Farid Zaripov
Filament choice decides more about a print than any slicer setting. A part that warps off the bed, cracks between layers, or softens in a parked car usually failed because the material was wrong for the job, not because the profile needed tuning. This guide covers what each common filament is actually good at, and the arithmetic for working out how much of it a print will consume.
The Materials
| Filament | Nozzle | Bed | Heat resistance | Difficulty |
|---|---|---|---|---|
| PLA | 190–220 °C | 50–60 °C | ~50–60 °C | Easy |
| PETG | 230–250 °C | 70–85 °C | ~70–80 °C | Moderate |
| ABS | 230–260 °C | 95–110 °C | ~95–105 °C | Hard |
| ASA | 240–260 °C | 95–110 °C | ~95–105 °C | Hard |
| TPU (flexible) | 210–240 °C | 40–60 °C | ~60–80 °C | Moderate |
| Nylon (PA) | 240–270 °C | 70–90 °C | ~120 °C+ | Hard |
PLA — the default, and usually correct
Prints at low temperatures, barely warps, needs no enclosure, and holds fine detail better than anything else on this list. It is also stiff, which people mistake for strong — PLA has high tensile strength but low impact resistance, so it takes load well and shatters when dropped.
Its real limitation is heat. PLA begins softening around 50–60 °C, which a closed car in summer comfortably exceeds. Any part that lives outdoors, near electronics, or in a vehicle should not be PLA.
Right for: prototypes, models, display pieces, indoor fixtures, anything where dimensional accuracy matters more than toughness.
PETG — the practical middle
Tougher than PLA, survives roughly 70–80 °C, resists moisture and UV reasonably well, and warps far less than ABS. The trade-offs are stringing — PETG produces fine whiskers between features unless retraction is tuned — and a tendency to stick to the bed so enthusiastically that it can pull chunks out of a smooth PEI sheet. A thin layer of glue stick as a release agent is standard practice.
Right for: functional parts, brackets, enclosures, outdoor items, anything mechanical that does not need extreme heat resistance.
ABS and ASA — heat and outdoors
Both handle around 100 °C and can be smoothed with acetone vapor. Both also shrink significantly as they cool, which causes warping and layer splitting without a stable warm environment — an enclosure is effectively mandatory, not optional. ABS additionally emits styrene while printing and needs real ventilation.
ASA is the better choice of the two outdoors: it is essentially UV-stable, where ABS yellows and grows brittle in sunlight over months.
Right for: automotive parts, outdoor fittings, anything that must survive direct sun or high temperatures.
TPU — flexible
Sold by shore hardness: 95A is firm and manageable, 85A is soft and difficult. Flexible filament buckles in Bowden extruders like a rope being pushed, so a direct-drive setup makes an enormous difference. Print slowly — 15–30 mm/s — and disable retraction or reduce it heavily.
Right for: gaskets, phone cases, vibration dampers, grips, wheels.
Nylon — engineering use
Excellent layer adhesion, high impact strength, good wear resistance, and heat tolerance beyond 120 °C. It is also hygroscopic to an extreme degree: nylon absorbs enough atmospheric moisture in a day to print badly, popping and stringing as trapped water boils out of the nozzle. Drying before every print is not optional.
Moisture Is the Hidden Variable
Every filament absorbs water; they differ only in how quickly and how much it matters. Wet filament produces popping and hissing during extrusion, visible bubbles, rough surfaces, stringing that no retraction tuning fixes, and weak layer bonding.
Ranked by how fast they degrade in ambient air: nylon and TPU worst, PETG in the middle, PLA and ABS most tolerant. Drying temperatures and times: PLA 40–45 °C for 4–6 hours, PETG 60–65 °C for 6 hours, ABS and ASA 70 °C for 4 hours, nylon 70–80 °C for 12 hours or more. Store spools in sealed containers with desiccant — a printer parked in a humid room can ruin an open spool within a week.
How Much Filament a Print Uses
Slicers estimate this, but knowing the arithmetic lets you check a quote or plan a purchase before slicing.
A 1.75 mm filament has a cross-sectional area of π × (0.875 mm)² = 2.405 mm². So:
Volume (mm³) = length (mm) × 2.405
And weight follows from density:
Weight (g) = volume (cm³) × density (g/cm³)
| Material | Density | Length in a 1 kg spool (1.75 mm) |
|---|---|---|
| PLA | 1.24 g/cm³ | ≈ 335 m |
| PETG | 1.27 g/cm³ | ≈ 327 m |
| ABS | 1.04 g/cm³ | ≈ 400 m |
| ASA | 1.07 g/cm³ | ≈ 388 m |
| TPU (95A) | 1.21 g/cm³ | ≈ 343 m |
| Nylon | 1.14 g/cm³ | ≈ 364 m |
Note that ABS gives noticeably more length per kilogram than PETG — same spool weight, roughly 20 % more material by volume. When comparing filament prices, cost per cubic centimeter is the honest metric, not cost per kilogram. The filament calculator converts between length, weight, volume and cost, and the unit converter handles the 1.75 mm to 2.85 mm comparison, where the same length carries 2.65 times the material.
What Actually Drives Consumption
- Infill. Going from 20 % to 50 % roughly doubles the material in the interior — and adds far less strength than expected, because most of the strength lives in the perimeters.
- Perimeters. Three or four walls strengthen a part more efficiently than dense infill, for less filament and less time.
- Supports. Frequently 20–40 % of the total on an unoptimised orientation. Rotating the model is usually cheaper than printing scaffolding.
- Layer height. Affects print time strongly, filament volume barely — the same solid is filled either way.
Calibrating a New Spool
Filament varies between brands and even between colors from one brand, since pigments change flow behavior. Two quick tests settle the settings for a new roll:
- A temperature tower — a single print stepping through nozzle temperatures in bands, so you can see where stringing stops and where layer adhesion starts to fail. Generating a tower for your range takes a minute and saves hours of guessing.
- A calibration cube — a 20 mm cube measured with callipers on each axis. Consistent oversize means over-extrusion or flow rate error; a difference between X and Y points at belt tension or steps-per-mm. A calibration cube is the standard first print on any new machine or material.
Choosing Quickly
- Display piece, prototype, fine detail → PLA
- Functional part, mild heat, outdoor use → PETG
- Car interior, direct sun, above 80 °C → ASA (or ABS with an enclosure)
- Needs to bend, grip or seal → TPU
- High impact, wear surfaces, gears → nylon, dried before every print
- Unsure → PLA first to check the geometry, then reprint in the final material
