3D Printing Info

Filament comparison

e-TPU vs PA6-CF

Compare printing settings, strength, heat resistance, dated prices and sources.

Foaming / expanded TPU (TPU Aero / TPU Air) guideCarbon-fibre PA6 (PA6-CF) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PA6-CF comparisons
e-TPU vs PA6-CF — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXCarbon-fibre PA6 (PA6-CF)PA
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$62.48/kg median; $39.00–$133.32/kg across 6 dated product listings
Identity & Market
Base polymer / chemistryFoaming thermoplastic polyurethane — a blowing agent expands the extrudate so the printed Shore hardness can be tuned by flow rate[1]PA6 reinforced with chopped carbon fibre — Polymaker's grade is 20 wt%[2][3]
Densityg/cm³1.15 filament (Siraya Tech Flex TPU Air) and 1.05 (Roamr TPU Air HR), ISO 1183; the printed part falls to 0.51–0.93 depending on nozzle temperature (ISO 845)[4][5]1.09 (Bambu Lab), 1.17 (Polymaker Fiberon and 3DXTech), ISO 1183[3][2][6]
Typical priceUSD/kg1 kg-equivalent spools span 42–85; the middle of the market is about 52[7][8][9][10][11][12]1 kg-equivalent spools span 39–133; the middle of the market is about 80[3][13][14][15]
Price range across brandsUSD/kg42–85 across brands; QIDI TPU-Aero 42, Siraya Tech Flex TPU Air 45, Phaetus aeFlex TPU-Aero 49 direct and 40 at West3D, Roamr TPU Air HR 80A 55 at 800 g, Recreus Filaflex Foamy 73 at 750 g, colorFabb varioShore 85 at 700 g[7][8][9][10][11][12][16]39–133 across brands; IEMAI 3D 39, Bambu Lab 43, YXPOLYER 45, Polymaker Fiberon 80, 3DXTech CarbonX 83, Obsidian 133[3][13][17][18][14][15]
Market availability1–5Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[1][7][8][9][11][12]Stocked by most mainstream brands[3][13][18][17][14][15]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][7][9][10][12]1.75 and 2.85 mm; 0.5, 0.75, 1 and 2 kg spools[13][18][3]
Typical applicationsCushioning, midsoles, insoles and soft-touch parts where the softness needs to vary within one print; Siraya Tech's Roamr line is aimed specifically at printed footwear[1][10]Load-bearing brackets, tooling and drone frames that must hold strength above 150 °C[3][2]
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[4][5]Not documented
Printing Parameters
Nozzle temperature°C230–270 (QIDI and Siraya Tech), 220–260 (Roamr); foaming activates near 230 °C and is strongest at the top of the range[1][4][5][11]260–290 (Bambu Lab); 280–300 (Polymaker Fiberon)[3][2]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][11]40–50 (Polymaker Fiberon)[2]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][5]Enclosure required (passive) — Bambu Lab specifies a 45–60 °C chamber, Polymaker room temperature[3][2]
Recommended chamber temperature°CNot documented45–60 (Bambu Lab); room temperature (Polymaker Fiberon)[3][2]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]Not documented
Bed surface & adhesion aidPEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent, and Siraya Tech recommends PVP glue or Magigoo as a release agent on PEI[19][20][4]Engineering or high-temperature plate with glue (Bambu Lab)[3]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[9]8 at Bambu Lab's 100 mm/s cap on a 0.4 mm nozzle at 0.2 mm layer; Polymaker rates its grade to 300 mm/s[3][2][21]
Bed-adhesion difficulty1–5Not documentedNeeds a specific surface plus adhesive[3]
Stringing / oozing tendency1–5Severe — the material expands inside the hot end, so it oozes on travel moves; QIDI states retraction tuning cannot fix it and Siraya Tech advises setting retraction distance and speed to zero[4][11]Moderate — retraction tuning needed[22]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Expert / industrial hardware only — enclosure, hardened nozzle, an 80 °C dry and a printer that can hold the filament dry throughout[3][2][23]
Extruder requirementDirect drive; the base material is a 92A TPU[1][24]0.6 mm nozzle recommended by Bambu Lab; 0.4 and 0.8 also supported[3]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[25][5]Hardened steel required — Polymaker measures brass nozzle life at about 9 h on PA6-CF20 and recommends hardened steel or ruby[2]
Abrasiveness1–5Non-abrasive[25]Highly abrasive — standard CF composite; Polymaker puts brass nozzle life at roughly 9 h[2]
Nozzle clog risk1–5Not documentedVery high — frequent jams without careful setup; the combination of moisture and fibre is the worst case in the dataset[23][2]
Heat-creep / jam sensitivity1–5Not documentedModerate — good heatbreak cooling needed[26]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[19]Hardened steel or ruby nozzle plus an all-metal hot end rated to 300 °C[2][3]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[23]Very high (>2 %) — 2.35 % saturated at 25 °C / 55 % RH (Bambu Lab)[3]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[11]2.35 saturated at 25 °C / 55 % RH (Bambu Lab)[3]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[4][5][11]80 °C for 8–12 h (Bambu Lab); 100 °C for 10 h (Polymaker Fiberon)[3][2]
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface; Siraya Tech adds that moisture wrecks the foaming itself, not only the surface[23][4]Popping and cracking during extrusion, then hard-to-diagnose defects[27]
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[23]Polymaker publishes dry and wet printed blocks for PA6-CF20 itself: at 5.30 % moisture tensile falls 109.3 → 54.7 MPa and modulus 8636 → 2508 MPa, while notched Charpy rises 11.0 → 35.6 kJ/m². Fibre reinforcement reduces but does not remove the effect[2][27]
Storage requirementSealed with desiccant; often kept in a dryer during the print[23]Sealed below 20 % RH with desiccant; often needs to stay in a dryer while printing[23]
Hydrolysis at melt temperatureNot documentedPolymaker specifies an 80–100 °C dry and storage below 20 % RH; no molecular-weight loss figure is published, and the wet data it does publish is conditioning rather than melt hydrolysis[2][28]
Mechanical Properties
Tensile strength (XY)MPaFalls with foaming: colorFabb 24 unfoamed and 12 foamed (ISO 527-1A); Siraya Tech 10.3 at break printed at 240 °C down to 3.8 at 270 °C; QIDI 6.81 at break (ISO 527, XY)[1][4][11]102 ± 7 (Bambu Lab) and 109.3 ± 2.4 (Polymaker Fiberon, dry/annealed) printed XY, ISO 527; the Fiberon grade falls to 54.7 ± 1.1 conditioned to 5.30 % moisture; 3DXTech quotes 63 at break[3][2][6]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]4430 ± 310 (Bambu Lab) and 8636 ± 211 (Polymaker Fiberon, dry/annealed) printed XY, ISO 527; Fiberon falls to 2508 ± 83 conditioned; 3DXTech quotes 3800[3][2][6]
Elongation at break%465 unfoamed and 450 foamed (colorFabb, ISO 527-1A); Siraya Tech 629 at 240 °C down to 475 at 270 °C; Roamr 760 down to 540; QIDI 576 (ISO 527, XY)[1][4][5][11]5.8 ± 1.6 printed XY, ISO 527 (Bambu Lab); 3DXTech quotes 3 at break[3][6]
Flexural strengthMPaNot documented161.0 ± 3.9 printed XY dry, 64.9 ± 4.9 conditioned, ISO 178 (Polymaker Fiberon); 3DXTech quotes 84[2][6]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]7038 ± 205 printed XY dry and 2286 ± 185 conditioned, ISO 178 (Polymaker Fiberon); 3DXTech quotes 3750[2][6]
Charpy impact, notchedkJ/m²Not documented11.0 ± 0.3 printed XY dry and 35.6 ± 1.2 conditioned, ISO 179 notched (Polymaker Fiberon)[2]
Other impact dataNot documentedCharpy unnotched 24.0 ± 1.0 printed XY dry and 73.0 ± 2.0 conditioned, 7.5 ± 2.7 printed Z dry (Polymaker Fiberon); Bambu Lab 40.3 ± 2.5 unnotched, 13.4 ± 1.7 notched[2][3]
Layer adhesion / Z tensileMPaNot documented48 ± 6 (Bambu Lab) and 54.0 ± 5.2 (Polymaker Fiberon, dry) printed Z, ISO 527; Fiberon falls to 25.5 ± 1.2 conditioned[3][2]
Brittleness1–5Very ductile — bends far before failing[1]Moderate[3][2]
Hardness (scale-specific)Shore A / Shore D / RockwellTunable by nozzle temperature: colorFabb 92 Shore A unfoamed; Siraya Tech 78 A printed at 240 °C falling to 63 A at 270 °C, Roamr TPU Air HR 80A 80 A down to 66 A and HR 85A 83 A down to 70 A (ISO 7619)[1][4][5][29]Rockwell M88 / R117 on extruded PA66-GF30 stock (ASTM D785); no figure is published for a carbon-fibre nylon filament[30]
Creep resistance / sustained load1–5Poor — no foamed-grade creep test; a printed 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[31]Good. Ensinger rates its PA66-CF30 injection-moulding compound for exceptional performance under both static and dynamic loading with 110 °C continuous service; in a printed part the fibre restrains the matrix, but conditioning to equilibrium moisture still softens it[32][27]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[20]Good. Ensinger states its PA66-CF30 compound has improved fatigue strength in tension, flexure and compression against unfilled and glass-filled PA66[32]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Rigid[3]
Z strength as % of XY%Not documented47 (Bambu Lab) to 49 (Polymaker Fiberon), printed[3][2]
Thermal Properties
HDT at 0.45 MPa°CNot documented186 (Bambu Lab) and 215 (Polymaker Fiberon), ISO 75 at 0.45 MPa[3][2]
HDT at 1.8 MPa°CNot documented164 (Bambu Lab) and 173 (Polymaker Fiberon), ISO 75 at 1.8 MPa[3][2]
Glass transition (Tg)°CNot documented68 (Bambu Lab) to 74.2 (Polymaker Fiberon), DSC; 3DXTech quotes 70[3][2][6]
Melting point / Vicat°CVicat softening drops as the foam expands: 83 printed at 240 °C to 53 at 270 °C (Siraya Tech, ISO 306); QIDI 70.4[4][11]223 melting (Bambu Lab, DSC); Vicat 212 (ISO 306)[3]
Continuous service temperature°CNot documentedBounded by heat deflection of 164–173 °C at 1.8 MPa; no loaded-bar service figure is published[3][2]
Annealing responseFoaming activates near 230 °C and expands the extrudate about 1.6×; colorFabb advises dropping flow to 60–70 % to realise the weight saving, and Siraya Tech publishes a flow schedule from 85–90 % at 230 °C down to 50–55 % at 270 °C[1][4]100 °C for 16 h (Polymaker Fiberon)[2]
Thermal expansion (CTE)µm/m·KNot documented94 in the XY direction and 180 in Z, measured on XY-built specimens (79 and 148 on XZ/ZX-built specimens), room temperature to 60 °C, ASTM E831. From Stratasys FDM Nylon-CF10, a blended-nylon matrix with 10 wt% carbon fibre — the closest published printed CTE for a carbon-fibre nylon[33]
Flammability / UL 94Not documentedFlammable; no UL 94 rating published[2]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[20]Months outdoors before embrittlement — unstabilised polyamide yellows and chalks under UV[22]
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[20]Withstands oils, fuels and alkalis[22]
Water / humidity resistance in service1–5Not documentedAbsorbs water, properties shift[27]
Food contactNot food safe without specific certification (Polymaker)[20]Not food-contact certified[22]
Biodegradability / compostabilityNot biodegradable[20]Not biodegradable[22]
RecyclabilityNot accepted in household plastic collection[20]Fibre-filled polyamide is not accepted in household plastic collection[22]
Electrical & ESD propertiesNot documentedSurface resistance above 10⁹ ohm/sq — not static-dissipative (3DXTech, ASTM D257)[6]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[34]Moderate — measurable VOCs and UFPs, ventilation advised[34]
VOC emission rateµg/minNot documentedUp to 180 caprolactam, the dominant VOC from nylon and the largest single-VOC rate in the study[34]
Ultrafine-particle emission rateparticles/minNot documented≈2 × 10⁸ median for nylon — low for particles despite the highest VOC mass measured[34]
Hazardous species emittedNot documentedCaprolactam, at up to 180 µg/min from nylon filament[34]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[34]Ventilated room or enclosure recommended[34]
Dust & fibre handling hazardNot documentedFibre is bound in the matrix; sanding dust should not be inhaled[2]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[20]Sands to a matte finish; the fibre makes it cut more cleanly than unfilled nylon[26]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[20]Cyanoacrylate; no common solvent welds polyamide[26]
Vapour / chemical smoothingNo practical vapour smoothing[20]No practical vapour smoothing[26]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[20]PolyDissolve S1 (Polymaker Fiberon)[2]
Dimensional accuracy & detailFoamed surfaces are matte and textured; holding a consistent hardness means holding the nozzle temperature steady, and the printed density moves by nearly a factor of two across the 230–270 °C window[1][4]Conditioned parts grow; Polymaker declines to publish a standard dimensional allowance because it depends on geometry and infill[27]
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[35]Formic acid, phenol, m-cresol and hexafluoroisopropanol dissolve the matrix at 23 °C, leaving the fibre; laboratory reagents.[36]
Softened or crazed byToluene and benzene swell it up to +50 % by weight at 23 °C; the foamed wall soaks up esters and alcohols faster still.[35]Zinc chloride solutions stress-crack the nylon matrix, alcoholic calcium chloride dissolves it, mineral acids attack it.[36]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[35]None — nylon's only solvents (formic acid, phenol, HFIP) degrade the part, and the fibre blocks surface flow anyway.[36]

Material entries describe families or representative grades, not an interchangeable specification for every spool. Test methods, orientations and conditions may differ. Unknown values are marked “Not documented”. Prices and source dates remain historical snapshots; check the linked guide for product details. Differences highlight text, not a universal winner.

Sources for this comparison

  1. varioShore TPU Technical Data Sheet colorFabb · 2026-08 · tds
  2. Fiberon PA6-CF20 Technical Data Sheet V1.1 Polymaker · 2024-12 · tds
  3. Bambu Filament Technical Data Sheet — PA6-CF Bambu Lab · 2026-08 · tds
  4. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  5. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · tds
  6. CarbonX Carbon Fiber Nylon (Gen3) Technical Data Sheet v3.0 3DXTech · 2026-08 · tds
  7. Recreus product catalogue Recreus · 2026-08 · vendor
  8. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  9. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  10. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  11. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  12. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  13. Polymaker product catalogue Polymaker · 2026-08 · vendor
  14. YXPOLYER PA6 CF-Black 1 kg — product page YXPOLYER · 2026-08 · vendor
  15. IEMAI 3D CF-PA6 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  16. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  17. Printed Solid product catalogue Printed Solid · 2026-08 · vendor
  18. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  19. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. TPU — material basics Polymaker Wiki · 2026-08 · doc
  21. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  22. PA (Nylon) — material basics Polymaker Wiki · 2026-08 · doc
  23. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  24. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  25. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  26. Nylon — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  27. Moisture Conditioning — effect on printed nylon properties Polymaker Wiki · 2026-08 · doc
  28. PolyMide CoPA Technical Data Sheet V5.4 (dry and wet status blocks) Polymaker · 2024-11 · tds
  29. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  30. TECAMID 66 GF30 black (PA66-GF30) — stock shape properties Ensinger · 2026-08 · tds
  31. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  32. TECACOMP PA66 CF30 black — injection-moulding compound Ensinger · 2026-08 · tds
  33. FDM Nylon-CF10 — Material Data Sheet (blended nylon, 10 wt% carbon fibre) Stratasys · 2026-08 · tds
  34. Emissions of Ultrafine Particles and Volatile Organic Compounds from Commercially Available Desktop Three-Dimensional Printers with Multiple Filaments (Azimi et al.) Environmental Science & Technology 50(3) 1260-1268 · 2016-01 · paper
  35. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  36. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds