3D Printing Info

Filament comparison

e-TPU vs PC-FR

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

Foaming / expanded TPU (TPU Aero / TPU Air) guideFlame-retardant PC (PC-FR) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PC-FR comparisons
e-TPU vs PC-FR — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXFlame-retardant PC (PC-FR)PC
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$87.50/kg median; $54.99–$224.00/kg across 4 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]Flame-retardant polycarbonate. Polymaker builds its grade on Covestro's Makrolon family and rates it UL 94 V-0[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]1.18 (Bambu Lab) and 1.2 (Polymaker), 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-equivalent spools span 55–224; the two mainstream 1 kg grades are 55 and the industrial grades 120–224[3][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]55–224 across brands; Bambu Lab and Polymaker 55, 3DXTech FR PC/ABS 120, 3DXLABS FR-PC 224[3][12][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]Available from several mainstream brands[3][12][14]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][6][8][9][11]1.75 mm; 0.75 and 1 kg spools[12][14][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][9]Electrical enclosures, transport interiors and battery housings that must meet a flammability rating[2][3]
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[4][5]±0.03 (Bambu Lab PC FR)[3]
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]260–280 (Bambu Lab); 250–270 (Polymaker)[3][2]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][10]90–110 (Bambu Lab); 90–105 (Polymaker)[3][2]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][5]Enclosure required (passive) — Bambu Lab specifies a 45–60 °C chamber, Polymaker 70–100 °C[3][2]
Recommended chamber temperature°CNot documented45–60 (Bambu Lab); 70–100 (Polymaker)[3][2]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]0–60 % (Bambu Lab)[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[15][16][4]Smooth or textured PEI plate (Bambu Lab)[3]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[8]24 at Bambu Lab's 300 mm/s cap on a 0.4 mm nozzle at 0.2 mm layer[3][17]
Warping tendency1–5Not documentedSevere — heated chamber needed[2][18]
Bed-adhesion difficulty1–5Not documentedNeeds a specific surface plus adhesive[19][20]
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]Moderate — retraction tuning needed; Polymaker flags stringing as a common PC problem[20]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Advanced — enclosure, hardware upgrades, tuning[3][18]
Extruder requirementDirect drive; the base material is a 92A TPU[1][21]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[22][5]Brass fine indefinitely[18]
Abrasiveness1–5Non-abrasive[22]Non-abrasive[2]
Nozzle clog risk1–5Not documentedModerate — needs dry filament and a clean nozzle; 3DXTech lists no special nozzle concerns but a 6 h pre-dry at 80 °C[23]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[19]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[15]All-metal hot end required (Simplify3D)[19]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[24]Low (0.1–0.3 %) — 0.12 % saturated at 25 °C / 55 % RH (Bambu Lab), half that of unfilled Bambu Lab PC[3][25]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[10]0.12 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]75 °C for 6 h (Polymaker)[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[24][4]Bubbling and popping at the nozzle, stringing and a rough surface[24]
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[24]No dry-versus-conditioned figures are published. Polymaker calls PC highly hygroscopic and requires a 70–80 °C dry for 6–8 h; run wet, the loss shows as surface defects and poor layer adhesion[20][24]
Storage requirementSealed with desiccant; often kept in a dryer during the print[24]Airtight containers with desiccant to prevent reabsorption[20]
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]60 ± 4 (Bambu Lab) and 67 ± 4.5 (Polymaker) printed XY, ISO 527[3][2]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]1670 ± 40 (Bambu Lab) and 2634 ± 182 (Polymaker) printed XY, ISO 527[3][2]
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]2.4 ± 0.3 (Bambu Lab) and 3.49 ± 0.7 (Polymaker) at break, printed XY, ISO 527 — the retardant roughly halves unfilled PC's elongation[3][2][26]
Flexural strengthMPaNot documented96.6 ± 1.3 printed XY, ISO 178 (Polymaker)[2]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]2518 ± 53 printed XY, ISO 178 (Polymaker)[2]
Charpy impact, notchedkJ/m²Not documented11.7 ± 1.6 printed XY, ISO 179, notched (Polymaker)[2]
Other impact dataNot documentedNotched Charpy 7.5 ± 1.6 kJ/m² at −30 °C printed XY (Polymaker, ISO 179-1/1eA)[2]
Layer adhesion / Z tensileMPaNot documented21 ± 3 (Bambu Lab) and 46 ± 4.8 (Polymaker) printed Z, ISO 527[3][2]
Brittleness1–5Very ductile — bends far before failing[1]Moderate[3][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][4][5][27]Rockwell 70 (118) — the source does not name the scales and Shore D 79 on extruded unfilled PC stock (ASTM D785, D2240); no figure is published for a flame-retardant filament[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[29]Good. Moulded unfilled PC sustained 41 MPa tensile creep at room temperature without breaking, but the retardant package drops the glass transition to 115 °C in Polymaker's grade, so the unfilled rating is not carried over in full[30][2]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[16]Not documented
Elasticity / flexibility1–5Rubbery / highly elastic[1]Rigid[2]
Z strength as % of XY%Not documented35 (Bambu Lab) to 69 (Polymaker), printed[3][2]
Thermal Properties
HDT at 0.45 MPa°CNot documented110 (Polymaker) and 113 (Bambu Lab), ISO 75 at 0.45 MPa[2][3]
HDT at 1.8 MPa°CNot documented107 (Polymaker) and 108 (Bambu Lab), ISO 75 at 1.8 MPa[2][3]
Glass transition (Tg)°CNot documented115 (Polymaker) and 145 (Bambu Lab), DSC[2][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]Amorphous — no melting point; Vicat 114 (Bambu Lab, ISO 306)[3]
Continuous service temperature°CNot documented113 — Prusa publishes this as the temperature resistance of Prusament PC Blend[31]
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 documented68.4 on extruded unfilled PC stock (ASTM D696; source states 3.8e-5 in/in/°F); no figure is published for a flame-retardant grade[28]
Flammability / UL 94Not documentedUL 94 V-0 (Polymaker PolyMax PC-FR); 3DXTech rates its FR PC/ABS V-0 at 1.5 mm on the base resin[2][32]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[16]Degrades within weeks outdoors unless stabilised[20]
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[16]Withstands oils, solvents and fuels; Polymaker rates it good against weak acids[20]
Food contactNot food safe without specific certification (Polymaker)[16]Bisphenol-A polycarbonate is not offered as food-contact filament[20]
Biodegradability / compostabilityNot biodegradable[16]Not biodegradable[20]
RecyclabilityNot accepted in household plastic collection[16]Mechanically recyclable but not accepted in household plastic collection[20]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[33]Moderate — measurable VOCs and UFPs, ventilation advised[33]
Ultrafine-particle emission rateparticles/minNot documented≈4 × 10¹⁰ median — the highest ultrafine-particle rate of the nine filaments in the chamber study, above every ABS tested[33]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[33]Ventilated room or enclosure recommended[33][18]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[16]Sands and machines well; the toughness means it cuts rather than chips[19]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[16]Cyanoacrylate; dichloromethane solvent-welds PC but is a laboratory reagent[19]
Vapour / chemical smoothingNo practical vapour smoothing[16]No practical vapour smoothing[19]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[16]Prints its own supports; 3DXTech sells a dedicated PC break-away support[19]
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]Not documented
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[34]Dichloromethane, chloroform, DMF and dioxane dissolve it outright (Covestro, 6 days at 23 °C). Laboratory reagents.[35]
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.[34]Methanol, butyl acetate, ether, 1 % NaOH and phthalate plasticisers stress-crack it; acetone, MEK and xylene swell it.[35]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[34]Dichloromethane cement welds PC — 16.5 MPa lap shear at one week (IPS Weld-On 3). A controlled carcinogen.[36]

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. PolyMax PC-FR Technical Data Sheet V5.5 Polymaker · 2024-11 · tds
  3. Bambu Filament Technical Data Sheet V1.0 — PC FR 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. Polymaker product catalogue Polymaker · 2026-08 · vendor
  13. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  14. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  15. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  16. TPU — material basics Polymaker Wiki · 2026-08 · doc
  17. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  18. ABS / ASA / PC Usage Guide Bambu Lab Wiki · 2026-08 · doc
  19. Polycarbonate — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. PC — material basics Polymaker Wiki · 2026-08 · doc
  21. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  22. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  23. 3DXTech Firewire FR-PC/ABS product page 3DXTech · 2026-08 · vendor
  24. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  25. Bambu Filament Technical Data Sheet V2.0 — PC Bambu Lab · 2026-08 · tds
  26. PolyLite PC Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  27. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  28. TECANAT natural (PC) — stock shape properties Ensinger · 2026-08 · tds
  29. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  30. Experimental data for creep and dynamic mechanical properties of polycarbonate and polycarbonate/ABS Data in Brief 42:108264 · 2022-06 · paper
  31. Prusament PC Blend Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  32. Firewire Flame Retardant PC/ABS Technical Data Sheet Rev 3.0 3DXTech · 2026-08 · tds
  33. 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
  34. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  35. Makrolon — The chemical resistance (Makrolon 2800, 6 days at 23 °C and 50 °C) Covestro · 2016-12 · tds
  36. Weld-On 3 Acrylic Plastic Cement — technical data sheet (shipped as dichloromethane) IPS Corporation · 2002-07 · tds