My hotend is now scrap ...aka "HELP!"

[GarageBay9]

I've got about a month of my Rostock up and running, and I am not having great luck...

[img]https://sphotos-a-sea.xx.fbcdn.net/hpho ... 7088_n.jpg[/img]

Just started a print, bed temp and hotend temp were stable, hotend temp PID was all dialed in, temp-over-time graphs were rock steady. Maybe two minutes into the print, the hotend temp graph starts spiking both higher and lower than the average temp (which stays rock solid at 220); I saw fluctuations of 200c to 260c then down to 210c and up to 280c in less than a second.

Then a very loud SNAP and she's toast.

I didn't even have time to realize exactly what was going on and kill the power. Thermistor is good and was well-seated, wiring to thermistor and hotend power was checked end-to-end for proper circuit and was good. I have no idea what happened.

[cope413]

Wow. That's crazy. If it's a defect, the SeeMe guys will make it right.

Otherwise, I'll sell you my stock hot end for cheap if you're interested.

[GarageBay9]

Wow. That's crazy. If it's a defect, the SeeMe guys will make it right.

Otherwise, I'll sell you my stock hot end for cheap if you're interested.

I'm hesitant to call any of this their fault, because the rest of my Rostock has been amazingly well done and works like a champ. I always suspect I made a mistake somehow, somewhere... I'm just not sure where (if you want proof, just ask my wife! ). Probably should suss that out first before I try again, so I don't end up with the same result.

[626Pilot]

Congratulations! You now have an excuse to buy an E3D hot end.

[GarageBay9]

On closer inspection, it appears that ring of what looked like burned material at the failure point isn't burnt PEEK, but actually melted filament that somehow escaped out at that joint. There was also some escaping out between the nozzle threads. I'd had issues with it oozing from there before but nothing like this.

No idea if the filament got where it wasn't supposed to be earlier, or if that only happened after the hotend failed catastrophically. Would a short-seated thermistor have caused this by giving bad temp readings somehow? It was secured in the thermistor hole pretty well but the tip of the bulb may not have been fully up against the bottom of the hole... maybe .5mm or less of a gap. I hadn't gotten heat spikes like this previously, though.

[jtaylor]

I bought two of the original extruders and was going to try a dual head setup but both of them died the exact same way as yours.

I just installed the E3D and so far so good. Having some problems with the extruder temp but I'm sure I'll figure it out.