Materials for your 3D print

PLA stands for polylactic acid, a thermoplastic based on lactic acid. It is the most widely used filament in FDM printing because it melts at a low temperature and barely shrinks. For a print, what matters is this: PLA is stiff and dimensionally stable, it is the material in which fine detail and sharp colour boundaries come out best, and it is the cheapest filament in the rates. It is also rather brittle: it breaks before it bends.

It suits decorative and lightly functional prints indoors: name signs, keychains, planters, lamps, storage boxes, holders, scale models and enclosures for low-voltage electronics. Prototypes to judge shape and fit are usually printed in PLA too.

Wood-filled PLA remains a plastic that looks like wood: you cannot stain or plane it, and it is not suited to very fine detail. That the filament contains wood powder and that the colour can vary slightly per batch is stated on the Bambu Lab PLA Wood product page. Horizontal grooves or ribs in the design strengthen the wood effect, as on the base of the Valley Lamp.

PETG is a variant of PET, the plastic of drinks bottles, with glycol added so that the material stays tough and prints well. Descending from bottle plastic does not make a print suitable for food: the layers hold residue and the filament has no food-contact certificate.

The price of that toughness is a less tidy surface, sometimes with fine strings, and less crisp detail. Layers and seams show more than on matte PLA. For a decorative piece with sharp areas of colour, PLA remains the better-looking choice. For years in full sun, ASA is the better one.

Bambu Lab recommends an enclosed printer for PETG, so that a cold room does not weaken the bond between layers. That is stated in the Bambu Lab filament guide. The P1S is such an enclosed printer. Two of the price examples are worked out in PETG: a replacement knob for an appliance and a batch of fifty clips.

ABS (acrylonitrile butadiene styrene) is the hard plastic of building bricks and car dashboards, among other things. ASA (acrylonitrile styrene acrylate) was developed as an alternative to ABS with better weather resistance: it withstands UV light, oxidation and ageing. In a print the two are much alike. The difference lies in what the sun does to them. The figures and the comparison come from the Bambu Lab ASA product page.

The downside is shrinkage. Large, flat parts can warp or split between the layers, so ABS and ASA mainly suit smaller, compact parts. Both need a warm print chamber, which the enclosed P1S provides. On the Bambu Lab ABS product page the manufacturer also warns about odour during printing. That stays with the printer: a finished part does not smell.

An enclosure in ABS or ASA is meant for low-voltage electronics. For mains voltage, for parts right up against a heating element and for anything somebody's safety depends on, nothing is printed, in any material. ABS and ASA have the highest rate per gram, which covers the filament itself and the greater risk of a failed print. If you have no heat and no sun, you do not need them and would only be paying more.

You do not have to make the choice yourself. Write in your request what the part is for and where it will end up; the recommended material is then in your quote. The most common mistake is choosing PLA for something that lives in a car. The second is choosing ASA for something that sits on a bookshelf.

The full comparison, with a table per property, is in the guide PLA vs PETG vs ABS/ASA: which material should you pick?.

The advantage is that you are not tied to whatever happens to be on the shelf. The drawback is that a small part in an unusual colour has to wait for a spool. If you are in a hurry and the colour does not matter, say so: then the spool that arrives soonest is ordered.