3D printing materials explained: PLA, PETG, TPU, ABS and resin

There are five best-known 3D printing materials: PLA for everyday pieces, gifts and colourful pieces; PETG for pieces that need to take more heat and knocks; TPU for flexible parts that bend and spring back; ABS and ASA for pieces facing high heat or sun; and resin for small figures with fine detail. The first four are filaments for FDM printers; resin is a liquid for resin printers.

PLA: the most common material

• What it is: a plastic made from plant starch such as corn or sugarcane, and the material most printers start with.
• Look and feel: a huge range of colours, sharp detail, clear letters, and a matte or slightly glossy surface.
• Strength: rigid and strong enough for everyday use, but with no flex, so if bent hard it snaps rather than bends.
• Heat: it starts to soften at roughly 55 to 60 °C, its biggest weak point.
• Suits: keychains, clickers, coasters, bookmarks, figures and gifts.

Special kinds of PLA

• Silk PLA: a silky shine like metal or satin that makes a piece gleam. Slightly softer on sharp details than regular PLA.
• Matte PLA: a surface with no shine that hides layer lines better.
• Toughened PLA (sold as PLA+ or Tough): less brittle than the regular kind.
• Filled PLA: glow-in-the-dark, wood-fill or carbon fibre. Some of these fillers wear down a regular nozzle, so they need a hardened steel one.

PETG: tougher and more heat-tolerant

• Close to the plastic water bottles are made from, in filament form.
• Tougher than PLA against knocks, with slight flex, so it bends a little before it breaks.
• Takes more heat than PLA, softening at roughly 70 to 80 °C.
• Drawbacks: more stringing while printing, and very small details come out softer and less crisp than PLA.
• Suits: pieces kept in a car, holders and tools under load, and outdoor pieces in the shade.

TPU: the flexible material

• Like rubber: it squeezes, bends and returns to shape. Its softness is measured on the Shore scale, with 95A the most common.
• Suits: phone cases, bumpers, small wheels and parts that absorb shocks.
• Doesn't suit: pieces that must stay rigid, or sharp detail.
• It prints slower and harder than PLA, and not every printer handles it easily.

ABS and ASA: for heat and sun

• ABS is a tough plastic that takes more heat than PETG, and one of the long-standing materials in industry. ASA is similar but resists sun and UV better, so it doesn't fade quickly outdoors.
• They start to soften at roughly 95 to 100 °C.
• Drawbacks: they shrink as they cool and warp easily, so they need an enclosed printer, and they give off fumes while printing, so they need ventilation.
• Suit: car parts, outdoor parts and technical parts.

Engineering materials

Factories and engineering parts use materials such as nylon, polycarbonate and carbon-fibre-filled filaments. They're stronger and tougher, but need special printers, nozzles and drying, and you don't need them for gifts and everyday pieces.

Resin

• A liquid that hardens under light in resin printers, giving the smoothest surface and the finest detail.
• Kinds: standard, tough (ABS-like) and water-washable, which cleans with water instead of alcohol.
• Drawbacks: pieces are harder and break more easily, need washing and curing after printing, and standard resin can yellow in the sun over time.
• Suits: small figures and display statues.

Moisture and storage

Printing filaments absorb moisture from the air, especially PETG, TPU and nylon. Damp filament prints with bubbles, crackling, strings and a rough surface. That's why hobbyists keep spools in sealed boxes with desiccant, or dry them in a filament dryer before printing, which matters even more in humid coastal cities.

How to choose a material

- A gift, keychain, clicker, coaster or desk figure: PLA.
- You want shine: silk PLA.
- A piece in a car or near heat: PETG, or ASA if it will sit in the sun.
- A piece that must bend or absorb a knock: TPU.
- A very small figure with facial detail for display: resin.
Heat and care for printed pieces are covered in detail in the care guide for printed pieces.

At Kun

We print in PLA, and some pieces in silk PLA, on a Bambu Lab A1 mini. If you send your file through Print your design, we print it in PLA in the colour you choose. For pieces you design yourself with no file, see name keychains and clickers. How the printers themselves differ is in Types of 3D printers.