Choosing the right filament is the second most important decision after picking your printer. Use the wrong material and you’ll waste hours on failed prints, warped parts, and brittle prototypes.
Here’s a no-nonsense breakdown of the three most common filaments — PLA, PLA+, and PETG — and when to use each one.
Quick Comparison
| PLA | PLA+ | PETG | |
|---|---|---|---|
| Ease of printing | Easiest | Easy | Moderate |
| Strength | Low-medium | Medium | Medium-high |
| Heat resistance | Low (~55°C) | Low-medium (~60°C) | Medium (~75°C) |
| Flexibility | Brittle | Slightly flexible | Flexible |
| Bed adhesion | Great | Great | Needs glue stick |
| Stringing | Minimal | Minimal | Common |
| Best for | Prototypes, display | Functional parts | Mechanical, outdoor |
| Price | $ | $ | $$ |
PLA: The Default Choice
PLA (polylactic acid) is where everyone starts, and for good reason. It prints at low temperatures, sticks to the bed without fuss, doesn’t warp, and comes in every color imaginable.
Use PLA when:
- You’re printing display models, prototypes, or concept pieces
- The part won’t experience mechanical stress or heat
- You want the cleanest surface finish
- You’re running a lab and want the easiest material for students
Skip PLA when:
- The part needs to survive outdoors or in a car (PLA softens in heat)
- You need any impact resistance (PLA is brittle — it snaps rather than bends)
PLA+: The Upgrade You Should Be Using
PLA+ is PLA with additives (usually impact modifiers and toughening agents) that make it stronger and less brittle. It prints almost identically to PLA but produces parts that can actually take some abuse.
Use PLA+ when:
- You want PLA’s ease of printing with better mechanical properties
- You’re printing functional parts, jigs, fixtures, or tools
- You’re running a lab — PLA+ should be your default, not PLA
Our top PLA+ picks:
- SUNLU PLA+ 2.0 (4KG Bundle) — Best value. Consistent quality and great layer adhesion. This is what we stock as the default in every lab we work with.
- SUNLU PLA+ Starter Colors (Black/White/Blue/Red) — The four colors that cover 80% of use cases. Buy these first.
- OVERTURE PLA+ — Solid alternative at ~$20/kg. Good color accuracy and reliable diameter tolerance.
Pro tip: PLA+ from different brands prints differently. Pick one brand, dial in your profile, and stick with it. Switching brands mid-project causes more failed prints than any other filament mistake.
PETG: When You Need Durability
PETG (polyethylene terephthalate glycol) is the step up when PLA+ isn’t strong enough. It’s more heat resistant, more flexible, and better for parts that need to survive real-world conditions.
Use PETG when:
- The part will be used outdoors or in a hot environment
- You need impact resistance and some flexibility
- You’re printing mechanical parts, brackets, or enclosures
- Chemical resistance matters
Skip PETG when:
- You’re new to 3D printing (start with PLA+ first)
- You need tight tolerances — PETG strings more and overhangs aren’t as clean
- Surface finish matters more than strength
PETG printing tips:
- Use a glue stick or PEI sheet — PETG bonds to bare glass so well it can rip chunks off your bed
- Print 5-10°C hotter than PLA (230-245°C nozzle)
- Slow down by ~20% compared to PLA speeds
- Increase retraction to fight stringing
What About ABS, ASA, TPU?
Quick takes on the other common materials:
- ABS — The old standard for strong parts. Requires an enclosure and good ventilation. Most labs have moved to PETG or PLA+ instead.
- ASA — ABS but UV-stable. Use it for outdoor parts that need to survive sun exposure. Requires enclosure.
- TPU — Flexible rubber-like filament. Great for phone cases, gaskets, and grips. Needs a direct-drive extruder (Bowden tubes struggle with it).
Our Recommendation
For most labs and workshops:
- Stock PLA+ as your default — it covers 80% of use cases
- Keep PETG on hand for functional parts that need more strength or heat resistance
- Buy in bulk — the per-kg price drops significantly at 4KG+
- Standardize on one brand — it saves hours of profile tuning
The SUNLU PLA+ 4KG bundles are the best value we’ve found for lab use. At roughly $11/kg, you’re getting a reliable PLA+ at near-PLA prices.
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