The extruder barrel guides the filament in an aligned manner into the nozzle. The barrel is screwed into the extruder core
(where the heater cartridge
is situated) until it reaches the thread of the nozzle
. This way the entire duct is sealed and protected from leaks in the joint.
The thread is M6 and aprox. 26 mm long.
The inside of the barrel for 1,75mm filament is lined with a PTFE tube which prevents from obstruction in case the filament gets welded to the metal due to excess temperature.
The low friction coefficient of PTFE makes the filament feeding easier.