3D Printer Filament Types Explained: PLA, PETG, ABS, ASA, TPU

There are dozens of filaments, but five cover nearly everything a home printer is used for. The question for each is what it is good at and what it asks of the printer.

At a glance

Filament	Good for	Needs	Ease
PLA	Models, templates, indoor parts	Any printer	Easiest
PETG	Tougher parts, some heat, outdoor-ish use	Any printer	Easy
TPU	Flexible parts: bumpers, gaskets, grips	Direct-drive extruder helps	Moderate
ABS	Heat-resistant parts	Enclosure, ventilation	Harder
ASA	Outdoor, UV- and heat-resistant parts	Enclosure, ventilation	Harder
CF blends	Stiff, light parts	Hardened nozzle	Moderate

PLA

Start here. PLA prints at low temperatures, barely warps, smells faintly at most, and is the cheapest. It is stiff and holds dimensions well. Its weakness is heat: it softens at temperatures a closed car reaches in summer. Perfect for models, templates, storage and setup blocks.

PETG

The everyday step up. Tougher and slightly flexible, so it bends where PLA would snap. It also handles more heat. It strings more than PLA and sticks very hard to some print surfaces. For dust adapters and parts that take knocks, it is the default. See workshop jigs and fixtures.

TPU

A rubbery filament for flexible parts: feet, bumpers, gaskets, grips and phone cases. It prints slowly. A direct-drive extruder, like the one on the Ender-3 V3 SE or the Bambu printers, handles it far better than a long Bowden tube.

ABS and ASA

Both handle heat well and can be sanded and smoothed. ASA also resists UV, so it is the one for parts that live outdoors. Both shrink as they cool. On an open printer, the corners lift and tall parts crack between layers, so in practice they need an enclosure such as the Bambu P1S or Creality K1C. They give off fumes while printing, so ventilate the room.

Carbon-fibre blends

PLA-CF, PETG-CF and nylon-CF carry chopped carbon fibre, which makes parts stiffer and lighter and gives a matte finish. The fibres are abrasive and wear a standard brass nozzle out of shape fast. You need a hardened steel nozzle; the K1C ships with one.

Buying filament

• Keep it dry. Many filaments, PETG, TPU and nylon especially, absorb moisture from the air and then print poorly, with popping and stringing. Store spools sealed with desiccant, and dry them if prints get worse.
• Diameter. Almost every current printer uses 1.75 mm filament. Check before buying.
• Start with known brands. Cheap filament with an inconsistent diameter causes failed prints that look like printer faults.