3D Printing Info

Filament comparison

ASA Aero vs e-TPU

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

Foaming ASA (ASA Aero) guideFoaming / expanded TPU (TPU Aero / TPU Air) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore ASA Aero comparisonsMore e-TPU comparisons
ASA Aero vs e-TPU — documented properties and sources
PropertyFoaming ASA (ASA Aero)ASAFoaming / expanded TPU (TPU Aero / TPU Air)FLEX
Market snapshot
Listing priceUSD/kg; dated snapshots$49.99/kg median; $49.99–$49.99/kg across 1 dated product listings$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings
Identity & Market
Base polymer / chemistryASA with a heat-activated blowing agent that expands at the nozzle[1][2]Foaming thermoplastic polyurethane — a blowing agent expands the extrudate so the printed Shore hardness can be tuned by flow rate[3]
Densityg/cm³0.99 filament (Bambu Lab, ISO 1183); Formfutura's grade reaches 0.33 g/cm³ fully expanded[1][2]1.15 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]
Typical priceUSD/kg1 kg spools cluster near 50[6]1 kg-equivalent spools span 42–85; the middle of the market is about 52[7][8][9][10][11][12]
Price range across brandsUSD/kg50 at Bambu Lab's 1 kg listing[6]42–85 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][13]
Market availability1–5Niche, a handful of specialist brands[6][2]Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[3][7][8][9][11][12]
Spool sizes & diameters1.75 mm; 1 kg spools[6]1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[3][7][9][10][12]
Typical applicationsDrone airframes, RC parts and floating or outdoor applications where mass matters and UV exposure rules out LW-PLA[2]Cushioning, 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[3][10]
Diameter tolerance± mmNot documented0.03 (Siraya Tech and Roamr, 1.75 mm)[4][5]
Printing Parameters
Nozzle temperature°C240–280 (Bambu Lab); 220–285 (Formfutura), with foaming activating near 230 °C and peaking between 270 and 285 °C[1][2]230–270 (QIDI and Siraya Tech), 220–260 (Roamr); foaming activates near 230 °C and is strongest at the top of the range[3][4][5][11]
Bed temperature°C80–90 (Bambu Lab); 50–90 (Formfutura)[1][2]30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][11]
Enclosure / chamber requirement1–5Enclosure recommended — Bambu Lab specifies a 45–60 °C chamber[1][14]Open frame is fine — Roamr states no enclosure is required[3][5]
Recommended chamber temperature°C45–60 (Bambu Lab)[1]Not documented
Part cooling fan0–80 % (Bambu Lab); 0–50 % (Formfutura)[1][2]100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]
Bed surface & adhesion aidPEI sheet, BuildTak or an adhesion aid such as Magigoo (Polymaker); Simplify3D also lists Kapton tape and ASA slurry[15][16]PEI 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[17][18][4]
Maximum volumetric flow (mm³/s; see test conditions)mm³/s12 at Bambu Lab's 150 mm/s cap on a 0.4 mm nozzle at 0.2 mm layer[1][19]Up to 12 (Siraya Tech, Flex TPU Air)[9]
Bed-adhesion difficulty1–5Needs a specific surface plus adhesive[15]Not documented
Stringing / oozing tendency1–5Slight — Polymaker advises 1–2 mm retraction at 20–30 mm/s[15]Severe — 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]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; flow has to be cut to match the expansion and the density follows nozzle temperature[2][1]Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[3]
Extruder requirementNot documentedDirect drive; the base material is a 92A TPU[3][20]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely[14]Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[21][5]
Abrasiveness1–5Non-abrasive[14]Non-abrasive[21]
Heat-creep / jam sensitivity1–5Slightly sensitive[16]Not documented
Hotend requirementNo special hotend required[16]No special hot-end required, but a direct-drive extruder is (Simplify3D)[17]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5High — 0.80 % saturated at 25 °C / 55 % RH, nearly double unfilled Bambu Lab ASA[1][22]Moderate[23]
Equilibrium moisture content at ~50 % RH%0.80 saturated at 25 °C / 55 % RH (Bambu Lab)[1]1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[11]
Drying temperature & time80 °C for 8 h (Bambu Lab)[1]70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[4][5][11]
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface[23]Bubbling and popping at the nozzle, stringing and a rough surface; Siraya Tech adds that moisture wrecks the foaming itself, not only the surface[23][4]
Effect of moisture on strengthNo dry-versus-conditioned figures are published; Polymaker groups the styrenics as moderate-sensitivity and absorbed water shows as bubbling and poor layer adhesion[23]Polymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[23]
Storage requirementSealed with desiccant; Polymaker rates the styrenics moderate-sensitivity[23]Sealed with desiccant; often kept in a dryer during the print[23]
Mechanical Properties
Tensile strength (XY)MPa32 ± 4 printed XY, ISO 527 (Bambu Lab)[1]Falls 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)[3][4][11]
Young's modulusMPa2010 ± 260 printed XY, ISO 527 (Bambu Lab)[1]50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[3]
Elongation at break%5.1 ± 1.6 printed XY, ISO 527 (Bambu Lab)[1]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)[3][4][5][11]
Flexural strengthMPa58 ± 6 printed XY, ISO 178 (Bambu Lab)[1]Not documented
Flexural modulusMPa1510 ± 120 printed XY, ISO 178 (Bambu Lab)[1]50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[3]
Charpy impact, notchedkJ/m²8.2 ± 1.6 printed XY, ISO 179, notched (Bambu Lab)[1]Not documented
Other impact dataCharpy unnotched 32.0 ± 2.5 printed XY (Bambu Lab, ISO 179)[1]Not documented
Layer adhesion / Z tensileMPa21 ± 4 printed Z, ISO 527 (Bambu Lab); flexural Z falls to 24 against 58 in XY[1]Not documented
Brittleness1–5Moderate[1]Very ductile — bends far before failing[3]
Hardness (scale-specific)Shore A / Shore D / RockwellNot documentedTunable 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)[3][4][5][24]
Creep resistance / sustained load1–5Below average — no creep test found; the foamed structure drops modulus to 2010 MPa and load is carried by a lower solid fraction[1][22]Poor — 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[25]
Fatigue / repeated-flex resistance1–5Moderate — no foamed-grade S-N curve; unfilled printed ASA holds a fatigue limit at 25 % of tensile strength[1][26]Excellent — living hinges viable[18]
Elasticity / flexibility1–5Rigid[1]Rubbery / highly elastic[3]
Z strength as % of XY%66 by tensile, 41 by flexural (printed, Bambu Lab)[1]Not documented
Thermal Properties
HDT at 0.45 MPa°C85 (ISO 75, 0.45 MPa, Bambu Lab) against 100 for unfilled Bambu Lab ASA[1][22]Not documented
HDT at 1.8 MPa°C78 (ISO 75, 1.8 MPa, Bambu Lab) against 92 for unfilled Bambu Lab ASA[1][22]Not documented
Melting point / Vicat°CNot documentedVicat 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]
Continuous service temperature°C93 — Prusa publishes this as the temperature resistance of Prusament ASA[27]Not documented
Annealing responseNot documentedFoaming 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[3][4]
Flammability / UL 94Flammable; no UL 94 rating published[22]Not documented
Environment & Chemical
UV resistance1–5Excellent — designed for permanent outdoor use; Formfutura states the foaming grade retains ApolloX's UV resistance[2][28]Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[18]
Chemical resistanceGood against weak acids, weak alkalis, oils and grease; dissolved by acetone[29]Withstands industrial solvents and UV exposure (Polymaker)[18]
Food contactNot food safe[15]Not food safe without specific certification (Polymaker)[18]
Biodegradability / compostabilityNot biodegradable[15]Not biodegradable[18]
RecyclabilityNot accepted in household plastic collection[15]Not accepted in household plastic collection[18]
Health & Safety
Fume toxicity1–5High — hazardous VOC such as styrene; enclosure and filtration needed[30][14]Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[30]
Hazardous species emittedStyrene. Bambu Lab states ABS and ASA release harmful gases such as styrene at printing temperature, which can be toxic and cause dizziness or nausea. Azimi et al. measured styrene from every styrenic filament tested but did not test ASA itself[14][30]Not documented
Ventilation / filtration requirement1–5Enclosure with carbon and HEPA filtration[30][14]Open a window / occasional ventilation[30]
Post-Processing
Sanding & machiningSands well and takes filler before painting[15]Difficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[18]
Painting & finishingPaints readily; ASA holds colour outdoors so many parts are left unpainted[15]Not documented
Gluing & solvent weldingSolvent-welds with acetone[29]Cyanoacrylate bonds TPU; no common solvent welds it[18]
Vapour / chemical smoothingAcetone vapour smoothing works[29]No practical vapour smoothing[18]
Support material pairingHIPS breaks away or dissolves in d-limonene; Bambu Lab sells a Support for ABS that also serves ASA[14]Polymaker warns TPU supports are often very difficult to remove[18]
Dimensional accuracy & detailMatte, textured surface that hides layer lines; colour lightens as the foaming degree rises, which doubles as a visual density cue[2]Foamed 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[3][4]
Solvents & Solubility
Soluble inAcetone dissolves it (Polymaker); MEK, THF, ethyl acetate and the chlorinated solvents dissolve the styrenic backbone.[31][29]DMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[32]
Softened or crazed byLimonene attacks some grades — Prusa reports Prusament ASA Orange flaking apart as layer adhesion fails.[33]Toluene and benzene swell it up to +50 % by weight at 23 °C; the foamed wall soaks up esters and alcohols faster still.[32]
Solvent welding & smoothing agentAcetone vapour, ~20 min at 80 °C over 5 mm of liquid; the foamed wall absorbs solvent, so cut the exposure well short.[34]None practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[32]

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 V1.0 — ASA Aero Bambu Lab · 2026-08 · tds
  2. ApolloX Foaming Technical Data Sheet Formfutura · 2025-07 · tds
  3. varioShore TPU Technical Data Sheet colorFabb · 2026-08 · 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. ASA Aero — product page Bambu Lab US Store · 2026-08 · vendor
  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. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  14. ABS / ASA / PC Usage Guide Bambu Lab Wiki · 2026-08 · doc
  15. ASA — material basics Polymaker Wiki · 2026-08 · doc
  16. ASA — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  17. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  18. TPU — material basics Polymaker Wiki · 2026-08 · doc
  19. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  20. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  21. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  22. Bambu Filament Technical Data Sheet V3.0 — ASA Bambu Lab · 2026-08 · tds
  23. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  24. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  25. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  26. Mechanical, Fatigue, and Thermal Characterization of ASA, Nylon 12, PC and PC-ABS Manufactured by Fused Filament Fabrication (FFF) Polymers 18(2):302 · 2026-01 · paper
  27. Prusament ASA — material page Prusa Polymers · 2026-08 · doc
  28. ASA — FDM Material Data Sheet (includes 1000 h QUV exposure results) Stratasys · 2026-08 · tds
  29. PolyLite ASA Technical Data Sheet Polymaker · 2024-11 · tds
  30. 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
  31. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds
  32. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  33. HIPS — Knowledge Base Prusa Research · 2026-08 · doc
  34. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc