Is FDM or SLA stronger?

FDM is stronger for working parts. Our FDM plastics run from 35 MPa for TPU up to about 80 MPa for PA-CF, and PETG at 50 MPa bends before it breaks. Most SLA resin is stiff but brittle, so a drop or a steady load can crack it. Tough resins help, but they give up the fine detail that made SLA attractive.

Which is cheaper, FDM or SLA?

FDM, for almost anything functional. Filament costs less than resin per part, and FDM parts come off the machine ready to use. Every SLA part needs an alcohol wash and a UV cure, and that labor lands in the price. FDM also scales better on repeat runs.

When should I choose SLA over FDM?

When the part is about looks and fine detail, and it will never take a load. SLA cures very thin resin layers, so small text, sharp edges, and smooth curves come out crisp. It fits small models, jewelry patterns, dental parts, and display pieces. For anything that has a job to do, FDM is the better pick.

Do SLA parts last as long as FDM parts?

Usually not, and outdoors is the worst case for them. Resin keeps curing after the print, and sunlight speeds that up. So a resin part slowly gets more brittle, and it can yellow. FDM parts in PETG or ABS handle sun and rain much better, holding shape to about 73 C and 98 C.

Can FDM parts be made smooth?

Yes, with extra work. FDM lays plastic in lines about 0.4 mm wide at a 0.20 mm layer height, so a curved face shows light lines. Those parts sand and paint well, and ABS takes paint best of the five materials we print. Decide up front whether anyone will actually see the face.

What method does your shop use?

FDM only, in PETG, PLA, ABS, PA-CF, and TPU, made in the USA. We do not run SLA, SLS, or metal printing. If your part is a better fit for one of those, we will say so instead of pushing it onto the process we happen to own.

Which process is better for a production run?

FDM, in almost every case. The same file runs one part or a thousand. The build plate handles a longest side up to 220 mm. The per-part price steps down at 10, 50, 250, and 1,000 units. SLA carries a wash and cure step on every single part, so its per-part cost does not fall the same way.

FDM vs SLA: how to pick the right 3D printing method

By the 3D Printer on Demand team · Updated July 2026

FDM melts plastic and stacks it in layers. SLA uses light to harden liquid resin. That one thing decides all the rest. FDM parts are tough, cheap, and built to work, which is why they suit brackets, housings, jigs, and production runs. SLA parts are smooth and sharp, which is why they suit small models, patterns, and display pieces. If the part has a job to do, FDM is almost always the answer. We run FDM, and parts are made in the USA.

The short answer, side by side

Pick FDM when the part has to work. Pick SLA when the part has to look perfect and never take a load. Everything below is detail on that one line.

FDM and SLA compared on the things that decide a part.
	FDM	SLA
How it builds	Melts plastic and lays it in lines	Light hardens liquid resin
Strength	Tough, bends before it breaks	Stiff but brittle
Best materials	PETG, PLA, ABS, PA-CF, TPU	Resins, most of them brittle
Finish	Light layer lines you can see	Smooth, very fine detail
Heat limit	Up to 140 C with PA-CF	Usually much lower
Cleanup	None, parts ship ready	Alcohol wash plus a UV cure
Outdoor life	Good with PETG or ABS	Poor, sun makes resin brittle
Cost per part	Lower	Higher
We run it	Yes	No

What FDM and SLA actually mean

FDM stands for fused deposition modeling. A hot nozzle melts a plastic thread and lays it down line by line. Each layer cools and welds to the one under it. It is the most common kind of 3D printing, and it is the only process we run.

SLA stands for stereolithography, and it works the other way around. A light source aims into a tray of liquid resin. The light hardens the resin one thin layer at a time, and the part is pulled up out of the tray as it builds.

So one builds with melted plastic and one builds with hardened resin. That shapes how each part looks, how it feels, and how long it lasts.

Strength: FDM wins for parts that work

FDM plastics are made for load. PETG pulls to about 50 MPa and gives a little before it breaks. PA-CF, which is nylon with carbon fiber, pulls to about 80 MPa and stays stiff. Those are the numbers behind a bracket that holds.

Most SLA resin is the opposite. It is stiff and it holds detail beautifully, and then it snaps. A drop on a concrete floor is often enough. Tough resins exist and they help, but they trade away the detail that made SLA attractive in the first place.

So if the part carries weight, gets handled, takes a knock, or clamps onto something, FDM is the safer call. That is why we print working parts with FDM.

Detail and finish: SLA wins for fine work

SLA holds finer detail than FDM, and it is not close. Light can cure very thin layers, so tiny text, sharp edges, and smooth curves all come out crisp.

FDM lays plastic in lines about 0.4 mm wide, at a standard layer height of 0.20 mm. You can see and feel those lines on a curved face. On a bracket inside a machine, nobody cares. On a display model, it shows.

FDM parts do sand and paint well if the look matters. ABS takes paint best of our five. It is extra work, so decide up front whether the face is one anybody will look at.

Cost, cleanup, and what happens after the print

FDM parts come off the machine ready to use. Supports snap off, and that is the whole post-print step.

SLA has a second half. Every part needs a wash in alcohol and then a cure under UV light. The liquid resin is sticky, it needs gloves, and the used alcohol is waste that has to be handled. That work costs money, and it lands in the price of the part.

Resin also costs more per part than filament to begin with. Add the two together and FDM is the cheaper path for almost anything functional.

Size, volume, and repeat runs

FDM scales more easily. Our standard build plate handles a longest side up to 220 mm, and the same file runs one part or a thousand. The per-part price steps down at 10, 50, 250, and 1,000 units. The tiers are on our pricing page.

SLA machines are usually smaller, and every part carries that wash and cure step no matter how many you order. That keeps the per-part cost from falling the way it does with FDM.

For a pilot run or bridge production, this gap matters more than anything on the finish side.

How each one holds up over time

This is the part most comparisons skip, and it is where a lot of resin parts disappoint.

SLA resin keeps curing after it leaves the machine. Sunlight speeds that up, and the part slowly gets more brittle and can yellow. A resin part sitting in a window is on a clock.

FDM plastics hold up better outdoors. PETG handles sun and rain and holds shape to about 73 C. ABS holds to about 98 C. PLA is the exception in our lineup, since it softens at 57 C and gets brittle in the sun, so we keep it indoors.

Which one to pick for your part

Run your part down this list and the answer is usually obvious.

Brackets, mounts, housings, jigs, fixtures, guards, spare parts: FDM.
Anything outdoors or near heat: FDM, in PETG or ABS.
Anything that has to flex, seal, or grip: FDM, in TPU.
A load-bearing part that must not move: FDM, in PA-CF.
A pilot run or bridge production: FDM, because the price scales.
Small models and figures, jewelry patterns, dental parts, display pieces: SLA.
A part with detail finer than about 0.5 mm that also has to look perfect: SLA.

What about SLS and metal printing?

They are real options, and we do not run either one. Being straight about that saves you time.

SLS and MJF fuse nylon powder in a bed. They suit complex nylon parts that would need a lot of supports any other way. Metal powder bed printing melts metal with a laser, and it suits metal shapes a mill cannot reach.

If your part needs one of those, we will tell you rather than talk you into FDM. See our guide to additive manufacturing for a look at every process side by side.

Get a price for your part

Upload your STL at our instant quote page. No login is needed to see a number.

PLA and PETG price instantly. ABS, PA-CF, and TPU route to a fast human quote, and our team replies within four business hours. Every price is flat per part and held for 30 days.

Not sure which material fits? Our materials comparison puts all five side by side. Parts ship in 2 to 5 days, made in the USA.

Quick takeaways

FDM melts plastic in layers. SLA hardens liquid resin with light.
FDM is tougher. PETG pulls to about 50 MPa and PA-CF to about 80 MPa. Most resin is stiff but brittle.
SLA holds finer detail and a smoother face. That suits models and patterns, not working parts.
FDM parts ship ready. SLA needs an alcohol wash and a UV cure, and that cost lands in the part.
Resin keeps curing in sunlight and gets brittle. FDM in PETG or ABS holds up outdoors.
FDM scales better on repeat runs, with the per-part price stepping down at 10, 50, 250, and 1,000.
We run FDM only. If your part needs SLA, SLS, or metal, we will tell you.

Have a part to print? Get an instant price.

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Common questions

Is FDM or SLA stronger?: FDM is stronger for working parts. Our FDM plastics run from 35 MPa for TPU up to about 80 MPa for PA-CF, and PETG at 50 MPa bends before it breaks. Most SLA resin is stiff but brittle, so a drop or a steady load can crack it. Tough resins help, but they give up the fine detail that made SLA attractive.
Which is cheaper, FDM or SLA?: FDM, for almost anything functional. Filament costs less than resin per part, and FDM parts come off the machine ready to use. Every SLA part needs an alcohol wash and a UV cure, and that labor lands in the price. FDM also scales better on repeat runs.
When should I choose SLA over FDM?: When the part is about looks and fine detail, and it will never take a load. SLA cures very thin resin layers, so small text, sharp edges, and smooth curves come out crisp. It fits small models, jewelry patterns, dental parts, and display pieces. For anything that has a job to do, FDM is the better pick.
Do SLA parts last as long as FDM parts?: Usually not, and outdoors is the worst case for them. Resin keeps curing after the print, and sunlight speeds that up. So a resin part slowly gets more brittle, and it can yellow. FDM parts in PETG or ABS handle sun and rain much better, holding shape to about 73 C and 98 C.
Can FDM parts be made smooth?: Yes, with extra work. FDM lays plastic in lines about 0.4 mm wide at a 0.20 mm layer height, so a curved face shows light lines. Those parts sand and paint well, and ABS takes paint best of the five materials we print. Decide up front whether anyone will actually see the face.
What method does your shop use?: FDM only, in PETG, PLA, ABS, PA-CF, and TPU, made in the USA. We do not run SLA, SLS, or metal printing. If your part is a better fit for one of those, we will say so instead of pushing it onto the process we happen to own.
Which process is better for a production run?: FDM, in almost every case. The same file runs one part or a thousand. The build plate handles a longest side up to 220 mm. The per-part price steps down at 10, 50, 250, and 1,000 units. SLA carries a wash and cure step on every single part, so its per-part cost does not fall the same way.