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j-hotend V6 BADLY jammed

Posted by adenton 
j-hotend V6 BADLY jammed
March 28, 2017 06:12PM

During my last print the fan on my hotend turned off and I was not there to see it, thus I have a crazy jam in my hotend... I've tried heating it and poking the jam through with a tool, but that didn't work. I read online that acetone can hep, so I disassembled it and have been soaking the piece with the jammed PLA in it but no luck so far. I heard that drilling through it can solve the problem, but obviously you risk damaging the part...

Any suggestions??

And just to clarify that part that is jammed is NOT the nozzle of the extruder. I don't know what the part is actually called but its the one that sits above the nozzle in the aluminum square, if that makes senses....
Re: j-hotend V6 BADLY jammed
March 28, 2017 07:13PM
Acetone is only good for ABS, not PLA.

I'm not familiar with the "j-hotend V6". I assume you mean "J-head V6"?

The threaded tube thing screwed into the aluminium heater block is called a "heat break". It has a heatsink screwed onto it. Depending on the type of hot-end, there might be a PTFE liner inside the heat break.

I'd start by getting all the parts disassembled...
  • Heat up the hot-end, maybe 190 might be enough, but if that doesn't work you can go up to maybe 250C.
  • If you can't unscrew the heatsink off the heat break, take the fan off, so that the heatsink gets hot too.
  • Sometimes the heat break will unscrew from the heater block rather than from the heatbreak. In that case, get two M6 nuts and lock them against each other on the heat break so that you can apply enough torque to get the heat sink off. Heat breaks aren't strong... you might have to replace it if you use too much torque. On the plus side, (a) I never broke one this way, and (b) they're not expensive.
  • Remove the nozzle.
  • Remove the liner, if one exists. You might have to trash the liner... if it has overheated, the bottom can be blackened and charred and swollen enough to jam itself in there. It may also have globs of charred PLA stuck to it.
  • Once the liner is gone, you can use as much heat as you like to melt whatever is still in the heat break, and scrape/push it out.

Good luck!
Re: j-hotend V6 BADLY jammed
March 28, 2017 08:00PM
Ethyl acetate will dissolve PLA, acetone sometimes softens PLA but will not dissolve it. Have you tried the atomic pull method? Some also have luck heating the parts with a blow torch to pull crud out. If neither of these work then you are looking at trying to poke out whatever is blocking the nozzle! Sometimes cheap filament can have unwanted bits in it... I once had filament with small chunks of metal in.. I say small but one was 3 times the diameter of the filament.
Re: j-hotend V6 BADLY jammed
March 28, 2017 08:16PM
I heard that drilling through it can solve the problem, but obviously you risk damaging the part...

What I've done in the past is to hold the drill bit in my finger and rotate it backwards with my fingers. Since it's drilling plastic and your not using the drill threads to dig into the plastic, your fairly safe from causing any major damage. Thankfully I've only had to do this twice, and both times I used a smaller drill bit than the path which was enough for the stuck PLA to relax off the sides and then just get pushed out. No heat necessary.

I would however, highly recommend against using a drill as that could easily scratch the inside path your drilling out.
Re: j-hotend V6 BADLY jammed
March 30, 2017 04:30PM
Thank you for all of the replies, yes I did mean J-head V6. I cleared the jammed today!! I used small drill bit to manually chip away at the plastic in the heat break. Then I used a wrench to lightly tap the drill bit through the jam and it cam flying out!! Yay!! No heat needed smiling smiley
Re: j-hotend V6 BADLY jammed
April 02, 2017 08:43PM

I wanted to add that this is not a real J-head. Real J-heads are like these --> [reprap.org]

There was no such thing as a J-Head V6.

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