3D Printing Info

Filament comparison

e-TPU vs rPLA

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

Foaming / expanded TPU (TPU Aero / TPU Air) guideRecycled PLA (rPLA) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore rPLA comparisons
e-TPU vs rPLA — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXRecycled PLA (rPLA)PLA
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$20.79/kg median; $16.05–$40.64/kg across 8 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]PLA regranulated from post-industrial PLA manufacturing waste; post-consumer feedstock is rare[2][3][4]
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)[5][6]1.24 (ISO 1183)[2]
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 spools run 20–22[13][14][15]
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][16]16–41 across brands; Fiberlogy refill 16, Filamentive 750 g 41[17][18]
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[3][4][15]
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; 0.75, 0.85 and 1 kg spools plus spool-less refills[19][17][3]
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]General-purpose printing where the feedstock's recycled content matters more than an exact colour match[3][4]
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[5][6]±0.03 guaranteed by Prusa Research today; the 2021 datasheet specified ±0.05, against ±0.02 for virgin Prusament PLA[3][2][20]
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][5][6][11]210 ± 10 (Prusament); 200 ± 15 (Filamentive)[2][4]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[5][6][11]40–60 (Prusament); up to 60 (Filamentive)[2][4]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][6]Open frame is fine[2][21]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[5][6]100 %[2]
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[22][23][5]Not documented
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[9]Not documented
Warping tendency1–5Not documentedNone — brim not generally needed[2]
Bed-adhesion difficulty1–5Not documentedSticks to anything[24]
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[5][11]Not documented
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Beginner — prints on any machine out of the box[2][21]
Extruder requirementDirect drive; the base material is a 92A TPU[1][25]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[26][6]Brass fine indefinitely[21]
Abrasiveness1–5Non-abrasive[26]Non-abrasive[27][21]
Nozzle clog risk1–5Not documentedVery low[21]
Heat-creep / jam sensitivity1–5Not documentedModerate — good heatbreak cooling needed; PLA softens below 60 °C[28]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[22]No special hot-end required[24]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[29]Moderate — 0.3 % after both 24 h and 7 days at 28 °C / 37 % RH (Prusa Polymers method), against 0.19 % in 7 days for virgin Prusament PLA[2][20]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[11]0.3 after 24 h and 7 days at 28 °C / 37 % RH (Prusa Polymers method)[2]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[5][6][11]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[29][5]Bubbling and popping at the nozzle, stringing, rough surface and weak layers[29]
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[29]Polymaker rates PLA low-sensitivity — the loss shows as poor layer adhesion and brittle layers rather than a published strength figure[29]
Storage requirementSealed with desiccant; often kept in a dryer during the print[29]Sealed with desiccant below 20 % RH; shelf life at ambient is long[30][24]
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][5][11]49 printed horizontal and 55 printed vertical XZ (ISO 527-1, yield); virgin Prusament PLA gives 51 and 59 by the same method[2][20]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]2100 printed horizontal, 2300 printed vertical XZ (ISO 527-1); virgin Prusament PLA 2300 and 2400[2][20]
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][5][6][11]3.1 at yield printed horizontal (ISO 527-1); virgin Prusament PLA 2.9[2][20]
Flexural strengthMPaNot documented82 printed horizontal, 87 printed vertical XZ (ISO 178); virgin Prusament PLA 83 and 99[2][20]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]3100 printed horizontal (ISO 178) — the same as virgin Prusament PLA[2][20]
Other impact dataNot documentedCharpy unnotched 14.0 printed horizontal (ISO 179-1); virgin Prusament PLA 13[2][20]
Layer adhesion / Z tensileMPaNot documented21 ± 2 (Prusa Polymers interlayer adhesion test); virgin Prusament PLA 17 ± 3 by the same test[2][20]
Brittleness1–5Very ductile — bends far before failing[1]Brittle — snaps with little warning[28][27]
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][5][6][31]80 Shore D (Prusa Polymers in-house method); virgin Prusament PLA 81[2][20]
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[32]Poor — no recycled-PLA creep data published; virgin PLA sagged from 12 to 18.7–20.3 mm over 5 days at 1.25 kg[33][34]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[23]Poor — no grade-specific S-N curve; plain printed PLA ran 38 000–49 000 cycles at 30 % of tensile strength (R = 0.2)[35][28]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Rigid[27]
Thermal Properties
HDT at 0.45 MPa°CNot documented55 (ISO 75, 0.45 MPa) — the same as virgin Prusament PLA[2][20]
HDT at 1.8 MPa°CNot documented53 (ISO 75, 1.8 MPa); virgin Prusament PLA 55[2][20]
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[5][11]Not documented
Continuous service temperature°CNot documented55 (Filamentive states heat resistance up to 55 °C)[4]
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][5]Not documented
Thermal expansion (CTE)µm/m·KNot documented96–99 for plain printed PLA (fibre Bragg grating, 25–50 °C); no grade-specific measurement published[36]
Flammability / UL 94Not documentedFlammable; no UL 94 rating published by the major brands[30][37]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[23]Degrades within weeks outdoors[28][38]
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[23]Good against weak acids, oils and grease; poor against strong acids and alkalis; dissolved by chloroform, THF and hot benzene[37][28]
Water / humidity resistance in service1–5Not documentedGood — insoluble in water[30]
Food contactNot food safe without specific certification (Polymaker)[23]Filamentive certifies its rPLA to EN 71-3 and lists it food safe; printed layer grooves still harbour bacteria[4][28]
Biodegradability / compostabilityNot biodegradable[23]Industrially compostable only — needs sustained 55 °C; not home compostable[4]
RecyclabilityNot accepted in household plastic collection[23]The feedstock itself; Filamentive uses 50 % post-industrial content and runs a PLA take-back scheme[4][18]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[39]Low hazard — minimal VOC and particle emission[39]
Hazardous species emittedNot documentedPrusament rPLA Corn Pigment uses organic waste pigments such as red algae, which give a noticeable scent while printing[3]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[39]None needed in a normal room[39]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[23]Wet sanding — dry sanding heats the surface by friction and smears it[38][28]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[23]Superglue for most joints; acetone works on some grades depending on additives and colour[3]
Vapour / chemical smoothingNo practical vapour smoothing[23]No practical vapour smoothing — only chloroform, hot benzene or THF, which are laboratory-only[28]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[23]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][5]Not documented
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[40]Chloroform: 10 % w/v in 2–4 h at 23 °C, every grade and morphology; THF and DMF only at 65 °C. Laboratory reagents.[41]
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.[40]Acetone, ethyl acetate and toluene plasticise it but dissolve <1 % even at 65 °C; submersion in acetone crazes and destroys parts.[41][42]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[40]Chloroform vapour smooths and welds PLA at the cost of tensile strength; acetone does not smooth it at all.[43][42]

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. Prusament PLA Recycled Technical Datasheet v1.0 Prusa Polymers · 2021-12 · tds
  3. Prusament rPLA Corn Pigment 1kg — product page Prusa Research · 2026-08 · vendor
  4. Filamentive PLA (recycled) — product page Filamentive · 2026-08 · vendor
  5. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  6. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · 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. 3D-Fuel ReFuel Recycled PLA 1kg 3D-Fuel · 2026-08 · vendor
  14. Proto-pasta Black Recycled PLA 1kg Proto-pasta · 2026-08 · vendor
  15. Formfutura ReForm rPLA (White) 1kg Filament2Print · 2026-08 · vendor
  16. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  17. Fiberlogy rPLA Refill Anthracite 850 g 3DJake International · 2026-08 · vendor
  18. Filamentive PLA (rPLA) 750 g CREATE Education · 2026-08 · vendor
  19. Kimya PLA-R 750 g Crea3D · 2026-08 · vendor
  20. Prusament PLA Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  21. Filament Material Guide Prusa Knowledge Base · 2026-08 · doc
  22. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  23. TPU — material basics Polymaker Wiki · 2026-08 · doc
  24. PLA — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  25. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  26. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  27. Prusament PLA — material page Prusa Polymers · 2026-08 · doc
  28. PLA — material guide Prusa Knowledge Base · 2026-08 · doc
  29. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  30. Bambu Filament Technical Data Sheet V3.0 — PLA Basic Bambu Lab · 2026-08 · tds
  31. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  32. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  33. BambuLab PLA Basic vs PLA Tough vs PLA-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  34. PolyTerra PLA vs PLA+ — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  35. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  36. Characterization of Thermal Expansion Coefficient of 3D Printing Polymeric Materials Using Fiber Bragg Grating Sensors Materials 17(18):4668 · 2024-09 · paper
  37. PolyLite PLA Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  38. Prusament PLA Technical Data Sheet v1.0 Prusa Polymers · 2018-09 · tds
  39. 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
  40. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  41. Solubility Study of Ingeo Biopolymer Grades in Common Organic Solvents (NWPD003) NatureWorks · 2019-10 · tds
  42. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc
  43. Effect of vapour smoothing in trichloromethane on 3D printed PLA — surface, mechanical and chemical structure Pitale, Keche & Chopra, Engineering Research Express 6(4) 045579 · 2024-12 · paper