The assembly has a powerful electric stepper-motor with attached to a gear assembly that pulls the filament in through a hole in the top. It forces the filament down through a heated nozzle. PLA is a common filament type, it requires the nozzle be at 215C to extrude well. The brass nozzle puts out a 0.45mm wide extrusion (it is mounted to the bottom of a small aluminum block at the bottom). The nozzle has a heat sensor and its own cooling fan (enabling the controller to precisely maintain nozzle temperature). An additional fan and heatsink (on the left side) keep the motor and filament feed area cool. The entire head assembly is pulled left and right along stainless steel rods by a gear-belt controlled by the X-axis motor. Inserting filament can be tricky in machines like this. The best strategy is pre-heating the nozzle, pressing release level (to enable free filament movement) and then pushing the filament to feed it manually through the nozzle, then pulling it out suddenly. To reload, cut it to a point (using scissors), configure the printer to preheat the nozzle to 215C, then feed it down through until it extrudes.
Standard 3D printers (not clay 3D printers) are incredibly useful in ceramic production and design, bringing difficult processes within reach of potters and hobbyists.