Comparison of PLA and ABS 3D printing materials
Two filaments cover most FDM work, and they fail in opposite ways. PLA prints easily but softens in a hot car. ABS survives heat and impact but warps and smells. This page compares the two on the numbers that decide a part, then says which one to pick for which job.
In this article
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PLA and ABS compared on the numbers that matter
Typical values for standard grades. Additives and annealing shift results.
| Property | PLA | ABS |
|---|---|---|
| Print nozzle temperature | 195–220 °C | 230–260 °C |
| Bed temperature | 0–60 °C | 90–110 °C |
| Glass transition temperature | 55–60 °C | 100–105 °C |
| Tensile strength (XY) | 45–65 MPa | 35–45 MPa |
| Impact resistance | Low, brittle | Moderate to high |
| Warping tendency | Low | High on long parts |
| Acetone smoothing | No | Yes |
| Indoor odor while printing | Low | Noticeable |
| Cost per kg | Lower | Higher |
Which material to choose for which part
Use this as a starting filter, then confirm with a test print or a machined sample.
| Part or condition | Pick | Reason |
|---|---|---|
| Fit-check prototype, tight tolerance | PLA | Low warp, sharp detail, cheap to reprint |
| Car interior trim, 70 °C soak | ABS | Holds shape above 100 °C glass transition |
| Snap-fit clip, repeated flex | ABS | Absorbs impact instead of cracking |
| Display model, fine text | PLA | Better detail at 0.1–0.15 mm layers |
| Long thin part over 150 mm | PLA or machined | ABS warps without a heated chamber |
| Continuous load above 100 °C | Neither | Use PC, PA, POM, or PEEK |
| Solvent-smoothed cosmetic shell | ABS | Acetone vapor polish, PLA has no match |
Why the two filaments behave so differently
PLA is a polyester built from lactic acid. Its polymer chains are stiff and pack tightly, which gives it high tensile strength and a low printing temperature. That same stiffness is the problem: past roughly 60 °C the chains start to move, so a part left on a dashboard or in a warm enclosure creeps under load.
ABS is a styrene-based terpolymer. Its chains slide past each other before they break, so it absorbs impact instead of shattering. The trade-off is that it needs a hot nozzle and a hot bed to bond, and it shrinks as it cools. Shrinkage of 0.4–0.8 % on a 200 mm part is several tenths of a millimeter of movement.
Neither material is 'better'. PLA wins on printability, stiffness, and surface detail. ABS wins on heat, impact, and chemical resistance. The rest of this page is about the conditions that flip the decision.
Heat resistance decides most functional parts
Start by asking where the part lives. A bracket inside a climate-controlled enclosure at 25 °C never sees the glass transition temperature of PLA, so the cheaper filament is fine. A part near a motor, a lamp, or a car interior will sit at 60–90 °C and PLA will sag.
ABS holds its shape to about 100 °C before softening. That is enough for under-hood covers that are not directly bolted to the block, and for parts that see short-term heat soak rather than continuous load.
If the part must survive 120 °C or more, neither filament is the answer. Move to PC, PA, or a machined plastic such as POM or PEEK.
One trap: PLA in a closed car can reach 70 °C on a sunny day. A decorative part is fine. A latch under load is not.
Part size and geometry change the ABS calculus
ABS warping scales with the longest dimension. Small brackets under 80 mm usually print cleanly on a 100 °C bed with an enclosure. Long thin parts above 150 mm pull off the plate at the corners unless the chamber holds 45–60 °C.
Corner geometry matters too. Sharp corners concentrate shrinkage stress, so a 1 mm chamfer or a 2 mm fillet at the base often removes a lifted corner without changing the design intent.
PLA has the opposite profile. It barely warps, so it can print tall thin walls and fine features that would curl in ABS. When a part is mostly cosmetic or a fit check, PLA's dimensional behavior is easier to manage.
For anything that has to match a machined mating surface, we usually print the prototype in the production plastic, not a substitute.
Print settings and post-processing
PLA prints at 195–220 °C with a bed at 0–60 °C and no enclosure. Layer bonding is good at 0.2 mm, and part cooling can run at full fan speed to sharpen overhangs.
ABS needs 230–260 °C at the nozzle, a bed at 90–110 °C, and an enclosure. Keep part cooling low, often 20–40 %, or interlayer strength drops. A draft shield helps on tall parts.
Acetone vapor smoothing works on ABS and gives a glossy, near-injection-molded surface. It also rounds edges and can distort thin walls, so mask or fixture the part before the vapor bath. PLA has no comparable solvent polish; sanding and primer are the practical route.
Annealing raises the heat deflection of both materials but adds shrinkage. For ABS, 80 °C for 2 hours in a fixture is a workable starting point.
Cost, reprints, and when to switch to machining
PLA costs less per kilogram and prints faster, so a first article is cheaper. But a failed ABS print wastes a long run, and a warped batch wastes more. Count reprints, not just filament price.
For low quantities, FDM in PLA or ABS is usually the fastest route to a physical part. Past a few hundred units, or when the part needs ±0.005 mm and an Ra 0.8–1.6 μm finish, subtractive machining takes over.
We run both. Custom 3D printing covers prototypes and low-volume parts; 5-axis CNC machining holds tolerance on the final geometry and can cut from the same ABS or PC stock used in production.
A useful rule: print to check fit and form, machine to check function. If the part carries load, seals a fluid, or mates with a bearing, the last step should be a machined sample.
- 1Prototype fitFDM in PLA or ABS, 0.2 mm layers.
- 2Functional checkCNC in the production plastic.
- 3Production runInjection molding or die casting past a few thousand.
The verdict
If the part stays below 50 °C, needs fine detail, and is reprinted often, choose PLA. If it sees heat, impact, or solvent finishing, choose ABS and budget for an enclosure and a 100 °C bed. Above 100 °C, choose neither.
PLA and ABS questions we get from engineers
Can PLA and ABS be printed on the same machine?
Yes, with different profiles. PLA runs at 195–220 °C with a cool or unheated bed. ABS needs 230–260 °C and a bed at 90–110 °C.
Switch the filament and purge well between them. Residual ABS in a PLA print leaves dark specks, and residual PLA in an ABS print weakens the bond.
Does ABS really need an enclosure?
For small parts, no. A 100 °C bed and a draft-free room are often enough.
For any part longer than about 150 mm, an enclosure holding 45–60 °C is the difference between a flat part and a lifted one. It also reduces the odor in the room.
Which material is stronger?
PLA is stiffer and has higher tensile strength in the XY plane, typically 45–65 MPa against 35–45 MPa for ABS.
ABS is tougher. It bends before it breaks, so it survives drops and snap-fits that crack PLA. Strength and toughness are not the same property.
Can I smooth PLA like ABS?
Not with acetone. PLA is not soluble in acetone, so vapor smoothing does nothing.
Sanding from 400 to 1,500 grit, then filler primer, is the practical route. ABS can be vapor smoothed in acetone, but the process rounds edges and needs a fixture for thin walls.
What tolerance should I expect from FDM parts?
On a well-tuned printer, ±0.2 mm is realistic on small features, and ±0.5 % of the longest dimension on larger parts.
ABS adds shrinkage on top of that, so a 200 mm part can move 0.8–1.6 mm as it cools. If the drawing calls for ±0.005 mm, the part needs machining.
When should I switch from printing to CNC?
Switch when the part carries load, seals against a fluid, or mates with a bearing or a machined surface.
We quote both paths from the same file, with free DFM analysis inside 12 hours, so the cost comparison is on one page.
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