3D Printing Info

Filament comparison

PLA Metal vs TPU-CF

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

Metal-filled PLA guideCarbon-fibre TPU guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PLA Metal comparisonsMore TPU-CF comparisons
PLA Metal vs TPU-CF — documented properties and sources
PropertyMetal-filled PLAPLACarbon-fibre TPUFLEX
Market snapshot
Listing priceUSD/kg; dated snapshots$79.69/kg median; $24.99–$94.99/kg across 6 dated product listings$107.05/kg median; $107.05–$107.05/kg across 1 dated product listings
Identity & Market
Base polymer / chemistryPLA loaded with real metal powder — bronze, copper, steel or iron. Bambu Lab's PLA Sparkle TDS states it has "metal particles included in its composition"; its separately sold PLA Metal does not, and the store page says so explicitly[1][2][3][4][5][6]Carbon-fibre reinforced thermoplastic polyurethane at the hard end of the range[7]
Densityg/cm³1.26 (Bambu Lab Sparkle, a trace-metal glitter grade) up to 3.9–4.0 for colorFabb bronze and copper and 2.3 for Proto-pasta steel, ISO 1183[4][1][2][8]1.22 (Extrudr FLEX HARD CF, ISO 2781)[7]
Typical priceUSD/kg1 kg spools cluster near 78[9][10][3]107 for the only retail listing found (Extrudr 0.5 kg coil, incl. VAT)[11]
Price range across brandsUSD/kg25–95 across brands; Bambu Lab Sparkle 25, Proto-pasta iron 65, colorFabb bronze and copper 84, Proto-pasta steel 95[9][3][10][8]One listing only: EUR 49.56 incl. VAT per 0.5 kg coil, direct from Extrudr; no reseller or second brand found[11]
Market availability1–5Available from several mainstream brands[10][3][8][9]Niche, a handful of specialist brands — Extrudr's FLEX HARD CF is the only carbon-filled flexible with a published datasheet found here[7]
Spool sizes & diameters1.75 and 2.85 mm; 0.1, 0.5, 0.75, 1 and 1.5 kg spools[12][10]1.75 mm; 0.5 and 2 kg coils[11]
Typical applicationsDecorative castings and props that are polished or left to patinate; the density gives prints a metallic heft[1][3]Stiffened flexible parts — damping mounts and semi-rigid brackets[7]
Printing Parameters
Nozzle temperature°C195–220 (colorFabb bronze and copper); 192 (Proto-pasta iron); 198 (Proto-pasta steel); 190–230 (Bambu Lab Sparkle)[1][3][8][4]230–260 (Extrudr FLEX HARD CF)[7]
Bed temperature°C50–60 (colorFabb, Proto-pasta); 35–45 (Bambu Lab)[1][3][4]50–90 (Extrudr FLEX HARD CF)[7]
Enclosure / chamber requirement1–5Open frame is fine[1]Open frame is fine[7]
Part cooling fanOn (colorFabb copper); 0–100 % (colorFabb bronze)[1][2]Not documented
Bed surface & adhesion aidGlass plate with glue stick or tape (colorFabb)[1][2]PEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent[13][14]
Maximum volumetric flow (mm³/s; see test conditions)mm³/s1.6–2.4 at Proto-pasta's 20–30 mm/s for iron and steel, 3.2–8 at colorFabb's 40–100 mm/s, on a 0.4 mm nozzle at 0.2 mm layer[3][8][1][15]1.6–8 at the 20–100 mm/s Extrudr specifies on a 0.4 mm nozzle at 0.2 mm layer[7]
Overall printing difficulty1–5Intermediate — dry filament and a tuned profile; brittle in filament form and slow to print[3][8]Advanced — enclosure, hardware upgrades, tuning; hardened nozzle needed[7]
Extruder requirementProto-pasta advises an extrusion width 0.05 mm larger than the nozzle and warns that feeding is inconsistent below 0.4 mm and on Bowden machines[3][8]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass acceptable; hardened steel for volume work[3][8]Hardened steel required — Extrudr marks FLEX HARD CF as needing a hardened nozzle where its unfilled FLEX grades do not[7]
Abrasiveness1–5Moderately abrasive — metal fill[3][8]Highly abrasive — standard CF composite[7]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle[8]High — jams from moisture, heat creep or particles; a flexible base plus chopped carbon fibre, which Prusa lists as a higher nozzle-clogging risk, and Extrudr requires a hardened nozzle[16][7][13]
Hotend requirementProto-pasta recommends a wear-resistant or larger nozzle for longer service intervals[3][8]No special hot-end required, but a direct-drive extruder is (Simplify3D)[13]
Other hardware wearProto-pasta warns of more frequent nozzle replacement and first-layer adjustment[3][8]Not documented
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate — the PLA matrix takes up 0.40–0.51 % saturated; the metal powder itself does not absorb water[17][18]Moderate[19]
Drying temperature & timeNot documented60 °C for 6 h (Extrudr FLEX HARD CF)[7]
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface[19]
Effect of moisture on strengthPolymaker 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[19]Polymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[19]
Storage requirementNot documentedSealed with desiccant; often kept in a dryer during the print[19]
Mechanical Properties
Tensile strength (XY)MPa25 (colorFabb copper) and 30 (colorFabb bronze), ISO 527-1A; Bambu Lab Sparkle 39 ± 3 printed XY, ISO 527[1][2][4]Not documented
Young's modulusMPa1940 ± 230 printed XY, ISO 527 (Bambu Lab Sparkle)[4]35 (Extrudr FLEX HARD CF, ISO 527-2/5A/500)[7]
Elongation at break%3–10 (colorFabb copper) and 5–10 (colorFabb bronze), ISO 527-1A; 11.7 for Bambu Lab Sparkle printed XY[1][2][4]380 ultimate elongation (Extrudr FLEX HARD CF, ISO 527-2/5A/500), against 490 for the unfilled FLEX HARD[7]
Flexural strengthMPa75 ± 4 printed XY, ISO 178 (Bambu Lab Sparkle)[4]Not documented
Flexural modulusMPa2350 ± 140 printed XY, ISO 178 (Bambu Lab Sparkle)[4]Not documented
Charpy impact, notchedkJ/m²23.2 ± 2.4 printed XY, ISO 179, notched (Bambu Lab Sparkle)[4]Not documented
Other impact dataIzod notched 4.5 kJ/m² for colorFabb bronzeFill and 10 kJ/m² for copperFill (ISO 180); Charpy unnotched 66.5 kJ/m² for Bambu Lab Sparkle[1][2][4]Not documented
Layer adhesion / Z tensileMPa32 ± 2 printed Z, ISO 527 (Bambu Lab Sparkle)[4]Not documented
Brittleness1–5Brittle — Proto-pasta describes both its iron and steel grades as more brittle than standard PLA in filament form[3][8]Very ductile — bends far before failing[7]
Hardness (scale-specific)Shore A / Shore D / RockwellNot documented70 Shore D (Extrudr FLEX HARD CF, ISO 868), against 58 Shore D for the unfilled FLEX HARD[7]
Creep resistance / sustained load1–5Poor — no metal-filled creep test; plain printed PLA sagged from 12 to 16.2–21.8 mm over 5 days at 1.25 kg[20][21][22]Below average — no CF-grade creep test; the grade is 70 Shore D where a 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[7][23]
Fatigue / repeated-flex resistance1–5Poor — no grade-specific S-N curve; plain printed PLA ran 38 000–49 000 cycles at 30 % of tensile strength and Proto-pasta describes its iron and steel grades as more brittle than standard PLA[24][3][8]Good — 380 % ultimate elongation and a damping application set (Extrudr cites longboard wheels), below the unfilled grades[7]
Elasticity / flexibility1–5Rigid[4]Semi-flexible[7]
Z strength as % of XY%82 by tensile (printed, Bambu Lab Sparkle)[4]Not documented
Wear resistance & frictionNot documentedAbrasion 26 mm³ (Extrudr FLEX HARD CF, ISO 4649-A) — the same as the unfilled FLEX HARD[7]
Thermal Properties
HDT at 0.45 MPa°C55 (ISO 75, 0.45 MPa, Bambu Lab Sparkle)[4]Not documented
HDT at 1.8 MPa°C53 (ISO 75, 1.8 MPa, Bambu Lab Sparkle)[4]Not documented
Glass transition (Tg)°C56 (DSC, Bambu Lab Sparkle)[4]-24 (Extrudr FLEX HARD CF)[7]
Melting point / Vicat°C156 peak melt (DSC, Bambu Lab Sparkle)[4]Vicat A 140 (Extrudr FLEX HARD CF, ISO 306)[7]
Environment & Chemical
UV resistance1–5Degrades within weeks outdoors[25]Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[14]
Outdoor durabilityProto-pasta markets its iron grade as rustable — the iron oxidises deliberately when exposed to moisture[3]Not documented
Chemical resistanceNot documentedWithstands industrial solvents and UV exposure (Polymaker)[14]
Food contactNot documentedNot food safe without specific certification (Polymaker)[14]
Biodegradability / compostabilityNot documentedNot biodegradable[14]
RecyclabilityNot documentedNot accepted in household plastic collection[14]
Electrical & ESD propertiesProto-pasta magnetic iron PLA is ferromagnetic and responds to magnets[3]Not documented
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission[26]Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[26]
Ventilation / filtration requirement1–5None needed in a normal room[26]Open a window / occasional ventilation[26]
Dust & fibre handling hazardNot documentedCarbon fibre is bound in the matrix; sanding dust should not be inhaled[7]
Post-Processing
Sanding & machiningPolishing is the intended finish — colorFabb and Proto-pasta both sell these grades to be sanded and buffed to a metallic shine[1][2][8]Difficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[14]
Gluing & solvent weldingNot documentedCyanoacrylate bonds TPU; no common solvent welds it[14]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[14]
Support material pairingNot documentedPolymaker warns TPU supports are often very difficult to remove[14]
Dimensional accuracy & detailcolorFabb notes the metal fill increases die swell, so flow needs raising above plain PLA[2]Tear strength 165 kN/m (Extrudr FLEX HARD CF, ISO 34-1B)[7]
Solvents & Solubility
Soluble inChloroform dissolves the PLA matrix (10 % w/v, 2–4 h at 23 °C) and leaves the filler as loose sludge; laboratory reagent.[27]DMF, DMSO, NMP and THF dissolve the TPU matrix and leave the fibre; ketones are partial solvents. Laboratory reagents.[28]
Softened or crazed byAcetone, ethyl acetate and toluene plasticise the matrix but dissolve <1 % even at 65 °C; acetone submersion crazes parts.[27][29]Toluene and benzene swell it up to +50 % by weight at 23 °C; esters swell it severely; ethanol and IPA soften it.[28]
Solvent welding & smoothing agentChloroform vapour attacks only the resin fraction, so the filler is left standing proud; no workshop-safe agent exists.[30][29]None practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[28]

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. bronzeFill technical data sheet colorFabb · 2026-08 · tds
  2. copperFill technical data sheet colorFabb · 2026-08 · tds
  3. Magnetic Iron PLA — product page and technical data Proto-pasta · 2026-08 · tds
  4. Bambu Filament Technical Data Sheet — PLA Sparkle Bambu Lab · 2026-08 · tds
  5. PLA Metal — product page Bambu Lab US Store · 2026-08 · vendor
  6. Bambu Filament Technical Data Sheet V3.0 — PLA Metal Bambu Lab · 2026-08 · tds
  7. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  8. Stainless Steel PLA — product page and technical data Proto-pasta · 2026-08 · tds
  9. PLA Sparkle — product page Bambu Lab US Store · 2026-08 · vendor
  10. bronzeFill — product page colorFabb US · 2026-08 · vendor
  11. Extrudr TPU FLEX Hard CF — product page (1.75 mm, 0.5 and 2 kg coils, price) Extrudr (FD3D GmbH) · 2026-08 · vendor
  12. Proto-pasta product catalogue Proto-pasta · 2026-08 · vendor
  13. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  14. TPU — material basics Polymaker Wiki · 2026-08 · doc
  15. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  16. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  17. Bambu Filament Technical Data Sheet V3.0 — PLA Basic Bambu Lab · 2026-08 · tds
  18. PolyLite PLA Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  19. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  20. BambuLab PLA Basic vs PLA Tough vs PLA-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  21. Polymaker PLA Pro vs PLA-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  22. Carbon Fiber PLA vs META-PLA vs PLA+ vs PLA by Sunlu — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  23. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  24. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  25. PLA — material guide Prusa Knowledge Base · 2026-08 · doc
  26. 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
  27. Solubility Study of Ingeo Biopolymer Grades in Common Organic Solvents (NWPD003) NatureWorks · 2019-10 · tds
  28. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  29. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc
  30. 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