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3D printing · Guide · By Mohammed Almuhanna · Updated
Which filament should I use?
Filament choice mostly comes down to one question: where does the part live? Everything else is detail. The short form below turns that into a ranked verdict, from PLA and PETG up through ASA, TPU, and the engineering tier (nylon, polycarbonate, PP). Every field is optional, every answer moves the ranking, and when two materials genuinely tie, it says so and tells you to use whichever is on your shelf. I print daily in a hot, dusty climate and I have killed parts by choosing wrong. The everyday picks below come from those autopsies; the engineering tier comes from datasheets, and the tool tells you which is which.
The logic behind the picks
Where the part lives decides most of it. A filament's softening point and UV tolerance are fixed properties, and no slicer setting negotiates with them. PLA softens around 55 to 60C. PETG deflects at 71C on its datasheet and hits glass transition near 80. ASA holds to around 100C, ABS to 87. Indoors, almost anything works and you pick on printability. Outdoors in shade, PETG's numbers hold. Direct sun or a parked car will pass 80C where I live, my dashboard measured 98C, so those parts get ASA, full stop. The hot-car test shows it with photos.
Function and looks pull in different directions. PLA prints the sharpest detail with the least effort, which makes it the right answer for models and decor and the wrong answer for a bracket holding real weight, where it snaps instead of bending. PETG is the opposite: uglier overhangs, more stringing, and far tougher when something actually leans on the part. Pick by the part's job, not by which spool is loaded.
The engineering tier earns its price only under real load. Nylon for parts that slide and wear, polycarbonate for heat past ABS and ASA, polypropylene for chemicals, and the fiber-filled nylons when heat and stiffness stack (PA6-CF deflects around 186C by its datasheet, against plain nylon's ~111C). Two things come with the tier: these picks are from datasheets and community consensus rather than my own bench, and the CF and GF versions chew brass nozzles and, outside a few named first-party spools, stay out of the AMS. One more trap for enclosed-printer owners: the low-temperature filaments, PLA, PETG, and TPU, must not bake in a heated chamber. Above roughly 45C they soften in the feed path, which is why Bambu's own docs tell you to open the door when printing PLA on a hot bed.
Carbon fiber buys stiffness, and heat resistance only on the right base. On PLA and PETG, CF fill softens at the same temperature as the base plastic; the upgrade is rigidity, not temperature. On semi-crystalline bases the story changes: fiber-filled nylon and PET post dramatically higher deflection temperatures on their datasheets. What it adds is rigidity, and an abrasive surface that eats brass nozzles and feels wrong on anything people grip. My rack bracket is PETG-CF and it is perfect there, mounted, loaded, and never touched.
What I actually stock
Around 15 kg of ASA, 6 kg of high-flow PETG, 8 to 9 kg of PLA, a kilo of 85A TPU, and half a kilo each of PLA-CF and PETG-CF. That ratio is the advice in physical form: ASA carries the functional load in my climate, PETG covers the everyday brackets and boxes, PLA does the occasional looks-first job, and TPU comes out when something needs to grip or take a hit. If you print in a milder climate, your shelf can lean harder on PETG and save the ASA money for the parts that see sun.
The wider shelf, with the real numbers
Everything below is printable on an enclosed 350C-nozzle machine like mine, and the heat column is the manufacturer's own datasheet figure (heat deflection at 0.45 MPa, ISO 75), not marketing copy. Cost is a relative tier, cheap, mid, engineering, premium, because prices move; check them wherever you buy.
| Material | Deflects around | Hardened nozzle | Cost | The call |
|---|---|---|---|---|
| PLA | 57C | No | cheap | Sharpest detail, least fight. Indoors only. |
| PLA-CF | 55C | Yes | mid | Stiffer PLA, same heat limit, matte and clean. |
| PETG | 71C | No | cheap | The functional default. Shade yes, sun no. |
| PETG-CF | 74C | Yes | mid | Stiffness upgrade, not a heat upgrade. |
| PET-CF | 205C | Yes | engineering | The sleeper: 200C-class heat, hates moisture, refuses the AMS. Some brands only hit their number after annealing. |
| ABS | 87C | No | cheap | ASA minus the UV resistance. Only if it is already on the shelf. |
| ABS-GF | 99C | Yes | mid | Stiffer, less warpy ABS. |
| ASA | 100C | No | mid | The outdoor and car default. What I actually print. |
| ASA-CF | 110C | Yes | mid | ASA stiffened for bigger structural parts. |
| ASA Aero | 85C | No | mid | Self-foaming featherweight ASA. RC-plane niche. |
| PC | 112C | No | mid | Tough and heat-tolerant. Printed PC is a blend; the molded 140C number does not apply. |
| PC FR | 113C | No | engineering | PC that resists catching fire. Electronics enclosures. |
| PA6-CF | 186C | Yes | engineering | The wear-and-heat pick, IF you keep it bone dry. |
| PA6-GF | 182C | Yes | engineering | PA6-CF's cheaper sibling, nearly the same numbers. |
| PAHT-CF | 194C | Yes | engineering | The nylon built to stay strong wet. You pay for that. |
| PPA-CF | 227C | Yes | premium | Near-ceiling heat, premium money, 100C-plus drying, no AMS. |
| PPS-CF | 264C | Yes | premium | The consumer ceiling. Locked to 350C-nozzle machines (X1E, H2 series). |
| TPU 85A to 95A | flexes instead | No | mid | Rubber parts. Regular TPU refuses the AMS; the 68D "TPU for AMS" is the exception. |
| PVA | n/a | No | engineering | Dissolvable supports for PLA. Absorbs moisture in hours; calcium chloride desiccant or nothing. |
| HIPS | n/a | No | cheap | Sold as break-away ABS support. The old dissolve-in-limonene pairing is shaky; limonene attacks ABS too. |
And the tier this table deliberately leaves out: PEEK and Ultem (PEI). The published floor to print them is a 375 to 410C nozzle, a 90C-plus actively heated chamber, and 120 to 150C drying, and PEEK costs several times anything in the table above. No consumer machine qualifies, mine included, with its 350C nozzle and 65C chamber. If a part genuinely needs PEEK, it needs a machine shop, not a hobby printer.
Numbers are the manufacturers' datasheets (Bambu Lab TDS for the table, cross-checked against Prusament, Polymaker, eSUN, and 3DXTech documentation). Where brands disagree, the row says so.
Common questions
What filament should a beginner start with?
PLA, easily. It prints cool, sticks without a fight, barely warps, and fails gently while you learn the machine. Move to PETG when a part needs to survive real use, and to ASA when it needs to survive weather.
Is PETG better than PLA?
Different jobs. PETG is tougher, handles heat better, and takes knocks; PLA prints easier and looks sharper. For functional parts I default to PETG, for display parts PLA. The full comparison works through the numbers.
What filament survives outdoors?
In shade, PETG does fine and resists moisture and UV well enough. In direct sun, ASA is the only common filament I trust, because it keeps its shape to around 100C and does not go chalky. PLA is an indoor material, period. The outdoor guide ranks them with the temperatures.
Do I need carbon fiber filament?
Only if a rigid part flexes and hands rarely touch it. On PLA and PETG, CF adds stiffness, not heat resistance, and its surface is abrasive, wrong for grips and handles, hard on brass nozzles. On nylon and PET bases the fill does raise heat deflection sharply (PA6-CF measures 186C against plain nylon's roughly 111C). Print any of it through hardened steel or not at all.
Is PET better than PETG?
Plain PET is stiffer than PETG (roughly double the flexural modulus on eSUN's datasheets) and slightly more heat tolerant, and it is meaningfully harder to print; Prusa's own guide says plain PET offers no advantage over PETG. Where PET earns its place is PET-CF: the fiber turns it into a 200C-class material. For everyday parts, PETG stays the sane default.
What about PEEK or Ultem?
No. The machines that print them need 375 to 410C nozzles and actively heated 90C-plus chambers, and PEEK itself costs several times anything on the consumer shelf. Nothing a homelab or a hobby workshop prints needs it; PPS-CF and the CF nylons cover the hot end of real projects for a fraction of the money.