FDM stands for fused deposition modelling, which basically means building a shape by laying down melted material. You'll also often see FFF, for fused filament fabrication. It's the same thing. The printer pulls a plastic thread, the filament, off a spool. A heated nozzle melts it and traces the outline of each layer, laying the plastic down like a fine bead. Then the nozzle moves up a little, or the build plate moves down, and the next layer follows.
The layers are thin. With a standard 0.4 mm nozzle, the layer height is usually between 0.1 and about 0.3 mm. Thinner layers give finer surfaces but take longer. Inside, a part is usually not solid but filled with a lattice, which saves material and time. Overhangs that would otherwise hang in mid-air need support structures, which are removed after printing. The common materials:
- PLA: stiff, cheap and easy to print. Goes soft in the heat, for example in a car in summer.
- PETG: tougher and more resistant to heat and moisture. Good for parts that need to take more in everyday use.
- TPU: flexible and rubbery, for example for bumpers, seals or cases.
For a business, FDM is interesting because it doesn't need any tooling. Injection moulding needs a mould first. According to Formlabs, an aluminium mould costs around 2,000 to 5,000 euros. For a prototype, a spare part or a small batch, that's rarely worth it. With FDM printing, that investment disappears. Merchandise in your company colours can also be made this way in small quantities.
What to watch out for: the layers stay visible as fine lines. For high-gloss surfaces or tiny details, other processes such as resin printing are a better fit. A part is weaker between layers than within a layer, so for heavily loaded parts the print direction matters. And the material has to suit the job. We print with FDM in PLA, PETG and TPU and give you a fixed quote before printing.
A restaurant on the Lucerne lakeshore needs new table number holders for its terrace. The old model isn't available any more. A holder is modelled from photos and measurements and first printed once in PLA to check size and fit. Because the holders stand outside in the sun, the run of forty is then printed in PETG, which copes better with heat. For such a small quantity, an injection mould would have been far too expensive.