...
The most critical issue on assembly is that you ensure that all inner parts are tightly butting up against each other in order to avoid any material seeping out of a connection point and either oozing out of the hot end and ruining the whole assembly, or just creating a mass that will then jam the flow.
YOUR HOT END IS MOST LIKELY MADE OF THE FOLLOWING BASIC COMPONENTS (FROM THE FILAMENT FEED TO THE NOZZLE):
PTFE tube or Bowden Tube: (unless direct drive)- leads filament into hot end and keeps it running low friction, Teflon is PTFE - same non stick stuff used on pans!)
...
examples of retention and locking clips
...
FROM HERE WE MOVE INTO THE COOLING ZONE, WHICH IS MADE OF:
Heat Sink: this is the metal finned area who's goal is to pull heat away from the filament as quickly as possible, and it's normally hooked up to the hot end fan which keep air blowing across the fins for efficient cooling.
...
There should be gap here, where the Heat break is exposed.
THEN WE MOVE INTO THE MELT ZONE WHICH IS MADE OF:
The other end of the Heat Break feeds into the Heater Block.
...
Nozzle: screwed into the heat block and must but up to the Heat Break. Usually made of Brass, but may find in hardened steel, or stainless, the diameter hole is what determines the thickness of the printed filament.
DISMANTLE YOUR HOT END FROM PRINTER:
First remove previous filament and flush with cleaning filament if you can.
Heat Nozzle to temperature of last filament setting.
Hold Heater Block with large pliers and unscrew Nozzle with wrench when hot. (be careful not to use bare hands)
Completely cool down Hot End.
Disassemble Hot end from machine. (you may find it to be difficult to remove the Bowden Tube from the Coupling and if so, unscrew the Coupling with tube inside. You can cut it away or free it up after. Bring the Hot End to a work bench and take it all apart: unscrew Coupling, heat sink, Heat Throat, Heater Block, Heater, Thermistor, Nozzle. Note: be careful not to damage Thermistor (wires and tip are thin) when you unscrew and remove from Heater Block.
Inspect each part, make sure there is no residual plastic, check the Coupling, check the Heat Sink inner throat, make sure there is no plastic melted down at bottom of where Bowden Tube rests, check the Heat Throat, check the nozzle.
If there is plastic, try scraping out with small picks or tweezers, if unsuccessful, put in a vice and use a heat gun or butane torch to melt it out, use a thin nail to push through and remove melted plastic, use Q-tips to clean if they fit.
If your Nozzle is too blocked, throw it away and buy a new one.
Make sure each part is clean before putting back together.
REASSEMBLY, THE ORDER IS VERY IMPORTANT HERE.
Once every part is clean follow these steps:
...