3D Printing Info

Filament comparison

e-TPU vs PA aramid

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

Foaming / expanded TPU (TPU Aero / TPU Air) guideAramid-fibre nylon guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PA aramid comparisons
e-TPU vs PA aramid — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXAramid-fibre nylonPA
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listingsNot documented
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]Aramid-fibre reinforced polyamide[2]
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)[3][4]Not documented
Typical priceUSD/kg1 kg-equivalent spools span 42–85; the middle of the market is about 52[5][6][7][8][9][10]Not documented
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[5][6][7][8][9][10][11]Not documented
Market availability1–5Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[1][5][6][7][9][10]Special order, 1–2 makers worldwide — no aramid-filled nylon filament was found in any catalogue searched; the aramid filaments that do exist in the retail market use an ASA matrix[12][13]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][5][7][8][10]Not documented
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][8]Not documented
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[3][4]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][3][4][9]Not documented
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[3][4][9]Not documented
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][4]Enclosure required (passive) — as for every nylon[2]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[3][4]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[14][15][3]Not documented
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[7]Not documented
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[3][9]Not documented
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Not documented
Extruder requirementDirect drive; the base material is a 92A TPU[1][16]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[17][4]Hardened steel required — no aramid-filled nylon datasheet was obtainable; Polymaker measures about 9 h of brass nozzle life on its fibre-filled nylons[18]
Abrasiveness1–5Non-abrasive[17]Highly abrasive — fibre-reinforced nylon composite[18]
Nozzle clog risk1–5Not documentedHigh — jams from moisture, heat creep or particles; nylon already needs a drybox and Prusa names kevlar among the fibres that raise nozzle-clogging risk[19]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[14]Not documented
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[20]Very high (>2 %) — the polyamide matrix governs uptake[20]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[9]Not documented
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[3][4][9]Not documented
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[20][3]Not documented
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[20]Polymaker's printed dry-versus-wet blocks for its CoPA nylon show what conditioning does to the family: tensile 78.0 → 34.3 MPa and modulus 2703 → 724 MPa, with notched Charpy rising 6.9 → 27.7 kJ/m². Fibre reinforcement reduces but does not remove the effect[21][22]
Storage requirementSealed with desiccant; often kept in a dryer during the print[20]Not documented
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][3][9]Not documented
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]Not documented
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][3][4][9]Not documented
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]Not documented
Brittleness1–5Very ductile — bends far before failing[1]Not documented
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][3][4][23]Not documented
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[24]Not documented
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[15]Not documented
Elasticity / flexibility1–5Rubbery / highly elastic[1]Not documented
Thermal Properties
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[3][9]Not documented
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][3]Not documented
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[15]Not documented
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[15]Not documented
Food contactNot food safe without specific certification (Polymaker)[15]Not documented
Biodegradability / compostabilityNot biodegradable[15]Not documented
RecyclabilityNot accepted in household plastic collection[15]Not documented
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[25]Moderate — measurable VOCs and UFPs, ventilation advised[25]
VOC emission rateµg/minNot documentedUp to 180 caprolactam, the dominant VOC from nylon and the largest single-VOC rate in the study[25]
Ultrafine-particle emission rateparticles/minNot documented≈2 × 10⁸ median for nylon — low for particles despite the highest VOC mass measured[25]
Hazardous species emittedNot documentedCaprolactam, at up to 180 µg/min from nylon filament[25]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[25]Ventilated room or enclosure recommended[25]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[15]Not documented
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[15]Not documented
Vapour / chemical smoothingNo practical vapour smoothing[15]Not documented
Support material pairingPolymaker warns TPU supports are often very difficult to remove[15]Not documented
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][3]Not documented
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[26]Formic acid, phenol, m-cresol and hexafluoroisopropanol dissolve the matrix at 23 °C, leaving the fibre; laboratory reagents.[27]
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.[26]Zinc chloride solutions stress-crack the nylon matrix, alcoholic calcium chloride dissolves it, mineral acids attack it.[27]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[26]None — nylon's only solvents (formic acid, phenol, HFIP) degrade the part, and the fibre blocks surface flow anyway.[27]

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. PA (Nylon) — material basics Polymaker Wiki · 2026-08 · doc
  3. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  4. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · tds
  5. Recreus product catalogue Recreus · 2026-08 · vendor
  6. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  7. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  8. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  9. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  10. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  11. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  12. Polymaker product catalogue Polymaker · 2026-08 · vendor
  13. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  14. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  15. TPU — material basics Polymaker Wiki · 2026-08 · doc
  16. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  17. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  18. Fiberon PA6-CF20 Technical Data Sheet V1.1 Polymaker · 2024-12 · tds
  19. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  20. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  21. PolyMide CoPA Technical Data Sheet V5.4 (dry and wet status blocks) Polymaker · 2024-11 · tds
  22. Moisture Conditioning — effect on printed nylon properties Polymaker Wiki · 2026-08 · doc
  23. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  24. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  25. 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
  26. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  27. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds