FDM printing: how it works and what it is good for

How FDM works

FDM stands for fused deposition modelling. The name is a trademark of Stratasys, the company that invented the technology in the late 1980s, which is why you will also come across the generic term FFF. In practice they mean the same thing.

The printer feeds plastic strand from a spool, called filament. The nozzle melts it and lays it onto the build plate in thin layers until the whole part is formed. The inside of the part is not solid but filled with a lattice, whose density is set by the infill.

How we print

We print on Elegoo Centauri Carbon 2 printers with a 0.4 mm nozzle and a layer height of 0.2 mm. We have two materials, PLA and PETG, and we can use up to 4 colours on one part. The largest part we can print in one go is 246 × 246 × 256 mm.

You choose the strength in the calculator: light has 10 % infill, standard 15 % and strong 40 %. More infill means more grams of material and a longer print, which is why a strong part costs more.

What to expect from FDM

• Visible layers. At 0.2 mm you will see fine ridges on the surface, especially on sloped and curved faces. That does not matter for functional parts. For figurines with fine detail, resin SLA printing is better, but we do not offer it.
• Strength depends on direction. A part holds best along the layers. It is weaker between layers, so for parts under load, the way we rotate it on the plate matters.
• Overhangs need supports. Parts that hang in mid-air are printed on supports. They are broken off after printing and can leave a rougher surface.