3D Printing Info

Filament comparison

PEI 9085 vs PET-CF

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

PEI (ULTEM 9085) guideCarbon-fibre PET (PET-CF) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PEI 9085 comparisonsMore PET-CF comparisons
PEI 9085 vs PET-CF — documented properties and sources
PropertyPEI (ULTEM 9085)HIGHTEMPCarbon-fibre PET (PET-CF)PETG
Market snapshot
Listing priceUSD/kg; dated snapshots$309.80/kg median; $220.00–$392.00/kg across 6 dated product listings$39.99/kg median; $26.00–$49.98/kg across 4 dated product listings
Identity & Market
Base polymer / chemistryPolyetherimide, ULTEM 9085 grade — the flame-retardant PEI used for aircraft interiors[1]Semi-crystalline PET reinforced with carbon fibre — a different polymer from PETG-CF, with the glycol modifier removed so the matrix can crystallise[2][3]
Densityg/cm³1.34 (ISO 1183, 3DXTech) against 1.27 specific gravity on moulded plaques (ASTM D792, Stratasys) — the two suppliers disagree[1][4]1.29 (Bambu Lab) and 1.34 (Fiberon PET-CF17), ISO 1183[2][3]
Typical priceUSD/kg1 kg-equivalent spools cluster near 298[5][6][7][8]1 kg spools cluster near 45[2][9]
Price range across brandsUSD/kg220-392 across brands and formats; 3DXTech ThermaX PEI 9085 220 at 2 kg, 3D4Makers 270 at 2 kg, Fiberlogy 298 at 500 g, Kimya 321 at 500 g, IEMAI 3D 385 at 1 kg, 3DXTech CarbonX PEI 9085+CF 392[5][6][7][8][10]26–50 across brands; ELEGOO 26 in a 5 kg pack, Bambu Lab 45, Fiberon 50[11][2][9]
Market availability1–5Niche, a handful of specialist brands[5][6][7][8]Available from several mainstream brands[2][9][11]
Spool sizes & diameters1.75 and 2.85 mm; 250 g to 2 kg spools, plus Stratasys canisters[5][8][4]1.75 mm; 0.5 and 1 kg spools[9][2]
Typical applicationsAircraft interior parts and rail rolling stock, where the flame, smoke and toxicity rating is the requirement[1]Load-bearing parts that must survive above PETG's 70 °C ceiling without moving to PA or PC[2][3]
Printing Parameters
Nozzle temperature°CNot documented260–290 (Bambu Lab)[2]
Bed temperature°C130–140 (3DXTech)[1]80–100 (Bambu Lab)[2]
Enclosure / chamber requirement1–5Actively heated chamber required[12][13]Enclosure recommended — Bambu Lab specifies a 45–60 °C chamber[2]
Recommended chamber temperature°CNot documented45–60 (Bambu Lab)[2]
Part cooling fanNot documented0–60 % (Bambu Lab)[2]
Bed surface & adhesion aidNot documentedTextured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[14][15]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sNot documented8 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[2][16]
Warping tendency1–5Severe — heated chamber needed[12]Not documented
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive — the problem is releasing the part, not sticking it[14][15]
Stringing / oozing tendency1–5Not documentedModerate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[15]
Overall printing difficulty1–5Expert / industrial hardware only[12][13]Advanced — enclosure, hardware upgrades, tuning[2]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely for unfilled grades, but brass softens near these nozzle temperatures — hardened or plated hot ends are the norm[12]Hardened steel required[2]
Abrasiveness1–5Non-abrasive when unfilled[1]Highly abrasive — standard CF composite[2]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle; 3DXTech lists no special nozzle concerns but a mandatory 120 °C pre-dry before every print[17]Moderate — needs dry filament and a clean nozzle; Prusa lists higher risk of nozzle clogging for carbon-filled composites[18]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[19]
Hotend requirementNot documentedNo special hot-end required[19]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Not documentedModerate — 0.37 % saturated at 25 °C / 55 % RH (Bambu Lab); 0.53 % equilibrium (Fiberon)[2][3]
Equilibrium moisture content at ~50 % RH%Not documented0.37 saturated at 25 °C / 55 % RH (Bambu Lab); 0.53 equilibrium (Fiberon PET-CF17)[2][3]
Drying temperature & timeNot documented80 °C for 8–12 h (Bambu Lab) — the longest and hottest dry in the polyester family; Fiberon specifies 100 °C for 10 h[2][3]
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface[20]
Effect of moisture on strengthNo dry-versus-conditioned figures are published; 3DXTech mandates a 120 °C, 4 h pre-dry before every print because trapped water flashes to steam at these nozzle temperatures[17]Bambu Lab publishes its whole mechanical table under the heading "Mechanical Properties (Dry state)" — the quoted figures apply only to dried filament[2]
Storage requirementNot documentedSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[20][15]
Hydrolysis at melt temperatureNot documentedThe 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[2][3]
Mechanical Properties
Tensile strength (XY)MPa63-77 at break (printed XZ, ASTM D638, Stratasys F900/F3300/Fortus 450mc, three tips and two colours); 54 (printed XY, ISO 527, 3DXTech)[4][1]65.9 (Fiberon) to 74 (Bambu Lab) printed XY, ISO 527[2][3]
Young's modulusMPa2040-2540 (printed XZ, ASTM D638, Stratasys); 2050 (printed XY, ISO 527, 3DXTech)[4][1]4730 ± 260 (Bambu Lab) and 5481 ± 224 (Fiberon) printed XY, ISO 527[2][3]
Elongation at break%5.4-9.1 at break (printed XZ, ASTM D638, Stratasys); 1.9-4.3 in ZX; 3DXTech quotes 3 (ISO 527)[4][1]2.4 ± 0.5 printed XY, ISO 527 (Fiberon PET-CF17)[3]
Flexural strengthMPa104-116 at break (printed XZ, ASTM D790 Procedure A, Stratasys); 72-98 in ZX; 3DXTech quotes 90 (ISO 178)[4][1]109.3 ± 2.0 printed XY, ISO 178 (Fiberon PET-CF17)[3]
Flexural modulusMPa2400-2550 (printed XZ, ASTM D790, Stratasys F900 T16 and T16A) against 2120-2130 in ZX; 3DXTech quotes 2170 (ISO 178)[4][1]4744 ± 136 printed XY, ISO 178 (Fiberon PET-CF17)[3]
Charpy impact, notchedkJ/m²Not documented5.1 ± 0.2 printed XY, ISO 179 notched (Fiberon PET-CF17); unnotched 25.1 ± 2.8[3]
Other impact dataIzod notched 88.5-140 J/m XZ against 37-80 J/m ZX; unnotched 647-2260 J/m XZ against 169-633 J/m ZX (printed, ASTM D256/D4812, Stratasys, across three printers and three tips)[4]Not documented
Layer adhesion / Z tensileMPa39-63 at break (printed ZX, ASTM D638, Stratasys); the low end is the F900 T16 baseline, the high end the F3300 N500 hot end[4]27.9 (Fiberon) and 35 ± 5 (Bambu Lab) printed Z, ISO 527[2][3]
Brittleness1–5Brittle — snaps with little warning[1]Very brittle — elongation at break 2.4 % in XY and 0.8 % in Z[3]
Hardness (scale-specific)Shore A / Shore D / RockwellRockwell M110 / R126 on extruded PEI stock (ASTM D785)[21]Not documented
Creep resistance / sustained load1–5Excellent — holds load for years. Printed ZX coupons keep 87 % of room-temperature tensile strength at 104 °C and 70 % at 132 °C (ASTM D638); extruded PEI stock is rated 170 °C long-term service[4][21]Good — 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[3][2]
Fatigue / repeated-flex resistance1–5Not documentedBelow 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[3]
Elasticity / flexibility1–5Rigid[1]Rigid[2]
Z strength as % of XY%56-86 (Stratasys ZX against XZ tensile at break, ASTM D638, across F900/F3300/Fortus 450mc and T16/T20/T40A tips); 58 on the F900 T16 baseline[4]42 (Fiberon) to 47 (Bambu Lab), printed[2][3]
Thermal Properties
HDT at 0.45 MPa°C158 (printed XY, ISO 75 at 0.45 MPa, 3DXTech) to 178 (printed XY 178.2 and ZX 178.4, ASTM D648 Method B at 66 psi, Stratasys); moulded 176.9[1][4]147.5 (Fiberon) and 205 (Bambu Lab), ISO 75 at 0.45 MPa[2][3]
HDT at 1.8 MPa°C170-173 (printed XY 170.2 and ZX 172.6, ASTM D648 Method B at 264 psi); moulded 172.9[4]105 (Fiberon) and 182 (Bambu Lab), ISO 75 at 1.8 MPa[2][3]
Glass transition (Tg)°C177 (moulded plaque, ASTM D7426 inflection point, Stratasys); 186 (DSC, 3DXTech)[4][1][22]75 (Bambu Lab) and 79.3 (Fiberon), DSC[2][3]
Melting point / Vicat°CNot documented241.3 (Fiberon) and 250 (Bambu Lab) melting, DSC; Vicat 226–238[2][3]
Continuous service temperature°C170 long-term service on extruded PEI stock, converted from 338 °F; 200 short term[21]Not documented
Annealing responseNot documentedThe PET matrix crystallises on annealing, which is what separates this grade from PETG-CF[3][2]
Thermal expansion (CTE)µm/m·K44.9 (printed XY, -50 to 80 °C, ASTM E831), falling to 31.4 over 80-160 °C; ZX gives 44.5 over -50 to 60 °C. Black pigment raises it to 51.9[4]Not documented
Flammability / UL 94UL 94 V-0 at 1.5 mm on the base resin. Printed parts are tested to 14 CFR 25.853, BSS 7238 and 7239 and AITM 2.0007B and 3.0005 covering 60 s and 12 s vertical burn, 15 s horizontal burn, smoke density, toxic gas emission and OSU heat release[1][4]Flammable; no UL 94 rating published for standard grades[23]
Environment & Chemical
UV resistance1–5Good — years with some colour shift. 1000 h of QUV cycling to ASTM G154 left printed ZX coupons at 55.5 MPa yield against 56.0 unexposed, with elongation and modulus unchanged[4]Not documented
Chemical resistanceNot documentedWithstands acids, alkalis, oils and UV exposure[15]
Food contactNot documentedNot certified for food contact as filament[15]
Biodegradability / compostabilityNot documentedNot biodegradable[15]
RecyclabilityNot documentedNot accepted in household plastic collection[15]
Electrical & ESD propertiesNot documentedSurface resistivity above 10¹² ohm — insulating (Fiberon PET-CF17, ANSI/ESD S11.11)[3]
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised. None of these polymers was in the chamber study, and all are processed far above the temperatures it covered[24]Moderate — measurable VOCs and UFPs, ventilation advised[24]
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[24]Ventilated room or enclosure recommended[24][2]
Dust & fibre handling hazardNot documentedCarbon fibre is bound in the matrix; sanding dust should not be inhaled[3]
Post-Processing
Sanding & machiningNot documentedSands poorly — the material is tough and gums rather than powders[19]
Gluing & solvent weldingNot documentedCyanoacrylate; no common solvent welds PETG cleanly[19]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[19]
Support material pairingNot documentedPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[19]
Dimensional accuracy & detailNot documentedBambu Lab markets it on low warping and shrinkage relative to other high-temperature composites[2]
Solvents & Solubility
Soluble inChlorinated hydrocarbons — dichloromethane and chloroform — are solvents for polyetherimide. Laboratory reagents.[25][26]None common; fluorinated solvents such as hexafluoroisopropanol dissolve linear polyester at 23 °C. Laboratory only.[27][26]
Softened or crazed byAcetone, MEK, benzene, toluene and butyl acetate craze or stress-crack it; alcohols, fuels and dilute acids do not.[26][25]Ensinger rates polyester not resistant to chloroform or dichloromethane and only conditionally resistant to acetone and MEK.[26]
Solvent welding & smoothing agentDichloromethane is the only welding route, and it is a controlled carcinogen rather than a workshop material.[25][26]Dichloromethane attacks polyester and can be brushed on, but the carbon fibre blocks any useful surface flow.[26][28]

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. ThermaX PEI 9085 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  2. Bambu Filament Technical Data Sheet — PET-CF Bambu Lab · 2026-08 · tds
  3. Fiberon PET-CF17 Technical Data Sheet V1.0 Polymaker · 2026-08 · tds
  4. ULTEM 9085 Resin — FDM Material Data Sheet Stratasys · 2026-04 · tds
  5. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  6. Kimya PEI-9085 Natural 2.85 mm 500 g igo3d · 2026-08 · vendor
  7. Fiberlogy PEI 9085 Natural, 1.75 mm / 500 g 3DJAKE · 2026-08 · vendor
  8. 3D4Makers product catalogue 3D4Makers · 2026-08 · vendor
  9. Polymaker product catalogue Polymaker · 2026-08 · vendor
  10. IEMAI 3D PEI 9085 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  11. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  12. Prusament PEI 1010 Technical Datasheet v1.0 Prusa Polymers · 2024-09 · tds
  13. Prusament PEI 1010 — material page Prusa Polymers · 2026-08 · doc
  14. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  15. PETG — material basics Polymaker Wiki · 2026-08 · doc
  16. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  17. THERMAX PEI 9085 — product page (print recommendations) 3DXTech · 2026-08 · doc
  18. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  19. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  21. TECAPEI natural (PEI) — stock shape properties Ensinger · 2026-08 · tds
  22. ThermaX PEI 1010 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  23. Prusament PETG V0 Technical Datasheet Prusa Polymers · 2026-08 · tds
  24. 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
  25. Radel PPSU, Veradel PESU, Acudel modified PPSU Design Guide — environmental stress cracking tables Solvay Specialty Polymers · 2026-08 · tds
  26. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds
  27. Resistance of Ultramid, Ultraform and Ultradur to chemicals (TI-KTU/AS-28 e) BASF · 2000-10 · tds
  28. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc