Voron Carbon Fiber Nylon Printing Guide — PA-CF and PA-GF
Materials Printing Advanced
Carbon fiber and glass fiber reinforced nylons — PA-CF and PA-GF — are the sweet spot for Voron structural and functional parts. They combine nylon's toughness and chemical resistance with the stiffness, dimensional stability, and reduced warping that carbon or glass fibers provide. For Voron builders, PA-CF has become the go-to material for parts that must survive chamber temperatures, resist wear, and hold tight tolerances. This guide covers everything specific to printing filled nylons on Voron printers: the hardware upgrades required (hardened nozzles, abrasion-resistant extruder gears), mandatory drying procedures, print temperature profiles, bed adhesion strategies, post-processing, and the best PA-CF and PA-GF filament brands. Last updated: May 2025.
This guide does not cover unfilled nylon (PA6, PA12) — see our general Voron Nylon Printing Guide for that. Here we focus exclusively on fiber-filled variants and the unique challenges and advantages they present.
PA-CF vs PA-GF — Which One Should You Choose?
| Property | PA-CF (Carbon Fiber) | PA-GF (Glass Fiber) |
|---|---|---|
| Fiber content (typical) | 10-20% by weight | 15-30% by weight |
| Young's Modulus (stiffness) | 5-8 GPa | 4-7 GPa |
| Tensile Strength | 80-120 MPa | 70-100 MPa |
| Heat Deflection Temp (HDT) | 145-155°C | 150-165°C |
| Density | 1.2-1.3 g/cm³ (lighter) | 1.4-1.6 g/cm³ (heavier) |
| Surface finish | Matte black, uniform, hides layer lines | Textured beige/light gray |
| Abrasiveness | Moderate — carbon fibers are abrasive but short | High — glass fibers are harder and more abrasive |
| Warping tendency | Low (carbon fiber reduces CTE significantly) | Low to moderate |
| Cost per kg | $50-80 | $40-65 |
| Best for Voron | Structural parts, toolhead components, AB drive mounts | Enclosure panels, deck plates, budget structural parts |
Our recommendation: Start with PA-CF. It is more forgiving than PA-GF (less abrasive, better surface finish, lower density) and produces excellent Voron parts. Polymaker PA6-CF is the gold standard. Choose PA-GF if you need maximum heat resistance at a lower cost, or if you want the distinctive textured appearance of glass-filled parts.
Hardware Requirements — What Your Voron Needs for Filled Nylon
Fiber-filled nylons are abrasive. They will destroy standard brass nozzles, brass extruder gears, and PTFE-lined hotend components. Before printing PA-CF or PA-GF, ensure your Voron has these upgrades:
Hardened Nozzle (Mandatory)
Carbon and glass fibers erode brass nozzles at a rate of approximately 0.01-0.02mm of orifice enlargement per 100g of filament. After one spool (1kg), a 0.4mm brass nozzle becomes 0.5-0.6mm — causing over-extrusion, stringing, and poor print quality. Use a hardened steel nozzle (e.g., Slice Engineering Vanadium, Micro Swiss hardened, or E3D X-Carbide) or a ruby-tipped nozzle. Recommended sizes:
- 0.4mm hardened steel: For detailed parts with fine features. Acceptable for PA-CF, may clog with PA-GF if the glass fibers are long.
- 0.5mm hardened steel: The best all-around size for filled nylons. Balances detail with clog resistance. Use this for most Voron parts.
- 0.6mm hardened steel: For large structural parts where speed matters. Virtually no clog risk. Good for PA-GF with long glass fibers.
Note on nozzle materials: Hardened steel nozzles have lower thermal conductivity than brass — approximately 15 W/mK vs 110 W/mK. This means the nozzle tip temperature can be 5-15°C lower than the thermistor reading at high flow rates. Compensate by increasing the hotend temperature by 5-10°C when switching from brass to hardened steel, especially at high volumetric flow rates above 12 mm³/s.
Hardened Extruder Gears (Mandatory)
Standard brass extruder drive gears will wear smooth after 200-500g of filled nylon. At that point, the extruder can no longer grip the filament and will skip or grind. Replace your extruder gears with:
- Clockwork 2 steel drive gear: The standard Voron Clockwork 2 extruder can be upgraded with a hardened steel drive gear from the Voron store or a third-party supplier. This gear is compatible with the stock Clockwork 2 body and idler.
- Galileo 2 hardened gears: The Galileo 2 extruder uses robust steel gears as standard. If you have an earlier version, upgrade to the hardened gear set.
- Bondtech LGX hardened gears: The Bondtech LGX extruder has an optional hardened gear set (CHT or standard). These are excellent for PA-CF and PA-GF but require the LGX extruder body.
- Sherpa Mini or Orbiter with steel gears: Both of these compact extruders offer hardened gear options. The Orbiter 2.0, in particular, has an excellent hardened gear set that lasts 2000+ hours with abrasive filaments.
All-Metal Hotend (Mandatory)
Filled nylons print at 270-300°C. PTFE-lined heatbreaks (as found in standard V6 hotends or the Creality-style hotend on a Switchwire) will degrade above 260°C, releasing toxic fumes and causing the PTFE to deform and clog the filament path. You need an all-metal hotend:
- Dragon HF/UHF (High Flow / Ultra High Flow): Excellent for filled nylons. The bimetal heatbreak provides a sharp thermal transition zone, reducing heat creep. The HF version handles up to 20 mm³/s, the UHF up to 30 mm³/s with a 0.6mm nozzle.
- Rapido HF/UHF: Similar to Dragon but with a longer melt zone. Excellent for high-flow PA-CF printing. The UHF version uses a CHT-type nozzle (two internal channels) that increases melt capacity by 30-50%.
- Goliath: A high-flow hotend designed specifically for Voron V2.4 and Trident. Handles PA-CF at 25-30 mm³/s with ease. Requires a specific toolhead mount.
- Mosquito / Mosquito Magnum: Premium hotend with excellent thermal isolation. The Magnum version has a longer melt zone for high-flow printing.
- Copperhead with CE (Carbide Edge) heatbreak: A budget-friendly option. The CE heatbreak has a tungsten carbide coating on the internal bore that resists abrasion from fiber-filled filaments.
Sturdy Enclosure (Highly Recommended)
While filled nylons warp less than unfilled nylon, they still require a stable thermal environment. A Voron enclosure (V2.4, Trident, or V0.2) at 50-65°C chamber temperature is ideal. The Switchwire, being an open-frame design, will struggle with large PA-CF parts. For the Switchwire, build an enclosure (even a simple corrugated plastic or foam-core box enclosure) and preheat the chamber to at least 45°C before printing filled nylon parts larger than 50mm in any dimension.
Drying — Critical for Filled Nylons
Fiber-filled nylons are just as hygroscopic as unfilled nylon — the fibers do not absorb moisture, but the nylon matrix does. PA-CF and PA-GF can absorb 3-6% moisture by weight, and printing wet filled nylon causes the same defects as wet unfilled nylon: popping, sizzling, surface defects, catastrophic loss of layer adhesion, and stringing. However, there are two drying-specific concerns for filled nylons:
- Fibers trap moisture near the nozzle: The carbon or glass fibers create micro-channels in the molten filament that allow steam to travel forward and explode out of the nozzle as bubbles. Wet PA-CF produces a distinctive rough, pockmarked surface that looks like sandblasted metal.
- Longer drying time needed: The fibers create a physical barrier to moisture diffusion, so moisture takes longer to migrate out of the filament during drying. PA-CF requires 10-12 hours of drying at 75-80°C, compared to 6-8 hours for unfilled PA6.
| Material | Drying Temperature | Drying Time | Max Safe Temperature |
|---|---|---|---|
| PA-CF (PA6 base) | 75-80°C | 10-12 hours | 85°C (sintering risk above this) |
| PA-CF (PA12 base) | 65-75°C | 8-10 hours | 80°C |
| PA-GF (PA6 base) | 75-80°C | 10-12 hours | 85°C |
| PA-GF (PA66 base) | 80-85°C | 12-15 hours | 90°C |
Do not exceed the max safe temperature. At temperatures above 85-90°C, the nylon matrix can begin to sinter (the filament particles fuse together), permanently deforming the spool and making it impossible to feed through the extruder. Use a filament dryer with accurate temperature control (PrintDry Pro, Sunlu S2 with high-temp firmware, or a convection oven with an independent thermometer). A kitchen oven set to 75°C with the door slightly ajar works well — verify with an oven thermometer, as most oven dials are inaccurate by 10-20°C.
Print from a dry box: Feed PA-CF and PA-GF directly from a sealed dry box with desiccant (silica gel beads) and a digital hygrometer showing 0-10% humidity. Do not leave the spool exposed to ambient air for more than 30 minutes. If you must change spools mid-print, have the next spool pre-dried and sealed in a dry box ready to go.
Print Temperature Settings
| Parameter | PA-CF (PA6 base) | PA-CF (PA12 base) | PA-GF (PA6 base) | PA-GF (PA66 base) |
|---|---|---|---|---|
| Hotend Temperature | 275-295°C | 260-280°C | 280-300°C | 290-310°C |
| Bed Temperature | 100-120°C | 90-110°C | 100-120°C | 110-130°C |
| Chamber Temperature | 55-70°C | 50-65°C | 55-70°C | 60-75°C |
| Part Cooling Fan | 0% | 0-10% | 0% | 0% |
| Max Volumetric Flow | 10-15 mm³/s | 12-18 mm³/s | 8-12 mm³/s | 8-12 mm³/s |
| Print Speed (perimeters) | 40-70 mm/s | 50-80 mm/s | 35-60 mm/s | 35-60 mm/s |
| Print Speed (infill) | 60-100 mm/s | 70-120 mm/s | 50-80 mm/s | 50-80 mm/s |
| First Layer Speed | 15-20 mm/s | 15-25 mm/s | 15-20 mm/s | 15-20 mm/s |
| Retraction Length | 0.4-0.8 mm | 0.5-0.8 mm | 0.3-0.6 mm | 0.3-0.6 mm |
| Retraction Speed | 30-40 mm/s | 30-40 mm/s | 25-35 mm/s | 25-35 mm/s |
Temperature Notes
- Start at the lower end of the temperature range and increase if layer adhesion is poor. The fiber filler increases the melt viscosity of the nylon — it needs higher temperatures to flow properly and bond between layers. If you see layer delamination during post-processing (drilling, sanding, tapping), increase hotend temperature by 5-10°C.
- The chamber temperature must be stable before printing. Preheat the bed to the target temperature and let the chamber stabilize for at least 30 minutes before starting the print. A cold chamber causes the part to cool unevenly, which is the primary cause of warping in filled nylons.
- Max volumetric flow is lower than unfilled nylon because the fibers increase melt viscosity. Run a max flow test (Klipper's MFLOW or a manual extrusion test) to find your hotend's limit with PA-CF. A Dragon HF with a 0.5mm hardened nozzle typically maxes out at 12-14 mm³/s with PA-CF, while a Rapido UHF can reach 18-22 mm³/s.
Bed Adhesion for Filled Nylons
The fiber content in PA-CF and PA-GF actually makes bed adhesion easier than unfilled nylon — the fibers reduce the CTE (coefficient of thermal expansion), which means less shrinkage force pulling on the edges of the part during cooling.
- Garolite G10/FR4 (Highly Recommended): This is the best surface for filled nylons. The textured epoxy-glass surface provides mechanical grip without chemical bonding. PA-CF and PA-GF adhere strongly to G10 at 100-110°C and release cleanly when the bed cools below 50°C. Lightly scuff with 220-grit sandpaper every 50-100 prints to maintain grip. Clean with isopropyl alcohol between prints.
- PEI (Textured) with Magigoo Nylon: Textured PEI works well with PA-CF and PA-GF when used with Magigoo's Nylon-specific formula (blue applicator). Apply a thin coat before each print. The adhesive creates a strong bond during printing that releases when the bed cools. Without Magigoo, filled nylons can fuse permanently to PEI — test on a corner first.
- PVA Glue Stick on Smooth PEI: A thick layer of standard PVA glue stick (Elmer's purple or clear) on smooth PEI provides good adhesion for PA-CF. The PVA dissolves in water for easy cleanup. Apply 2-3 coats, let dry to a milky white, then print. Reapply every 2-3 prints.
- Nylon-specific build plates: Polymaker sells a dedicated Nylon Adhesion Sheet that works exceptionally well with PA-CF. It is a thin flexible sheet with a proprietary textured coating. Expensive ($40-60) but excellent results.
Brim is recommended for parts larger than 75mm in any dimension. Use a 10-15mm outer brim (0mm gap) for PA-CF and PA-GF parts. The brim provides extra surface area to resist the remaining shrinkage forces. For large flat parts (enclosure panels, deck plates), use a 20-25mm brim.
Slicer Configuration for PA-CF/PA-GF
| Setting | OrcaSlicer / Bambu Studio | SuperSlicer | Notes |
|---|---|---|---|
| Filament profile | Generic PA-CF (custom) | PA-CF (custom) | No Voron-specific preset available; create custom |
| Nozzle diameter | 0.5mm | 0.5mm | 0.4mm acceptable; 0.6mm for large parts/clog reduction |
| Layer height | 0.2mm | 0.2mm | 0.24mm for faster prints, 0.12mm for fine details |
| First layer height | 0.2mm | 0.2mm | Same as layer height; do not squish too much |
| Extrusion width | 0.5mm (0.55mm for first layer) | 0.5mm | Wider extrusion improves layer bonding |
| Hotend temp (PA-CF) | 285°C | 285°C | Adjust per brand; Polymaker PA6-CF runs well at 285°C |
| Bed temp | 110°C | 110°C | For G10 or PEI+PVA |
| Chamber temp | 60°C | 60°C | Preheat for 30 min minimum |
| Max volumetric speed | 12 mm³/s | 12 mm³/s | Conservative start; increase if hotend allows |
| Print speed (perimeters) | 50 mm/s | 50 mm/s | Slow perimeters for best layer adhesion |
| Print speed (infill) | 80 mm/s | 80 mm/s | Gyroid infill recommended; reduces vibration |
| Part cooling fan | 0% | 0% | No fan for PA-CF or PA-GF |
| Retraction length | 0.6mm | 0.6mm | Direct drive; filled nylons ooze less than unfilled |
| Retraction speed | 35 mm/s | 35 mm/s | Standard |
| Brim type | Outer brim | Outer brim | 15mm width for most parts; 25mm for large flat parts |
| Z hop when retracted | 0.4mm | 0.4mm | Prevents nozzle dragging; important for filled materials |
Post-Processing Filled Nylon Parts
Drilling and Tapping
Filled nylons machine beautifully. The fiber content makes the material stiffer and less prone to the "gummy" behavior of unfilled nylon during machining.
- Drilling: Use sharp HSS or carbide drill bits. The fibers are abrasive — carbide bits last significantly longer. Drill at moderate speed (2000-3000 RPM for 3mm holes) with light, consistent feed pressure. Use cutting oil or WD-40 as lubricant. The chips should be small and powdery (not stringy) — if they are stringy, the material is wet and needs further drying.
- Tapping: Use a roll-form (thread-forming) tap for the strongest threads. Roll-form taps displace material rather than cutting it, creating threads with continuous fiber reinforcement around the thread profile. Standard cut taps also work well — use a lubricant and back the tap out frequently to clear debris.
- Heat-set inserts: Brass heat-set inserts (M3, M4, M5) install at 260-280°C. The filled nylon holds inserts very securely because the fibers prevent the plastic from creeping under load. Use a soldering iron with a dedicated insert tip. Insert temperature: 270°C. Apply light downward pressure, wait 5 seconds, then release. Let cool for 10 seconds before moving the part.
Sanding and Finishing
- PA-CF sanding: Carbon fiber nylon sands to a smooth, matte finish. Start with 220-grit to remove layer lines, progress to 400, then 800 for a furniture-grade finish. The carbon fibers create a fine black dust — use a mask and vacuum extraction, as carbon fiber dust is an irritant and conductive (can short electronics). Wet sanding (with water or mineral oil) eliminates airborne dust and produces a smoother finish.
- PA-GF sanding: Glass fiber nylon is more abrasive to sandpaper. Use silicon carbide paper (not aluminum oxide) — it lasts 3-5x longer on glass-filled materials. Start with 180-grit, progress to 400, then 1000. The glass fibers create a white/gray dust that is also an irritant — use PPE.
- Surface sealing: Filled nylon parts have a slightly porous surface from the fiber ends exposed at the surface. For parts that need to be fluid-tight (e.g., filtration components), apply a thin coat of cyanoacrylate (CA) glue or epoxy. The CA glue wicks into the surface pores and seals them. Wipe off excess before it cures.
Annealing Filled Nylon
Annealing PA-CF and PA-GF parts further improves their heat resistance and dimensional stability, though the improvement is less dramatic than for unfilled nylon because the fibers already provide significant dimensional stability.
- Annealing temperature: 80-90°C for PA6-based, 70-80°C for PA12-based. Hold for 2-3 hours.
- Method: Place the part on a bed of silica gel beads or between glass plates (with PTFE release film) in a convection oven. Ramp up at 5°C/min, hold, then cool at 2°C/min to below 50°C before removing.
- Shrinkage: Expect 0.3-0.5% shrinkage — less than unfilled nylon (which shrinks 0.5-1.5%). Account for this in your CAD model if precise dimensions are required.
- Moisture conditioning: Annealed filled nylon is very dry. For parts that need impact resistance (not just stiffness), condition in a 50% humidity environment for 24-48 hours to restore 2-3% moisture content, which restores the nylon's toughness.
Recommended PA-CF and PA-GF Brands
- Polymaker PA6-CF: The undisputed gold standard for carbon fiber nylon on Voron printers. Excellent consistency (±0.02mm diameter tolerance), low warp, beautiful matte black finish, and reliable printing at 280-290°C. Pre-dried and vacuum-sealed with desiccant. Price: $55-70/kg. The top recommendation for all Voron structural parts.
- MatterHackers NylonX: A PA6 + carbon fiber blend that is slightly easier to print than Polymaker PA6-CF (lower temperature requirement, ~270°C). Good layer adhesion and impact strength. Available in multiple colors. Price: $55-75/kg.
- eSun ePA-CF: A budget-friendly PA-CF from a brand well-known to Voron builders. Good consistency for the price, prints at 265-285°C. Slightly more prone to stringing than premium brands. Excellent value for non-critical parts. Price: $35-50/kg.
- 3DXTech PA6-GF: The best glass fiber nylon for Voron. Excellent heat resistance (HDT ~155°C). Prints at 270-290°C. More affordable than PA-CF with similar stiffness. The glass fiber content gives a textured beige surface that hides layer lines well. Price: $50-65/kg.
- Polymaker PA12-CF: A low-moisture PA12 base with carbon fiber reinforcement. The PA12 base absorbs only 1.5% moisture (vs 9.5% for PA6), making this significantly easier to print. Excellent dimensional stability. Price: $70-90/kg.
- Fiberlogy Nylon GF: A European PA-GF with 20% glass fiber content. Excellent impact resistance and layer adhesion. Prints at 265-285°C. Price: $45-60/kg.
- Priline PA-CF: An economy option from China. Requires aggressive drying (12+ hours at 80°C) and careful tuning. Diameter tolerance is wider (±0.05mm). Good for large parts where absolute precision is not critical. Price: $28-40/kg.
Common Issues and Troubleshooting
Clogging — The #1 Problem with Filled Nylons
Clogs are the most frequent issue when printing PA-CF and PA-GF. The fibers can accumulate in the nozzle or heatbreak, blocking the flow of filament. Prevention and fixes:
- Use a 0.5mm or 0.6mm nozzle. A 0.4mm nozzle is more prone to clogging because the fiber length is a larger proportion of the orifice diameter. Most PA-CF filaments have fiber lengths of 50-200 microns. A 0.5mm nozzle provides a comfortable margin.
- Maintain a clean hotend. Any carbon buildup or degraded plastic in the nozzle will catch fibers. Clean the nozzle with a brass brush or a nozzle cleaning filament (e.g., eSun cleaning filament) between spools.
- Check the heatbreak for fiber accumulation. Fibers can separate from the nylon matrix in the melt zone and accumulate in the heatbreak. If you see a gradual reduction in flow over the course of a print, the heatbreak is filling with fibers. Disassemble the hotend, clean the heatbreak bore with a 2.5mm drill bit rotated by hand, and reassemble.
- Reduce retraction. High retraction distances (1.5mm+) can pull molten filled nylon back into the heatbreak, where it solidifies and blocks the next extrusion. Keep retraction under 0.8mm.
Layer Delamination or Poor Z-Strength
If your PA-CF part splits along layer lines under stress, the layers are not bonding properly. This is almost always a temperature issue:
- Increase hotend temperature by 5-10°C. The fibers increase the melt viscosity, requiring higher temperatures for proper inter-layer diffusion.
- Reduce print speed. At high speeds, each layer has less time to bond with the previous layer. Slow perimeters to 40 mm/s and infill to 60 mm/s.
- Verify chamber temperature. If the chamber is below 50°C, the part surface cools too quickly for the next layer to bond. Increase chamber temperature to 60-65°C.
- Check for moisture. Wet filled nylon has severely reduced layer adhesion. If you see popping or sizzling during printing, the filament is wet — dry it for 12 hours and try again.
Stringing and Oozing
Filled nylons string less than unfilled nylon because the fibers increase the melt's internal friction. However, if you see stringing:
- Increase retraction slightly (up to 0.8mm at 40 mm/s).
- Ensure the filament is completely dry — moisture causes steam that pushes filament out of the nozzle during travel moves.
- Check the nozzle for wear — an enlarged orifice from abrasion will cause excessive oozing.
Poor Surface Finish (Rough or Pockmarked)
A rough, pitted surface on PA-CF or PA-GF almost always indicates moisture contamination. Dry the filament for 12+ hours and restart. If the surface is rough but not pitted, the print speed may be too high for your hotend's melting capacity — reduce volumetric flow by 15-20% and slow down perimeters.