3D Printing Info

Filament comparison

e-TPU vs PLA Stone

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

Foaming / expanded TPU (TPU Aero / TPU Air) guideStone-filled PLA guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PLA Stone comparisons
e-TPU vs PLA Stone — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXStone-filled PLAPLA
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$22.99/kg median; $15.99–$49.16/kg across 6 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 filled with stone or mineral powder — Formfutura StoneFil declares 40–50 wt% stone powder[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]1.22 (Bambu Lab PLA Marble) and 1.50–1.70 (Formfutura StoneFil), ISO 1183[3][2]
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 spools cluster near 21[12][13]
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][14]16–49 across brands; SUNLU 16, ELEGOO 19, Polymaker 21, Bambu Lab 25, Prusament 38, Filament PM MarbleJet 49 on 0.5 kg spools[15][13][12][16][17][18]
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]Stocked by most mainstream brands[12][13][15]
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; 0.5 and 1 kg spools plus refills[13][2]
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]Architectural models, sculpture and props with a matte mineral surface[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][10]190–230 (Bambu Lab)[3]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][10]35–45 (Bambu Lab)[3]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][5]Open frame is fine[3]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]Fan on[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[19][20][4]Not documented
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[8]Not documented
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]Easy — minor profile tuning; 0.2 mm nozzles are not usable[21]
Extruder requirementDirect drive; the base material is a 92A TPU[1][22]Nozzles below 0.4 mm are not compatible (Bambu Lab)[21]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[23][5]Brass acceptable; hardened steel for volume work — Bambu Lab's compatibility table says no hardened nozzle is needed while the note under the same table groups PLA Marble with particle-filled materials that should always use one[21]
Abrasiveness1–5Non-abrasive[23]Moderately abrasive — stone fill[21][2]
Nozzle clog risk1–5Not documentedModerate — needs dry filament and a clean nozzle[21]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[19]Not documented
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[24]Moderate — 0.44 % saturated at 25 °C / 55 % RH[3]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[10]0.44 saturated at 25 °C / 55 % RH (Bambu Lab)[3]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[4][5][10]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[24][4]Not documented
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[24]Polymaker rates PLA low-sensitivity and publishes no dry-versus-conditioned figures for this grade; absorbed water flashes to steam and shows as bubbling and poor layer adhesion[24]
Storage requirementSealed with desiccant; often kept in a dryer during the print[24]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][4][10]33 ± 4 printed XY, ISO 527 (Bambu Lab)[3]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]2330 ± 240 printed XY, ISO 527 (Bambu Lab)[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]6.7 ± 0.5 printed XY, ISO 527 (Bambu Lab)[3]
Flexural strengthMPaNot documented75 ± 5 printed XY, ISO 178 (Bambu Lab)[3]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]2920 ± 180 printed XY, ISO 178 (Bambu Lab)[3]
Charpy impact, notchedkJ/m²Not documented9.5 ± 2.6 printed XY, ISO 179, notched (Bambu Lab)[3]
Other impact dataNot documentedCharpy unnotched 24.0 printed XY (Bambu Lab, ISO 179)[3]
Layer adhesion / Z tensileMPaNot documented30 ± 4 printed Z, ISO 527 (Bambu Lab)[3]
Brittleness1–5Very ductile — bends far before failing[1]Brittle — snaps with little warning[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][25]Not documented
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[26]Poor — no stone-filled creep test; plain printed PLA sagged from 12 to 16.2–21.8 mm over 5 days at 1.25 kg[27][28][29]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[20]Poor — no grade-specific S-N curve; plain printed PLA ran 38 000–49 000 cycles at 30 % of tensile strength and the mineral filler leaves a brittle compound[30][3]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Rigid[3]
Z strength as % of XY%Not documented91 by tensile, 73 by flexural (printed, Bambu Lab)[3]
Thermal Properties
HDT at 0.45 MPa°CNot documented56 (ISO 75, 0.45 MPa)[3]
HDT at 1.8 MPa°CNot documented53 (ISO 75, 1.8 MPa)[3]
Glass transition (Tg)°CNot documented56 (DSC)[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]156 peak melt (DSC); Formfutura gives a 120–170 melting range for StoneFil[3][2]
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
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[20]Degrades within weeks outdoors[31]
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[20]Not documented
Food contactNot food safe without specific certification (Polymaker)[20]Not documented
Biodegradability / compostabilityNot biodegradable[20]Not documented
RecyclabilityNot accepted in household plastic collection[20]Not documented
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[32]Low hazard — minimal VOC and particle emission[32]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[32]None needed in a normal room[32]
Dust & fibre handling hazardNot documentedFormfutura's SDS sets an occupational limit of 1 mg/m³ for the stone powder and lists it as both a fibre and a particulate — do not dry-sand without extraction[2]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[20]Sands to a stone-like matte surface[2]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[20]Not documented
Vapour / chemical smoothingNo practical vapour smoothing[20]Not documented
Support material pairingPolymaker warns TPU supports are often very difficult to remove[20]Support for PLA (Bambu Lab)[3]
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]Matte mineral surface hides layer lines; 55° overhangs and 30 mm bridges as for plain PLA[3]
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[33]Chloroform dissolves the PLA matrix (10 % w/v, 2–4 h at 23 °C) and leaves the filler as loose sludge; laboratory reagent.[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 and toluene plasticise the matrix but dissolve <1 % even at 65 °C; acetone submersion crazes parts.[34][35]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[33]Chloroform vapour attacks only the resin fraction, so the filler is left standing proud; no workshop-safe agent exists.[36][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. StoneFil safety data sheet Formfutura · 2026-08 · msds
  3. Bambu Filament Technical Data Sheet — PLA Marble Bambu Lab · 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. PLA Marble — product page Bambu Lab US Store · 2026-08 · vendor
  13. Polymaker product catalogue Polymaker · 2026-08 · vendor
  14. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  15. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  16. Printed Solid product catalogue Printed Solid · 2026-08 · vendor
  17. SUNLU High Speed PLA Marble 3D Printer Filament 1 kg SUNLU · 2026-08 · vendor
  18. Filament PM PLA MarbleJet technical data sheet Filament PM (Plasty Mladec) · 2026-08 · tds
  19. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. TPU — material basics Polymaker Wiki · 2026-08 · doc
  21. PLA Usage Guide Bambu Lab Wiki · 2026-08 · doc
  22. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  23. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  24. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  25. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  26. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  27. BambuLab PLA Basic vs PLA Tough vs PLA-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  28. Polymaker PLA Pro vs PLA-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  29. Carbon Fiber PLA vs META-PLA vs PLA+ vs PLA by Sunlu — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  30. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  31. PLA — material guide Prusa Knowledge Base · 2026-08 · doc
  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. Solubility Study of Ingeo Biopolymer Grades in Common Organic Solvents (NWPD003) NatureWorks · 2019-10 · tds
  35. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc
  36. 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