All About FDM/FFF Printers
This article is a continuation on the All About 3D Printers article, if you have not read it, i suggest you read it here
The FDM/FFF printer, usually called a filament printer is a very common and easy to use printer, and it can be almost anywhere. These printers work by heating plastic to its melting point, then squashing it out of a nozzle onto the bed, and onto other layers.
The Hotend & Extruder
The hotend & extruder are printer specific parts only found on FDM/FFF printers and their relatives, these parts are used to heat up a long strand of plastic, known as filament usually of a diameter of 1.75mm and a industry standard of 0.05mm accuracy, and squirt it out of the nozzle to create a 3d part made of plastic (possibly with additives such as carbon fiber, metal powder, glass fiber, etc.). These printers only need the amount of filament to create the object and any support structures, no more and no less.
The extruder is a system of parts that push and pull the filament from the roll and into the hotend to be melted and extruded, due to the pressure created by the addition of more filament to the hotend.
The first part is the extruder gears, they grip onto the filament and shove it through a PTFE tube and into the hotend, they do so by using a spring loaded gear system that squashes itself into the filament and pulls it through with minimal damage dealt. Some gears have a gear on both sides, rather than a roller wheel and a single gear, these systems work way better because they have extra grip due to the hold on both sides, and that happens to be crucial to using flexible filaments.
Next comes the PTFE tube and the heatbreak, The PTFE tube is there for low friction management of the filament, to make sure it goes where it needs to go. The heatbreak is for keeping the filament solid, then almost instantly melting it in the hotend, to minimalise wasted filament.
The hotend is the system that converts the solid filament strand into a very fine strand of molten plastic that is placed on top of the bed, and other layers.
The first part, that also happens to be the last part of the extruder is the heatbreak, consisting of an insulator and a heatsink, to minimalise wasted filament.
The second part is the heater is known as the hotend, its job is to heat the filament to its melting point and keep it at that point until it has reached where it needs to be.
The third part is the nozzle, that turns the large and not so accurate filament into a very accurate strand about 1/3 of the size of the filament, possibly even smaller.
The fourth and final part is the cooling fan, it stops the filament from drooping and warping by removing the heat the moment it gets into place.
The X, Y And Z Axis
the x, y and z axis are driven by high accuracy actuators or by stepper motors, and these dimensions need the ability to move the printer head in 3d relative to the part.
Wikipedia – Fused Filament Fabrication