Printer: TAZ Pro
Material: 2x polylite pla. Extruder 2 is red, and extruder one is using true green. While we've had the green for a few weeks, it was just taken out from its box yesterday. The red is a few months old, and was dried in an oven recently.
First incident: about ~3 hours into a print, the printer stopped with a "filament 1 extruder error" message. I extruded the filament a bit to confirm that it was not stripping out, then hit resume print. The toolhead went down onto the print in progress and just sat in the same spot. In the past I've seen it go really slow on resume, so I left it there for about 10-15 mins. It didn't make any progress so I canceled the print.
Second incident: started the same print as last time, but then same thing happened about 30 mins into the print. Got the error, confirmed the filament was still extruding, hit resume, and then the head just sat on top of the print. Canceled.
Third incident: Started the same print again. I watched it do the skirt and begin the print as normal. I left it to go back to my desk. A few minutes later, I start to smell something funny, and then realize there's smoke coming off the printer. I immediately shut down and unplugged it, and pulled the bed forward to assess the damage. As attached, the toolhead had just sat in one position on the bed and just melted away. The second extruder was also melting filament, as that's why there's a red blob next to it. (I wish I took note of the extruder temps, but I was more concerned with turning everything off.)
I should also note that I've been getting a few filament extruder errors, where despite the printer giving the error, the head would still extrude just fine. Sometimes though, I'd let it extrude a lot, and it'd get all thin, and then a glob would come out, and then extrude normally. Before the third incident, I took apart extruder 1, but didn't find anything out of the ordinary.
The print is one that I've done a few times before. I got it from: https://www.thingiverse.com/thing:3430925, and this print is scaled up 120% with a bed temp of 45C.