3D Printing Info

Filament comparison

e-TPU vs PEEK

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

Foaming / expanded TPU (TPU Aero / TPU Air) guidePEEK guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PEEK comparisons
e-TPU vs PEEK — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXPEEKHIGHTEMP
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$531.87/kg median; $296.14–$770.00/kg across 5 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]Polyether ether ketone — a semi-crystalline polyaryletherketone[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]1.30 (ISO 1183)[2][5]
Typical priceUSD/kg1 kg-equivalent spools span 42–85; the middle of the market is about 52[6][7][8][9][10][11]1 kg-equivalent spools span 296–770; the middle of the market is about 532[12][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[6][7][8][9][10][11][15]296-770 across brands and spool sizes; 3D4Makers recycled R-PEEK 296 at 750 g, IEMAI 3D 420 at 1 kg, LEHVOSS Luvocom 3F PEEK 9581 532 at 2 kg, 3DXTech ThermaX PEEK 770 at 500 g[12][13][14]
Market availability1–5Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[1][6][7][8][10][11]Niche, a handful of specialist brands[12][13][5]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][6][8][9][11]1.75 and 2.85 mm; 200 g to 2 kg spools[12][13][5]
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][9]Aerospace brackets, semiconductor handling, sterilisable medical tooling and downhole parts[2]
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][10]380-400 (3DXTech printed-specimen conditions); Victrex quotes a 340-450 melt range for AM 450 FIL[2][5]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[3][4][10]130–140 (3DXTech)[2]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][4]Actively heated chamber required[16][17]
Recommended chamber temperature°CNot documentedNot less than 150 for semi-crystalline printing (Victrex AM 450 FIL); bed above 150[5]
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[18][19][3]Not documented
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[8]Not documented
Warping tendency1–5Not documentedSevere — heated chamber needed[16]
Bed-adhesion difficulty1–5Not documentedVery difficult — special plates or slurry required[16]
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][10]Not documented
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Expert / industrial hardware only[16][17]
Extruder requirementDirect drive; the base material is a 92A TPU[1][20]An all-metal hot end rated above 400 °C and a heated chamber; 3DXTech tests at 0.25 mm layer height on a 0.4 mm nozzle[2][16]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[21][4]Brass fine indefinitely for unfilled grades, but brass softens near these nozzle temperatures — hardened or plated hot ends are the norm[16]
Abrasiveness1–5Non-abrasive[21]Non-abrasive when unfilled[2]
Nozzle clog risk1–5Not documentedModerate — needs dry filament and a clean nozzle; 3DXTech lists no special nozzle concerns but a mandatory 120 °C pre-dry before every print[22]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[18]Not documented
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[23]Not documented
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[10]0.45 at saturation, 23 °C (ISO 62); 0.55 at 100 °C[5]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[3][4][10]120 °C for 5 h, target below 0.020 % moisture (Victrex AM 450 FIL)[5]
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[23][3]Not documented
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[23]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[22]
Storage requirementSealed with desiccant; often kept in a dryer during the print[23]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][10]60-100 (printed XY): Victrex AM 450 FIL 60-80 at yield and 3DXTech 100, both ISO 527; 98 at yield injection-moulded[2][5]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]3000-4000 (printed XY, ISO 527, Victrex AM 450 FIL); 3720 (3DXTech); 4000 injection-moulded[2][5]
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][10]28 (printed XY, ISO 527) — remarkably ductile for a high-temperature polymer[2]
Flexural strengthMPaNot documented130 (printed XY, ISO 178)[2]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]2700 (printed XY, ISO 178)[2]
Charpy impact, notchedkJ/m²Not documented6.0 (injection-moulded, ISO 179/1eA); unnotched does not break[5]
Other impact dataNot documentedIzod notched 7.0 kJ/m2 injection-moulded (ISO 180/A). Printed anisotropy is extreme: VICTREX AM 200 on a Stratasys F900 gives Izod notched 1380-1530 J/m XZ against 30-62 J/m ZX (ASTM D256)[5][24]
Layer adhesion / Z tensileMPaNot documented20-85 at yield (printed ZX, ISO 527, Victrex AM 450 FIL); the spread is set by chamber temperature and weld quality[5]
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][3][4][25]Shore D 84.5 (injection-moulded, ISO 868); Rockwell M100 / R125 on extruded PEEK stock (ASTM D785)[5][26]
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[27]Excellent — holds load for years. Victrex rates PEEK for long-term creep; injection-moulded flexural stress at 3.5 % strain falls only from 125 MPa at 23 °C to 85 MPa at 125 °C, and extruded stock is rated to 249 °C continuous[28][5][26]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[19]Excellent — living hinges viable. Victrex rates PEEK for long-term fatigue as well as creep[28]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Rigid[2]
Z strength as % of XY%Not documented71-84 (VICTREX AM 200 LMPAEK printed on the Stratasys F900 and Fortus 450mc, ZX against XZ tensile yield, ASTM D638); unfilled PEEK's own ZX spread is wider[24]
Thermal Properties
HDT at 0.45 MPa°CNot documented140 (printed XY, ISO 75 at 0.45 MPa, 3DXTech)[2]
HDT at 1.8 MPa°CNot documented152 (unannealed, ISO 75-2/Af, Victrex AM 450 FIL); 160 on extruded stock (ASTM D648 at 264 psi)[5][26]
Glass transition (Tg)°CNot documented143 (DSC, 3DXTech); Victrex gives onset 143 and midpoint 150 (ISO 11357-2)[2][5]
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][10]343 melting (ISO 11357-3, Victrex); VICTREX AM 200 LMPAEK melts at 303[5][24]
Continuous service temperature°CNot documented240 UL 746B relative thermal index, strength (RTI electrical 260, impact 180); Ensinger rates extruded PEEK stock at 249 long term[5][26]
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
Thermal expansion (CTE)µm/m·KNot documented37.8 (extruded PEEK stock, 23-60 °C, ASTM E831; source states 2.1e-5 in/in/°F), rising to 41.9 at 60-100 °C and 55.8 at 100-150 °C[26]
Flammability / UL 94Not documentedUL 94 V-0 at 1.5 mm on the base resin; glow-wire flammability index 960 °C at 2.0 mm (IEC 60695-2-12)[2][5]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[19]Not documented
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[19]Outstanding — resistant to almost all solvents and to steam sterilisation[2]
Water / humidity resistance in service1–5Not documentedExcellent — essentially unaffected; 0.45 % water at saturation and resistant to steam sterilisation[5][2]
Food contactNot food safe without specific certification (Polymaker)[19]Not documented
Biodegradability / compostabilityNot biodegradable[19]Not documented
RecyclabilityNot accepted in household plastic collection[19]Not documented
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. None of these polymers was in the chamber study, and all are processed far above the temperatures it covered[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[19]Not documented
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[19]Not documented
Vapour / chemical smoothingNo practical vapour smoothing[19]Not documented
Support material pairingPolymaker warns TPU supports are often very difficult to remove[19]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.[30]95–98 wt% sulphuric acid dissolves it — 10 g per 100 mL at 40–70 °C gives a dark red solution. Laboratory route only.[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]Concentrated nitric, hydrofluoric, hydrobromic and hydriodic acids attack it; DCM, DMSO and THF swell thin-walled sections.[33][32]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[30]None — no solvent softens PEEK, so parts are joined thermally or mechanically, never chemically.[33][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. varioShore TPU Technical Data Sheet colorFabb · 2026-08 · tds
  2. ThermaX PEEK Technical Data Sheet v3 3DXTech · 2026-08 · tds
  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. VICTREX AM 450 FIL — datasheet Victrex · 2025-12 · tds
  6. Recreus product catalogue Recreus · 2026-08 · vendor
  7. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  8. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  9. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  10. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  11. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  12. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  13. 3D4Makers product catalogue 3D4Makers · 2026-08 · vendor
  14. IEMAI 3D PEEK 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  15. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  16. Prusament PEI 1010 Technical Datasheet v1.0 Prusa Polymers · 2024-09 · tds
  17. Prusament PEI 1010 — material page Prusa Polymers · 2026-08 · doc
  18. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  19. TPU — material basics Polymaker Wiki · 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. ThermaX PEEK — product page 3DXTech · 2026-08 · vendor
  23. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  24. VICTREX AM 200 — FDM Material Data Sheet Stratasys · 2024-04 · tds
  25. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  26. TECAPEEK natural (PEEK) — stock shape properties Ensinger · 2026-08 · tds
  27. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  28. PEEK polymers — product overview Victrex · 2026-08 · doc
  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. The Effects of Sulfonated Poly(ether ether ketone) Ion Exchange Preparation Conditions on Membrane Properties Yee, Zhang & Ladewig, Membranes 3(3) 182–195 · 2013-07 · paper
  32. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds
  33. What solvents are not compatible with PEEK? — fluidics technical FAQ IDEX Health & Science · 2026-08 · doc