Most FDM parts we print in Sangli go out in one of three filaments: PLA, PETG or ABS. Buyers often pick one by habit, or because it was the only name they knew, and then find the bracket cracked, the cover warped in the sun, or the enclosure cost more than it needed to.
This guide is a practical comparison for engineers and buyers choosing a filament for a functional part. It uses typical published property ranges for the base polymers and our experience of what fails in use. We have not run our own lab tests, and every brand and grade varies, so treat the numbers as a guide and test anything critical.
The short answer
| If the part… | Choose |
|---|---|
| is a model, mock-up or fit check at room temperature | PLA |
| is a working bracket, clip, cover or guard indoors or outdoors | PETG |
| runs warm, must look like a finished product, or will later be moulded | ABS |
| slides, rotates or wears | none of these — use Nylon |
| is tiny and needs fine detail | none of these — use resin |
The rest of this guide explains why.
Heat resistance
Heat is the most common reason a printed part fails, and the clearest difference between the three.
| PLA | PETG | ABS | |
|---|---|---|---|
| Typical glass transition | ~55–60 °C | ~75–80 °C | ~95–105 °C |
| Practical working limit (unloaded, rough guide) | ~50 °C | ~65–70 °C | ~85–90 °C |
Glass transition is the temperature where the plastic changes from rigid to rubbery. A part under load starts to creep and deform below that point, so the practical limits are lower.
What this means in practice:
- A PLA part on a car dashboard, in a control panel with a transformer, or on a metal roof in May can soften and sag. Ambient temperature in Maharashtra summers, plus direct sun, can get there.
- PETG survives most indoor and outdoor ambient conditions but not hot machinery.
- ABS is the safe choice near motors, lamps, power supplies and inside vehicles.
If the part is close to anything that is hot to touch, start with ABS or Nylon.
Toughness and strength
“Strong” usually means two different things:
- Stiffness and peak strength — how much load before it bends or breaks.
- Toughness — how much energy it absorbs before it cracks; what happens when it is dropped, over-tightened or flexed.
PLA is stiff and fairly strong in a static test, but brittle. It fails suddenly, often along a layer line, and it creeps under constant load over weeks.
PETG is slightly less stiff but much tougher. It bends, then yields. Its layers bond well, so printed PETG parts split less often between layers.
ABS is also tough, with good impact resistance from its rubbery phase. Layer bonding is good when printed in a warm, draught-free environment, and weaker if the part cooled too fast.
For snap-fits, clips and anything that gets screwed down: PETG or ABS, not PLA.
Sunlight and outdoor use
| PLA | PETG | ABS | |
|---|---|---|---|
| UV resistance (unpainted) | Poor | Fair to good | Poor — yellows and embrittles |
| Moisture | Slowly degrades over long exposure | Good | Good |
| Heat in direct sun | Can soften | Usually fine | Fine |
For outdoor FDM parts, PETG is usually the best of the three. ABS works outdoors if painted. PLA is a poor choice for anything left outside. For long outdoor life at higher volumes, moulded HDPE or UV-stabilised PP outperform all three.
Chemical resistance
General behaviour of the base polymers (always test with your actual chemical):
- PETG resists water, dilute acids and alkalis, and many oils well. It is the most chemically robust of the three.
- ABS handles water and many oils but is attacked by acetone, many solvents and fuel.
- PLA handles water briefly but is not suited to sustained chemical, oil or hot-water exposure.
If the part sits in fertiliser, coolant or cleaning chemicals, PETG is the first candidate. For continuous chemical contact at volume, look at moulded PP or HDPE.
Printability and accuracy
This matters to you because it affects cost, accuracy and what geometry is realistic.
| PLA | PETG | ABS | |
|---|---|---|---|
| Warping on large flat parts | Very low | Low | High |
| Dimensional accuracy | Best | Good | Good on small parts; needs care on large ones |
| Fine detail and sharp edges | Very good | Good (some stringing) | Good |
| Bridging and overhangs | Very good | Good | Good |
ABS shrinks as it cools, so large flat ABS parts tend to lift at the corners. We control this with settings and orientation, and we will tell you if a design needs a change. PLA is the most dimensionally predictable, which is why it is preferred for fit checks. PETG sits in between.
Finishing
- PLA sands, fills, primes and paints very well. Most of the models and exhibition pieces we paint are PLA.
- ABS also sands and paints well, and is the closest of the three to a moulded product surface. It can be vapour-smoothed with solvents, which needs care.
- PETG is harder to sand cleanly and needs a suitable primer for paint to stick. It is usually left as printed.
Our painting and finishing service can take any of them to a presentable finish.
Cost per gram
Our quote formula, excluding 18% GST:
| Material | Rate | Handling per part |
|---|---|---|
| PLA | ≈ ₹3.13 per gram | ₹18.75 |
| PETG | ≈ ₹3.13 per gram | ₹18.75 |
| ABS | ≈ ₹4.05 per gram | ₹18.75 |
| Nylon (for comparison) | ≈ ₹7.06 per gram | ₹18.75 |
Worked examples from the same formula (indicative, excl. GST):
| Part | PLA or PETG | ABS |
|---|---|---|
| Small gear 30 × 30 × 10 mm, solid (~11 g) | ₹53 | ₹62 |
| Bracket 50 × 30 × 20 mm, 3 mm wall (~18 g) | ₹76 | ₹93 |
| Enclosure 100 × 60 × 30 mm, 2 mm wall (~48 g) | ₹170 | ₹214 |
| IoT box 163 × 163 × 62 mm, 2.5 mm wall (~269 g) | ₹862 | ₹1,109 |
Two observations:
- PETG gives you a big step in toughness for no extra cost over PLA. For functional parts that do not need ABS heat resistance, PETG is often the best value.
- ABS costs roughly 15–30% more on a typical part. That is worth paying when heat, finish or a later move to moulding matters, and wasted when it does not.
FDM has almost no quantity discount, so ten enclosures cost about ten times one. Ten PLA enclosures come to ₹1,699 plus ₹306 GST, or ₹2,005 in total. When quantities reach hundreds or thousands, compare against injection moulding, where ABS, PP and HDPE are moulded on our 250-tonne press. Final prices always depend on your actual file.
Decision table
Print this, or use it in a design review.
| Question | PLA | PETG | ABS |
|---|---|---|---|
| Will the part see more than ~50 °C? | No | Up to ~65–70 °C | Up to ~85–90 °C |
| Will it be dropped, over-tightened or flexed? | Avoid | Good | Good |
| Will it live outdoors unpainted? | Avoid | Good | Avoid (or paint) |
| Will it touch oils or chemicals? | Avoid | Best of three | Check the chemical |
| Must it be dimensionally exact? | Best | Good | Good on small parts |
| Must it be painted to a product finish? | Good | Harder | Best |
| Will the final part be moulded in ABS? | No | No | Yes — prototype in ABS |
| Lowest cost? | Yes | Yes (same rate) | ~15–30% more |
A few common mistakes
- Using PLA for a part near a motor or in a vehicle. It may pass a bench test and fail in the first hot week.
- Using ABS for every functional part “to be safe”. PETG is often tougher in practice, prints more accurately and costs less.
- Testing snap-fits in PLA for an ABS moulding. Stiffness and toughness are different; the snap that worked in PLA may be too stiff or too weak in ABS.
- Ignoring layer direction. All three are weakest between layers. Tell us the load direction and we will orient the part.
What to send us
Send a STEP or STL file and tell us three things: what the part does, the hottest place it will be, and whether it lives outdoors. With that, we can recommend the filament and quote it. Our guide on how to get a quote fast lists everything that helps. You can also call or WhatsApp +91 93568 71008.