Catastrophic failure

Last night I start a print and, when I get up this morning to check on it, I find this…
The bed, during the print, shifted way off, the nozzle burned into the PEI sheet, the main body of the print head snapped at the screws where the extruder mounts, and the screen shows mintemp error so the thermistor line has probably broken. But that’s not the strangest thing. Upon closer inspection, I see this.
It looks like, somehow, the heater block had started to come unscrewed. So here’s my question. Do I pull out my spare parts and put it all back together, resolder the thermistor line, and rescrew the heater block back on… Or is there something else that could have caused this that would cause me to want to buy a new hot end? I’ve put a few hundred hours on this printer since I upgraded to the Olive/6 body parts so having it just completely fall apart like this is a little unexpected.

I think the root cause of this isn’t the hotend. Maybe the z-stepper (driver) failed, and after laying down some layers at same z height it blocked itself, leading to the X-Y shift. Next question would be, how is it possible that the nozzle touched the bed after it was already some mm above it…

I would:
.) Have a close look at the gcode file, searching for strange movements.
.) Test x,y,z axis free movement.
.) Do a dry run of the code until a point after the failure.

I think that it touched the bed because the body broke and everything tilted forward and down.

But either way the extruder assembly needs significant repairs.

Look to see if your heat sink for the Z driver is missing or fell off on the control board. The driver can overheat and reduce/cut power to the driver and make the nozzle drag across the part sometimes and break the extruder.

That’s actually kind of interesting. I just put my printer in an enclosure last week and it has been hot in my garage (where I keep it) this week. Think that could have possibly contributed?

Around 92 degrees you will start losing steps if you have no heat-sink on the part, and with a heat-sink I do not know at what temp you will lose steps. But if in an enclosure the control box needs cool air flowing into it to work reliably.

The electronics does not tolerate heat very well. If you put your printer in an enclosure, and you want the inside of the enclosure greater than about 30 Celsius, you should somehow vent or cool your electronics with outside air.

Bill D.

Not “possibly”. Directly caused.

Alright… I’m now back to limping along. The PEI is (obviously) toast. Luckily, I had another sheet ready to go because I’m preparing to do the glass to aluminum plate conversion. As a temporary fix, I was able to acetone weld the broken parts back together and it seems rigid enough. I also took this as a chance to take my octopi control box extension off since I wasn’t using it anymore. Hopefully that will help a bit as well.

Ive seen a couple of these failures pop up when browsing the forum over the last year or so.

Is there no way to program a fail safe into the firmware or something to shut the machine off before it causes all this wreckage?

The failure is that the programming locks up. There isn’t a board thermistor in the case that I know of to give it a temperature to auto shut off on. So even if you did have something programmed to stop print at a certain temperature, it wouldn’t trigger. You could probably add a thermistor to the i2c bus and measure the temperature that way, but that would require hardware.

I’m no machine/programming/electrics whizz. I don’t really know what’s possible. I Just wondered if anyone had thought about making a fail safe as whilst it’s not a common issue, it’s seems to hve happened a few times, and I can’t imagine it’s cheap or fun to fix.

Maybe a pressure sensor somewhere in the extruder body that triggers a kill switch?

It wasn’t really a terrible fix. More tedious and time consuming than anything. Worst part was having to replace the pei sheet, but I already had a replacement on order for the aluminum bed upgrade. The rest was a little solder and acetone and understanding what I screwed up so it doesn’t happen again.

We might want to have a sticky at some point for these questions that new people don’t necessarily think about. “before you start printing, here are some common mistakes” or something like that.