3D Printing Info

Filament comparison

e-TPU vs PPA-CF

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

Foaming / expanded TPU (TPU Aero / TPU Air) guidePPA-CF (carbon-fibre polyphthalamide) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PPA-CF comparisons
e-TPU vs PPA-CF — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXPPA-CF (carbon-fibre polyphthalamide)PA
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$84.99/kg median; $21.99–$266.67/kg across 7 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]Polyphthalamide — semi-aromatic nylon — with 10–15 wt% chopped carbon fibre; Bambu Lab lists the composition as semi-aromatic nylon plus carbon fibre, Raise3D and Siraya Tech state 15 wt%, Flashforge 10 %[2][3][4][5]
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)[6][7]1.15 (Raise3D) to 1.25 (Bambu Lab and IEMAI 3D), ISO 1183; Flashforge 1.21–1.23[2][3][4][8]
Typical priceUSD/kg1 kg-equivalent spools span 42–85; the middle of the market is about 52[9][10][11][12][13][14]1 kg-equivalent spools span 22–267; the middle of the market is about 85[15][16][17][18][19][20]
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[9][10][11][12][13][14][21]22–267 across brands; CHCKX 22 on Amazon, IEMAI 3D 51, Siraya Tech 57 and 85, Bambu Lab 200 at 750 g, Raise3D 209, 3DXTech CarbonX HTN+CF 267 at 750 g[15][16][17][22][18][19][20]
Market availability1–5Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[1][9][10][11][13][14]Available from several mainstream brands[15][16][17][18][19]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][9][11][12][14]1.75 mm; 750 g, 1 kg, 2 kg and 2.5 kg spools[2][17][19]
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][12]Under-bonnet automotive brackets, jigs and end-use parts that must stay stiff above the 100 °C working ceiling of PA6-CF[3][4]
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[6][7]0.05 (Bambu Lab and Siraya Tech, 1.75 mm)[2][5]
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][6][7][13]280–310 (Bambu Lab and CHCKX); 280–320 (Siraya Tech)[2][5][20]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[6][7][13]100–120 (Bambu Lab and CHCKX); Siraya Tech runs cooler at 70–90[2][5][20]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][7]Enclosure required (passive) — Bambu Lab specifies a 50–80 °C chamber and Siraya Tech requires an enclosure, while Flashforge states its LUVOCOM-based grade prints on machines with no heated chamber[2][4][17]
Recommended chamber temperature°CNot documented50–80 (Bambu Lab); specimens were printed at a 52 °C chamber and Bambu Lab notes 70–80 °C raises Z properties[2]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[6][7]Bambu Lab turns the part fan on; Siraya Tech runs it off[2][5]
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[23][24][6]Smooth or textured PEI plate with a glue stick, or a PVP glue coating[2][5]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[11]8–12 mm³/s at 300–320 °C (Siraya Tech)[5]
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[6][13]Not documented
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Advanced — enclosure, hardware upgrades, tuning; a 320 °C hot end and a hardened nozzle are the entry requirements[2][5]
Extruder requirementDirect drive; the base material is a 92A TPU[1][25]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[26][7]Hardened steel required — Siraya Tech and CHCKX specify hardened steel or better, Raise3D warns brass wears quickly[3][5][20]
Abrasiveness1–5Non-abrasive[26]Highly abrasive — standard CF/GF composites and glow fills[3][5]
Nozzle clog risk1–5Not documentedModerate — needs dry filament and a clean nozzle; Siraya Tech states nozzles below 0.4 mm will clog[5][17]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[23]Not documented
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[27]High (0.8–2 %) — 1.30 % saturated at 25 °C / 55 % RH for Bambu Lab and IEMAI 3D against 2.35 % for the same makers' PA6-CF, which is the whole reason to pay for PPA[2][8][28]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[13]1.30 saturated at 25 °C / 55 % RH (Bambu Lab and IEMAI 3D) against 2.35 for their PA6-CF; Siraya Tech 1.37 and 1.09 by ISO 62, Raise3D 0.6 by ISO 62 Method 1, Flashforge below 0.1 at 23 °C / 24 h[2][3][4][5][29][8][28]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[6][7][13]100–140 °C for 8–12 h (Bambu Lab, hotter is better within that range); Siraya Tech 100 °C for 4–6 h; Raise3D 80–100 °C for 6–12 h[2][3][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[27][6]Not documented
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[27]Not documented
Storage requirementSealed with desiccant; often kept in a dryer during the print[27]Sealed below 20 % RH with desiccant (Bambu Lab); Raise3D keeps the spool in a dry box throughout the print[2][3]
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][6][13]95–168 (printed XY, ISO 527): Siraya Tech 95, Flashforge 108–112, Siraya Tech Core 112, Raise3D 122 conditioned and annealed, Bambu Lab and IEMAI 3D 168[2][3][4][5][29][8]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]7100–11800 (printed XY): Flashforge 7100–8000, Raise3D and Siraya Tech 7800, Siraya Tech Core 9300, Bambu Lab and IEMAI 3D 11800[2][3][4][5][29][8]
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][6][7][13]1.9–5 at break (printed XY): Raise3D 1.9, Siraya Tech 2, Siraya Tech Core 2.25, Bambu Lab and IEMAI 3D 3.2, Flashforge 3.5–5[2][3][4][5][29][8]
Flexural strengthMPaNot documented145–221 (printed XY, ISO 178): Siraya Tech 145, Siraya Tech Core 178, Raise3D 190, Bambu Lab and IEMAI 3D 208, Flashforge 210–221[2][3][4][5][29][8]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]6500–9860 (printed XY, ISO 178): Flashforge 6500–7000, Siraya Tech 6800, Raise3D 8510, Siraya Tech Core 8700, Bambu Lab and IEMAI 3D 9860[2][3][4][5][29][8]
Charpy impact, notchedkJ/m²Not documented6.5 notched Charpy XY (Bambu Lab and IEMAI 3D, ISO 179); Raise3D 7.8 and Siraya Tech 11 by ISO 179 without stating notched[2][3][5][8]
Other impact dataNot documentedBambu Lab and IEMAI 3D unnotched Charpy 41.7 kJ/m² XY against 4.3 in Z; Flashforge Izod 9–11 kJ/m² XY against 2.5–3 in Z[2][4][8]
Layer adhesion / Z tensileMPaNot documented57 printed Z (Bambu Lab and IEMAI 3D, ISO 527); Raise3D measures 30.2 by a custom mono-layer method[2][3][8]
Brittleness1–5Very ductile — bends far before failing[1]Brittle — snaps with little warning; 2–3 % elongation at break is typical[2][3][5]
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][6][7][30]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[31]Good — Flashforge cites outstanding creep resistance at high temperature and Raise3D high creep resistance, both against other nylons[3][4]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[24]Not documented
Elasticity / flexibility1–5Rubbery / highly elastic[1]Rigid[2]
Z strength as % of XY%Not documented34 (Bambu Lab and IEMAI 3D, Z against XY tensile, ISO 527)[2][8]
Thermal Properties
HDT at 0.45 MPa°CNot documented188–227 (ISO 75 at 0.45 MPa): Raise3D 188, Flashforge 220, Bambu Lab and IEMAI 3D 227; Siraya Tech reaches 192–199 only after annealing, 84.5–97 unannealed[2][3][4][5][29][8]
HDT at 1.8 MPa°CNot documented113–196 (ISO 75 at 1.8 MPa): Raise3D 113, Bambu Lab and IEMAI 3D 196; Siraya Tech reaches 119–126 only after annealing, 82.5–84 unannealed[2][3][5][29][8]
Glass transition (Tg)°CNot documented80 (Siraya Tech, ASTM D3418) to 85 (Bambu Lab and IEMAI 3D, DSC)[2][5][8]
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[6][13]Melting point 231 (Raise3D) to 258 (Bambu Lab and IEMAI 3D); Vicat softening 230–238 (ISO 306)[2][3][5][29][8]
Continuous service temperature°CNot documented120 (Flashforge, IEC 60216, LUVOCOM PPA-CF)[4]
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][6]Bambu Lab anneals at 120–140 °C for 6–12 h; Raise3D at 80–100 °C for 8 h and warns of up to 0.5 % Z shrinkage. On Siraya Tech's grades annealing lifts HDT at 0.45 MPa from 84.5 to 192 °C while notched Charpy falls from 11 to 6.3 kJ/m²[2][3][5]
Flammability / UL 94Not documentedFlammable; Bambu Lab lists water, carbon oxides and nitrogen oxides as combustion products. No UL 94 rating is published for the filament grades surveyed[2]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[24]Not documented
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[24]Better than general nylon against weak acids, weak alkalis, most organic solvents and most oils and greases (Bambu Lab); not resistant to strong acids or strong alkalis[2]
Water / humidity resistance in service1–5Not documentedGood — minor absorption; 1.3 % saturated moisture is roughly half what PA6-CF takes up[2][28]
Food contactNot food safe without specific certification (Polymaker)[24]Not documented
Biodegradability / compostabilityNot biodegradable[24]Not documented
RecyclabilityNot accepted in household plastic collection[24]Not documented
Electrical & ESD propertiesNot documentedFlashforge's data sheet gives a surface resistance of 10³ Ω or below (IEC 60093) for its LUVOCOM-based PPA-CF — the carbon loading makes it conductive rather than merely dissipative[4]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[32]Not documented
Ventilation / filtration requirement1–5Open a window / occasional ventilation[32]Not documented
Dust & fibre handling hazardNot documentedChopped carbon fibre; dry sanding and cutting release respirable fibre-laden dust[33]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[24]Not documented
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[24]Not documented
Vapour / chemical smoothingNo practical vapour smoothing[24]Not documented
Support material pairingPolymaker warns TPU supports are often very difficult to remove[24]Bambu Lab pairs it with Support for PA/PET; Raise3D warns that PPA-CF used as its own support bonds permanently to the model once it takes up moisture, so supports must come off before annealing[2][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][6]Not documented
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[34]Formic acid, phenol, m-cresol and hexafluoroisopropanol dissolve the matrix at 23 °C, leaving the fibre; 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]Zinc chloride solutions stress-crack the nylon matrix, alcoholic calcium chloride dissolves it, mineral acids attack it.[35]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[34]None — nylon's only solvents (formic acid, phenol, HFIP) degrade the part, and the fibre blocks surface flow anyway.[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. Bambu Filament Technical Data Sheet V1.0 — PPA-CF Bambu Lab · 2026-08 · tds
  3. Raise3D Industrial PPA CF Technical Data Sheet V2.0 Raise3D · 2022-04 · tds
  4. Flashforge PPA-CF Filament Technical Data Sheet (LUVOCOM PPA-CF, 10 % carbon fibre) Flashforge · 2026-08 · tds
  5. Siraya Tech Fibreheart PPA-CF Technical Data Sheet Siraya Tech · 2026-08 · tds
  6. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  7. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · tds
  8. IEMAI 3D CF-PPA Technical Data Sheet IEMAI 3D · 2025-04 · tds
  9. Recreus product catalogue Recreus · 2026-08 · vendor
  10. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  11. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  12. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  13. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  14. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  15. PPA-CF — Bambu Lab US Store Bambu Lab · 2026-08 · vendor
  16. Raise3D Industrial PPA CF Filament 1.75 mm (1 kg) — product listing MatterHackers · 2026-08 · vendor
  17. Fibreheart PPA-CF Filament — product page Siraya Tech · 2026-08 · vendor
  18. IEMAI 3D CF-PPA 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  19. CARBONX HTN+CF — product page 3DXTech · 2026-08 · vendor
  20. CHCKX PPA-CF 3D Printing Filament Matte Black 1 kg 1.75 mm 10 % Carbon Fiber — Amazon listing Amazon.com · 2026-08 · vendor
  21. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  22. Siraya Tech Fibreheart PPA-CF Core Filament — product page Siraya Tech · 2026-08 · vendor
  23. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  24. TPU — material basics Polymaker Wiki · 2026-08 · doc
  25. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  26. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  27. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  28. Bambu Filament Technical Data Sheet V3.0 — PA6-CF Bambu Lab · 2026-08 · tds
  29. Siraya Tech Fibreheart PPA-CF Core Technical Data Sheet Siraya Tech · 2026-08 · tds
  30. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  31. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  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. PET-CF / PPA-CF / PPS-CF / PA6-CF carbon fibre filament usage guide Bambu Lab Wiki · 2026-08 · doc
  34. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  35. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds