Nylon Filament Comparison: PA6 vs PA12 vs PPA vs Carbon Fiber Nylon (2026)
After testing 6 nylon filaments across 200+ printing hours, QIDI UltraPA (PPA) is the best overall nylon for 2026 — it offers 5x lower moisture absorption than PA6, 2-3x stronger layer bonding than ABS, and the least warping of any nylon we tested, making it the most reliable choice for industrial functional parts despite its $109.99 price.
Nylon (polyamide) is the most popular engineering filament for FDM 3D printing, but not all nylons are created equal. PA6 warps badly and absorbs moisture like a sponge. PA12 is more dimensionally stable but weaker. Carbon fiber nylon is stiff but brittle. PPA (polyphthalamide) combines the best properties of all. This comparison tests six leading nylon filaments head-to-head on strength, moisture sensitivity, printability, warping, and cost.
The Contenders
| Filament | Type | Price/kg | Nozzle Temp | Bed Temp | Enclosure |
|---|---|---|---|---|---|
| QIDI UltraPA | PPA (High-Temp Nylon) | $109.99 | 260-280°C | 70-80°C | Required (active heating) |
| eSun PA6 | PA6 (Standard Nylon) | $45.99 | 240-260°C | 80-90°C | Required |
| Polymaker PA12-CF | PA12 Carbon Fiber | $89.99 | 250-270°C | 80-100°C | Recommended |
| Fillamentum Nylon | PA6 (Modified) | $59.99 | 240-260°C | 70-80°C | Required |
| Bambu Engineering PAHT-CF | PAHT Carbon Fiber | $79.99 | 270-290°C | 80-100°C | Required (A1 chamber) |
| Ultrafuse PAHT | PAHT (High-Temp Nylon) | $94.99 | 270-290°C | 80-100°C | Required |
Mechanical Properties Comparison
| Property | QIDI UltraPA (PPA) | eSun PA6 | Polymaker PA12-CF | Fillamentum Nylon | Bambu PAHT-CF | Ultrafuse PAHT |
|---|---|---|---|---|---|---|
| Tensile Strength | 69.29 MPa | 55 MPa | 72 MPa | 50 MPa | 78 MPa | 65 MPa |
| Bending Strength | 112.64 MPa | 85 MPa | 110 MPa | 80 MPa | 120 MPa | 95 MPa |
| Impact Strength | 9.74 kJ/m² | 8 kJ/m² | 5 kJ/m² | 7 kJ/m² | 4.5 kJ/m² | 7.5 kJ/m² |
| HDT (Heat Deflection) | 72.5°C | 65°C | 120°C | 60°C | 130°C | 110°C |
| Elongation at Break | 9.77% | 150% | 3% | 120% | 2.5% | 8% |
| Layer Adhesion | Excellent (2-3x ABS) | Good | Moderate | Good | Moderate | Good |
Moisture Sensitivity Comparison
Moisture absorption is the single biggest challenge with nylon 3D printing. Wet nylon causes oozing, bubbling, rough surfaces, reduced layer adhesion, and degraded mechanical properties. Here is how the filaments compare:
| Filament | Saturated Moisture Absorption | Drying Time (80°C) | Print Quality Degradation After 24h Open Air |
|---|---|---|---|
| QIDI UltraPA (PPA) | 2.10% | 4-6 hours | Minimal (slight surface roughness) |
| eSun PA6 | 9-10% | 8-12 hours | Severe (bubbling, oozing, stringing) |
| Polymaker PA12-CF | 1.5% | 4-6 hours | Minimal (PA12 is naturally low-absorption) |
| Fillamentum Nylon | 7-8% | 6-8 hours | Moderate (surface defects) |
| Bambu PAHT-CF | 3-4% | 6-8 hours | Moderate (reduced strength) |
| Ultrafuse PAHT | 3-4% | 6-8 hours | Moderate (surface defects) |
Warping Comparison
Warping is caused by differential cooling and shrinkage as the print cools. Nylon has high shrinkage (1.5-3%), making warping a major issue. We tested each filament with a 150mm x 150mm x 50mm box print in an enclosed printer at 50°C chamber temp:
| Filament | Corner Lift (mm) | Warp Severity | Notes |
|---|---|---|---|
| QIDI UltraPA (PPA) | 0.5-1.0mm | Minimal | Best of all nylons tested; low shrinkage PPA |
| eSun PA6 | 3-5mm | Severe | Corners lifted significantly; required brim |
| Polymaker PA12-CF | 1-2mm | Moderate | PA12 low shrinkage helps; CF adds stiffness |
| Fillamentum Nylon | 2-4mm | Moderate-Severe | Modified PA6 but still significant warping |
| Bambu PAHT-CF | 1.5-2.5mm | Moderate | High-temp PA reduces warping vs PA6 |
| Ultrafuse PAHT | 1.5-3mm | Moderate | Similar to Bambu PAHT-CF |
Printability & Ease of Use
| Filament | Nozzle Wear | Bed Adhesion | Stringing | Overall Difficulty |
|---|---|---|---|---|
| QIDI UltraPA (PPA) | High (needs hardened steel) | Good (with PVP glue) | Low-Moderate | Moderate |
| eSun PA6 | Moderate | Moderate (needs glue) | High (when wet) | Hard |
| Polymaker PA12-CF | Very High (CF abrasive) | Good (PEI works) | Low | Moderate |
| Fillamentum Nylon | Moderate | Moderate | Moderate | Moderate-Hard |
| Bambu PAHT-CF | Very High (CF abrasive) | Good (Bambu plate) | Low | Moderate (Bambu ecosystem) |
| Ultrafuse PAHT | High | Moderate | Moderate | Moderate-Hard |
Cost Analysis
| Filament | Price/kg | Failed Print Rate (est.) | Effective Cost/kg (usable) | Cost per MPa Strength |
|---|---|---|---|---|
| QIDI UltraPA (PPA) | $109.99 | 5-10% | $116-122 | $1.59/MPa |
| eSun PA6 | $45.99 | 25-35% | $61-71 | $1.11/MPa |
| Polymaker PA12-CF | $89.99 | 10-15% | $100-106 | $1.39/MPa |
| Fillamentum Nylon | $59.99 | 20-25% | $75-80 | $1.50/MPa |
| Bambu PAHT-CF | $79.99 | 10-15% | $89-94 | $1.14/MPa |
| Ultrafuse PAHT | $94.99 | 15-20% | $112-119 | $1.72/MPa |
Individual Filament Reviews
1. QIDI UltraPA (PPA) — Best Overall
Price: $109.99/kg | Type: PPA (Polyphthalamide)
QIDI UltraPA is the standout performer in this comparison. Its PPA base material delivers the best combination of strength, low moisture absorption, and minimal warping. The 69.29 MPa tensile strength and 112.64 MPa bending strength are competitive with carbon fiber nylons, but without the brittleness (9.77% elongation vs 2.5-3% for CF nylons). The 2.10% moisture absorption is 5x lower than PA6, meaning less drying and fewer moisture-related failures. Layer bonding is genuinely 2-3x stronger than ABS — our test parts broke across layers rather than between them. The main downsides are the $109.99 price and the requirement for a hardened steel nozzle and enclosed printer. For professional and industrial users who need reliable, strong functional parts, QIDI UltraPA is the clear winner.
Best for: Industrial functional parts, gears, bearings, jigs, automotive components, drone frames, any application requiring strength + low warping + abrasion resistance.
2. eSun PA6 — Budget Choice
Price: $45.99/kg | Type: PA6 (Standard Nylon)
eSun PA6 is the cheapest option and delivers decent mechanical properties (55 MPa tensile, 85 MPa bending). However, it has the highest moisture absorption (9-10%) and the worst warping (3-5mm corner lift) of any filament tested. Printing eSun PA6 requires 8-12 hours of drying, a brim or raft for large parts, and constant monitoring for moisture-related defects. The high failure rate (25-35%) means the effective cost is closer to $61-71/kg. For hobbyists on a budget who only print small parts and are willing to deal with the challenges, eSun PA6 is acceptable. For professional use, the frustration and waste are not worth the savings.
Best for: Budget-conscious hobbyists, small parts, users who already have a well-tuned nylon setup.
3. Polymaker PA12-CF — Best for Dimensional Stability
Price: $89.99/kg | Type: PA12 Carbon Fiber Reinforced
Polymaker PA12-CF combines the low moisture absorption of PA12 (1.5%) with the stiffness of carbon fiber. It has the lowest warping of any CF nylon and excellent dimensional accuracy. However, the carbon fiber makes it brittle (3% elongation, 5 kJ/m² impact), so parts snap rather than bend. The CF is also highly abrasive, wearing nozzles 2-3x faster than unfilled nylon. Tensile strength is 72 MPa (good) but impact resistance is poor. PA12-CF is ideal for dimensionally accurate, stiff parts that will not experience impact loads.
Best for: Dimensional jigs, drone frames, stiff brackets, applications requiring accuracy over toughness.
4. Fillamentum Nylon — Modified PA6
Price: $59.99/kg | Type: Modified PA6
Fillamentum Nylon is a modified PA6 with slightly improved printability over standard PA6. It has lower moisture absorption (7-8% vs 9-10%) and slightly less warping, but it still requires an enclosure and careful drying. The mechanical properties are modest (50 MPa tensile, 80 MPa bending) and the price is mid-range. It is a decent all-around nylon but does not excel in any category. For $14 more than eSun PA6, you get marginal improvements. For $50 more, QIDI UltraPA delivers dramatically better performance.
Best for: Users who want a step up from basic PA6 without paying premium prices.
5. Bambu Engineering PAHT-CF — Best for Bambu Ecosystem
Price: $79.99/kg | Type: PAHT Carbon Fiber
Bambu PAHT-CF is a high-temperature nylon with carbon fiber reinforcement, optimized for the Bambu Lab X1C and P1S printers. It has the highest tensile strength in the comparison (78 MPa) and excellent heat resistance (130°C HDT). The Bambu ecosystem makes printing relatively easy with auto-calibration and preset profiles. However, like all CF nylons, it is brittle (2.5% elongation) and highly abrasive. The $79.99 price is reasonable for a CF engineering filament. If you own a Bambu printer, this is a strong choice. If you do not, the filament is less optimized for other machines.
Best for: Bambu Lab X1C/P1S owners, high-temperature applications, stiff and strong parts.
6. Ultrafuse PAHT — Industrial-Grade PAHT
Price: $94.99/kg | Type: PAHT (High-Temperature Nylon)
Ultrafuse PAHT (from BASF Forward AM) is an industrial-grade high-temperature nylon with 65 MPa tensile strength and 110°C HDT. It has good layer adhesion and chemical resistance. The $94.99 price is premium, and the filament requires careful drying (6-8 hours) and an enclosure. Print quality is good but not exceptional — it sits between PA6 and PPA in most categories. For users who specifically need BASF's industrial certification and documentation, Ultrafuse is a solid choice. For most users, QIDI UltraPA offers better performance at a similar price point.
Best for: Industrial users requiring BASF certification, high-temperature applications, chemical resistance.
Which Nylon Should You Buy?
| Use Case | Best Filament | Why |
|---|---|---|
| Best overall (strength + reliability) | QIDI UltraPA (PPA) | Best combination of strength, low moisture, low warping, excellent layer bonding |
| Budget / hobbyist | eSun PA6 | Cheapest option; acceptable for small parts with careful setup |
| Dimensional accuracy / stiffness | Polymaker PA12-CF | Lowest warping, excellent accuracy, but brittle |
| Bambu Lab printer owner | Bambu PAHT-CF | Optimized for Bambu ecosystem, highest tensile strength |
| Impact resistance / toughness | QIDI UltraPA (PPA) | 9.77% elongation + 9.74 kJ/m² impact — far tougher than CF nylons |
| Gears / bearings / wear parts | QIDI UltraPA (PPA) | Self-lubricating PPA, low friction, excellent abrasion resistance |
| High-temperature (100°C+) | Bambu PAHT-CF or Polymaker PA12-CF | 120-130°C HDT; CF reinforcement improves heat resistance |
| Industrial certification needed | Ultrafuse PAHT | BASF Forward AM documentation and certification |
Final Verdict
Winner: QIDI UltraPA (PPA) — $109.99/kg
QIDI UltraPA is the best nylon filament for 2026 because it solves the two biggest problems with nylon 3D printing: moisture absorption and warping. With 5x lower moisture than PA6 and the least warping of any nylon tested, it delivers the highest print success rate (90-95%) of any filament in this comparison. Its 69.29 MPa tensile strength, 112.64 MPa bending strength, and 2-3x ABS layer bonding make it strong enough for industrial functional parts. The self-lubricating PPA is ideal for gears and bearings. While the $109.99 price is higher than basic PA6, the low failure rate and superior mechanical properties make it the most cost-effective choice for professional users.
Who should buy it: Engineers, product designers, and makers who need reliable, strong, abrasion-resistant functional parts. Owners of enclosed printers (QIDI Max 4, X-MAX 3, Bambu X1C, Prusa XL) with hardened steel nozzles.
Who should not buy it: Beginners without an enclosure or hardened nozzle. Users printing decorative parts where PLA/PETG suffices. Those on a strict budget who only print small nylon parts occasionally.
Nylon Filament Printing Tips from 200+ Hours of Testing
Tip 1: Always Pre-Dry Even Vacuum-Sealed Filament
We tested filament directly from a sealed vacuum bag and found it still contained 1.2-2.5% moisture depending on the brand. While this is below the saturation point, it is enough to cause minor bubbling and surface defects on high-quality prints. Always dry for the recommended time before use. QIDI UltraPA needs only 4-6 hours due to its low moisture absorption, while PA6 needs 8-12 hours. The small time investment prevents costly failed prints.
Tip 2: Use a Dry Box During Printing
The biggest mistake we see is users drying filament, then leaving it on an open spool holder while printing. Nylon reabsorbs moisture from the air within 30-60 minutes (PA6) or 2-4 hours (PPA/PA12). For multi-hour prints, this means the first layers print great but later layers degrade in quality. Use a dry box or sealed bag with desiccant feeding directly to the printer. The QIDI Dryer Box is purpose-built for this and maintains humidity below 15% RH.
Tip 3: Calibrate Flow Rate for Nylon
Nylon has different flow characteristics than PLA or PETG due to its higher melting temperature and viscosity. We recommend calibrating the flow rate (extrusion multiplier) for each nylon filament using a 100% infill 20mm cube. Measure the wall thickness with calipers and adjust the flow rate until the measured width matches the expected width. For QIDI UltraPA, we found a flow rate of 1.02-1.05 (2-5% over-extrusion) produced the strongest parts with best layer bonding.
Tip 4: Print Small Test Parts First
Before committing to a large, expensive print with $109.99/kg filament, always print a small calibration test first. A 20mm temperature tower or retraction test takes 10-15 minutes and uses less than 5g of filament ($0.55). It verifies that the filament is dry, temperatures are correct, and bed adhesion is working. This simple step saves hours of failed prints and dollars of wasted filament.
Tip 5: Keep a Log of Successful Settings
Nylon printing has many variables (temperature, speed, retraction, drying time, chamber temp, glue type). Keep a log of settings that produce successful prints for each filament and printer combination. This makes it easy to replicate good results and troubleshoot when something changes. We maintain a spreadsheet with filament brand, color, drying time, nozzle temp, bed temp, chamber temp, speed, and notes for every successful print.
Future of Nylon 3D Printing Filaments
The nylon filament market is evolving rapidly. In 2026, we expect to see more PPA-based filaments from manufacturers like Polymaker, Bambu, and Fillamentum, as the low-moisture, low-warping advantages of PPA become widely recognized. Carbon fiber reinforced PPA is already in development, which could combine the strength of CF nylon with the toughness and low moisture of PPA. We also expect improved packaging standards, with more brands adopting vacuum aluminum foil to reduce moisture during shipping and storage. For now, QIDI UltraPA remains the benchmark for PPA nylon performance and reliability, and we will update this comparison as new contenders enter the market.
