3D Printing Info

Filament comparison

e-TPU vs PCTG

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

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

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PCTG comparisons
e-TPU vs PCTG — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXPCTGPETG
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$34.99/kg median; $14.00–$50.67/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]Poly(cyclohexylenedimethylene terephthalate) glycol — a copolyester with a higher cyclohexanedimethanol content than PETG[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]1.23 (Extrudr, ASTM D792; 3DXTech, ISO 1183)[3][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 spools cluster near 34[13][6][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]14–51 across brands; CHCKX 14 in a 10-roll bundle, Push Plastic 30, Proto-pasta 35 at 1 kg, 3DXTech 51[13][6][16]
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][6][14][17]
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; 0.5, 0.75, 1, 3 and 5 kg spools[13][14][6]
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]Transparent covers, guards and impact-loaded parts where PETG cracks[2][3]
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]250–270 (Spectrum, Extrudr)[2][3]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][11]60–100 (Spectrum)[2]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][5]Open frame is fine — Spectrum and Extrudr both say a closed chamber is not necessary, Extrudr adds it helps on larger parts[2][3]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]Up to 100 % (Spectrum); 20–50 % (Extrudr)[2][3]
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][4]Textured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[20][21]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[9]1.6–16 at the 20–200 mm/s Extrudr rates the material for, on a 0.4 mm nozzle at 0.2 mm layer[3][22]
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive — the problem is releasing the part, not sticking it[20][21]
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; Polymaker names stringing as PETG's common quirk[21]
Shrinkage%Not documented0.2–0.5 (Extrudr, ASTM D955)[3]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Easy — minor profile tuning[2][3]
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[24][5]Brass fine indefinitely — Extrudr explicitly states no hardened nozzle is needed[3]
Abrasiveness1–5Non-abrasive[24]Non-abrasive[3]
Nozzle clog risk1–5Not documentedLow — 3DXTech lists no special nozzle concerns and no minimum layer height for PCTG, only a 65 °C pre-dry[25]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[26]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[18]No special hot-end required[26]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[27]Moderate (0.3–0.8 %) — the copolyester matrix reaches 0.40 % saturated at 25 °C / 55 % RH and 3DXTech specifies a 65 °C, 4 h pre-dry[20][25]
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]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[27][4]Bubbling and popping at the nozzle, stringing and a rough surface[27]
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[27]Polymaker groups PETG with nylon, PVA and TPU as highly hygroscopic; no dry-versus-conditioned strength figures are published for this grade and the loss shows as bubbling and poor layer adhesion[27]
Storage requirementSealed with desiccant; often kept in a dryer during the print[27]Sealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[27][21]
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]43–44 at yield and 45–46 at break (ISO 527, injection-moulded resin data from Spectrum and Extrudr); 48 on My Tech Fun printed bars[2][3][28]
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][4][5][11]215–220 at break on moulded specimens (ISO 527); 4.3–4.4 at yield[2][3]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]Not documented
Charpy impact, notchedkJ/m²Not documented93–94 notched Izod at 23 °C on moulded specimens (ISO 180); 3DXTech quotes 8 by ISO 180/A[2][3][6]
Other impact dataNot documentedIzod 4.14 kJ/m² on My Tech Fun printed bars, against 3.37 for PETG on the same rig[28]
Layer adhesion / Z tensileMPaNot documented21.6 on My Tech Fun 4×4 mm printed bars, against 32.9 for PETG[28]
Brittleness1–5Very ductile — bends far before failing[1]Tough — absorbs impact, yields before breaking[2][3]
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][29]69 Shore D measured by My Tech Fun, against 72 for PETG[28]
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[30]Below average — a 12 mm bar sagged to 19.4 mm over 5 days at 1.25 kg, slightly worse than PETG's 18.2[28]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[19]Good — 215 % elongation at break and 94 kJ/m² notched Izod on moulded specimens (Extrudr, Spectrum)[2][3]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Slightly flexible in thin sections[28]
Thermal Properties
Glass transition (Tg)°CNot documented78 (3DXTech, DSC)[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]Amorphous — no melting point; Vicat 88 (Spectrum, Extrudr)[2][3]
Continuous service temperature°CNot documented68 — loaded bars begin to move at this temperature, against 65 for PETG[28]
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
Flammability / UL 94Not documentedFlammable; no UL 94 rating published for standard grades[31]
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]Withstands acids, alkalis, oils and UV exposure[21]
Water / humidity resistance in service1–5Not documentedGood — minor absorption; Spectrum describes the polymer as hydrophobic[2]
Food contactNot food safe without specific certification (Polymaker)[19]Not certified for food contact as filament[21]
Biodegradability / compostabilityNot biodegradable[19]Not biodegradable[21]
RecyclabilityNot accepted in household plastic collection[19]Not accepted in household plastic collection[21]
Electrical & ESD propertiesNot documentedSurface resistance above 10¹³ ohm/sq — insulating (3DXTech, ASTM D257)[6]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[32]Moderate — measurable VOCs and UFPs, ventilation advised[32]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[32]Open a window / occasional ventilation[32]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[19]Sands poorly — the material is tough and gums rather than powders[26]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[19]Cyanoacrylate; no common solvent welds PETG cleanly[26]
Vapour / chemical smoothingNo practical vapour smoothing[19]No practical vapour smoothing[26]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[19]Prints its own supports; Polymaker rates PolyDissolve S1 for PETG[26]
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]Optical clarity is the selling point; Extrudr recommends a layer height at most 50 % of nozzle diameter[3]
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[33]No common workshop solvent; Eastman's CHDM copolyester data shows 1,2-dichloroethane destroying it within a week.[34]
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.[33]Acetone, ethyl acetate, toluene and DMF swell and soften the copolyester; methanol crazes it (Eastman, 1 y at 23 °C).[34]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[33]Dichloromethane brushed on is the only agent that smooths PETG — a controlled carcinogen, not workshop stock.[35]

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. Spectrum Premium PCTG Technical Data Sheet Spectrum Filaments · 2026-08 · tds
  3. Extrudr PCTG technical data Extrudr · 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. MAX-G PCTG Technical Data Sheet 3DXTech · 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. Push Plastic product catalogue Push Plastic · 2026-08 · vendor
  14. Proto-pasta product catalogue Proto-pasta · 2026-08 · vendor
  15. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  16. CHCKX 10KG Multicolor PCTG Filament bundle CHCKX (Amazon US) · 2026-08 · vendor
  17. Atomic Filament product catalogue Atomic Filament · 2026-08 · vendor
  18. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  19. TPU — material basics Polymaker Wiki · 2026-08 · doc
  20. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  21. PETG — 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. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  25. MAX-G PCTG — product page (print recommendations) 3DXTech · 2026-08 · doc
  26. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  27. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  28. PCTG vs PETG comparison — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  29. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  30. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  31. Prusament PETG V0 Technical Datasheet Prusa Polymers · 2026-08 · tds
  32. 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
  33. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  34. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  35. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc