PLA for FDM 3D printing — when to use it and when not to

What is PLA?

PLA (polylactic acid) is a bioplastic made from renewable sources such as corn starch or sugar cane. In the FDM 3D printing world, PLA is the material almost every user starts with — it is easy to print, virtually odourless, does not require a heated chamber, and produces clean, sharp detail on the model.

Advantages of PLA

• Easy to print: low nozzle temperature (190–220 °C), minimal warping, no need for an enclosed chamber.
• Sharp detail: excellent transfer of fine geometry, text and small features — ideal for figures, scale models and visual prototypes.
• Dimensionally stable: very little creep at room temperature — the model keeps its measurements for days and weeks.
• Huge range of colours and effects: matte, glossy, silk, dual-colour, wood, metal, glow-in-the-dark — the widest selection on the market.
• Bioplastic: made from renewable feedstock, industrially compostable (with a caveat below).
• Affordable: among the cheapest filaments in the "ready to print" quality tier.

Disadvantages of PLA

• Low heat resistance: deforms already around 55–60 °C — a car in the summer sun is fatal for it.
• Brittle under impact: it is strong in tension, but under a sudden hit it snaps sharply without an elastic zone.
• UV and outdoor exposure: long-term sun and moisture cause loss of gloss and increased brittleness.
• Hard to machine: sanding and drilling work, but the material easily smears at higher tool speeds.
• "Compostable" does not mean "backyard-degradable": decomposition requires an industrial compost facility above 55 °C.

Where PLA is the ideal choice

• Visual prototypes and scale models: sharp detail, clean surfaces, cheap enough for many iterations.
• Figures, models, home printing: the huge palette of colours and effects gives a professional look without post-processing.
• Assembly aids and short-life fixtures: jigs, templates, spacers — anything that operates at room temperature.
• Education and office use: no smell and no enclosure needed, safe for a shared workspace.
• Ergonomic and medical concepts (not final products): for hand-feel test models before moving to the final material.

When PLA is not a good choice

• Parts exposed to sun or heat: car interiors, terraces, kitchens, near heating.
• Mechanically loaded parts with impacts: tool holders, functional parts under dynamic load.
• Parts exposed to moisture and UV for a long time: outdoor use — ASA, ASA by Crofil or PETG are better.
• Chemical resistance: PLA is not resistant to solvents, oils or fuel.
• Parts that need to flex: for elasticity we use TPU, not PLA.

PLA vs. PLA+ / Tough PLA

Most manufacturers today also offer "PLA+" or "Tough PLA" variants. These are modified PLAs with impact modifiers — they remain as easy to print as classic PLA, but with much better impact resistance. For functional prototypes and parts that need to survive a drop or a tightened screw, PLA+ is almost always the better choice than plain PLA, at a very small price difference.

Print parameters (typical)

• Nozzle temperature: 200–220 °C
• Bed temperature: 50–60 °C (unheated bed can also work with good adhesion)
• Print speed: 60–200 mm/s depending on the printer
• Part cooling: 100 % — PLA loves cool air
• Nozzle: standard 0.4 mm, hardened is not required except for silk/glitter variants

Conclusion

PLA is still the "default" FDM material for a reason — the easiest to print, the widest colour selection and the best ratio of price to visual quality. But PLA is not a universal material: the moment a part has to get hot, live outdoors or take impacts, we switch to PETG, ASA by Crofil, PA6-CF or TPU. At the 3D4U workshop we use PLA for scale models, presentation pieces and quick prototypes, and produce functional parts from the appropriate technical materials.