FDM stands for Fused Deposition Modelling. You start with 300mm of filament that’s 1.75mm in diameter on a spool. The 3D printer has a head that moves in the X and Y directions. There is also a print bed that moves in the Z direction. On the carriage is a hotend assembly which consists of various parts including a heater and a nozzle which is usually between 0.2mm and 0.8mm. The nozzle heats up to around 200 celsius depending on the material. Filament is then pushed or pulled through to the nozzle where it’s extruded as the carriage moves around. Imagine making a coil pot from clay and that’s kind of what this does but it does it layer by layer instead of one continuous coil. Layers are generally around 0.2mm high. So a 10mm high model will have 50 layers.

It’s a fascinating process to watch. Simple parts can take 20 or 30 minutes. Large parts can take up to 100 hours for one part. A Fender Stratocaster body we printed was around 350 hours in total. So, patience is definitely a virtue. And then you get your failures. Sometimes, just because, a print will fail. The tolerances between the print head and the model are tiny. A blob of filament 0.5mm high in the wrong place can cause the nozzle to hit the model and knock it over. After that, if you don’t spot it, you just get “spaghetti” where the printer keeps trying to print in mid air.

We have 3 FDM 3D printers. A little portable printer best suited to smaller models. It prints at around 50mm/s and will print PLA up to about 165mm x 165mm x 165mm.

Then we have a fully enclosed printer that will print PLA, PETG, TPU and ABS. And it’s fast! 250mm/s is about the middle of the road but it will go faster if the model is right without any discernible loss of quality.