Filament Jammed In Hotend Top  

Re: Filament Jammed In Hotend Top

Chances are your fan wire has broken from flexing, so you need to resolve that issue,

if you dissassemble the hot end carefully, you should be able to recover most of the components.

However... if you are feeling lucky, and the filament is still attached to the extruder
open the bondtech trap door,
heat up the extruder,

Remove the Nozzle carefully, probably a good idea to remove the part fan shroud too...

with the left hand fan not running, let the heat soak intentionally into the heat break and bottom of the heatsink, and keep a firm pressure downwards on the filament, the filament should soften, and push out... once it's moving easily, withdraw the remaining filament, and reassemble the hotend.

replace the fan shroud, and nozzle,

confirm that the left hand fan is now fully functional (usually cabling faults show up when the extruder is to the right hand side of the X axis.)

if all is good, try loading filament and try a sample print.

Hope this works for you...

alternatively if you have to disassemble the hot end, begin by heating the hot end and removing the nozzle, then letting everything cool. cut the filament above the extruder if it hasn't already come off.

when cold, dissassemble the left fan, front fan and front extruder housing, to expose the hot end assembly and the cold end heatsink

Cut the cable ties holding the heater and thermistor wires in place to give you a little 'wriggle room,' Remove the extruder assembly from the housing carefully (There is a knack to this, have a look at the instructions to replace the PTFE liner https://manual.prusa3d.com/Guide/How+to+change+a+PTFE+tube+-+Original+Prusa+i3+MK3-MK2.5/761?lang=en )

this should leave you with the extruder assembly available for disassembly.

if there is a circlip, similar to the Blue or red parts in the picture above, remove tit by sliding out from under the edges of the black collet (Black circular bit around the PTFE) press the black part into the heatsink to release the grip on the PTFE,
cut the filament at the top of the PtFE tube, and then unscrew the heatsink from the heatbreak.
the PTFE tube should the heatsink should unscrew relatively easily and the PTFE Tube should stay in the heatsink, while the filament pulls out from inside it, and stays with the heatblock/heatbreak assembly....
now you can look at the problems that caused your blockage...
and resolve them

my reccommendations,
always change the PTFE tube in the extruder, if you have disassembled the extruder...
put antiseize paste on the nozzle threads and the threads where the heatbreak screws into the heat block. (like Coppaslip)
Put heat sink compound on the heatbreak threads, as you reassemble the heatbreak into the heatsink

regards Joan

Re: Filament Jammed In Hotend Top

Thanks so much!

This is good stuff. I will attempt this right away. I better order the PTFE tubing right away as shipping takes a bit to get here to the states.

If I cannot resolve this issue, or the filament is in blocking the hotend to the point where I can't print FLEX -

Where do I buy a new hotend? Any ideas?

Thanks

Re: Filament Jammed In Hotend Top

The hot end is an e3dV6 hotend,
made by e3d.

here is a list of resellers,
https://e3d-online.com/resellers

your Mk2 uses a 12 volt heater cartridge.

the e3d parts have a plug connector in the wiring, which Prusa found to be problematic. it also makes cable management 'interesting!' some folk simply cut the connector out and re solder the wires.

neither the heater nor thermistor are polarity conscious.

Prusa moved to a subtly different heat break configuration when the MMUv1 was introduced, depending on the age of your Mk2, you may actually have one of these in your current hotend.

because the different hot ends are difficult to differentiate, prusa have started marking these modified heatbreaks, with a band of red paint around the waist area of the heatbreak.

Aliexpress and ebay lookalike heatbreaks / extruders, are manufactured to varying quality, and may give you more problems than they may save in up front cost.

good luck

regards Joan