3D Printing Info

Filament comparison

e-TPU vs PE

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

Foaming / expanded TPU (TPU Aero / TPU Air) guidePolyethylene (PE) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PE comparisons
e-TPU vs PE — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXPolyethylene (PE)POLYOLEFIN
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$87.72/kg median; $87.72–$87.72/kg across 1 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]Polyethylene — the simplest polyolefin, non-polar and highly crystalline. The one retailed filament grade, Spectrum HDPE, uses what Spectrum calls Low Warp technology and is denser and stiffer than plain HDPE[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]1.10 (Spectrum HDPE filament, ISO 1183) against 0.95 for extruded HDPE stock — the filament is a modified formulation[2][3]
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 cluster near 88[12]
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][13]87.72 — Spectrum's 500 g spools at 3DJAKE are the only PE filament listing found[12]
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 — Spectrum HDPE in six colours is the only PE filament in the 3DJAKE and igo3d product sitemaps, at MatterHackers or at Printed Solid, but it is a normal stocked item rather than a special order[14][15][16][12]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][6][8][9][11]1.75 mm; 500 g spools in six colours[12][14]
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]Chemically resistant containers, packaging prototypes and consumer goods where HDPE is the production material[2]
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][10]240-290 (Spectrum HDPE)[2]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][10]80-100 (Spectrum HDPE)[2]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][5]Enclosure recommended — Spectrum recommends a closed chamber for larger prints[2]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]0-50 % part cooling (Spectrum HDPE)[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[17][18][4]Spectrum states no adhesive is necessary for its low-warp HDPE, depending on geometry[2]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[8]Not documented
Warping tendency1–5Not documentedModerate — needs adhesion aid or draught shield. Spectrum's low-warp grade is sold as printable on desktop machines, which is not true of plain polyethylene[2]
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive; Spectrum states no adhesive is necessary but recommends a closed chamber for large parts[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][10]Not documented
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Intermediate — dry filament and a tuned profile; Spectrum sells the grade as desktop-printable with no dry box and no hardened nozzle[2]
Extruder requirementDirect drive; the base material is a 92A TPU[1][19]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[20][5]Brass fine indefinitely — Spectrum states a ruby or hardened nozzle is not required[2]
Abrasiveness1–5Non-abrasive[20]Non-abrasive[2]
Nozzle clog risk1–5Not documentedLow — Spectrum lists no drybox and no ruby or hardened nozzle for HDPE, and very low moisture absorption[2]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[17]Not documented
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[21]Negligible (<0.1 % EMC) — Spectrum lists very low moisture absorption and no dry box[2]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[10]Not documented
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[4][5][10]No drying step published; Spectrum lists a dry box as not required[2]
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[21][4]Not documented
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[21]Not applicable in practice — Spectrum lists very low moisture absorption and no drybox requirement for HDPE[2]
Storage requirementSealed with desiccant; often kept in a dryer during the print[21]Store dry at 18-25 °C out of sunlight; Spectrum quotes a 24-month shelf life[2]
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][10]29 at break (Spectrum HDPE, ISO 527; specimen type not stated) against 25.5 at yield on extruded HDPE stock (ASTM D638, from 3700 psi)[2][3]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]3500 (Spectrum HDPE, ISO 527) against 965 on extruded HDPE stock (ASTM D638, from 140,000 psi) — the filament grade is nearly four times stiffer than plain polyethylene[2][3]
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][10]18 at break (Spectrum HDPE, ISO 527) against above 100 on extruded stock (ASTM D638)[2][3]
Flexural strengthMPaNot documented27.6 on extruded HDPE stock (ASTM D790; converted from 4000 psi)[3]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]3200 (Spectrum HDPE, ISO 178) against 965 on extruded stock (ASTM D790, from 140,000 psi)[2][3]
Other impact dataNot documentedCharpy 10 kJ/m2 (Spectrum HDPE, ISO 179-1; notch condition not stated); Izod 104 J/m on extruded stock, converted from 1.94 ft-lb/in (ASTM D256)[2][3]
Brittleness1–5Very ductile — bends far before failing[1]Tough — absorbs impact, yields before breaking; 18 % elongation at break on the filament and above 100 % on extruded stock[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][22]Shore D 67 and Rockwell R54 on extruded HDPE stock (ASTM D2240, D785); Spectrum quotes Rockwell 80 HRM for its filament (ISO 2039-2)[3][2]
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[23]Not documented
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[18]Good — Spectrum lists outstanding abrasion and crack resistance for its HDPE, but no repeated-flex or fatigue test data was found for any PE filament[2]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Slightly flexible in thin sections — Spectrum's low-warp grade has a 3.5 GPa tensile modulus; plain extruded HDPE at 965 MPa is genuinely semi-flexible[2][3]
Thermal Properties
HDT at 0.45 MPa°CNot documented75 on extruded HDPE stock (ASTM D648 at 66 psi; converted from 167 °F)[3]
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][10]Not documented
Continuous service temperature°CNot documented110 stated as heat resistance by Spectrum with no test standard given; extruded stock is rated 120 long-term maximum (converted from 248 °F) and brittle below -76[2][3]
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 documented117 (extruded HDPE stock, ASTM D696; source states 6.5e-5 in/in/°F)[3]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[18]Moderate — a season or two. Spectrum describes its HDPE as UV-stable and weather-resistant but publishes no exposure data[2]
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[18]Excellent chemical resistance to acids, bases, oils and solvents (Spectrum); Ensinger lists broad chemical compatibility for HDPE stock[2][3]
Water / humidity resistance in service1–5Not documentedExcellent — essentially unaffected; Ensinger lists low moisture absorption for HDPE stock and Spectrum very low absorption for the filament[2][3]
Food contactNot food safe without specific certification (Polymaker)[18]Not documented
Biodegradability / compostabilityNot biodegradable[18]Not documented
RecyclabilityNot accepted in household plastic collection[18]Spectrum states the filament is fully recyclable; HDPE is resin code 2[2]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[24]Not documented
Ventilation / filtration requirement1–5Open a window / occasional ventilation[24]Not documented
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[18]Easy to machine — Ensinger lists machinability as a headline property of HDPE stock[3]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[18]Not documented
Vapour / chemical smoothingNo practical vapour smoothing[18]Not documented
Support material pairingPolymaker warns TPU supports are often very difficult to remove[18]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][4]Spectrum lists a shiny surface finish and no adhesive requirement; shrinkage remains the limit on large flat parts[2]
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[25]None at room temperature; xylene dissolves HDPE at about 105 °C and LDPE at 75 °C. Hot decalin does the same.[26][27]
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.[25]Toluene, xylene, styrene, chloroform, dichloromethane, MEK and trichloroethylene are all unsatisfactory at 21 °C.[27]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[25]None — polyethylene has no room-temperature solvent, so joints are made by heat welding.[27][26]

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 HDPE Technical Data Sheet Spectrum Filaments · 2025-10 · tds
  3. TECAFINE HDPE natural — stock shape properties Ensinger · 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. 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. Spectrum HDPE Traffic Black, 1.75 mm / 500 g 3DJAKE · 2026-08 · vendor
  13. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  14. 3DJAKE product catalogue 3DJAKE · 2026-08 · vendor
  15. igo3d product sitemap (17452 product URLs) igo3d · 2026-08 · vendor
  16. Printed Solid product catalogue Printed Solid · 2026-08 · vendor
  17. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  18. TPU — material basics Polymaker Wiki · 2026-08 · doc
  19. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  20. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  21. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  22. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  23. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  24. 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
  25. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  26. US 5,278,282 Polymer recycling by selective dissolution — xylene dissolution temperatures Nauman & Lynch, Rensselaer Polytechnic Institute · 1994-01 · paper
  27. HDPE Chemical Resistance Guide (21 °C and 60 °C) INEOS Olefins & Polymers USA · 2026-08 · tds