Understand
FDM or resin (SLA): which 3D printing technology to choose?
Two families of machines, two logics. Here is how to choose between FDM and resin for your part: use, precision, material, budget.
Published on 27 June 2026 · 8 min read
When you start a 3D printing project, one question always comes before the others: FDM or resin? These are the two families we use in the workshop, and they do not answer the same needs. Neither is "better" than the other — they are complementary.
This article gives you what you need to decide for yourself, without unnecessary jargon. And if a doubt remains, this is exactly the kind of trade-off we work through with you before launching any print.
Two families of machines, two logics
FDM builds a part by depositing a molten plastic filament, layer after layer. Resin, on the other hand, hardens a light-sensitive liquid, point by point or layer by layer. Every other difference flows from this: precision, available materials, strength, surface finish, budget.
FDM: fused filament deposition
The principle
A nozzle heats a filament and lays it down following the shape of the part, level by level. It is the most widespread 3D technology, and the one that covers the widest range of uses.
What it does best
- Functional and mechanical parts: an enclosure, a bracket, a spare part, a workshop jig.
- Large format: our machines print up to around 25 cm per side, in a single piece.
- Material choice: PLA, PETG, ABS, ASA, flexible TPU, nylon, carbon- or glass-fibre-filled composites. From the decorative part to the technical component under load.
- Budget: for an equal volume, it is generally the most economical solution.
Its limits
Layers remain visible to the touch and the eye on sloped surfaces. For a smooth result, sanding is required. And on very small details — fine engravings, micro-reliefs — FDM reaches its limit of fineness.
Resin (SLA / MSLA): photopolymerisation
The principle
A screen or a laser cures a liquid resin, layer after layer, with very fine precision. The part is then washed and post-cured under UV.
What it does best
- Detail and precision: this is its number-one strength. Tight tolerances, micro-reliefs, sharp edges.
- Surface finish: smooth straight off the machine, ideal for aesthetic parts.
- Specialised uses: miniatures, jewellery, scale models, presentation prototypes, dental applications.
Its limits
The build volume is smaller than with FDM. The process requires washing and curing steps. And depending on the resin, the part can be more brittle than a good FDM plastic — although technical resins (tough, flexible, ABS-like) partly correct this.
FDM or resin: the comparison
| Criterion | FDM | Resin (SLA / MSLA) |
|---|---|---|
| Precision / detail | Good | Excellent |
| Surface finish | Visible layers | Smooth |
| Mechanical strength | High (depending on material) | Variable |
| Large format | Yes (up to ~25 cm) | Limited |
| Material choice | Very wide | Specialised |
| Budget | More economical | Higher on small parts |
| Typical uses | Functional parts, prototypes, short runs | Fine detail, aesthetics, miniatures, dental |
Four questions to decide
- What is the part for? Functional and under load → FDM. Aesthetic or highly detailed → resin.
- What size? Beyond a few centimetres with detail, FDM regains the advantage.
- What level of finish? Immediate smooth surface → resin. Tolerant of slight layer texture, or ready to sand → FDM.
- What budget? For an equivalent use, FDM is often more economical. To understand what drives the price, see our article on how much a 3D print costs.
Our advice
In practice, most projects have an obvious answer once the use is clarified. A functional prototype goes to FDM; a miniature or a presentation part goes to resin. To go further, our dedicated pages detail each technology: FDM and resin. The materials page lists the available options.
Still unsure? Tell us about your project or start an online estimate: we steer you toward the technology and material that serve your need, not the other way around. It is often a matter of a few minutes' conversation, especially for rapid prototyping.
Frequently asked questions
Is resin more precise than FDM?
Yes, on fine detail and surface finish, resin is clearly superior. But on a medium-sized functional part, FDM's precision is more than enough — and the part is often stronger.
Which technology is the strongest?
FDM, in most cases, especially with materials like PETG, ABS, nylon or composites. Some technical resins come close, but FDM remains the reference for mechanical parts.
Can both be combined on the same project?
Yes. We sometimes print the body of an object in FDM and its fine details in resin. We choose the most relevant combination depending on the expected result.
How do I know which to choose for my part?
By answering four questions: use, size, finish, budget. If in doubt, send us your project — advice upfront is part of our work, before any quote.