FDM or resin? Filament and resin printing compared
are explained briefly when you hover over or tap them.
The short answer: for most beginners and for functional parts, a filament printer (FDM) is the better choice. A resin printer is worthwhile when fine detail matters more than anything else, for example with miniatures, jewellery or dental models, and when you have a room with good ventilation.
The comparison
| FDM (filament) | Resin (MSLA) | |
|---|---|---|
| Detail | limited by nozzle and filament, layer lines visible, especially on curves | very fine detail, smooth surface straight after printing |
| Build volume | large, many devices around 25 x 25 cm | usually smaller, example Saturn 4 Ultra 16K: 21 x 12 x 22 cm |
| Strength | weaker in the Z direction than in X and Y | equal in all directions, but standard resin is brittle |
| Material per kg | filament about €12 to €30 (PLA, PETG) | hobby resin from about €16 |
| Post-processing | remove supports, done | wash, dry, post-cure, remove supports |
| Health | emissions when heated, ventilation recommended | liquid resin irritates and can cause allergies, more VOCs, gloves and ventilation mandatory |
| Colours | very many colours and effects | smaller choice, often painted |
Detail and surface
Here resin clearly wins. The pixels of modern hobby devices are about 14 to 50 µm, and according to Formlabs the surface is smooth straight after printing. An FDM part often needs a lot of sanding for a comparable surface. How the resolution comes about is explained in Resin printing explained.
Strength
FDM parts are weaker along the layers because the layers only adhere to each other. Resin parts are equally strong in all directions. Standard resin, however, is brittle and not very suitable for brackets, clips or tools. Tough resins partly close this gap but cost more. For robust functional parts, PETG or ASA on an FDM printer is usually still the simpler solution.
Costs
Hobby resin is available from about €16 per kilo, filament from about €12. With resin there are further costs: gloves, isopropanol, paper towels, disposal via the hazardous waste collection and wear parts such as the film in the vat bottom. Resin parts are also usually printed solid or just hollowed out, not with infill. Which resins exist and what they cost is covered under Resin types.
Effort and health
An FDM print is usually finished once you take it off. A resin print has to be washed and cured, which takes time and needs space for containers and a lamp. Then there is handling the resin: it irritates the skin and can cause a permanent allergy. A study by UL measured 3 to 6 times more volatile organic compounds from a resin printer than the average for FDM printing, but considerably fewer particles. But FDM is not emission-free either: the Ministry of Education of Baden-Württemberg requires extraction or adequate ventilation for schools. Everything important about protection is covered under Safety in resin printing.
What for what?
- FDM: functional parts, brackets, spare parts, large parts, prototypes, decoration, multicolour printing, getting started with 3D printing
- Resin: miniatures and tabletop figures, jewellery (with casting resin also for investment casting), dental models, very small parts with fine detail
In the end, many makers have both. If you only want one device and do not know exactly what you will print, start with a filament printer: Which 3D printer suits me? For resin, you will find all devices in the overview of resin printers.
Sources
- Formlabs: When to choose SLA or FDM (Formlabs only sells resin printers)
- Siraya Tech: Types of resin
- UL Chemical Insights: Emissions from a resin printer (2021)
- Ministry of Education of Baden-Württemberg: risk assessment for 3D printers (no longer online)
- Safety data sheet: Anycubic Standard Resin
- Elegoo: Standard Resin
- Filament prices: Filaments compared