PLA vs PETG vs TPU: which 3D printing filament should you use?

The quick answer

Choose PLA for display pieces, prototypes, figures, organisers and most first prints. It is the easiest to print and gives the best detail.

Choose PETG for functional parts that need toughness, some heat resistance or exposure to water. Examples include brackets, clips, holders and garden or workshop parts.

Choose TPU when the part has to flex or absorb impact, such as bumpers, feet, gaskets, grips and protective covers.

The rest of this guide explains the trade-offs, using what Prusa, Bambu Lab and Polymaker publish about each material.

PLA: easy, detailed and heat-sensitive

Prusa's knowledge base describes PLA as a plant-based plastic that warps very little, prints well on large models and is friendly to beginners. That is why most starter spools are PLA. Its weaknesses matter just as much. Prusa says PLA starts to soften and deform above about 60 °C. It also notes that PLA is brittle, breaking along layers or into shards on impact, and has low resistance to UV light.

That makes PLA a poor choice for anything that will sit in strong sun, near a heat source or in a closed car on a summer day. Prusa specifically lists outdoor use, high temperatures and long UV exposure as jobs PLA isn't suited for.

PLA prints over a wide temperature range. Bambu Lab's material table lists 190 to 240 °C for its PLA, while Polymaker gives 190 to 230 °C for PolyLite PLA. Speciality PLAs such as silk, matte, wood-fill and glow-in-the-dark behave a little differently. Bambu, for example, marks its PLA Wood as needing drying before use and doesn't support it on a 0.2 mm nozzle.

PETG: tougher and more heat-tolerant, but stringier

Prusa describes PETG as tough and slightly flexible, with strong layer adhesion, low warping and good resistance to water and humidity. It says PETG parts are suitable for most indoor and outdoor uses below about 80 °C. That is a meaningful step up from PLA for anything functional.

The trade-offs are also on Prusa's list. PETG is prone to stringing, weaker at bridges and overhangs, not great for fine detail, and harder to remove supports from. It can also bond so strongly to a smooth PEI sheet that Prusa warns against printing on one without a release layer such as glue stick. Polymaker gives the same advice for its PETG.

PETG runs hotter than PLA. Bambu lists 240 to 270 °C for standard PETG and 230 to 260 °C for its HF and translucent versions. Bambu also recommends an enclosed printer for PETG, so that a cold room doesn't weaken the bond between layers. In Canada, that's worth considering if your printer lives in an unheated garage or a cool basement.

PETG is also more sensitive to moisture than PLA. CNC Kitchen's desiccant-cabinet write-up found the clearest print-quality difference with PETG spools that had been stored in the open. Polymaker calls its PETG very hygroscopic. If you print a lot of PETG, plan for drying and sealed storage.

TPU: flexible, tough and fussy

TPU is a rubbery plastic that stretches and returns to its shape. Bambu's TPU guide lists phone cases, shoe soles and toy parts as typical uses. Prusa's guide to flexible filaments adds spacer washers, stamps, RC tyres and belts. Prusa also notes that TPU stays flexible in the cold and resists wear and many chemicals, which suits outdoor parts in a Canadian winter.

Hardness is measured on the Shore scale. A higher number means stiffer and easier to print. Prusa says plainly that the softer the filament, the harder it is to print. Bambu recommends 85A or harder for stable feeding and doesn't support anything softer than 85A on its printers. A 95A filament such as Polymaker's PolyFlex TPU95 sits at the easier end of that range. Polymaker describes it as a balance between flexibility and easy handling, and says it can stretch to more than three times its original length.

TPU needs slow, gentle printing. Prusa suggests about 20 mm/s, with 30 to 40 mm/s as the upper limit, and recommends reducing or disabling retraction at first. Polymaker lists 20 to 40 mm/s for TPU95. Bambu doesn't support TPU on a 0.2 mm nozzle, and its softest 85A TPU can't be printed with a 0.4 mm nozzle.

The AMS question for Bambu Lab owners

If you print from an AMS, this matters as much as the material itself. Bambu's TPU guide says the AMS, AMS Lite and AMS 2 Pro aren't compatible with standard TPU. Only Bambu's specially formulated TPU for AMS can be fed automatically through them. The AMS HT can hold regular TPU as a sealed, drying enclosure, but the filament has to feed through a dedicated rear outlet rather than the automatic feeder.

PLA and PETG work in every AMS. The AMS 2 Pro spec sheet lists PLA, PETG and TPU for AMS among supported filaments, and lists generic TPU and TPE as unsupported. Because TPU absorbs moisture so readily, Bambu recommends printing it from an AMS HT or a sealed filament dry box rather than an open spool holder.

Moisture: how much care each one needs

The three materials need very different levels of care. Bambu's drying table lists drying before use as recommended for PLA Basic and PETG, and as required for its TPU, which should also be protected with desiccant while printing. Prusa groups TPU with nylon and PVA as the materials that need drying far more often than PLA.

In practice, PLA can usually live in a reasonably sealed bin. PETG benefits from drying before long prints. TPU should be dried before use and kept sealed even while it prints. CNC Kitchen also noted that TPU kept stringing even after heat drying, and he attributed that to print settings. Drying helps TPU, but it won't fix stringing caused by the settings.

Matching material to the job

Cosplay pieces, masks, figurines and display models: PLA for detail. Use PETG if the piece will be handled roughly or worn in warm conditions.

Shelf brackets, cable clips, tool holders and garden parts: PETG, because it is tougher and handles heat and water better.

Anything left in a car or near a window: PETG rather than PLA, because of PLA's roughly 60 °C softening point.

Bumpers, non-slip feet, gaskets, grips and drone or RC parts: TPU, ideally 95A unless you need it softer.

Food contact: none of these by default. Prusa doesn't recommend printed PLA or PETG dishes without extra precautions, and Bambu says its TPU isn't food-contact grade.

From a tech standpoint

Start with PLA to learn your printer, move to PETG when parts need to survive heat, water or knocks, and save TPU for parts that truly need to flex. Before buying TPU for a Bambu machine, check your AMS model, because standard TPU won't feed through most of them. If you'll print a lot of PETG or TPU, budget for dry storage at the same time.