PC-CF is polycarbonate with chopped carbon fiber blended into the resin before extrusion, the same approach used for PETG-CF and the other reinforced filaments on this site. The base plastic hasn’t changed, and it still warps badly enough that this site’s own polycarbonate filament guide calls a heated enclosure close to mandatory for the unfilled material. Fiber shifts that balance: parts come out stiffer, resist sagging under heat and load, and shrink less as they cool. The tradeoff is a nozzle that wears out within a spool or two, a hotter print process, and a toughness penalty at least one manufacturer has had to walk back in public. PC-CF also has fewer sellers than PETG-CF, and some major filament brands don’t make one at all. If you’re still deciding whether you need PC-CF or a different base material, the filament types overview is a better starting point than this guide.
What’s actually in the blend
Chopped carbon fiber, not woven or continuous strand, gets blended into polycarbonate resin during extrusion, the same process used for every other CF filament. Fiber content is rarely published consistently. Spectrum Filaments states its PC CF runs 10 percent carbon fiber by weight, built on what it calls its PC 275 base resin. Prusament and 3DXTech both sell established PC-CF products but don’t publish an exact fiber percentage, and the mechanical numbers on their data sheets suggest the loadings aren’t identical: 3DXTech’s CarbonX PC+CF posts a noticeably higher tensile and flexural modulus than Prusament’s PC Blend Carbon Fiber, pointing to a heavier fiber load or a different base resin. A few brands people expect to sell PC-CF, including Polymaker, Sunlu, eSUN, and Bambu Lab, currently don’t: all four sell carbon fiber filament in other base plastics, just not PC. See the carbon fiber 3D printing guide for how PC-CF fits alongside other CF filaments.
Stiffness up, toughness down
Stiffness is where fiber earns its keep. Prusament’s own data sheets show flexural modulus rising from 2.1-2.2 GPa in plain PC Blend to 3.5-4.2 GPa in PC Blend Carbon Fiber, with tensile modulus climbing from roughly 1.9-2.0 GPa to 2.6-3.2 GPa. 3DXTech’s CarbonX PC+CF goes further, listing a tensile modulus of 6.2 GPa and a flexural modulus of 5.89 GPa, well above what Prusament reports for its own blend. Both beat PETG-CF’s flexural modulus of 2.3-3.1 GPa by a real margin, matching what the PETG-CF guide predicts when it says PC-CF pushes stiffness and heat resistance higher still.
Toughness is a harder story, and Prusa’s own team has had to answer for it in public. Unfilled Prusament PC Blend doesn’t break at all in the unnotched Charpy test, rated simply “no break.” PC Blend Carbon Fiber does break in that test, at 32-35 kJ/m2. When a customer on Prusa’s blog pointed out that the data sheet contradicted marketing copy calling PCCF “stronger, tougher, and more resilient,” a Prusa engineer conceded the point: impact resistance really is lower than the unfilled blend, even though stiffness and wear resistance improved. 3DXTech’s own data sheet backs that up: tensile elongation at break for CarbonX PC+CF is just 2 percent, a fraction of what unfilled PC manages before it deforms. Fiber makes PC-CF resist bending. It doesn’t make it resist breaking.
Nozzle requirements and wear
Carbon fiber wears through brass fast. Every PC-CF data sheet checked for this guide calls for a hardened nozzle: Prusament requires hardened steel and warns brass wears with continued use, 3DXTech “strongly recommends” hardened steel over any softer metal with a 0.4 mm minimum bore, Spectrum lists “ruby or hardened nozzle” as a flat requirement, and Nanovia recommends a diameter above 0.4 mm for the same reason. That’s the same advice PETG-CF and PLA-CF data sheets give, for the same reason: the fiber, not the plastic around it, grinds the nozzle down. PC-CF parts also tend to run bigger than a PETG-CF bracket, pushing more total fiber through the same bore per print. See the brass vs hardened steel nozzle guide for the tradeoffs between nozzle materials.
Print settings: nozzle, bed, speed
Nozzle temperatures for PC-CF sit at or above plain PC’s high end, though the size of that jump depends on which plain PC gets compared. Prusament lists 285±10°C for PCCF against 275±10°C for its own unfilled PC Blend, a 10°C jump inside the same line. 3DXTech’s CarbonX PC+CF calls for 280-310°C. Spectrum runs 270-290°C through a 0.4 mm nozzle. Nanovia lists 260-290°C, identical to Bambu Lab’s published range for plain PC, a reminder that “hotter than plain PC” depends on whose plain PC you mean. Bed temperatures cluster tighter: Prusament and 3DXTech both call for 110-120°C, Nanovia allows 100-140°C, and Spectrum asks for at least 80°C.
Enclosure needs split by brand. 3DXTech recommends a heated chamber, and Spectrum recommends a closed chamber for larger prints. Prusament argues close to the opposite: its own blog markets no enclosure needed as an advantage of PCCF over its unfilled PC Blend, crediting the fiber with cutting warp below what the unfilled resin manages alone. Drying splits the same way: Prusament’s data sheet shows low moisture absorption, 0.09 percent in 24 hours, and says the filament doesn’t need drying before use, while 3DXTech specifies drying at 120°C for 4 hours. Check the data sheet for your specific spool rather than assuming one brand’s habits apply to another.
Surface finish
PC-CF prints come out matte and black. Every brand checked for this guide (Prusament, 3DXTech, Spectrum, Nanovia) sells PC-CF in black only, and none offer a natural or translucent version, a real loss since plain PC can be printed clear enough to see through and PC-CF can’t. Prusament markets the matte black finish as a feature in its own right, calling it a professional look. Layer lines read rougher than on unfilled PC because the chopped fiber breaks up the surface at a small scale, the same texture change PETG-CF and PLA-CF show. Fiber orientation can show as faint striping on large flat surfaces printed at higher speeds.
When PC-CF is worth it
PC-CF earns its cost and its printing hassle on parts that need to hold a precise shape under sustained heat and load at once. Prusa’s own materials list, gears, fan shrouds, tripods, mechanical housings, spells out the target use case, and the numbers back it up: Prusament’s PCCF holds its shape to 106°C under a 1.8 MPa load versus 93°C for unfilled PC Blend under the same test, a real gap near a motor or behind glass in the sun.
Against plain PC, the case isn’t automatic. Unfilled PC is tougher (it survives the unnotched Charpy test that breaks PCCF), cheaper (Bambu Lab’s plain PC runs about $40/kg against roughly $75 to $120/kg for the PC-CF spools checked here), and easier to print: no hardened nozzle, and on some data sheets, no enclosure either. Choose plain PC when impact resistance or budget matters more than stiffness.
Against sibling CF blends, PC-CF sits at the high end. PETG-CF is easier to print and doesn’t demand as extreme a nozzle range, but its heat resistance tops out well below PC-CF’s: unfilled PETG typically deflects under load around 60-75°C, nowhere near PCCF’s 106-130°C window. Nylon-CF pushes heat resistance up too, but adds drying discipline that PC-CF, at least on Prusament’s data sheet, doesn’t require. The engineering filaments guide covers how PC, nylon, and carbon fiber blends compare in more detail.
PC-CF filament checklist
- Swap to a hardened steel or ruby-tipped nozzle, 0.4 mm or larger, before loading the first spool.
- Run a temperature tower between 270°C and 300°C, then narrow in per the brand’s data sheet.
- Set the bed to 100-120°C, with a glue stick or PC-specific adhesive on PEI.
- Check whether an enclosure is required; brands disagree, and some only recommend one for larger prints.
- Check the data sheet before drying; some PC-CF report low moisture pickup, others call for 120°C.
- Keep part cooling low or off, the same rule as unfilled PC, to protect layer adhesion.
- Expect a matte black finish; no PC-CF on the market currently ships clear or in color.
- Anneal in an oven (140°C for two hours, per Prusament) for a further heat deflection boost if the part tolerates about 1 percent shrinkage.
- Choose PC-CF over plain PC when stiffness and heat resistance under load matter more than impact toughness or price, and over PETG-CF when the part needs to survive heat PETG-CF can’t.