PLA (polylactic acid) is the default 3D printing filament for a reason: it prints easily on any FDM machine without an enclosure, smells like cooking pancakes instead of burning plastic, and handles fine details better than any other common material. It also softens at 60 °C, so it's the wrong choice for anything sitting in a hot car or near a heat source. Here's when to use it, what settings work, and which PLA variant wins for your part.
Nozzle 200–220 °C, bed 55–65 °C, fan 100%, no enclosure. Use PLA for cosmetic prints, prototypes, fixtures, miniatures, and indoor parts. Don't use it for parts that will see >55 °C (car dashboards, anything outdoors in the sun), high-stress mechanical loads, or sustained outdoor UV.
Polylactic acid is a polyester made from fermented corn starch or sugarcane. Unlike ABS or PETG (petroleum-derived), PLA is biobased and theoretically biodegradable — but only in industrial composting facilities with sustained 60 °C+ temperatures. Don't bury your prints expecting them to vanish.
Its glass transition temperature (T g ) of ~60 °C is PLA's defining limit. Above it, the plastic softens and parts deform under their own weight. This is why PLA isn't suitable for parts that will live in a hot environment.
Annealing PLA (oven at 80–100 °C for 1–2 hours) can raise HDT to 90 °C+ but shrinks the part ~3% — only useful for non-precision pieces.
Avoid for: car interiors, outdoor parts in sun, mechanical parts under sustained load, anything you'll boil or autoclave, gears with high friction loads.