3D Printing Info

Filament comparison

PET-CF vs TPU soft

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

Carbon-fibre PET (PET-CF) guideSoft TPU (below 85A) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PET-CF comparisonsMore TPU soft comparisons
PET-CF vs TPU soft — documented properties and sources
PropertyCarbon-fibre PET (PET-CF)PETGSoft TPU (below 85A)FLEX
Market snapshot
Listing priceUSD/kg; dated snapshots$39.99/kg median; $26.00–$49.98/kg across 4 dated product listings$114.04/kg median; $109.80–$122.27/kg across 4 dated product listings
Identity & Market
Base polymer / chemistrySemi-crystalline PET reinforced with carbon fibre — a different polymer from PETG-CF, with the glycol modifier removed so the matrix can crystallise[1][2]Very soft thermoplastic elastomers below 85 Shore A. Fiberlogy's FiberFlex 30D measures 81 Shore A, the softest grade with a published datasheet found here[3]
Densityg/cm³1.29 (Bambu Lab) and 1.34 (Fiberon PET-CF17), ISO 1183[1][2]1.07 (Fiberlogy FiberFlex 30D, ISO 1183)[3]
Typical priceUSD/kg1 kg spools cluster near 45[1][4]1 kg-equivalent spools cluster near 115[5][6][7]
Price range across brandsUSD/kg26–50 across brands; ELEGOO 26 in a 5 kg pack, Bambu Lab 45, Fiberon 50[8][1][4]110–122 at 1 kg-equivalent; Recreus 70A 110 and 60A 116 at 500 g, NinjaTek Edge 83A 112, NinjaTek Chinchilla 75A 122; the Recreus 3 kg spools fall to 70–73[5][7][6]
Market availability1–5Available from several mainstream brands[1][4][8]Niche, a handful of specialist brands[3][9][5]
Spool sizes & diameters1.75 mm; 0.5 and 1 kg spools[4][1]1.75, 2.85 and 3 mm; 0.5, 0.85, 1, 2 and 3 kg spools[3][5][10][6]
Typical applicationsLoad-bearing parts that must survive above PETG's 70 °C ceiling without moving to PA or PC[1][2]Highly compliant seals, soft grips and prosthetic liners[3]
Printing Parameters
Nozzle temperature°C260–290 (Bambu Lab)[1]Not documented
Bed temperature°C80–100 (Bambu Lab)[1]50–70 (Fiberlogy FiberFlex 30D)[3]
Enclosure / chamber requirement1–5Enclosure recommended — Bambu Lab specifies a 45–60 °C chamber[1]Open frame is fine[3]
Recommended chamber temperature°C45–60 (Bambu Lab)[1]Not documented
Part cooling fan0–60 % (Bambu Lab)[1]Not documented
Bed surface & adhesion aidTextured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[11][12]PEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent[13][14]
Maximum volumetric flow (mm³/s; see test conditions)mm³/s8 at Bambu Lab's 100 mm/s cap on a 0.4 mm nozzle at 0.2 mm layer — half the speed it allows for PETG-CF[1][15]Not documented
Bed-adhesion difficulty1–5Needs the right surface or a thin adhesive — the problem is releasing the part, not sticking it[11][12]Not documented
Stringing / oozing tendency1–5Moderate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[12]Not documented
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning[1]Expert / industrial hardware only — below 85 Shore A the filament buckles in almost any feed path that is not a short, constrained direct drive[10][14]
Extruder requirementNot documentedDirect drive only, with a constrained filament path; Bowden is not viable at this hardness[10][9]
Hardware Wear & Reliability
Nozzle hardness required1–4Hardened steel required[1]Brass fine indefinitely[16]
Abrasiveness1–5Highly abrasive — standard CF composite[1]Non-abrasive[16]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle; Prusa lists higher risk of nozzle clogging for carbon-filled composites[17]High — jams from moisture, heat creep or particles; below 85 Shore A the filament buckles and compresses, and Simplify3D warns that raised feed rates most likely end in a jam[13][14][18]
Heat-creep / jam sensitivity1–5Slightly sensitive[19]Very high — softens in the cold zone readily[14]
Hotend requirementNo special hot-end required[19]No special hot-end required, but a direct-drive extruder is (Simplify3D)[13]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate — 0.37 % saturated at 25 °C / 55 % RH (Bambu Lab); 0.53 % equilibrium (Fiberon)[1][2]Moderate[18]
Equilibrium moisture content at ~50 % RH%0.37 saturated at 25 °C / 55 % RH (Bambu Lab); 0.53 equilibrium (Fiberon PET-CF17)[1][2]Not documented
Drying temperature & time80 °C for 8–12 h (Bambu Lab) — the longest and hottest dry in the polyester family; Fiberon specifies 100 °C for 10 h[1][2]Not documented
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface[18]Bubbling and popping at the nozzle, stringing and a rough surface[18]
Effect of moisture on strengthBambu Lab publishes its whole mechanical table under the heading "Mechanical Properties (Dry state)" — the quoted figures apply only to dried filament[1]Polymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[18]
Storage requirementSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[18][12]Sealed with desiccant; often kept in a dryer during the print[18]
Hydrolysis at melt temperatureThe 80–100 °C dry both suppliers mandate is far above the 55–65 °C used for PETG, consistent with a melt-hydrolysis risk in the semi-crystalline PET matrix; neither publishes a molecular-weight loss figure[1][2]Not documented
Mechanical Properties
Tensile strength (XY)MPa65.9 (Fiberon) to 74 (Bambu Lab) printed XY, ISO 527[1][2]Not documented
Young's modulusMPa4730 ± 260 (Bambu Lab) and 5481 ± 224 (Fiberon) printed XY, ISO 527[1][2]Not documented
Elongation at break%2.4 ± 0.5 printed XY, ISO 527 (Fiberon PET-CF17)[2]870 at break (Fiberlogy FiberFlex 30D, ISO 527) — the highest elongation in the dataset[3]
Flexural strengthMPa109.3 ± 2.0 printed XY, ISO 178 (Fiberon PET-CF17)[2]Not documented
Flexural modulusMPa4744 ± 136 printed XY, ISO 178 (Fiberon PET-CF17)[2]Not documented
Charpy impact, notchedkJ/m²5.1 ± 0.2 printed XY, ISO 179 notched (Fiberon PET-CF17); unnotched 25.1 ± 2.8[2]Not documented
Layer adhesion / Z tensileMPa27.9 (Fiberon) and 35 ± 5 (Bambu Lab) printed Z, ISO 527[1][2]Not documented
Brittleness1–5Very brittle — elongation at break 2.4 % in XY and 0.8 % in Z[2]Very ductile — bends far before failing[3]
Hardness (scale-specific)Shore A / Shore D / RockwellNot documented81 Shore A and 30 Shore D (Fiberlogy FiberFlex 30D, ISO 7619)[3]
Creep resistance / sustained load1–5Good — no creep test found; annealed PET-CF holds a 105 °C HDT at 1.8 MPa and a 4730–5481 MPa modulus against 1500–2311 for PETG[2][1]Poor — no creep test at this hardness; a printed 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[20]
Fatigue / repeated-flex resistance1–5Below average — no S-N curve; elongation at break is 2.4 % in XY and 0.8 % in Z, against 5.2–9.3 % for unfilled PETG[2]Excellent — living hinges viable[14]
Elasticity / flexibility1–5Rigid[1]Rubbery / highly elastic[3]
Z strength as % of XY%42 (Fiberon) to 47 (Bambu Lab), printed[1][2]Not documented
Wear resistance & frictionNot documentedTear strength 95 kN/m (Fiberlogy FiberFlex 30D, ISO 34-1)[3]
Thermal Properties
HDT at 0.45 MPa°C147.5 (Fiberon) and 205 (Bambu Lab), ISO 75 at 0.45 MPa[1][2]Not documented
HDT at 1.8 MPa°C105 (Fiberon) and 182 (Bambu Lab), ISO 75 at 1.8 MPa[1][2]Not documented
Glass transition (Tg)°C75 (Bambu Lab) and 79.3 (Fiberon), DSC[1][2]Not documented
Melting point / Vicat°C241.3 (Fiberon) and 250 (Bambu Lab) melting, DSC; Vicat 226–238[1][2]170 melting (Fiberlogy FiberFlex 30D, DSC)[3]
Annealing responseThe PET matrix crystallises on annealing, which is what separates this grade from PETG-CF[2][1]Not documented
Flammability / UL 94Flammable; no UL 94 rating published for standard grades[21]Not documented
Environment & Chemical
UV resistance1–5Not documentedGood — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[14]
Chemical resistanceWithstands acids, alkalis, oils and UV exposure[12]Withstands industrial solvents and UV exposure (Polymaker)[14]
Food contactNot certified for food contact as filament[12]Not food safe without specific certification (Polymaker)[14]
Biodegradability / compostabilityNot biodegradable[12]Not biodegradable[14]
RecyclabilityNot accepted in household plastic collection[12]Not accepted in household plastic collection[14]
Electrical & ESD propertiesSurface resistivity above 10¹² ohm — insulating (Fiberon PET-CF17, ANSI/ESD S11.11)[2]Not documented
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised[22]Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[22]
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[22][1]Open a window / occasional ventilation[22]
Dust & fibre handling hazardCarbon fibre is bound in the matrix; sanding dust should not be inhaled[2]Not documented
Post-Processing
Sanding & machiningSands poorly — the material is tough and gums rather than powders[19]Difficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[14]
Gluing & solvent weldingCyanoacrylate; no common solvent welds PETG cleanly[19]Cyanoacrylate bonds TPU; no common solvent welds it[14]
Vapour / chemical smoothingNo practical vapour smoothing[19]No practical vapour smoothing[14]
Support material pairingPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[19]Polymaker warns TPU supports are often very difficult to remove[14]
Dimensional accuracy & detailBambu Lab markets it on low warping and shrinkage relative to other high-temperature composites[1]Not documented
Solvents & Solubility
Soluble inNone common; fluorinated solvents such as hexafluoroisopropanol dissolve linear polyester at 23 °C. Laboratory only.[23][24]DMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[25]
Softened or crazed byEnsinger rates polyester not resistant to chloroform or dichloromethane and only conditionally resistant to acetone and MEK.[24]Toluene and benzene swell it up to +50 % by weight at 23 °C; esters swell it severely; ethanol and IPA soften it.[25]
Solvent welding & smoothing agentDichloromethane attacks polyester and can be brushed on, but the carbon fibre blocks any useful surface flow.[24][26]None practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[25]

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. Bambu Filament Technical Data Sheet — PET-CF Bambu Lab · 2026-08 · tds
  2. Fiberon PET-CF17 Technical Data Sheet V1.0 Polymaker · 2026-08 · tds
  3. FiberFlex 30D Technical Data Sheet Fiberlogy · 2026-08 · tds
  4. Polymaker product catalogue Polymaker · 2026-08 · vendor
  5. Recreus product catalogue Recreus · 2026-08 · vendor
  6. Chinchilla product page — print guidelines, spool sizes and price NinjaTek · 2026-08 · vendor
  7. NinjaFlex Edge product page — durometer, print guidelines and price NinjaTek · 2026-08 · vendor
  8. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  9. Filaflex 82A product page (Shore hardness and elongation) Recreus · 2026-08 · vendor
  10. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  11. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  12. PETG — material basics Polymaker Wiki · 2026-08 · doc
  13. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  14. TPU — material basics Polymaker Wiki · 2026-08 · doc
  15. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  16. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  17. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  18. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  19. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  21. Prusament PETG V0 Technical Datasheet Prusa Polymers · 2026-08 · tds
  22. 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
  23. Resistance of Ultramid, Ultraform and Ultradur to chemicals (TI-KTU/AS-28 e) BASF · 2000-10 · tds
  24. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds
  25. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  26. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc