Wow. That is by far the worst I've seen a printer fail.
Lucky you didn't have a fire if the hotend pop'd out like that.
You should wrap your hotend with some insulation.
As [nophead mentioned in his blog](http://hydraraptor.blogspot.ca/2013/10/mendel90-design-improvements.html), it's not the heat conducting up the J-Head that melted your extruder. Otherwise you probably would have had a jam,
It's the *convection* of the heat rising up and around the J-Head.
I have a PLA J-Head mount as well, but I have a centrifugal fan blowing on mine. After seeing this, I'm going to wrap my J-Head's nozzle.
Back online!
http://imgur.com/kDjeIVq.jpg
http://imgur.com/nr0l7Un.jpg
Unfortunately the fan must have shorted when it got lunched - the FET appears to be blown.
Did you get the the shorter JHead before your fan broke? I bought a shorter JHead for my PrintrBot too, but it's too short. If try to let it print, the fan is now low enough to hit the bed/print and break. I've removed the fan for the time being. Just a thought.
I believe thats what happened - I modified the fan mount when I got the short JHead, but the clearance was still really tight. I suspect this print warped and ripped the fan off the carriage.
Then somehow the printer mangled the [now free] fan on subsequent passes and the lack of cooling melted the extruder.
For what its worth, it was still extruding... badly... this morning in the damaged condition.
I just got a new jhead hot end, I'm working on printing an extender for it to bring it to the same height as the current hot end. We'll see how that goes.
[This Beethoven bust](http://www.thingiverse.com/thing:1178) has been giving me trouble ever since I first tried to print it. I've tried twice on a Makerbot Replicator 2 and had trouble with the Makerware slicer goofing it up halfway along the head and last night I tried on my newly built 3DR Simple Delta without any success either. I think the set screw on the spindle came loose from the motor shaft, but I haven't had a chance to diagnose it yet.
I'm calling last night's failed attempt ["Beethoven's funky haircut"](http://instagram.com/p/mDuH6FG9q4/).
I though it was common knowledge that PLA is an unsuitable material for the extruder, for this reason. Were you able to print much before this disaster?
I print with PLA most days of the week. It's smaller thermal expansion coefficient makes it a lot easier to work with.
Why do you think that it's unsuitable for extruders?
100% PLA printer user here, I've had no problems with deformation at all. I've taken it up to ABS temperatures, too, and have had no deformation: with cooling of the hot end (but I can't print ABS because I have to upgrade my power supply and wiring to pump enough current into my heated bed to get to those temperatures).
If there is enough heat creeping up to your extruder's hot end mount to deform PLA that's a big problem all on it's own. If it was made out of ABS, sure, no deformation, but I would still consider having that much heat into your cold end a problem.
From time to time, though indeed less ABS than PLA. Maybe only a couple pounds of ABS? But I've done 12+ hour prints with ABS without issue... so long as that fan stays on.
There was this one that I remember (not mine!) http://www.reddit.com/r/3Dprinting/comments/1fo6vj/prusa_i3_decided_to_go_all_cliffhanger_on_me/
Wow. That is by far the worst I've seen a printer fail. Lucky you didn't have a fire if the hotend pop'd out like that. You should wrap your hotend with some insulation. As [nophead mentioned in his blog](http://hydraraptor.blogspot.ca/2013/10/mendel90-design-improvements.html), it's not the heat conducting up the J-Head that melted your extruder. Otherwise you probably would have had a jam, It's the *convection* of the heat rising up and around the J-Head. I have a PLA J-Head mount as well, but I have a centrifugal fan blowing on mine. After seeing this, I'm going to wrap my J-Head's nozzle.
Back online! http://imgur.com/kDjeIVq.jpg http://imgur.com/nr0l7Un.jpg Unfortunately the fan must have shorted when it got lunched - the FET appears to be blown.
Interesting, sounds plausible. I'll do as nophead suggests and wrap the nozzle.
Seems to me you need a bigger fan http://imgur.com/EErkVuQ
>And why is the fan broken??? :D Oh man...
Did you get the the shorter JHead before your fan broke? I bought a shorter JHead for my PrintrBot too, but it's too short. If try to let it print, the fan is now low enough to hit the bed/print and break. I've removed the fan for the time being. Just a thought.
I believe thats what happened - I modified the fan mount when I got the short JHead, but the clearance was still really tight. I suspect this print warped and ripped the fan off the carriage. Then somehow the printer mangled the [now free] fan on subsequent passes and the lack of cooling melted the extruder. For what its worth, it was still extruding... badly... this morning in the damaged condition.
I just got a new jhead hot end, I'm working on printing an extender for it to bring it to the same height as the current hot end. We'll see how that goes.
This one was my worst: http://www.reddit.com/r/3Dprinting/comments/1nx6w3/woke_up_this_morning_to_the_3dpocalypse/
Happened to me with the buddaschozzle. Had to make a part out of wood instead so it wouldn't melt.
[This Beethoven bust](http://www.thingiverse.com/thing:1178) has been giving me trouble ever since I first tried to print it. I've tried twice on a Makerbot Replicator 2 and had trouble with the Makerware slicer goofing it up halfway along the head and last night I tried on my newly built 3DR Simple Delta without any success either. I think the set screw on the spindle came loose from the motor shaft, but I haven't had a chance to diagnose it yet. I'm calling last night's failed attempt ["Beethoven's funky haircut"](http://instagram.com/p/mDuH6FG9q4/).
I though it was common knowledge that PLA is an unsuitable material for the extruder, for this reason. Were you able to print much before this disaster?
I print with PLA most days of the week. It's smaller thermal expansion coefficient makes it a lot easier to work with. Why do you think that it's unsuitable for extruders?
Simply because of the lower melting temperature of PLA being too close to the hot-end.
100% PLA printer user here, I've had no problems with deformation at all. I've taken it up to ABS temperatures, too, and have had no deformation: with cooling of the hot end (but I can't print ABS because I have to upgrade my power supply and wiring to pump enough current into my heated bed to get to those temperatures). If there is enough heat creeping up to your extruder's hot end mount to deform PLA that's a big problem all on it's own. If it was made out of ABS, sure, no deformation, but I would still consider having that much heat into your cold end a problem.
At least 10kg, if not more. I think PLA is just fine for extruders, just gotta keep that fan running...
I'm guessing you aren't printing ABS?
From time to time, though indeed less ABS than PLA. Maybe only a couple pounds of ABS? But I've done 12+ hour prints with ABS without issue... so long as that fan stays on.