Print head

The next section in the manual for assembling the Prusa i3 Mk3 printer is called the E Axis. The 'E' is the extruder, what I think of as the print head. It is very compact and made of many parts, some printed plastic, some electronic and some prebuilt. There's a motor that draws the filament into the extruder. There's the extruder, known as the hotend, which melts the filament and forces it through a nozzle. There are two fans to ensure the extruder doesn't overheat. There's a filament sensor to check the feed hasn't run out and there's a sensor, known as a P.I.N.D.A., which senses the distance to the print bed to ensure the nozzle doesn't hit it.

All of this lot have a lot of cables. They are all carefully threaded to a printed half tube which then get enveloped with a robust cable wrap. The whole compact package is fixed to the X axis assembly which uses the captured nuts that have precariously sat in their little pockets.

The photo shows how compact the head is, but gives no read idea of the complexity.