (layer adhesion)." In every data sheet we checked that publishes both, the Z tensile strength figure is below the X-Y figure. Bambu Lab tells PLA-CF users to orient parts "to avoid receiving force on the layer direction," because "The XY axis offers better strength for load-bearing parts."

Where makers disagree

Not every maker accepts the trade-offs above for its own product:

• Siraya Tech claims its Fibreheart PETG-CF Pro HF, which uses chopped fiber rather than "powdered carbon fiber," is "tougher, more heat-resistant" than standard PETG-CF, and its product page lists "Significantly higher impact resistance" among the filament's features.
• Prusa says its PC Blend Carbon Fiber has "better tensile strength and toughness" than unmodified PC Blend.
• Polymaker claims "Superior Layer Adhesion" for Fiberon PA6-CF20, and SUNLU claims "excellent layer adhesion" for its PA6-CF.
• ELEGOO says its PETG-CF has "superior toughness" compared with PLA-CF and "is less prone to fracture under external stress and impact."

These are claims about specific products, so don't read them as rules for the whole category.

One maker's data, with and without fiber

Product claims are easy to make. The clearest test is one maker's data sheets for the same base plastic with and without fiber. Polymaker publishes both for PolyLite PLA and PolyLite PLA-CF, in the same data sheet version (V5.4), with the same test methods and the same specimen settings: 230 °C nozzle, 50 °C bed, 100% infill, fan on.

Polymaker's product page says the fiber "delivers exceptional rigidity and strength," but its own data sheets tell a mixed story. On those figures, PolyLite PLA-CF is slightly stiffer in bending and has a higher notched impact figure. It has a slightly lower tensile modulus, much lower tensile strength (especially between layers), and a lower heat deflection temperature than PolyLite PLA. That's one maker and one pair of products, and other brands' PLA-CF may behave differently. It does show why you should read the data sheet rather than assume "CF" means stronger. Our guide to which filament is strongest reads other makers' data sheets the same way, one maker at a time.

Base polymers: what each maker says about heat, moisture, and drying

Here are the heat figures makers publish for the carbon-fiber products in our catalog. The spread between base plastics is far wider than the gap between PolyLite PLA and PolyLite PLA-CF above. In every data sheet here that gives HDT (heat deflection temperature) at both loads, the 0.45 MPa figure is higher than the 1.8 MPa one, and Siraya Tech's and Polymaker's PET-CF documents show annealing raising HDT. Compare figures only at the same load and condition.

PLA-CF

PLA-CF is the easy entry point. Bambu Lab's filament guide says PLA and its CF/GF grades are "Not prone to warping" and suit "Open-frame or enclosed" printers, and Polymaker says PolyLite PLA-CF "will print on any stock printer" apart from needing a hardened nozzle. The catch is heat: Bambu Lab says PLA is "Not recommended for environments at about 50 ℃ or higher," and the PLA-CF figures above sit in the 50s.

Drying advice differs:

• Bambu Lab lists drying PLA-CF as "Recommended," at 55 ℃ for 8 hours in a blast drying oven, with desiccant during use "Optional."
• Polymaker's data sheet gives 55 °C for 6 hours.
• ELEGOO is stricter, listing drying as "Required" at 50 ± 5 °C for 8 hours, and printing and storage at or below 20% RH, sealed with desiccant.

Our ELEGOO PLA-CF vs PolyLite PLA-CF comparison puts two of these spools side by side, and our PLA-CF vs PETG-CF guide compares the two easiest CF grades.

PETG-CF

Bambu Lab's guide gives PETG and PETG-CF the same 240–270 °C nozzle range and the same heat deflection rating. It says PETG-CF works on open-frame printers but adds: "For PETG and PETG-CF/GF, an enclosed printer is recommended to prevent low ambient temperatures from reducing the model's interlayer strength." Its PETG-CF product page goes further and says to "Avoid using an open-frame printer" for stronger Z-axis adhesion, and not to set the cooling fan "too high, as overcooling can weaken layer bonding." Siraya Tech's FAQ calls an enclosure "highly recommended" for its PETG-CF Pro HF, while its data sheet says "Not mandatory, but it is recommended."

PETG-CF needs drying, but the makers' settings differ:

• Bambu Lab describes its PETG-CF as "highly moisture-absorbent," but its own drying figures differ: its filament guide lists 70 ℃ for 8 hours, the PETG-CF data sheet 65 °C for 8 hours in a blast drying oven, and its drying guide 60–65 °C for 8 hours in a forced-air oven.
• Polymaker says Fiberon PETG-rCF08 "is sensitive to moisture" and should be stored and used below 20% RH, with drying at 65 °C for 3 hours.
• Siraya Tech gives 70–80 °C for 4–6 hours.
• ELEGOO's specification table says 60 ± 5 °C for 8 hours, but one note elsewhere on the page gives 70 °C.

For two PETG-CF spools head to head, see ELEGOO PETG-CF vs Siraya Tech PETG-CF Pro HF.

PET-CF

PET and PETG are different plastics. Siraya Tech's data sheets list its PETG-CF as "Glycol-modified Polyethylene Terephthalate" and its PET-CF as "Polyethylene terephthalate" plus 15% carbon fiber. PET-CF runs hotter, at 270–300 °C for Polymaker's Fiberon PET-CF17 and 280–320 °C for Siraya Tech's Fibreheart PET-CF, and it holds much more heat after annealing.

The makers describe moisture very differently. Polymaker says PET-CF17 is "less sensitive to moisture" than many engineering filaments, and its print settings say to dry at 100 °C for 10 hours "Only if the material has absorbed moisture." The printing tips on the same page don't add that condition: "Dry at 100°C for 10 hours and keep the filament dry during use." Siraya Tech says its PET-CF ships dried and sealed and "can be used directly without drying," though its product page says to dry it at 90 °C for 4–6 hours before printing. Bambu Lab's guide is the strictest. It lists drying PET-CF/GF as "Required," at 80 ℃ for 8–12 hours, with desiccant "Required" during use. Our Fiberon PET-CF17 vs Siraya Tech PET-CF comparison sets the two PET-CF spools side by side.

Nylon (PA) CF: PA6, PA12, PA612, and PAHT

Nylon CF grades have the highest heat figures above, but they're the most demanding. Bambu Lab lists PA-CF/GF and PAHT-CF/GF drying as "Required," at 80 ℃ for 8–12 hours, with desiccant "Required" during use. Every nylon maker here calls for drying and dry storage:

• Polymaker gives 100 °C for 10 hours and storage below 20% RH for all three Fiberon nylons. It says PA12-CF10 "absorbs significantly less moisture than PA6/66 and PA6-based materials," and that PA612-CF15 has "significantly lower moisture sensitivity than traditional PA6/66 and PA6-based nylons." Its PA6-CF20 data sheet shows what water does: X-Y tensile strength falls from 109.3 MPa dry to 54.7 MPa after moisture conditioning, on annealed specimens.
• SUNLU says "Nylon 12 is the lowest water absorption of nylon consumables," but still says to dry PA12-CF once the bag has been open 6 hours, at 80 °C for 12 hours or 110 °C for 4 hours. It says to dry PA6-CF before use at 80 °C for 24 hours or 110 °C for 4 hours. Our Fiberon PA12-CF10 vs SUNLU PA12-CF comparison covers the two PA12-CF spools.
• ELEGOO lists drying PAHT-CF as "Required," at 80 ± 5 °C for 8 hours.
• Bambu Lab says its PAHT-CF is "highly sensitive to humidity" and should be dried at 80 °C for 12 hours before printing.

Makers also disagree on how warm nylon CF should print. Polymaker runs its Fiberon nylons on a 40–50 °C bed with the fan off, and says "an actively heated chamber is not required." Its FAQ explains that for its Warp-Free technology to work, "we want to make sure the build plate and the ambient air temperatures are both below 50˚C." ELEGOO and Bambu Lab both require an enclosed printer for their PAHT-CF, and ELEGOO lists a 45–60 °C chamber and a 90–110 °C bed. Our PA6-CF20 vs PAHT-CF comparison looks at those two approaches side by side.

Other base plastics come in CF versions too, including ASA-CF and PC-CF. Our carbon fiber filament shortlist covers ELEGOO ASA-CF and Prusament PC Blend Carbon Fiber.

What nozzle do you need for carbon fiber filament?

Every maker here calls for a wear-resistant nozzle, but they word it differently:

• Bambu Lab: a hardened steel nozzle is "Required" for PLA-CF/GF, PETG-CF, PA-CF/GF, PET-CF/GF, and other fiber grades. Its guide says not to use stainless steel or brass, because "Their hardness is insufficient." Its PLA-CF and PETG-CF product pages put it more softly: "Stainless Steel Nozzle NOT Recommended."
• Prusa: "it is necessary to use a hardened nozzle."
• Polymaker: its PETG-rCF08 and Fiberon nylon data sheets say "A wear-resistance nozzle, such as hardened steel and ruby nozzle, is highly recommended," and its product pages say "0.4mm+ hardened nozzle required."
• Siraya Tech: "Carbon hardened, hardened steel or higher grade nozzles," and its PETG-CF Pro HF FAQ says "A hardened steel or ruby nozzle is required."
• ELEGOO: "Hardened Steel Nozzle, ≥ 0.4 mm."
• SUNLU: "wear-resistant nozzles, e.g. hardened steel nozzles."

Makers agree on a minimum size, but not on the best size:

• Bambu Lab says not to use a 0.2 mm nozzle because "The clogging risk is extremely high." It names a 0.6 mm hardened nozzle as the "First choice" for fiber-filled filaments and a 0.4 mm as second choice (0.15–0.3 mm layers, about 100 mm/s maximum), though it calls the 0.4 mm "highly recommended" for its own PLA-CF and PETG-CF. Its PETG-CF product page instead says a 0.6 mm hardened nozzle "is recommended to further reduce the risk of clogging." Its PAHT-CF page says "0.6 mm Nozzle Recommended."
• Prusa calls a 0.4 mm nozzle and 0.2 mm layer height "The lowest optimal values."
• ELEGOO says its PETG-CF and PAHT-CF are not compatible with 0.2 mm nozzles.
• Siraya Tech recommends 0.4–1.0 mm, and at least 0.6 mm for high-speed PET-CF.

Polymaker's nozzle guide notes that hardened steel "Requires higher nozzle temperatures due to reduced thermal conductivity," so start from the filament maker's range and adjust carefully. For nozzle materials, fit, and wear signs, read our abrasive filament nozzle guide and nozzle sizes guide.

Enclosure and chamber

Bambu Lab explains why it wants enclosures for these grades: they "Require higher heatbed and chamber temperatures to suppress warping and layer separation, and to ensure sufficient interlayer strength." An enclosure isn't ventilation, though. Our enclosure planning guide covers what one does and doesn't do.

Does annealing make carbon fiber parts tougher?

Annealing means baking a finished print in an oven so the plastic can crystallize. Some Bambu Lab data sheets, such as PAHT-CF's, give heat figures from annealed specimens, while Polymaker's Fiberon sheets put their annealing note under the mechanical tables only, so check which applies to the figure you're reading.

• Polymaker PET-CF17: the data sheet's mechanical test specimens were annealed at 120 °C for 10 hours, and Polymaker "strongly recommend[s]" that cycle. Its FAQ says annealing raises HDT "from around 70°C to over 100°C," but "mainly increases the stiffness (modulus)" and "does not enhance impact resistance or layer adhesion." Its print settings offer 100 °C for 14 hours for parts with large overhangs or thin sections, and its printing tips say to let the print rest for more than 24 hours, or hold it at 80 °C for 2 hours, before annealing. In a reply labelled Polymaker on the product page, it adds that "annealing is only required if you need added heat resistance, not mechanical improvements."
• Polymaker nylons: all three Fiberon nylon data sheets recommend annealing at 100 °C for 16 hours, and the product pages recommend "Moisture conditioning after Annealing," because "When you anneal in a convection oven, you will dry the part out."
• Siraya Tech PET-CF: its data sheet shows annealing raising HDT from 76.6 °C to 118 °C at 1.8 MPa and Young's modulus from 5950 to 6700 MPa. The Charpy impact figure falls from 9 to 4.8 kJ/m² (ISO 179). Siraya Tech says the filament "can be used right off the spool without annealing," and suggests 90–100 °C for 4–6 hours "if you need to enhance its hardness," warning of "potential shrinkage."
• Prusament PC Blend Carbon Fiber: Prusa says annealing raises temperature resistance from 114 °C to 130 °C. Preheat the oven to 140 °C, put the part in for 120 minutes, then let it cool to room temperature.

Annealing changes dimensions and can warp thin parts, so test on a scrap print first. Polymaker suggests keeping the oven temperature uniform and not loading the part during the cycle.

AMS and other automatic feeders

Bambu Lab's AMS guidance is the most detailed, and it splits Bambu's own CF filaments from everyone else's:

• Notes for AMS: avoid "third-party fiber reinforcement materials (PA-CF/GF, PET-CF/GF, PLA-CF /GF, etc.)" because they "may wear AMS PTFE tubes" and cause "brittle breaks." Bambu Lab says its own "PLA-CF, PETG-CF, PAHT-CF and other official filaments are specially optimized."
• Filament guide: lists "certain brands of" PET-CF, PA-CF/GF, and PAHT-CF/GF as "Too brittle," and certain brands of PET-CF, PA-CF/GF, PAHT-CF/GF, and PLA-CF/GF as "Too hard and rough." Its compatibility table shows PLA-CF/GF as "Bambu PLA-CF: Compatible," PETG-CF as compatible with the AMS but "Not Recommended" for the AMS lite, PA-CF/GF as "Bambu PA-CF, PAHT-CF Compatible," and PET-CF/GF as "Not Compatible."
• Product pages: Bambu PLA-CF is "All AMS Series Compatible." Bambu PETG-CF and PAHT-CF are compatible with the AMS 2 Pro, AMS HT, and AMS, and "AMS lite NOT Compatible."

Filament makers' own statements:

• Siraya Tech doesn't recommend its PET-CF for the AMS, because it "can break inside the AMS feed path," and suggests a direct-drive extruder or loading it manually. Its FAQ says its PETG-CF Pro HF "is rigid enough for smooth loading in systems like the AMS."
• Polymaker says its spools fit the AMS, but "you will need to be careful when using any abrasive materials in the AMS." That's about the spool, not the filament.
• ELEGOO offers a printable spool ring that it says helps the spool "adapt to AMS," which is also about the spool. ELEGOO, SUNLU, and Prusa don't say their CF filaments are AMS compatible on the pages we checked.

When a filament maker says a filament will feed and the printer maker says it shouldn't, follow the printer maker's guidance. Our AMS filament compatibility guide covers the external spool route.

Which printers suit them

Printer fit comes down to three things: a hardened nozzle, a hotend hot enough for the filament, and, for the engineering grades, an enclosure. These notes come from printer makers' documentation and our printer pages:

• Open-frame Bambu Lab printers (A series, P1P): Bambu Lab's guide marks PLA-CF/GF and PETG-CF "Compatible," and PA-CF/GF and PET-CF/GF "Not Recommended." The A1 FAQ says the stock A1 nozzle is stainless steel, so you need to "replace the nozzle with a hardened steel material" before printing CF filaments. It also says PA-CF/GF and PET-CF/GF are not recommended on the A1 for large or high-infill parts that need high interlayer strength, though they "can be used on A1 for printing small-sized models with low infill densities." Bambu Lab also says "We don't recommend enclosing the A1."
• Enclosed Bambu Lab printers: the guide lists the H2 series, X2D, P2S, X1 series, and P1S as enclosed printers and marks them "Recommended" for PA-CF and PET-CF. Our catalog lists a 300 °C maximum hotend temperature for the P1S, P2S, and X1 Carbon, and 350 °C for the H2 series. The X1E has a hardened steel nozzle and a 320 °C maximum, per Bambu Lab.
• Prusa: the CORE One+ is enclosed, with active chamber heating "up to 55 °C," and a maximum nozzle temperature of 290 °C, or 400 °C with Prusa's HT hotend. Prusa suggests "adding a hardened nozzle (for abrasive engineering materials)." Our catalog lists 290 °C for the MK4S and XL too.
• Creality: the K1C's specs list a hardened steel nozzle, a 300 °C nozzle temperature, and an enclosed frame.

Check the filament's range against your hotend before you buy. A 300 °C hotend covers the published ranges for PLA-CF, PETG-CF, Polymaker's PET-CF17, and its Fiberon nylons, but only the lower part of Siraya Tech's 280–320 °C PET-CF range. On a printer limited to 290 °C, the 280–300 °C range on Polymaker's PA6-CF20 and PA12-CF10 data sheets leaves a narrow window. Never set a hotend above its maker's maximum.

Checklist before you buy a CF filament

• Decide on the base plastic first. Write down the highest temperature the part will see, and compare HDT figures only at the same load and annealing condition.
• Fit a hardened or other wear-resistant nozzle listed for your exact printer and hotend, 0.4 mm or larger. Bambu Lab prefers 0.6 mm for third-party fiber filaments.
• Check that your hotend's maximum covers the filament maker's nozzle range.
• For PET-CF and nylon CF, plan on an enclosed printer unless the filament maker says otherwise, and check what your printer maker says about enclosing it.
• Check your dryer's maximum temperature against the maker's drying setting, which runs from 50 °C to 110 °C across the products above.
• If the data-sheet heat figures assume annealing, plan for an oven cycle of up to 16 hours, and test-anneal a scrap part first.
• Don't load third-party CF filament into a Bambu Lab AMS or AMS lite unless both makers support it. Check your feeder maker's rules.
• Orient parts so the main load runs along the layers, not across them.

Ready to choose?

The carbon fiber filament shortlist groups verified CF spools by base plastic, with each maker's nozzle, heat, enclosure, and drying needs. Before you buy, check your nozzle in the replacement nozzle shortlist and your dryer in the filament dryer shortlist. If you already print CF and see problems, start with brittle filament, weak layer adhesion, or clog diagnosis.

How this page was checked

Every claim above comes from the manufacturer documents in the sources section. All of the pages and data sheets listed, including the ELEGOO, SUNLU, Siraya Tech, and Polymaker store pages, were retrieved on 2026-10-11. Where makers' pages disagree, we report each value. We used product-page Q&A replies only where they're visibly labelled as the maker. Figures vary by color, batch, and revision, so check the current data sheet for your spool. Read more in our editorial standards and affiliate disclosure.

Specialty materials: what to check before you buy a spool ↗