3D Printing Info

Filament comparison

e-TPU vs PA12

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

Foaming / expanded TPU (TPU Aero / TPU Air) guidePA12 (Nylon 12) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PA12 comparisons
e-TPU vs PA12 — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXPA12 (Nylon 12)PA
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$64.33/kg median; $36.00–$170.67/kg across 3 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]Polyamide 12 — the longest-chain common nylon, with the fewest amide groups per unit mass and so the least moisture uptake[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]1.01 specific gravity (Stratasys FDM Nylon 12, ASTM D792)[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 36–171; the middle of the market is about 64[13][14]
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][15]36–171 across brands; IEMAI 3D 36, Fiberlogy 64 at 3DJake, 3DXTech AmideX Nylon 12 171[13][16][14]
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]Available from several mainstream brands[13][16]
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; 750 g and 1 kg spools[16][13]
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]Dimensionally stable functional parts, ducting and living hinges where PA6 would move too much with humidity[2][17]
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 (Extrudr DURAPRO PA12)[18]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][11]110 (Extrudr DURAPRO PA12)[18]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][5]Enclosure required (passive)[2]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]Part cooling fan not required (Simplify3D)[19]
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[20][21][4]PEI sheet with a glue stick, or a dedicated adhesive such as Magigoo[19][2]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[9]12 at Extrudr's 150 mm/s cap on a 0.4 mm nozzle at 0.2 mm layer[18][22]
Bed-adhesion difficulty1–5Not documentedNeeds a specific surface plus adhesive[19][2]
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[2]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Advanced — enclosure, hardware upgrades, tuning[2]
Extruder requirementDirect drive; the base material is a 92A TPU[1][23]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[18][5]Brass fine indefinitely for unfilled grades[2]
Abrasiveness1–5Non-abrasive[18]Non-abrasive when unfilled[2]
Nozzle clog risk1–5Not documentedHigh — jams from moisture, heat creep or particles[17][24]
Heat-creep / jam sensitivity1–5Not documentedModerate — good heatbreak cooling needed[19]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[20]May require an all-metal hot end (Simplify3D)[19]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[24]High (0.8–2 %) — Polymaker's PA12-CF10 reaches 1.5 % equilibrium against 3.33 % for its PA6-GF25, and Polymaker developed the PA12 grade specifically for lower moisture sensitivity[3][17]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[11]Not documented
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[4][5][11]60–80 °C for 8–12 h (Extrudr DURAPRO PA12); 100 °C for 8 h (Polymaker CoPA)[18][25]
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[24][4]Popping and cracking during extrusion, then hard-to-diagnose defects[17]
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[24]Polymaker states its PA12 grade changes little between wet and dry, unlike its PA6-based materials; the CoPA dry-to-wet reference shows what the PA6-type response looks like[17][25]
Storage requirementSealed with desiccant; often kept in a dryer during the print[24]Sealed below 20 % RH with desiccant[24]
Hydrolysis at melt temperatureNot documentedPolymaker requires a 100 °C dry for 8 h and storage below 20 % RH; no molecular-weight loss figure is published, and the published wet data is conditioning rather than melt hydrolysis[25][26]
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]49.3 at yield and 33.4 at break printed XZ (Stratasys FDM Nylon 12, ASTM D638)[6]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]1510 printed XZ and 1250 ZX (Stratasys FDM Nylon 12, ASTM D638)[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]30 at break printed XZ against 6.5 in ZX (Stratasys FDM Nylon 12, ASTM D638)[6]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]Not documented
Charpy impact, notchedkJ/m²Not documented11 at +23 °C and 6.0 at -30 °C (Extrudr DuraPro PA12, ISO 179/1eA); unnotched does not break[18]
Other impact dataNot documentedIzod notched 138 J/m printed XZ against 71.0 J/m in ZX (Stratasys FDM Nylon 12, ASTM D256)[6]
Layer adhesion / Z tensileMPaNot documented41.8 at yield and 41.2 at break printed ZX (Stratasys FDM Nylon 12, ASTM D638) — higher than the XZ break figure, because XZ specimens draw and neck first[6]
Brittleness1–5Very ductile — bends far before failing[1]Tough — absorbs impact, yields before breaking[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][27]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[28]Moderate — the long-chain polyamides hold load better than PLA but below PC[2]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[21]Excellent — living hinges viable. Stratasys sells FDM Nylon 12 specifically for repetitive-flex parts such as snap-fit clips and press-fit inserts on the strength of its fatigue properties[2][6]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Semi-flexible[17]
Z strength as % of XY%Not documented85 (Stratasys FDM Nylon 12, ZX against XZ tensile yield, ASTM D638) — one of the least anisotropic unfilled filaments measured[6]
Thermal Properties
HDT at 0.45 MPa°CNot documented94.7 printed XY and 91.9 in XZ/ZX (Stratasys FDM Nylon 12, ASTM D648 at 66 psi)[6]
HDT at 1.8 MPa°CNot documented84.3 printed XY and 75.3 in XZ/ZX (Stratasys FDM Nylon 12, ASTM D648 at 264 psi)[6]
Glass transition (Tg)°CNot documented34.0 (Stratasys FDM Nylon 12, ASTM D7426 inflection point)[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]Vicat A 142 (Extrudr DURAPRO PA12, ISO 306)[18]
Continuous service temperature°CNot documentedBounded by a Vicat softening point of 142 °C (Extrudr DURAPRO PA12); no loaded-bar service figure is published[18]
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]Not documented
Thermal expansion (CTE)µm/m·KNot documented84-103 printed (Stratasys FDM Nylon 12, ASTM E831: 84.4 in XY and 85.6 in XZ/ZX over -50 to 10 °C, 89.1 over 10-45 °C, 98.2 over 45-70 °C); Extrudr quotes 100 for DURAPRO PA12 (ISO 11359-2)[18][6]
Flammability / UL 94Not documentedFlammable; no UL 94 rating published for the unfilled grades surveyed[18]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[21]Months outdoors before embrittlement[2]
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[21]Withstands oils, fuels and alkalis[2]
Water / humidity resistance in service1–5Not documentedGood — minor absorption; the least moisture-sensitive of the common nylons[17]
Food contactNot food safe without specific certification (Polymaker)[21]Not food-contact certified as filament[2]
Biodegradability / compostabilityNot biodegradable[21]Not biodegradable[2]
RecyclabilityNot accepted in household plastic collection[21]Mechanically recyclable but not accepted in household plastic collection[2]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[29]Moderate — measurable VOCs and UFPs, ventilation advised[29]
VOC emission rateµg/minNot documentedUp to 180 caprolactam, the dominant VOC from nylon; total VOC reached nearly 200 µg/min, the highest of the nine filaments tested[29]
Ultrafine-particle emission rateparticles/minNot documented≈2 × 10⁸ median — low for ultrafine particles despite the highest VOC mass of any filament tested[29]
Hazardous species emittedNot documentedCaprolactam, at up to 180 µg/min from nylon filament — the largest single-VOC emission rate measured in the study[29]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[29]Ventilated room or enclosure recommended[29]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[21]Sands poorly — gums rather than powders[19]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[21]Cyanoacrylate; no common solvent welds polyamide[19]
Vapour / chemical smoothingNo practical vapour smoothing[21]No practical vapour smoothing[19]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[21]Polymaker sells a break-away PolySupport matched to PA12[19]
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]Holds dimensions better than PA6 after conditioning — Polymaker singles its PA12 grade out on exactly this point[17]
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[30]Dissolved at 23 °C by formic acid, phenol, m-cresol, 96 % sulphuric acid or hexafluoroisopropanol — all laboratory reagents.[31][32]
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.[30]Not resistant to 10 % formic acid, phenol, chloroform or dichloromethane (Ensinger); zinc chloride stress-cracks nylon.[32][31]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[30]None — nylon's only solvents are formic acid, phenol and HFIP, all of which degrade the part they wet.[31]

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. Fiberon PA612-CF15 Technical Data Sheet V1.1 Polymaker · 2024-12 · 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. FDM Nylon 12 — Material Data Sheet Stratasys · 2021-09 · 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. Nylon PA12 — product listing 3DJake International · 2026-08 · vendor
  14. IEMAI 3D PA12 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  15. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  16. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  17. Moisture Conditioning — effect on printed nylon properties Polymaker Wiki · 2026-08 · doc
  18. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  19. Nylon — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  21. TPU — material basics Polymaker Wiki · 2026-08 · doc
  22. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  23. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  24. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  25. PolyMide CoPA Technical Data Sheet V5.4 (dry and wet status blocks) Polymaker · 2024-11 · tds
  26. PolyMide CoPA — Technical Data Sheet page Polymaker Wiki · 2026-08 · tds
  27. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  28. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  29. 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
  30. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  31. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds
  32. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds