3D Printing Info

Filament comparison

PA6 vs TPU soft

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

PA6 (Nylon 6) guideSoft TPU (below 85A) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PA6 comparisonsMore TPU soft comparisons
PA6 vs TPU soft — documented properties and sources
PropertyPA6 (Nylon 6)PASoft TPU (below 85A)FLEX
Market snapshot
Listing priceUSD/kg; dated snapshots$104.00/kg median; $38.99–$136.00/kg across 3 dated product listings$114.04/kg median; $109.80–$122.27/kg across 4 dated product listings
Identity & Market
Base polymer / chemistryPolyamide 6, ring-opened from caprolactam — the most hygroscopic of the common nylons[1][2]Very soft thermoplastic elastomers below 85 Shore A. Fiberlogy's FiberFlex 30D measures 81 Shore A, the softest grade with a published datasheet found here[3]
Densityg/cm³1.06 (ISO 1183, 3DXTech iOn PA6 alloy)[4]1.07 (Fiberlogy FiberFlex 30D, ISO 1183)[3]
Typical priceUSD/kg1 kg-equivalent spools span 39–136; the middle of the market is about 104, though budget unfilled PA6 has now arrived at 39[5][6]1 kg-equivalent spools cluster near 115[7][8][9]
Price range across brandsUSD/kg39–136 across brands; YXPOLYER 39, 3DXTech iOn Nylon 6 Alloy 104, WearX Nylon 6 136. Unfilled PA6 filament stays rare — most PA6 reaches the market glass- or carbon-filled[5][6]110–122 at 1 kg-equivalent; Recreus 70A 110 and 60A 116 at 500 g, NinjaTek Edge 83A 112, NinjaTek Chinchilla 75A 122; the Recreus 3 kg spools fall to 70–73[7][9][8]
Market availability1–5Niche, a handful of specialist brands[5]Niche, a handful of specialist brands[3][10][7]
Spool sizes & diameters1.75 and 2.85 mm; 500 g and 750 g spools[5]1.75, 2.85 and 3 mm; 0.5, 0.85, 1, 2 and 3 kg spools[3][7][11][8]
Typical applicationsWear parts, bushings and gears where PA6's toughness and abrasion resistance matter more than dimensional stability[1]Highly compliant seals, soft grips and prosthetic liners[3]
Printing Parameters
Nozzle temperature°C220–260 (Polymaker); 225–265 (Simplify3D)[1][12]Not documented
Bed temperature°C70–100 (Polymaker); 70–90 (Simplify3D)[1][12]50–70 (Fiberlogy FiberFlex 30D)[3]
Enclosure / chamber requirement1–5Enclosure required (passive)[13][1]Open frame is fine[3]
Part cooling fanPart cooling fan not required (Simplify3D)[12]Not documented
Bed surface & adhesion aidPEI sheet with a glue stick, or a dedicated adhesive such as Magigoo[12][1]PEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent[14][15]
Bed-adhesion difficulty1–5Needs a specific surface plus adhesive[12][1]Not documented
Stringing / oozing tendency1–5Moderate — retraction tuning needed[1]Not documented
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; the filament must be kept dry throughout the print[1][16]Expert / industrial hardware only — below 85 Shore A the filament buckles in almost any feed path that is not a short, constrained direct drive[11][15]
Extruder requirementNot documentedDirect drive only, with a constrained filament path; Bowden is not viable at this hardness[11][10]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely for unfilled grades[1]Brass fine indefinitely[17]
Abrasiveness1–5Non-abrasive when unfilled[1]Non-abrasive[17]
Nozzle clog risk1–5Very high — frequent jams without careful setup; wet nylon pops and cracks in the melt[18][16]High — jams from moisture, heat creep or particles; below 85 Shore A the filament buckles and compresses, and Simplify3D warns that raised feed rates most likely end in a jam[14][15][16]
Heat-creep / jam sensitivity1–5Moderate — good heatbreak cooling needed[12]Very high — softens in the cold zone readily[15]
Hotend requirementMay require an all-metal hot end (Simplify3D)[12]No special hot-end required, but a direct-drive extruder is (Simplify3D)[14]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Very high (>2 %) — Polymaker groups nylon with PVA as the most moisture-prone class, and its own PA6-based composites reach 2.35–3.33 % equilibrium[16][19]Moderate[16]
Drying temperature & time100 °C for 8 h (Polymaker CoPA); storage below 20 % RH[13][20]Not documented
Symptoms when wetPopping and cracking during extrusion, then defects that Polymaker describes as very hard to diagnose[18]Bubbling and popping at the nozzle, stringing and a rough surface[16]
Effect of moisture on strengthMeasured dry against wet on printed specimens at 6.16 % moisture (Polymaker CoPA): tensile 78.0 → 34.3 MPa, Young's modulus 2703 → 724 MPa, flexural strength 109.8 → 22.6 MPa, while notched Charpy rises 6.9 → 27.7 kJ/m² and elongation 12.7 → 13.2 %[13][18]Polymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[16]
Storage requirementSealed below 20 % RH with desiccant; Polymaker says nylon often needs to stay in a dryer while printing[20][16]Sealed with desiccant; often kept in a dryer during the print[16]
Hydrolysis at melt temperaturePolymaker requires a 100 °C dry for 8 h and storage below 20 % RH; no molecular-weight loss figure is published, and the published wet data is conditioning rather than melt hydrolysis[13][20]Not documented
Mechanical Properties
Tensile strength (XY)MPa62 at break (printed XY, ISO 527, 3DXTech iOn PA6 alloy); Stratasys FDM Nylon 6 conditioned to 20 °C / 50 % RH gives 67.6 ultimate and 49.3 at yield printed XZ (ASTM D638)[4][21]Not documented
Young's modulusMPa2110 (printed XY, ISO 527, 3DXTech iOn PA6 alloy); Stratasys FDM Nylon 6 conditioned gives 2232 printed XZ and 1817 ZX (ASTM D638)[4][21]Not documented
Elongation at break%9 at break (printed XY, ISO 527, 3DXTech iOn PA6 alloy); Stratasys FDM Nylon 6 conditioned gives 38 printed XZ against 3.2 in ZX (ASTM D638)[4][21]870 at break (Fiberlogy FiberFlex 30D, ISO 527) — the highest elongation in the dataset[3]
Flexural strengthMPa78 (printed XY, ISO 178, 3DXTech iOn PA6 alloy); Stratasys FDM Nylon 6 conditioned gives 97.2 printed XZ and 82 ZX (ASTM D790)[4][21]Not documented
Flexural modulusMPa2200 (printed XY, ISO 178, 3DXTech iOn PA6 alloy); Stratasys FDM Nylon 6 conditioned gives 2196 printed XZ and 1879 ZX (ASTM D790)[4][21]Not documented
Other impact dataIzod notched 106 J/m printed XZ against 43 J/m in ZX; unnotched 2873 against 192 J/m (Stratasys FDM Nylon 6, conditioned 20 °C / 50 % RH, ASTM D256 Method A) — a 15x anisotropy unnotched[21]Not documented
Layer adhesion / Z tensileMPa36.5 ultimate and 28.9 at yield printed ZX (Stratasys FDM Nylon 6, conditioned 20 °C / 50 % RH, ASTM D638)[21]Not documented
Brittleness1–5Tough — absorbs impact, yields before breaking[1]Very ductile — bends far before failing[3]
Hardness (scale-specific)Shore A / Shore D / RockwellShore D 86 and Rockwell 85 (108) — the source does not name the scales on extruded unfilled PA66 stock (ASTM D2240, D785); no figure is published for a PA6 filament[22]81 Shore A and 30 Shore D (Fiberlogy FiberFlex 30D, ISO 7619)[3]
Creep resistance / sustained load1–5Moderate[1]Poor — no creep test at this hardness; a printed 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[23]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[1]Excellent — living hinges viable[15]
Elasticity / flexibility1–5Semi-flexible[18]Rubbery / highly elastic[3]
Z strength as % of XY%54 (Stratasys FDM Nylon 6 conditioned, ZX against XZ ultimate tensile, ASTM D638); 59 on the yield figures[21]Not documented
Wear resistance & friction3DXTech sells a dedicated wear-resistant PA6 grade; abrasion resistance is the usual reason to choose PA6 over PA12[5]Tear strength 95 kN/m (Fiberlogy FiberFlex 30D, ISO 34-1)[3]
Thermal Properties
HDT at 1.8 MPa°C93 (Stratasys FDM Nylon 6, conditioned, ASTM D648 at 264 psi)[21]Not documented
Glass transition (Tg)°C105 (DSC, 3DXTech iOn PA6 alloy)[4]Not documented
Melting point / Vicat°CNot documented170 melting (Fiberlogy FiberFlex 30D, DSC)[3]
Thermal expansion (CTE)µm/m·K81.0 on extruded unfilled PA66 stock (ASTM D696; source states 4.5e-5 in/in/°F); no figure is published for a PA6 filament, and PA6 and PA66 expand almost identically[22]Not documented
Flammability / UL 94Flammable; no UL 94 rating published for the unfilled filament grades surveyed[4]Not documented
Environment & Chemical
UV resistance1–5Months outdoors before embrittlement — unstabilised polyamide yellows and chalks under UV[1]Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[15]
Chemical resistanceWithstands oils, fuels and alkalis — the usual reason to choose a polyamide[1]Withstands industrial solvents and UV exposure (Polymaker)[15]
Water / humidity resistance in service1–5Absorbs water, properties shift — a conditioned part is measurably softer and larger than the same part dry[18][13]Not documented
Food contactPolymaker notes medical-grade variants exist, but standard filament is not food-contact certified[1]Not food safe without specific certification (Polymaker)[15]
Biodegradability / compostabilityNot biodegradable[1]Not biodegradable[15]
RecyclabilityMechanically recyclable but not accepted in household plastic collection[1]Not accepted in household plastic collection[15]
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised[2]Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[2]
VOC emission rateµg/minUp to 180 caprolactam, the dominant VOC from nylon; total VOC reached nearly 200 µg/min, the highest of the nine filaments tested[2]Not documented
Ultrafine-particle emission rateparticles/min≈2 × 10⁸ median — low for ultrafine particles despite the highest VOC mass of any filament tested[2]Not documented
Hazardous species emittedCaprolactam, at up to 180 µg/min from nylon filament — the largest single-VOC emission rate measured in the study[2]Not documented
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[2]Open a window / occasional ventilation[2]
Post-Processing
Sanding & machiningSands poorly — the toughness makes it gum rather than powder[12]Difficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[15]
Gluing & solvent weldingCyanoacrylate; no common solvent welds polyamide[12]Cyanoacrylate bonds TPU; no common solvent welds it[15]
Vapour / chemical smoothingNo practical vapour smoothing[12]No practical vapour smoothing[15]
Support material pairingPVA dissolves cleanly against nylon; Polymaker sells a break-away PolySupport for PA12[12]Polymaker warns TPU supports are often very difficult to remove[15]
Dimensional accuracy & detailParts grow as they absorb moisture after printing; Polymaker declines to publish a standard dimensional allowance because it depends on geometry and infill[18]Not documented
Solvents & Solubility
Soluble inDissolved at 23 °C by formic acid above ~50 %, phenol, m-cresol, 96 % sulphuric acid or hexafluoroisopropanol — laboratory reagents.[24]DMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[25]
Softened or crazed byZinc chloride solutions stress-crack it — 10 % marginal, 37 % not resistant; alcoholic calcium chloride dissolves it.[24]Toluene and benzene swell it up to +50 % by weight at 23 °C; esters swell it severely; ethanol and IPA soften it.[25]
Solvent welding & smoothing agentNone — nylon's only solvents are formic acid, phenol and HFIP, all of which degrade the part they wet.[24]None practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[25]

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. PA (Nylon) — material basics Polymaker Wiki · 2026-08 · doc
  2. 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
  3. FiberFlex 30D Technical Data Sheet Fiberlogy · 2026-08 · tds
  4. iOn PA6-based Nylon Alloy Technical Data Sheet v2.0 3DXTech · 2026-08 · tds
  5. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  6. YXPOLYER PA6 Black 1 kg — product page YXPOLYER · 2026-08 · vendor
  7. Recreus product catalogue Recreus · 2026-08 · vendor
  8. Chinchilla product page — print guidelines, spool sizes and price NinjaTek · 2026-08 · vendor
  9. NinjaFlex Edge product page — durometer, print guidelines and price NinjaTek · 2026-08 · vendor
  10. Filaflex 82A product page (Shore hardness and elongation) Recreus · 2026-08 · vendor
  11. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  12. Nylon — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  13. PolyMide CoPA Technical Data Sheet V5.4 (dry and wet status blocks) Polymaker · 2024-11 · tds
  14. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  15. TPU — material basics Polymaker Wiki · 2026-08 · doc
  16. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  17. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  18. Moisture Conditioning — effect on printed nylon properties Polymaker Wiki · 2026-08 · doc
  19. Fiberon PA612-CF15 Technical Data Sheet V1.1 Polymaker · 2024-12 · tds
  20. PolyMide CoPA — Technical Data Sheet page Polymaker Wiki · 2026-08 · tds
  21. FDM Nylon 6 — data sheet (conditioned 20 °C / 50 % RH) Stratasys · 2017-11 · tds
  22. TECAMID 66 natural (PA66) — stock shape properties Ensinger · 2026-08 · tds
  23. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  24. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds
  25. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds