While using an FDM 3D printer, you may need to replace the hotend. In fact, a little space between the heatbreak and nozzle, or a failure of the heatsink fan, or any other type of problem could cause a clog that prevents normal extrusion during printing, and the only way to repair the fault is to disassemble or replace the hotend.
Replacing the hotend is an easy procedure but one that requires the utmost attention.
In order to proceed with the replacement, follow these steps.
Disassembly
1) Unscrew the screw that holds the thermistor in place and remove the thermistor and temperature sensor
2) Disassemble the Hotend, then unscrew the screw that holds the Heatsink in place and remove the heatsink.
3) Remove the PTFE tube from the heatbreak.
4) In case the end of the PTFE tube is damaged, cut the damaged part, taking care to make a vertical cut at 90 degrees; an inaccurate cut will cause molten material to leak during printing, causing a new clog. In order to proceed to a precise cut, it is recommended to use a "PTFE cutter" available as an accessory for 3D printing or you can proceed to print an STL file by searching on Thingiverse for "PTFE cutter."
Replacement
1) Screw the Heatbreak correctly into the heatblock.
2) Screw the Nozzle into the Heatblock
3) Install the Heatsink
4) Mount the Hotend on the 3D printer
5) Unscrew a little the Nozzle (about half a turn), then insert the PTFE tube until it hits with the nozzle.
6) Insert the thermistor and the temperature sensor into the block, fixing them with the appropriate screw
7) Heat the Hotend up to 200°C, then screw the Nozzle well so that it is tight with the PTFE tube and the heatbreak.
Once you have completed these steps, the new hotend will be ready to use.
The correct assembly ensures good operation and avoids new clogs due to leakage of molten material between the heatbreak and the nozzle.
