3D Printing Info

Filament comparison

PA6/66 vs PEI 9085

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

PA66 (Nylon 66) guidePEI (ULTEM 9085) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PA6/66 comparisonsMore PEI 9085 comparisons
PA6/66 vs PEI 9085 — documented properties and sources
PropertyPA66 (Nylon 66)PAPEI (ULTEM 9085)HIGHTEMP
Market snapshot
Listing priceUSD/kg; dated snapshotsNot documented$309.80/kg median; $220.00–$392.00/kg across 6 dated product listings
Identity & Market
Base polymer / chemistryPolyamide 66, condensed from hexamethylenediamine and adipic acid; melts around 40 °C above PA6[1]Polyetherimide, ULTEM 9085 grade — the flame-retardant PEI used for aircraft interiors[2]
Densityg/cm³1.14 (extruded unfilled PA66 stock)[3]1.34 (ISO 1183, 3DXTech) against 1.27 specific gravity on moulded plaques (ASTM D792, Stratasys) — the two suppliers disagree[2][4]
Typical priceUSD/kgNot documented1 kg-equivalent spools cluster near 298[5][6][7][8]
Price range across brandsUSD/kgNot documented220-392 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][9]
Market availability1–5Special order, 1–2 makers worldwide — no unfilled PA66 filament appeared in any catalogue searched, and the 3DXTech nylon range offers PA6, PA12 and a 6/66 copolymer but no straight PA66[5][10]Niche, a handful of specialist brands[5][6][7][8]
Spool sizes & diametersNot documented1.75 and 2.85 mm; 250 g to 2 kg spools, plus Stratasys canisters[5][8][4]
Typical applicationsNot documentedAircraft interior parts and rail rolling stock, where the flame, smoke and toxicity rating is the requirement[2]
Printing Parameters
Bed temperature°CNot documented130–140 (3DXTech)[2]
Enclosure / chamber requirement1–5Enclosure required (passive)[1]Actively heated chamber required[11][12]
Warping tendency1–5Not documentedSevere — heated chamber needed[11]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning[1]Expert / industrial hardware only[11][12]
Hardware Wear & Reliability
Nozzle hardness required1–4Not documentedBrass fine indefinitely for unfilled grades, but brass softens near these nozzle temperatures — hardened or plated hot ends are the norm[11]
Abrasiveness1–5Not documentedNon-abrasive when unfilled[2]
Nozzle clog risk1–5Very high — frequent jams without careful setup[13][14]Moderate — needs dry filament and a clean nozzle; 3DXTech lists no special nozzle concerns but a mandatory 120 °C pre-dry before every print[15]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Very high (>2 %)[14]Not documented
Equilibrium moisture content at ~50 % RH%8.5 at saturation on extruded PA66 stock (ASTM D570) — the highest uptake of any polymer in this dataset[3]Not documented
Effect of moisture on strengthMeasured dry against wet on printed specimens at 6.16 % moisture (Polymaker CoPA): tensile 78.0 → 34.3 MPa, Young's modulus 2703 → 724 MPa, flexural strength 109.8 → 22.6 MPa, while notched Charpy rises 6.9 → 27.7 kJ/m² and elongation 12.7 → 13.2 %[16][13]No 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[15]
Mechanical Properties
Tensile strength (XY)MPa82.7 at yield and 84.8 at break on extruded PA66 stock (ASTM D638; converted from 12,000 and 12,300 psi) — no printed figure exists because no unfilled PA66 filament was found[3]63-77 at break (printed XZ, ASTM D638, Stratasys F900/F3300/Fortus 450mc, three tips and two colours); 54 (printed XY, ISO 527, 3DXTech)[4][2]
Young's modulusMPa2413 on extruded PA66 stock (ASTM D638; converted from 350,000 psi)[3]2040-2540 (printed XZ, ASTM D638, Stratasys); 2050 (printed XY, ISO 527, 3DXTech)[4][2]
Elongation at break%50 at break on extruded PA66 stock (ASTM D638)[3]5.4-9.1 at break (printed XZ, ASTM D638, Stratasys); 1.9-4.3 in ZX; 3DXTech quotes 3 (ISO 527)[4][2]
Flexural strengthMPa113.8 on extruded PA66 stock (ASTM D790; converted from 16,500 psi)[3]104-116 at break (printed XZ, ASTM D790 Procedure A, Stratasys); 72-98 in ZX; 3DXTech quotes 90 (ISO 178)[4][2]
Flexural modulusMPa3034 on extruded PA66 stock (ASTM D790; converted from 440,000 psi)[3]2400-2550 (printed XZ, ASTM D790, Stratasys F900 T16 and T16A) against 2120-2130 in ZX; 3DXTech quotes 2170 (ISO 178)[4][2]
Other impact dataIzod 53 J/m on extruded PA66 stock, converted from 1.0 ft-lb/in (ASTM D256)[3]Izod 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]
Layer adhesion / Z tensileMPaNot documented39-63 at break (printed ZX, ASTM D638, Stratasys); the low end is the F900 T16 baseline, the high end the F3300 N500 hot end[4]
Brittleness1–5Not documentedBrittle — snaps with little warning[2]
Hardness (scale-specific)Shore A / Shore D / RockwellShore D 86 and Rockwell 85 (108) — the source does not name the scales on extruded PA66 stock (ASTM D2240, D785)[3]Rockwell M110 / R126 on extruded PEI stock (ASTM D785)[17]
Creep resistance / sustained load1–5Not documentedExcellent — 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][17]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[1]Not documented
Elasticity / flexibility1–5Semi-flexible[13]Rigid[2]
Z strength as % of XY%Not documented56-86 (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]
Wear resistance & frictionWear factor 200e-10 in3*min/(ft*lb*h) on extruded PA66 stock (ASTM D3702); Ensinger lists very good slide and wear properties[3]Not documented
Thermal Properties
HDT at 0.45 MPa°C232 on extruded PA66 stock (ASTM D648 at 66 psi; converted from 450 °F)[3]158 (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[2][4]
HDT at 1.8 MPa°C90 on extruded PA66 stock (ASTM D648 at 264 psi; converted from 194 °F) — the gap to the 0.45 MPa figure is the widest in the dataset[3]170-173 (printed XY 170.2 and ZX 172.6, ASTM D648 Method B at 264 psi); moulded 172.9[4]
Glass transition (Tg)°CNot documented177 (moulded plaque, ASTM D7426 inflection point, Stratasys); 186 (DSC, 3DXTech)[4][2][18]
Melting point / Vicat°C255 melting on extruded PA66 stock (ASTM D2133; converted from 491 °F)[3]Not documented
Continuous service temperature°C85 long term and 149 short term on extruded PA66 stock (converted from 185 °F and 300 °F)[3]170 long-term service on extruded PEI stock, converted from 338 °F; 200 short term[17]
Thermal expansion (CTE)µm/m·K81.0 (extruded PA66 stock, ASTM D696; source states 4.5e-5 in/in/°F)[3]44.9 (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]
Flammability / UL 94UL 94 V-2 on extruded PA66 stock[3]UL 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[2][4]
Environment & Chemical
UV resistance1–5Not documentedGood — 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]
Electrical & ESD propertiesVolume resistance 1e15 ohm-cm and dielectric constant 4 on extruded PA66 stock (ASTM D257, D150)[3]Not documented
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised[19]Moderate — 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[19]
VOC emission rateµg/minUp to 180 caprolactam, the dominant VOC from nylon; total VOC reached nearly 200 µg/min, the highest of the nine filaments tested[19]Not documented
Ultrafine-particle emission rateparticles/min≈2 × 10⁸ median — low for ultrafine particles despite the highest VOC mass of any filament tested[19]Not documented
Hazardous species emittedCaprolactam, at up to 180 µg/min from nylon filament — the largest single-VOC emission rate measured in the study[19]Not documented
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[19]Ventilated room or enclosure recommended[19]
Solvents & Solubility
Soluble inDissolved at 23 °C by formic acid above ~80 %, phenol, m-cresol, 96 % sulphuric acid or hexafluoroisopropanol — laboratory reagents.[20]Chlorinated hydrocarbons — dichloromethane and chloroform — are solvents for polyetherimide. Laboratory reagents.[21][22]
Softened or crazed byZinc chloride solutions stress-crack it — 10 % marginal, 37 % not resistant; alcoholic calcium chloride dissolves it.[20]Acetone, MEK, benzene, toluene and butyl acetate craze or stress-crack it; alcohols, fuels and dilute acids do not.[22][21]
Solvent welding & smoothing agentNone — nylon's only solvents are formic acid, phenol and HFIP, all of which degrade the part they wet.[20]Dichloromethane is the only welding route, and it is a controlled carcinogen rather than a workshop material.[21][22]

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. PA (Nylon) — material basics Polymaker Wiki · 2026-08 · doc
  2. ThermaX PEI 9085 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  3. TECAMID 66 natural (PA66) — stock shape properties Ensinger · 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. IEMAI 3D PEI 9085 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  10. Polymaker product catalogue Polymaker · 2026-08 · vendor
  11. Prusament PEI 1010 Technical Datasheet v1.0 Prusa Polymers · 2024-09 · tds
  12. Prusament PEI 1010 — material page Prusa Polymers · 2026-08 · doc
  13. Moisture Conditioning — effect on printed nylon properties Polymaker Wiki · 2026-08 · doc
  14. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  15. THERMAX PEI 9085 — product page (print recommendations) 3DXTech · 2026-08 · doc
  16. PolyMide CoPA Technical Data Sheet V5.4 (dry and wet status blocks) Polymaker · 2024-11 · tds
  17. TECAPEI natural (PEI) — stock shape properties Ensinger · 2026-08 · tds
  18. ThermaX PEI 1010 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  19. 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
  20. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds
  21. Radel PPSU, Veradel PESU, Acudel modified PPSU Design Guide — environmental stress cracking tables Solvay Specialty Polymers · 2026-08 · tds
  22. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds