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Material Selection

How to pick the right filament for a job: a side-by-side property matrix, a "which material for…" table, drying and storage figures, and honest notes on the variants that blur together on the shelf. This page builds on the Filaments quick reference, which covers print temperatures and handling for each material.

Starting points

Every number below comes from a manufacturer technical data sheet (TDS) or official guide, linked in Sources. Values vary by brand, colour and test method, and printed parts are weaker than moulded test bars. Treat them as a way to compare materials, not as design allowables — and check the TDS for the exact spool you buy.

Property matrix

The dot ratings are relative, within desktop FDM materials (●●●●● = best in class). They are an editorial summary of the TDS numbers further down, combined with the material notes on the Filaments page — not lab measurements in their own right.

Mechanical & thermal

Material Strength Stiffness Impact Layer adhesion Heat resistance
PLA ●●●○○ ●●●●○ ●●○○○ ●●●○○ ●○○○○
PLA+ / Tough PLA ●●●○○ ●●●○○ ●●●○○ ●●●●○ ●○○○○
PETG ●●●○○ ●●○○○ ●●●●○ ●●●●○ ●●○○○
PCTG ●●●○○ ●●○○○ ●●●●● ●●●●○ ●●○○○
ABS ●●●○○ ●●○○○ ●●●○○ ●●○○○ ●●●○○
ASA ●●●○○ ●●○○○ ●●●○○ ●●○○○ ●●●○○
TPU 95A ●●○○○ ●○○○○ ●●●●● ●●●●● ●○○○○
PA6 / PA12 (neat) ●●●●○ ●●○○○ ●●●●● ●●●●○ ●●●○○
PA-CF / PA-GF ●●●●● ●●●●● ●●●○○ ●●●○○ ●●●●●
PC ●●●●○ ●●●○○ ●●●●○ ●●●○○ ●●●●○
PP ●○○○○ ●○○○○ ●●●●○ ●●●○○ ●○○○○
PVB ●●○○○ ●●●○○ ●●○○○ ●●●○○ ●○○○○
PLA-CF / PETG-CF ●●●○○ ●●●●● ●●○○○ ●●○○○ per matrix

"Heat resistance" summarises the HDT table below. "Layer adhesion" is how well the part holds together when loaded across the layers (the Z direction) — the weak axis of every FDM print.

Environment, handling & cost

Material UV / outdoor Chemical resistance Moisture sensitivity Food-contact caveat Cost tier
PLA ●●○○○ ●●○○○ Low Brittle, softens in a hot dishwasher $
PLA+ / Tough PLA ●●○○○ ●●○○○ Low Additives undisclosed — rarely certified $
PETG ●●●○○ ●●●●○ Medium Some grades certified; layer lines still trap bacteria $
PCTG ●●●○○ ●●●●○ Medium As PETG $$
ABS ●○○○○ ●●○○○ (dissolves in acetone) Low–medium Not recommended $
ASA ●●●●● ●●○○○ Low–medium Not recommended $$
TPU 95A ●●●○○ ●●●●○ (oils, grease) High Not recommended unless certified $$
PA6 / PA12 (neat) ●●○○○ ●●●●○ (oils, fuels) Very high Not recommended $$$
PA-CF / PA-GF ●●●○○ ●●●●○ Very high Not recommended (fibres) $$$$
PC ●●○○○ ●●○○○ (solvent stress-cracking) High Not recommended $$$
PP ●●○○○ ●●●●● Very low Moulded PP is a food plastic; printed parts still have layer lines $$
PVB ●●○○○ ●○○○○ (dissolves in alcohol) Medium–high Not recommended $$
PLA-CF / PETG-CF ●●●○○ per matrix per matrix Not recommended (fibres) $$–$$$

Cost tier is a rough guide to the price per kg ($ = commodity PLA/PETG, $$$$ = fibre-filled engineering nylons). See Safety for why "food-safe filament" alone doesn't make a part food-safe.

Measured values (one brand, one test set)

To show where the dots come from, here is one manufacturer's published data for its own filaments, all tested the same way. XY = load along the layers, Z = load across them.

Material (Bambu Lab) Impact XY (kJ/m²) Impact Z (kJ/m²) Bending modulus XY (MPa) Saturated water absorption
PLA 26.6 13.8 2750 0.43 %
PETG 52.7 13.6 1670 0.32 %
ABS 39.3 7.4 1880 0.65 %
ASA 41.0 4.9 1920 0.45 %
PC 34.8 9.0 2310 0.25 %
TPU 95A 125.2 88.7 — 1.16 %
PLA-CF 23.2 7.8 3950 0.42 %
PETG-CF 41.2 10.7 2910 0.30 %
PAHT-CF 57.5 13.3 4230 0.88 %
PA6-CF 40.3 15.5 — 2.35 %

Source: Bambu Lab Filament Guide (water absorption at 25 °C, 55 % RH). Two things stand out: Z-direction impact is a fraction of XY for every rigid material (orientation matters more than material choice — see Design for printing), and saturation percentage isn't the whole story — Bambu still lists PC as "dry before use: required" despite its low absorption, because a little moisture does a lot of damage at PC's melt temperature.

Heat deflection temperature (HDT)

HDT (ISO 75) is the temperature at which a standard test bar bends a set amount under load. It is the best single number for "will this sag in a hot car?" — but the load matters: TDSs quote 0.45 MPa (method B, light load) or 1.8 MPa (method A, heavier load), and the 1.8 MPa figure is lower. Only compare like with like.

Material HDT @ 0.45 MPa HDT @ 1.8 MPa Source(s)
PLA 54–60 °C 54 °C Bambu PLA Basic 57 / 54 °C; Polymaker PolyLite PLA 60 °C; eSUN PLA 53.8 °C
Matte PLA 58 °C 52 °C Bambu PLA Matte
PLA+ / Tough PLA 55–59 °C — Polymaker PLA Pro 59 °C; PolyMax PLA 55 °C
High-speed PLA 53 °C — Polymaker PolySonic PLA
PETG 69–78 °C — Bambu PETG 69 °C; Polymaker PETG 69 °C; PolyLite PETG 78 °C
PCTG 76 °C 64 °C Fiberlogy PCTG
ABS 87–100 °C 84 °C Bambu ABS 87 / 84 °C; Polymaker PolyLite ABS 100 °C
ASA 100–103 °C — Bambu ASA 100 °C; Polymaker ASA 103 °C
TPU 95A n/a n/a Not meaningful for an elastomer (Bambu TDS lists N/A)
PA (neat, PA6/66 copolymer) 111 °C (annealed) — Polymaker PolyMide CoPA
PA6-CF 184–215 °C — Bambu PA6-CF 184 °C; Polymaker PA6-CF20 215 °C (annealed)
PAHT-CF 194 °C — Bambu PAHT-CF
PA6-GF 191 °C (annealed) — Polymaker PA6-GF25
PA12-CF 131 °C (annealed) — Polymaker PA12-CF10
PC 111–117 °C — Bambu PC 117 °C (guide); Polymaker PolyLite PC 111 °C, PolyMax PC 114 °C
PP 51 °C — Fiberlogy PP (Vicat softening 110 °C)
PLA-CF 54–55 °C — Bambu PLA-CF 55 °C; Polymaker PLA-CF 54 °C
PETG-CF 69–74 °C — Bambu PETG-CF 74 °C; Polymaker PETG-rCF08 68.6 °C
PET-CF 205 °C — Bambu PET-CF

Read the small print

  • Annealed vs as-printed. Polymaker tests all its nylons annealed; Bambu's figures are for its own test conditions. Annealing can transform some materials — Polymaker's HT-PLA goes from 61 °C to 107 °C — but standard PLA and PETG warp rather than improve. See Post-processing.
  • TDSs contain errors. Bambu's own PC TDS lists 112 °C at 0.45 MPa and 117 °C at 1.8 MPa — the wrong way round for the same material — while its filament guide gives 117 °C at 0.45 MPa. Cross-check before relying on a single number.
  • PP's low HDT is misleading. It deflects easily under load because it is soft, not because it melts (Vicat 110 °C). Unloaded PP parts tolerate heat far better than the HDT suggests.
  • PLA-CF ≈ PLA. Carbon fibre adds stiffness, not heat resistance — the matrix sets the temperature limit.

A useful rule: keep the service temperature at least 10–20 °C below the HDT for parts under load, and remember that a parked car's dashboard gets far hotter than the air outside.

Which material for…

Use First choice Alternative Avoid Why
Functional brackets (indoor) PETG PLA+ / Tough PLA, PA-CF Silk PLA PETG is tough and doesn't creep as readily as PLA; Tough PLA is fine for low, short-term loads. Silk additives weaken layers.
Outdoor parts ASA PETG, PCTG PLA, ABS ASA is UV-stable. PETG is a decent no-enclosure fallback. PLA softens and embrittles in sun; ABS yellows and cracks.
Car interiors ASA PC, PA-CF PLA, PETG Dashboards and parcel shelves exceed PETG's HDT (~70 °C) in summer. ASA (~100 °C) or PC/PA-CF for parts in direct sun.
Hinges / living hinges PP Neat nylon, TPU PLA, CF-filled PP and nylon survive thousands of flex cycles. PLA and fibre-filled materials crack after a few.
Gears Neat nylon (PA) PA-CF, POM-like grades PLA (for anything under real load) Nylon's low friction and toughness resist wear and tooth chipping. PLA is fine for prototypes.
Snap-fits PETG Nylon, PP, PCTG PLA, PLA-CF Snap-fits need strain without cracking. PLA snaps; PETG flexes. Design guidance: Design for printing.
Gaskets / bumpers / feet TPU 95A Softer TPU (85A–90A) Rigid materials Elastic recovery and grip. Softer grades seal better but are harder to feed.
Enclosures (electronics) PETG ASA, PC PLA near heat sources PETG prints easily, handles warm electronics. ASA/PC for hot or outdoor housings.
Kids' toys PLA PETG, PCTG Fibre-filled, ABS PLA is easy, low-emission and rigid. PETG/PCTG if toys get thrown about. Fibres can splinter; ABS emits more. See Safety.
Decorative PLA / Matte / Silk PVB (IPA-smoothable) Engineering materials Detail and finish matter more than strength. PVB smooths to a gloss with IPA.
High-temp parts PA-CF / PAHT-CF PC, PET-CF PLA, PETG 184–215 °C HDT at 0.45 MPa for PA6-based CF nylons (TDS). PC for impact plus heat. Needs a capable printer.
Wear parts (bushings, slides) Neat nylon PA-CF, PP PLA, PETG Nylon has low friction and abrades slowly. Fibres raise stiffness but can wear mating parts.
Stiff, light structures (jigs, frames) PLA-CF / PETG-CF PA-CF TPU, PP Fibres roughly 1.5× PLA stiffness (3950 vs 2750 MPa, Bambu) with low warp.

When in doubt, PETG

If a part needs to be functional and you don't have an enclosure, PETG is the safe default. Step up to ASA for sun, nylon for wear, PC or PA-CF for heat, TPU for flex. Use PLA when it only needs to look right and stay indoors.

Drying & storage

Wet filament pops, strings and prints weak (see Filaments → Storage & moisture). The table below collects manufacturers' own drying recommendations. Where they disagree, both are shown — the difference is usually how cautious each one is about spool and filament softening.

Material Bambu Lab (forced-air oven) Prusa (Prusament) Other TDS Dry before use?
PLA 50 °C, 8 h 45 °C, 6 h eSUN 50 °C, 8–12 h Recommended if open a while
Silk PLA 55 °C, 8 h — — Recommended
PLA-CF / GF 50–60 °C, 8 h — — Recommended
Wood-fill PLA 55–65 °C, 8 h 45 °C, 6 h — Required (Bambu)
PETG / PETG-CF 60–65 °C, 8 h 55 °C, 6 h — Recommended
PCTG — — Fiberlogy 60 °C, 4 h Recommended
ABS / ASA 75–85 °C, 8 h ASA 80 °C, 4 h — Recommended
TPU 70 °C, 8 h 60 °C, 4–6 h — Required
PC 75–85 °C, 8 h PC Blend 85 °C, 5 h — Required
PA / PA-CF / PA-GF 75–85 °C, 8–12 h PA11-CF 90 °C, 6 h — Required
PET-CF 80 °C, 8–12 h — — Required
PP — PP-CF/GF 70 °C, 2–4 h Fiberlogy PP 50 °C, 4 h Rarely needed
PVB — 45 °C, 8 h Polymaker PolySmooth 50 °C, 12 h Recommended
PVA 75–85 °C, 8–12 h — — Required

Bambu also publishes heated-bed drying figures (spool under a cardboard box or printed PC cover, flipped halfway) — for example PLA 60–70 °C and ABS/ASA 90–100 °C for 12 h. The bed is hotter than an oven setting because the spool sits under a cover, not in circulating air. Dedicated dryers (and AMS-style units with drying) typically run cooler and longer; follow their own presets.

Storage humidity

Condition Relative humidity What to expect (Bambu Lab guidance)
Typical indoor air 45–65 % RH Freshly dried filament absorbs enough moisture to affect quality within 2–12 h, depending on material
Sealed box with desiccant < 20 % RH Most filaments stay dry for 2–7 days at 20 % RH; lower is better
Long-term (nylons especially) As low as you can get PA-based filaments left in open air for ~3 months become very hard to dry at spool-safe temperatures
  • Store spools in sealed bins or vacuum bags with silica gel, and put a cheap hygrometer in the box so you know when the desiccant is spent.
  • Nylon, TPU, PC and PVA should be printed from a dry box feeding the printer, not just dried once.
  • PC can become brittle after repeated heat–cool drying cycles (Bambu). Dry it once, then keep it sealed so it needs little or no re-drying.

Don't cook the spool

  • Stay below the glass-transition temperature. PLA's Tg is about 60 °C (Bambu TDS) — dry hotter and the coils fuse into a solid lump. Prusa warns that exceeding its listed temperatures makes filament "soften and stick together".
  • Check the spool, not just the filament. Cardboard and some plastic spools deform or come apart with heat; Prusa notes its older black spools are only safe to 45 °C without a retaining screw. Third-party spools in an AMS-style dryer can warp too.
  • No microwaves or kitchen ovens (Bambu): heating is uneven, and the areas near the elements get hot enough to damage spool and filament. If you must use an oven, verify the temperature with an external thermometer (Prusa).
  • Check the dryer's limit. Many consumer dryers top out around 70 °C, which may not be enough for nylon or PC — and some static drying modes are unsuitable for low-softening filaments like PLA and TPU.

Brand & variant notes

The same name on a box can mean very different plastics. These are the comparisons that cause the most confusion.

"PLA+" has no standard definition. "PLA+", "Pro", "Tough" and "Max" are marketing names for PLA with undisclosed modifiers, and the results vary enormously. Polymaker's own range illustrates it: notched Charpy impact is 3.3 kJ/m² for PolyLite PLA, 17.1 kJ/m² for PLA Pro and 38.9 kJ/m² for PolyMax PLA — a 10× spread — while HDT stays at 55–60 °C for all three.

Variant What changes What doesn't Trade-off
PLA+ / Tough Impact strength, less brittle Heat resistance (~55–60 °C) Usually a little less stiff; quality depends entirely on the brand
Matte Hides layer lines, no gloss — Weaker between layers: Bambu PLA Matte's Z bending strength is 32 MPa vs 59 MPa for PLA Basic
High-speed Flows at high volumetric rates — Formulated for flow, not strength; Polymaker PolySonic's HDT (53 °C) and impact (5 kJ/m²) are close to basic PLA
Silk Glossy finish — Aesthetic only; see Filaments → Silk PLA
HT / heat-treatable PLA Can be annealed to ~107 °C HDT (Polymaker HT-PLA) Prints like PLA Parts shrink/warp slightly when annealed; plan for it

If a datasheet doesn't list impact strength and HDT, you're buying on marketing.

Both are glycol-modified copolyesters and print at similar settings, but PCTG is much tougher. Fiberlogy lists 92 kJ/m² notched Izod for its PCTG against 5–8 kJ/m² for PETG in the same test (the vendor's own comparison), plus an HDT of 76 °C at 0.45 MPa / 64 °C at 1.8 MPa — similar to PETG.

  • Choose PCTG for parts that get dropped, clipped or flexed: tool holders, clips, toys, drop-prone housings.
  • Choose PETG when cost and availability matter more — it's cheaper, comes in every colour, and is plenty for most brackets.
  • Neither is meaningfully more heat-resistant than the other. For heat, step up to ASA or PC.

Nearly identical to print (both need an enclosure and ventilation), but:

ABS ASA
UV / weather Yellows and embrittles outdoors Excellent — built for exterior use
HDT @ 0.45 MPa 87 °C (Bambu) – 100 °C (Polymaker) 100 °C (Bambu) – 103 °C (Polymaker)
Layer (Z) impact 7.4 kJ/m² (Bambu) 4.9 kJ/m² (Bambu)
Acetone smoothing Yes Yes (slower)
Price Cheaper Slightly more

ASA is the better default for anything near a window or outside. ABS is fine indoors and is slightly tougher across layers in Bambu's data. Both are among the higher-emitting materials — see Safety.

"Nylon" covers several polyamides with different trade-offs:

  • PA6 / PA6-66 copolymers — the toughest and most heat-resistant of the neat nylons, but the most hygroscopic. Must be dried and printed from a dry box.
  • PA12 (and PA11) — lower moisture uptake and better dimensional stability than PA6, at the cost of a lower HDT (Polymaker PA12-CF10: 131 °C vs PA6-CF20: 215 °C, both annealed). Easier to live with day to day.
  • PA-CF — chopped carbon fibre makes it much stiffer and reduces warping, which is why PA-CF is the most popular "engineering" filament on enclosed printers. Black only, abrasive, and less tough than neat nylon.
  • PA-GF — glass fibre gives similar heat resistance (Polymaker PA6-GF25: 191 °C) and stiffness gains, usually at lower cost, and can be coloured. Equally abrasive.

All fibre-filled grades need a hardened nozzle (see Filaments → Specialty & composite). For hinges and gears that flex, prefer neat nylon — fibres make it stiffer but more prone to cracking under repeated bending.

Sources & further reading