3D Printing Ranked
Choosing Filament by What the Part Has to Survive: Heat, Stiffness, Toughness and Moisture
After reading this you should be able to name the filament family your part needs, say which datasheet number drove the choice, find that same number on a datasheet for whatever brand of spool you actually buy, and check the two hardware fields — build surface and hot end — before the spool touches your printer.
Most filament advice starts from reputation: PETG is "stronger", ASA is "the outdoor one", nylon is "tough". Reputation is not a specification. This page starts from the part instead — how hot it gets, what load it carries, whether it gets hit — and matches that to a published number measured under a named test method.
The short answer, by what the part has to survive
Read this first: every number on this page comes from one manufacturer's datasheets (Prusa Polymers), plus one Polymaker sheet used for the cross-brand comparison. Some of the names below — PC Blend, PA11 Carbon Fiber, TPU 95A — are that brand's product names, not generic categories. Use them to identify the family, then read the datasheet for the spool you actually buy.
- Gets hot, carries little or no load: PLA softens first. Its heat deflection temperature is 55 °C at both standard loads, the lowest of this set. Every other material here is higher. PETG is 68 °C, ASA 93/86 °C, PC Blend 113/93 °C.
- Gets hot and carries load: use the 1.80 MPa column, not the 0.45 MPa one. PC Blend drops from 113 °C to 93 °C between them; PA11 Carbon Fiber drops from 192 °C to 152 °C.
- Must not snap when dropped: PLA is the brittle one — 13±1 kJ/m² unnotched, and its datasheet reports no notched figure at all. PETG and PC Blend do not break at all in the unnotched test.
- Has sharp internal corners, screw holes or other stress risers: the notched Charpy number is the one that matters. ASA, PC Blend and PA11 Carbon Fiber all read 12 kJ/m² notched; PETG is only 6±1.
- Must stay stiff without bending: PA11 Carbon Fiber (2.5 GPa) and PLA (2.3 GPa) are the stiffest. PETG is the softest rigid option at 1.5 GPa.
- Must flex or grip: TPU 95A. Its limits are print speed, the feed path and the sheet you print on — not temperature.
- Lives outdoors: neither ASA datasheet read for this page publishes a weathering result. See the last section for what to ask for instead.
Heat: read the deflection temperature, and the load it was measured at
Heat deflection temperature is the field to look up, but it is not a "safe working temperature". ISO 75-2 measures the temperature at which a specimen deflects a set amount under a constant flexural stress, and it defines separate methods for different stresses: method A at 1.80 MPa, method B at 0.45 MPa, method C at 8.00 MPa. A single HDT number tells you nothing until you find the load printed beside it — and it can be either one. The Prusament TPU 95A sheet, for instance, publishes only the 1.80 MPa figure (78.6 °C) and no 0.45 MPa figure at all.
For low-temperature materials the two loads give the same answer, so the distinction does not matter. PLA reads 55 °C at both. PETG reads 68 °C at both. The moment you move up the range they diverge, and the gap is large: ASA gives up 7 °C between the two loads, PC Blend 20 °C, PA11CF 40 °C.
Here is how to actually use the number, once you know your part's peak temperature. If that peak is at or above the material's 1.80 MPa figure, rule the material out — at that temperature a loaded test bar is already deflecting by the amount the standard defines as failure. A part that reaches 70 °C therefore excludes PETG on PETG's own number, because PETG's 1.80 MPa figure is 68 °C. ASA at 86 °C and PC Blend at 93 °C are still in play. What the datasheet cannot settle is the near-miss: a part at 80 °C against ASA's 86 °C. The test bar is not shaped like your part, is not loaded like your part, and HDT is a threshold rather than a rating, so the sheet gives you no way to resolve that case. Prototype it, or move up a material.
This page publishes no measurement of how hot a car interior, attic or engine bay actually gets. We have no sourced figure for that, so we do not guess one. If you do not know your part's peak temperature, measure it before choosing on this basis.
The PLA-versus-PETG trap: stiff is not the same as tough
This is the most common way people pick the wrong material. On the Prusa forum, a user who had a working PLA prototype switched to PETG because he had read it had superior physical properties, then found the PETG part broke instantly when he bent it. A reply put it plainly: PETG "is not stronger than PLA in most senses" — the failure mode differs, with PLA shattering and PETG deforming as it fails. Other replies suspected layer adhesion rather than the material itself.
The datasheets agree. Printed horizontally, PLA is both stiffer (2.3 GPa against 1.5 GPa) and higher in tensile yield (51±3 MPa against 47±2 MPa). PETG wins on impact only: it does not break in the unnotched Charpy test, where PLA absorbs 13±1 kJ/m². So "stronger" is two different questions. If the part must not bend, PLA is measurably better. If it must survive being dropped, PETG is. Decide which failure you are actually trying to prevent.
Print settings, build surface and heat resistance
| Material | Nozzle °C | Bed °C | Bed type, as the sheet states it | Max print speed | HDT 0.45 MPa | HDT 1.80 MPa |
|---|---|---|---|---|---|---|
| PLA | 210 ± 10 | 40–60 | smooth PEI, powder-coated or satin sheet | up to 200 mm/s | 55 °C | 55 °C |
| PETG | 250 ± 10 | 80 ± 10 | satin or powder-coated; smooth PEI with a glue stick | up to 200 mm/s | 68 °C | 68 °C |
| ASA | 260 ± 10 | 110 ± 5 | satin or smooth PEI; powder-coated with a glue stick | up to 200 mm/s | 93 °C | 86 °C |
| PC Blend | 275 ± 10 | 110 ± 10 | satin; smooth PEI and powder-coated with a glue stick | up to 200 mm/s | 113 °C | 93 °C |
| PA11 Carbon Fiber | 285 ± 5 | 110 ± 10 | special PA Nylon spring sheet, treated with clean water | up to 100 mm/s | 192 °C | 152 °C |
| TPU 95A | 230 ± 10 | 65 ± 10 | PA Nylon, PP, satin, textured; smooth PEI with a glue stick as a separate layer | up to 30 mm/s | not published | 78.6 °C |
The last three columns decide the material; the middle three decide whether your machine can run it. ASA, PC Blend and PA11CF all want a 110 °C bed. The PA11CF sheet also states that a hardened nozzle is necessary, and names a build surface most people do not own — a special PA Nylon spring sheet, treated with clean water. That is the field guides usually drop, and it is the one that costs money: choosing PA11 Carbon Fiber for a hot loaded bracket is a sheet purchase as well as a spool purchase. Before you buy, check your printer's spec sheet for its maximum bed temperature and whether its hot end is all-metal. More on those limits in the printer limits guide.
Stiffness and toughness
| Material | Tensile modulus | Tensile yield | Charpy unnotched | Charpy notched | Interlayer adhesion |
|---|---|---|---|---|---|
| PLA | 2.3 ± 0.1 GPa | 51 ± 3 MPa | 13 ± 1 kJ/m² | not applicable | 17 ± 3 MPa |
| PETG | 1.5 ± 0.1 GPa | 47 ± 2 MPa | no break | 6 ± 1 kJ/m² | 18 ± 4 MPa |
| ASA | 1.6 ± 0.1 GPa | 42 ± 1 MPa | 25 ± 3 kJ/m² | 12 ± 1 kJ/m² | 11 ± 1 MPa |
| PC Blend | 1.9 ± 0.1 GPa | 63 ± 1 MPa | no break | 12 ± 1 kJ/m² | 21 ± 2 MPa |
| PA11 Carbon Fiber | 2.5 ± 0.1 GPa | 42 ± 1 MPa | 30 ± 4 kJ/m² | 12 ± 2 kJ/m² | 20 ± 5 MPa |
Two things in that table are worth pausing on. PLA's notched Charpy is reported as "not applicable" — the datasheet gives no value and no explanation, which means you cannot compare PLA to the others on notched toughness at all. Treat that blank as a warning for any part with a sharp internal corner. And ASA has the weakest interlayer adhesion of the five rigid materials at 11±1 MPa, roughly half of PC Blend's 21±2 MPa.
Methodology: every row above comes from one manufacturer's testing of its own filament under the named ISO standard. Specimens were printed at 0.20 mm layers, 2 perimeters, 100% rectilinear infill, with top and bottom solid layers set to zero — on an Original Prusa i3 MK3 (PLA, PETG), MK3S (ASA, PC Blend) or MK3S/S+ (PA11CF). Even within one brand the test rig moved: the TPU 95A sheet, published in 2025, used an MK4S. Numbers from a different brand are not drop-in substitutes, because the specimen, printer and print profile all differ. This site ran none of these tests.
Orientation changes the numbers, and not always in the direction you expect
Each datasheet reports horizontal and vertical-xz specimens separately, and the difference is often larger than the difference between two materials. PETG's notched Charpy halves, from 6±1 kJ/m² horizontal to 3±1 vertical. That is the familiar layer-adhesion story.
PA11 Carbon Fiber runs the other way on six of the eight properties its printed-specimen table reports — including every strength and stiffness figure: 2.5 GPa modulus horizontal against 3.3 GPa vertical, 30±4 kJ/m² unnotched against 51±4, 42±1 MPa yield against 49±2. The two exceptions are elongation at yield point (3.3±0.2% horizontal against 2.6±0.3% vertical) and deflection at flexural strength (11.8±0.3 mm against 11.6±0.4 mm, a difference inside the stated tolerances). The datasheet reports all of this without explaining it. The lesson is not "print flat for strength" — it is that your material's own two columns are the only reliable guide, and a part's performance depends on how it sat on the bed. Layer height interacts with this too; the test specimens above were all printed at 0.20 mm, so see the nozzle and layer height guide if you print thicker or thinner.
Moisture: why nylon is the one everyone tells you to dry
Measured by the manufacturer's own in-house method — the Method column reads "Prusa Polymers", not an ISO standard — at 24 °C and 22% relative humidity, water uptake after seven days runs: PETG 0.10%, PC Blend 0.15%, ASA 0.17%, PLA 0.19%, PA11 Carbon Fiber 0.50%. Nylon takes up five times what PETG does, which is the whole reason it is singled out for drying. Because the method is unpublished, these five figures are comparable to each other and to nothing on any other brand's sheet. The manufacturer's support page names polyamide, PVA and TPU as the filaments most often needing drying, and gives drying settings per material: PLA 45 °C for 6 h, PETG 55 °C for 6 h, TPU 60 °C for 4–6 h, ASA 80 °C for 4 h, PC Blend 85 °C for 5 h, PA11CF 90 °C for 6 h.
TPU 95A is deliberately left out of that comparison. Its datasheet reports moisture at 25 °C and 20% RH — different conditions — so its 0.04% figure is not comparable to the five above.
TPU: the limits are the feed path and the sheet, not the temperature
TPU runs cooler than PETG, at 230±10 °C. The constraints are mechanical. Its datasheet caps print speed at 30 mm/s, and the manufacturer's flexible-materials guidance gives a typical speed of 20 mm/s with 30–40 mm/s as the maximum recommended, suggests raising nozzle temperature by 5 °C to lower filament resistance, and advises lower retractions — noting it is alright to turn them off completely. The feed path matters too: the guidance notes that the Original Prusa XL has a long path from the filament loader to the extruder nozzle, that flexibles need special attention when loaded in that machine, and that a flex filament bypass can be printed for it. CORE One+ and CORE One L have a hardware switch that loosens the filament sensor lever for the same reason.
Hardware warning, from the same support article: "Some very soft flex materials can bond to the bed too much and require the use of glue stick on the bed as a separator to prevent PEI damage." The guidance is to apply a separation layer — glue stick or Kapton tape — on smooth and satin sheets, and states that a powder-coated textured sheet needs none. The TPU 95A datasheet agrees, listing smooth PEI only with a glue stick as a separate layer. Check which sheet your printer has before the first TPU print.
One naming detail worth noticing: the product is called TPU 95A, but its datasheet reports measured hardness of Shore A 92±0.4. The number on the label and the number in the test column are not always the same thing.
The same material name from two brands is not the same material
This is the single most useful thing to internalise. Below are two PETG spools, each from its own manufacturer's published datasheet.
| Field | Prusament PETG | PolyLite PETG |
|---|---|---|
| HDT 0.45 MPa | 68 °C | 78 °C |
| HDT 1.80 MPa | 68 °C | 75 °C |
| Tensile modulus | 1.5 ± 0.1 GPa (1500 MPa) | 2116.8 ± 68.1 MPa |
| Notched Charpy | 6 ± 1 kJ/m² (ISO 179-1, edgewise) | 2.6 ± 0.2 kJ/m² (ISO 179 / GB/T 1043) |
| Nozzle temperature | 250 ± 10 °C | 230–260 °C |
| Bed temperature | 80 ± 10 °C | 70–80 °C |
| Hot end | not stated | all-metal hot-end needed |
| Test specimens | MK3, 0.20 mm, 2 perimeters, 0 top/bottom solid layers | Shell 2, 3 top and bottom layers; no printer or layer height named |
Same three letters, and the published numbers are far apart: seven to ten degrees on heat resistance depending on which load you read — 10 °C at 0.45 MPa, 7 °C at 1.80 MPa — and about 41% on stiffness. But part of that gap is the material and part is how each brand built its test bars. Polymaker's specimens carry three solid top and bottom layers; Prusa's carry none, which is a real difference in a tensile bar. Treat the impact row with more caution still: Prusa states ISO 179-1, notched, edgewise direction of blow, while Polymaker states only ISO 179 / GB/T 1043, with no part number, no notch type and no direction of blow. Those choices move notched Charpy values a long way, so the two figures may not be measuring the same thing. The sheets also report different tensile fields — Prusa publishes tensile yield strength (47±2 MPa), Polymaker publishes tensile strength (50.8±0.9 MPa) — and those are distinct measurements. None of this makes either sheet wrong. It makes the comparison unreliable, which is the point: you cannot carry a number from one brand's sheet onto another brand's spool.
How to read your own spool's datasheet
Search for the exact product name plus "TDS" or "technical data sheet". Most manufacturers publish a downloads library. Then find these fields:
- Heat deflection temperature, and the load beside it. If only one load is shown, check whether it is 0.45 or 1.80 MPa — under ISO 75-2 those are different methods, and either one may be the one published.
- Tensile modulus, in GPa or MPa. This is resistance to bending. 1 GPa = 1000 MPa, so watch the units when comparing sheets.
- Charpy impact, notched and unnotched — and the notch type and direction of blow, not just "ISO 179". Notched is the realistic number for parts with holes and corners, and it is the figure most often reported without enough method detail to compare.
- Recommended nozzle and bed temperature, to check your machine can reach them.
- Bed type or build surface, and any footnote about a separator or glue stick. This is where sheets get damaged. PA11 Carbon Fiber, for example, specifies a special PA Nylon spring sheet; PETG and PC Blend specify a glue stick on smooth PEI.
- Hot end and nozzle requirements. PolyLite PETG's current sheet states an all-metal hot end is needed; PA11 Carbon Fiber's states a hardened nozzle is necessary. A wrong guess here costs hardware.
- Moisture absorption, with the temperature and humidity it was measured at, and the method. A figure without conditions cannot be compared to anything, and an in-house method cannot be compared across brands.
- The print settings used for the test specimens — printer, layer height, perimeters, infill, and how many solid top and bottom layers. If the sheet does not name them, its mechanical numbers cannot be lined up against another sheet's.
If a brand publishes no datasheet at all, that is itself information. You can still print the spool, but you have no basis for a heat or load claim about the finished part, and you should not transfer numbers from a different brand's sheet onto it.
Outdoors: the question these datasheets do not answer
"It lives outside" is one of the most common reasons to ask this question, and it is the one this page cannot answer from the data it has. The Prusament ASA datasheet contains no UV, weathering or light-exposure result of any kind — a full-text search across all six Prusament sheets read for this page returns zero occurrences of UV, weathering, xenon, ISO 4892 or lightfastness. Polymaker's ASA documentation is a useful contrast: its product description states the material has improved weather resistance and UV resistance, but its property tables publish no weathering test result either. A prose claim in a product description is not a measurement.
So this page makes no claim that ASA is UV-stable, even though that is its common reputation. What you can do is ask for the right thing. The relevant standard is ISO 4892-2, "Plastics — Methods of exposure to laboratory light sources — Part 2: Xenon-arc lamps", which specifies methods for exposing specimens to xenon-arc light in the presence of moisture to reproduce weathering effects — temperature, humidity and wetting — that occur in real end-use environments. Ask the manufacturer whether they have tested to ISO 4892-2 or an equivalent, and if so, for how many hours, at what irradiance, and what property they measured afterwards — retained tensile strength, retained impact strength, or color change. An answer in writing on a datasheet is worth something. "ASA is the outdoor one" is not.
Check it on your own equipment
These take you to the manufacturers and standards bodies the page draws on, so you can look up your exact model.
- Manufacturer specification
Look up the datasheet for your exact Prusament spool (opens in a new tab)An index of Prusament filaments — 23 products when accessed on 2026-09-22 — including PLA, PETG, ASA, PC Blend, PA11 Carbon Fiber and TPU 95A. Each links to a product page carrying that material's technical data sheet PDF, which is where the HDT, tensile, Charpy and Bed Type figures used on this page come from. — prusament.com - Manufacturer specification
Find the datasheet for a Polymaker spool (opens in a new tab)A downloads library grouped by material family — PLA, PETG, ABS/ASA, PC, PPS, PA, TPU — with a TDS and SDS link beside each product. Use it to pull the same eight spec fields for a brand other than the one most of this page cites. The current PolyLite PETG sheet here is V6.0, dated 2026-06-09. — polymaker.com - Standards reference
Check what the two HDT load figures actually mean (opens in a new tab)The ISO catalog entry for ISO 75-2:2013. The free abstract names the three methods by flexural stress — method A at 1.80 MPa, method B at 0.45 MPa, method C at 8.00 MPa — which is the distinction that makes the two HDT columns on this page differ. The full standard is paid; the abstract is not. — www.iso.org - Standards reference
Get the weathering standard to name when you ask about outdoor use (opens in a new tab)The ISO catalog entry for ISO 4892-2:2013, xenon-arc exposure of plastics. The free abstract describes exposing specimens to xenon-arc light with moisture to reproduce real weathering. Quote this number when you ask a manufacturer whether their ASA has actually been weather-tested, and ask for hours, irradiance and the property measured afterwards. — www.iso.org
What this page does not tell you
- Almost every number on this page comes from one manufacturer, Prusa Polymers, testing its own filament, plus one Polymaker datasheet used for the cross-brand comparison. That makes the Prusament rows comparable to each other, which is the point, but it does not make them representative of the material family as a whole, and PC Blend, PA11 Carbon Fiber and TPU 95A are that brand's product names rather than generic categories.
- Every figure is transcribed from a document we downloaded or opened and cited, with the test method and access date attached.
- Heat deflection temperature is a standardized test result, not a service-temperature rating. A loaded part can deform below its HDT, and the test specimen is not shaped or loaded like your part. This page gives no safety margin because no cited source defines one.
- This page cannot tell you whether any of these materials survives outdoors. Neither ASA document read for it publishes a weathering result, and no weathering, UV or light-exposure figure appears anywhere in the six Prusament datasheets cited.
- This page publishes no measurement of ambient temperature in cars, attics, lofts or engine bays. If you do not know your part's peak temperature, the heat guidance here cannot be applied.
- Charpy impact figures should not be moved between datasheets. Notch type and direction of blow change the result, sheets state them to different levels of detail, and the cited Prusament sheets predate the current edition of ISO 179-1.
- The mechanical figures come from specimens printed at 0.20 mm layers with 2 perimeters and 100% rectilinear infill, with top and bottom solid layers disabled. A part printed with different layer height, infill or wall count will not match these numbers, and the Polymaker specimens were built to a different recipe again.
- Moisture and interlayer-adhesion figures on the Prusament sheets come from an in-house method the manufacturer does not describe. They are comparable to each other and to nothing on another brand's sheet.
- The datasheet versions cited range from 2022 to 2026 and manufacturers revise them. Check the version and date on the sheet you download against what is quoted here.
- No prices, cost-per-kilogram comparisons, rankings or brand quality judgements appear on this page, and none are implied by the order in which materials are listed.
Sources
Manufacturers revise specifications. Every source below is dated — open it before you buy.
- Prusament PLA recommended nozzle temperature is 210 ± 10 °C, heatbed 40–60 °C, print speed up to 200 mm/s, and Bed Type is 'smooth PEI sheet; powder coated sheet; satin sheet' with no glue-stick footnote.
- Prusament PLA heat deflection temperature is 55 °C at both 0.45 MPa and 1.80 MPa, by ISO 75.
- Prusament PLA printed horizontally has tensile modulus 2.3 ± 0.1 GPa and tensile yield strength 51 ± 3 MPa by ISO 527-1; vertical-xz values are 2.4 ± 0.1 GPa and 59 ± 2 MPa.
- Prusament PLA Charpy unnotched impact strength is 13 ± 1 kJ/m² horizontal by ISO 179-1, and the notched value is reported as 'not applicable' in both print directions with no explanation.
- Prusament PLA moisture absorption is 0.19% at 7 days, measured at 24 °C and 22% humidity by a method the sheet names only as 'Prusa Polymers'; interlayer adhesion is 17 ± 3 MPa by the same in-house method.
- Prusament PETG recommended nozzle temperature is 250 ± 10 °C, heatbed 80 ± 10 °C, print speed up to 200 mm/s, and Bed Type is 'satin sheet; powder coated sheet; smooth PEI sheet*' where the asterisk footnote reads 'with a glue stick'.
- Prusament PETG heat deflection temperature is 68 °C at both 0.45 MPa and 1.80 MPa, by ISO 75.
- Prusament PETG printed horizontally has tensile modulus 1.5 ± 0.1 GPa (equivalently 1500 MPa) and tensile yield strength 47 ± 2 MPa by ISO 527-1.
- Prusament PETG Charpy unnotched result is 'no break' in both print directions, while notched is 6 ± 1 kJ/m² horizontal and 3 ± 1 kJ/m² vertical-xz, by ISO 179-1, with a footnote specifying edgewise direction of blow.
- Prusament PETG moisture absorption is 0.10% at 7 days at 24 °C and 22% humidity by the manufacturer's in-house method; interlayer adhesion is 18 ± 4 MPa.
- Prusament ASA recommended nozzle temperature is 260 ± 10 °C, heatbed 110 ± 5 °C, print speed up to 200 mm/s, and Bed Type is 'satin sheet; smooth PEI sheet; powder coated sheet**' where the double asterisk footnote reads 'with a glue stick'.
- Prusament ASA heat deflection temperature is 93 °C at 0.45 MPa and 86 °C at 1.80 MPa, by ISO 75 — a 7 °C divergence between loads.
- Prusament ASA printed horizontally has tensile modulus 1.6 ± 0.1 GPa, tensile yield 42 ± 1 MPa, Charpy unnotched 25 ± 3 kJ/m² and notched 12 ± 1 kJ/m².
- Prusament ASA interlayer adhesion is 11 ± 1 MPa, the lowest of the five rigid Prusament materials compared here (PLA 17 ± 3, PETG 18 ± 4, PC Blend 21 ± 2, PA11CF 20 ± 5) and roughly half of PC Blend's figure.
- Prusament ASA moisture absorption is 0.17% at 7 days at 24 °C and 22% humidity, by the manufacturer's in-house method.
- None of the six Prusament datasheets read for this page — PLA, PETG, ASA, PC Blend, PA11 Carbon Fiber, TPU 95A — contains any UV, weathering or light-exposure test result.
- Prusament PC Blend recommended nozzle temperature is 275 ± 10 °C, heatbed 110 ± 10 °C, print speed up to 200 mm/s, and Bed Type is 'satin sheet; smooth PEI sheet**; powder coated sheet**' with the footnote 'with a glue stick' applying to both PEI and powder-coated.
- Prusament PC Blend heat deflection temperature is 113 °C at 0.45 MPa and 93 °C at 1.80 MPa, by ISO 75 — a 20 °C divergence between loads.
- Prusament PC Blend printed horizontally has tensile modulus 1.9 ± 0.1 GPa and tensile yield 63 ± 1 MPa, the highest yield strength of the materials compared here; Charpy unnotched is 'no break' and notched 12 ± 1 kJ/m²; interlayer adhesion is 21 ± 2 MPa.
- Prusament PC Blend moisture absorption is 0.15% at 7 days at 24 °C and 22% humidity, by the manufacturer's in-house method.
- Prusament PA11 Carbon Fiber recommended nozzle temperature is 285 ± 5 °C, heatbed 110 ± 10 °C, print speed up to 100 mm/s; Bed Type is 'special PA Nylon spring sheet treated with clean water'; and the Additional Info field states a hardened nozzle is necessary.
- Prusament PA11 Carbon Fiber heat deflection temperature is 192 °C at 0.45 MPa and 152 °C at 1.80 MPa, by ISO 75 — a 40 °C divergence between loads.
- Prusament PA11 Carbon Fiber's printed-specimen table reports eight properties in both horizontal and vertical-xz directions. Six are higher vertically — tensile yield (42±1 vs 49±2 MPa), tensile modulus (2.5±0.1 vs 3.3±0.1 GPa), flexural strength (63±2 vs 103±3 MPa), flexural modulus (3.0±0.1 vs 6.2±0.3 GPa), Charpy unnotched (30±4 vs 51±4 kJ/m²) and Charpy notched (12±2 vs 17±1 kJ/m²). Two are lower vertically: elongation at yield point (3.3±0.2 vs 2.6±0.3 %) and deflection at flexural strength (11.8±0.3 vs 11.6±0.4 mm). The datasheet offers no explanation.
- Prusament PA11 Carbon Fiber moisture absorption is 0.50% at 7 days at 24 °C and 22% humidity — five times the 0.10% reported for Prusament PETG under the same stated conditions and by the same in-house method.
- The Prusament mechanical test specimens for the five rigid materials were printed at 0.20 mm layers, 2 perimeters, 100% rectilinear infill and zero top and bottom solid layers, on an Original Prusa i3 MK3 (PLA, PETG), MK3S (ASA, PC Blend) or MK3S/S+ (PA11 Carbon Fiber).
- Prusament TPU 95A recommended nozzle temperature is 230 ± 10 °C, heatbed 65 ± 10 °C, print speed up to 30 mm/s, and Bed Type is 'PA Nylon, PP, Satin, Textured, and PEI smooth* sheet' with the footnote 'with a glue stick as a separate layer'. Heat deflection temperature is 78.6 °C at 1.80 MPa by ISO 75, and the sheet publishes no 0.45 MPa figure at all.
- Prusament TPU 95A measured hardness is Shore A 92 ± 0.4, despite the product being named 95A.
- Prusament TPU 95A moisture absorption is 0.04% at 7 days but was measured at 25 °C and 20% relative humidity, different conditions from the 24 °C / 22% used for the PLA, PETG, ASA, PC Blend and PA11CF figures, so it is not directly comparable.
- Prusament TPU 95A test specimens were printed on an Original Prusa i3 MK4S using PrusaSlicer 2.8.1 — a different printer from the MK3-family machines used for the five rigid Prusament materials.
- Prusament TPU 95A mechanical properties are reported under ISO 37 rather than ISO 527-1, and the printed-specimen table publishes no tensile modulus in GPa and no Charpy impact figures, so TPU cannot be placed in the same stiffness and toughness comparison as the rigid materials.
- Official guidance for flexible filaments gives a typical print speed of 20 mm/s with 30 to 40 mm/s as the maximum recommended, advises increasing nozzle temperature by 5 °C to lower filament resistance, and advises lower retractions, noting it is acceptable to turn them off completely. Nozzle range is given as 230–245 °C and bed 60–75 °C.
- The same flexible-materials guidance warns that very soft flexible materials can bond to the bed hard enough to damage a PEI surface, instructs applying a separation layer of glue stick or Kapton tape on smooth and satin sheets, and states that the powder-coated textured sheet needs no separation layer.
- The flexible-materials guidance states that the Original Prusa XL has a long path from the filament loader to the extruder nozzle, that flexible filaments need special attention when loaded in that printer, and that a flex filament bypass can be printed for it. CORE One+ and CORE One L have a hardware switch that loosens the filament sensor lever for easier flexible-filament loading.
- Manufacturer support guidance identifies polyamide, PVA and TPU as filaments more often in need of drying than more popular filaments like PLA, and gives drying settings of PLA/rPLA 45 °C/6 h, PETG (all versions) 55 °C/6 h, TPU 60 °C/4–6 h, ASA 80 °C/4 h, PC Blend 85 °C/5 h and PA11 Carbon Fiber 90 °C/6 h.
- ISO 75-2:2013 specifies three methods using different constant flexural stresses for determining temperature of deflection under load: method A at 1.80 MPa, method B at 0.45 MPa and method C at 8.00 MPa. It is published, edition 3, dated 2013-04, and was last reviewed and confirmed in 2025.
- Heat deflection temperature is defined as the temperature at which a specimen deflects a set amount under a stated constant flexural stress, so a part whose peak service temperature reaches or exceeds a material's 1.80 MPa HDT figure is at or past the point where the loaded test bar has already deflected by the standard's defined amount. It is a threshold from a standardized test, not a service-temperature rating, and it cannot resolve near-miss cases.
- ISO 179-1 covers determination of Charpy impact properties by non-instrumented impact test, defining specimen and test configurations and specifying different test parameters according to material, specimen type and notch type. The current edition is ISO 179-1:2026, edition 4, published 2026-03, superseding the withdrawn ISO 179-1:2023. The Prusament datasheets cited here are dated 2022 and therefore predate this edition; the standard has been revised since they were written, which is one more reason not to compare Charpy figures across sheets of different vintages.
- ISO 4892-2:2013 specifies methods for exposing plastics specimens to xenon-arc light in the presence of moisture to reproduce the weathering effects — temperature, humidity and/or wetting — that occur when materials are exposed in actual end-use environments to daylight or to daylight filtered through window glass. It is edition 3, published 2013-03, last reviewed and confirmed in 2023, and carries Amendment 1:2021 on classification of daylight filters.
- Polymaker PolyLite PETG reports heat deflection temperature of 78 °C at 0.45 MPa and 75 °C at 1.8 MPa by ISO 75, Young's modulus X-Y 2116.8 ± 68.1 MPa, tensile strength X-Y 50.8 ± 0.9 MPa, and notched Charpy impact strength X-Y 2.6 ± 0.2 kJ/m², with recommended nozzle 230–260 °C and build plate 70–80 °C.
- The current PolyLite PETG datasheet (V6.0) carries the footnote 'All-metal hot-end needed'. The Prusament PETG datasheet states no hot-end requirement.
- PolyLite PETG and Prusament PETG test specimens were built differently: Polymaker's 'How to make specimens' block specifies 2 shells, 3 top and bottom layers, 100% infill, 240 °C printing temperature and 80 °C bed, and names no printer and no layer height; the Prusament sheet specifies 2 perimeters, zero top and bottom solid layers, 100% rectilinear infill, 0.20 mm layers on a named Original Prusa i3 MK3.
- The two PETG sheets state their Charpy method to different levels of detail: Prusa specifies ISO 179-1 with a footnote giving notched, edgewise direction of blow, while Polymaker gives only 'ISO 179, GB/T 1043' with no part number, no notch type and no direction of blow. The two impact figures may therefore not be measuring the same thing.
- Prusament PETG and PolyLite PETG publish different tensile property fields: Prusa reports tensile yield strength (47 ± 2 MPa) while Polymaker reports tensile strength (50.8 ± 0.9 MPa), which are distinct measurements and are not directly comparable.
- Polymaker's PolyLite ASA product documentation describes the material as having improved weather resistance and UV resistance in its product description, but its published property tables contain no weathering or light-exposure test result.
- Polymaker's own product documentation independently restates the PolyLite PETG figures, including HDT 78 °C at 0.45 MPa and 75 °C at 1.8 MPa, Young's modulus X-Y 2116.8 ± 68.1 MPa and notched Charpy 2.6 ± 0.2 kJ/m².
- A user who replaced a working PLA prototype with PETG, expecting better physical properties, reported that the PETG part broke instantly when bent; a reply stated that PETG is not stronger than PLA in most senses and that the failure mode differs, with PLA shattering and PETG deforming as it fails. Other replies attributed the failure to layer adhesion rather than the material.
- Prusament publishes a materials index listing 23 filament products, each linking to a product page, including PLA, PETG, ASA, PC Blend, PA11 Carbon Fiber and TPU 95A.
- Polymaker publishes a downloads library grouping filaments by family — PLA, PETG, ABS/ASA, PC, PPS, PA, TPU, plus Special, Support and Rest — with TDS and SDS links per product and print profiles for most.