PLA is usually the first filament beginners try. It prints at lower temperatures than other plastics, requires minimal bed heating, and produces decent results with minimal tweaking. But understanding its actual properties—rather than marketing hype—will save you frustration.
What PLA Actually Is
PLA (polylactic acid) is a thermoplastic made from renewable resources like corn starch or sugarcane. It’s biodegradable under industrial composting conditions, though regular landfills stay too cold for it to break down meaningfully.
For printing, what matters is this: PLA melts around 160-180°C. It shrinks minimally after cooling. It’s relatively stiff when solid. And unlike some materials, it doesn’t absorb moisture from the air—you don’t need a dry box for PLA storage.
Printing Temperature and Bed Heat
Standard PLA prints at nozzle temperatures between 190-220°C. Most brands cluster around 200-210°C.
Here’s the practical part: a heated bed helps but isn’t mandatory. Many printers run PLA at 20-30°C bed temperature, or even unheated beds. A warm bed (50-60°C) improves adhesion, especially on textured surfaces. If your first layer struggles, try warming the bed before buying a new textured plate.
Pro tip: Layer height matters more than temperature for PLA quality. A 0.12mm layer height looks noticeably better than 0.2mm, even if both temperatures are fine.
Why PLA Is Finicky About Speed
PLA has a narrow window between “prints well” and “clogs.” Print too fast (above 120mm/s for detailed models), and the plastic cools in the nozzle and hardens mid-extrusion. Print too slow, and heat creeps up the nozzle shaft, softening filament that hasn’t reached the heater block yet.
This isn’t a PLA flaw—it’s physics. The material properties just don’t forgive careless settings the way PETG or ABS do.
Practical speeds:
- Fine details, 0.4mm nozzle: 60-80mm/s
- Normal prints: 80-120mm/s
- Simple models: 120-150mm/s
These aren’t hard limits, but staying in these ranges reduces troubleshooting.
Strength and Brittleness Trade-Off
PLA is stiffer than PETG but more brittle. A PLA part can snap cleanly under sudden stress, while PETG bends first. For decorative prints, this doesn’t matter. For functional parts—hinges, clips, mechanical components—PETG usually outperforms PLA.
The brittleness increases at cooler temperatures. A PLA hinge works fine in heated rooms but becomes fragile in a cold garage.
Moisture and Storage
Unlike nylon or ASA, PLA doesn’t absorb ambient moisture. You can store it in a normal sealed bag indefinitely without a desiccant. If you leave filament in a humid room for months, it still prints fine—just not optimally.
However, wet PLA (direct contact with water) produces weak prints with surface bubbling. If filament gets wet, dry it in a low oven (60°C, about 4 hours) before printing.
Color and Finish
PLA comes in every color imaginable. Basic colors are consistent across brands. Specialty colors—metallics, silk finishes, translucent—vary wildly in actual properties. A metallic PLA from one maker might print 20°C hotter than natural PLA from the same brand.
Test before committing to a big print.
Common Mistakes
Thinking hotter = better. Higher temperatures actually increase stringing, oozing, and clogging risk with PLA. If it prints well at 200°C, going to 210°C makes things worse.
Cooling too fast. PLA benefits from passive cooling. An active cooling fan (when printing) helps prevent overhanging layers from drooping, but ramming it with maximum fan speed before the layer solidifies causes warping and layer separation.
Expecting perfect strength. PLA isn’t weak, but it’s not a structural material. Don’t rely on 3D-printed PLA brackets for load-bearing parts unless you understand the failure mode.
When to Use PLA vs. Other Materials
PLA works great for:
- Display models and decorations
- Educational prints
- Prototypes for visual testing
- Simple mechanical parts in ambient temperature
Avoid PLA for:
- Outdoor parts (UV degrades it)
- Hot environments (softens above 50°C)
- High-stress components
- Items that need to bend repeatedly
The key to PLA is respecting its limits without fear. It’s not the easiest material (that’s debatable), but it’s predictable once you understand what it’s actually doing in the nozzle and on the bed. Print slow for details, keep temperatures moderate, and you’ll get reliable results.