FDM or SLA: which 3D printing technology for which business part
FDM and SLA compared for business parts: strength, finish, cost, lead time and materials. A decision table by part type and when 3D printing is the wrong route.
Most business parts that reach our studio could be printed either way. The result would differ: different strength, different surface, different price. This guide helps you decide before you ask for a quote.
How do the two technologies work?
FDM (fused deposition modelling) melts a plastic filament and lays it down in layers, usually 0.1 to 0.3 mm thick. SLA (stereolithography) cures liquid resin with light, layer by layer, typically 0.025 to 0.1 mm. Almost everything else follows from that. FDM gives tough parts with visible layers. SLA gives smooth, precise parts that are more brittle and, without a coating, sensitive to UV.
Neither is better. The question is what the part has to do.
How do they compare on what a business cares about?
Strength and durability
FDM parts in PETG, ASA or nylon take screws, bending and repeated load. They are weaker across the layers than along them, which we account for when orienting the part on the build plate. Standard resin is hard but brittle: drop it or lever it and it cracks. Tough resin behaves closer to ABS and suits clips and covers that need to flex a little.
Surface finish and detail
SLA wins clearly. Layers are not visible to the naked eye, and lettering and edges from 0.3 mm are legible. An FDM surface shows its layers; at 0.2 mm you can feel them. It can be sanded, filled and painted, but that is extra work and extra hours on the invoice.
Dimensional accuracy
For parts under 100 mm, expect roughly ±0.2 mm from FDM and ±0.1 mm from SLA. Resin parts can warp slightly during post-curing, so we prefer FDM for large flat parts.
Cost and lead time
FDM has lower material cost and less handling after printing. SLA needs an isopropyl alcohol wash, curing and support removal, which adds time and cost. For single pieces, a typical lead time is 3 to 5 working days for FDM and 3 to 6 for SLA. Small series up to 100 pieces usually take 5 to 10 working days depending on part size. We state the exact lead time in every quote.
Materials
| Material | Technology | Where it fits | Watch out for |
|---|---|---|---|
| PLA | FDM | visual models, unloaded jigs | softens from 60 °C, keep out of the sun |
| PETG | FDM | enclosures, brackets, indoor parts | less detail than PLA |
| ASA | FDM | outdoor parts, UV stable, up to 95 °C | needs an enclosed printer |
| PA (nylon) | FDM | gears, sliding parts, clips | absorbs moisture, dimensions drift |
| PC | FDM | heat-loaded parts, up to 110 °C | demanding to print, higher price |
| TPU | FDM | seals, dampers, protective covers | slow to print, limited detail |
| Standard resin | SLA | visual prototypes, figures, master patterns | brittle, not for outdoor use |
| Tough resin | SLA | functional clips, small detailed covers | less accurate than standard |
| Flexible resin | SLA | soft grips, seals with fine detail | ages faster than TPU |
Which technology for which part type?
| Part | We recommend | Why |
|---|---|---|
| Functional bracket | FDM, PETG or ASA | strength and cost, detail is secondary |
| Enclosure | FDM in PETG; SLA for parts under 80 mm | large enclosures FDM, small ones with fine clips SLA |
| Visual prototype | SLA | smooth surface with no sanding, ready for paint |
| Small detailed figure | SLA | FDM cannot resolve details under 0.5 mm |
| Jig or fixture | FDM, PETG or PA | wear resistance, low cost when repeated |
| Spare part outdoors | FDM, ASA | UV stability and heat resistance |
| Branded object, logo, trophy | FDM above 150 mm, SLA below 150 mm | large logos FDM with finishing, small detailed pieces SLA |
How do you decide in two minutes?
- The part will be screwed, bent or used outdoors: FDM.
- The part must be smooth and precise, and will be photographed or presented: SLA.
- The part is larger than 200 mm: almost always FDM.
- Not sure: send us the file and we will recommend a technology in the quote and explain why.
When will we tell you 3D printing is not the right route?
3D printing is a tool, not an answer to everything. An honest studio says so up front, not after delivery.
CNC machining makes sense for parts that must be metal or a precision plastic with tolerances under 0.05 mm, and for parts under high sustained load. We will suggest it for shafts, precision bushings and anything in aluminium.
Injection moulding pays off from roughly 500 to 1,000 pieces, once the tooling cost spreads across the run. Until then 3D printing, after that a mould. We are happy to print the first 50 and help adapt the design for moulding.
Laser cutting is faster and more accurate for flat parts in sheet metal, acrylic or plywood: panels, labels, spacers, flat logos. Printing a flat part makes no sense.
If one of these routes suits your part better, we will say so directly in the quote.
Send us a sketch, photo or file and you will have a quote within 48 hours.