Catastrophic failure

A forum dedicated to the stock LulzBot TAZ 3D Printer
Farris
Posts: 36
Joined: Sun Jul 19, 2015 5:30 pm

Catastrophic failure

Post by Farris » Sun Jun 05, 2016 6:37 am

Last night I start a print and, when I get up this morning to check on it, I find this...
20160605_080629.jpg
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.
20160605_082710.jpg
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.

Sebastian
Posts: 514
Joined: Sun Sep 13, 2015 5:54 am

Re: Catastrophic failure

Post by Sebastian » Sun Jun 05, 2016 6:57 am

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.

Farris
Posts: 36
Joined: Sun Jul 19, 2015 5:30 pm

Re: Catastrophic failure

Post by Farris » Sun Jun 05, 2016 7:01 am

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.

kmanley57
Posts: 1111
Joined: Sun Feb 01, 2015 3:53 pm

Re: Catastrophic failure

Post by kmanley57 » Sun Jun 05, 2016 7:32 am

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.
I will express my CRAZY ideas at any time! So you have been warned. None of my opinions are Lulzbots and can be wrong at any second.

Farris
Posts: 36
Joined: Sun Jul 19, 2015 5:30 pm

Re: Catastrophic failure

Post by Farris » Sun Jun 05, 2016 7:46 am

kmanley57 wrote: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?

kmanley57
Posts: 1111
Joined: Sun Feb 01, 2015 3:53 pm

Re: Catastrophic failure

Post by kmanley57 » Sun Jun 05, 2016 8:47 am

Farris wrote: 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.
I will express my CRAZY ideas at any time! So you have been warned. None of my opinions are Lulzbots and can be wrong at any second.

killacycle
Posts: 38
Joined: Mon Apr 04, 2016 2:14 pm

Re: Catastrophic failure

Post by killacycle » Sun Jun 05, 2016 9:59 am

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.

User avatar
piercet
Posts: 4025
Joined: Sun Aug 25, 2013 1:37 am
Location: Battleground, WA
Contact:

Re: Catastrophic failure

Post by piercet » Sun Jun 05, 2016 10:20 am

Farris wrote:
kmanley57 wrote: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?

Not "possibly". Directly caused.

Farris
Posts: 36
Joined: Sun Jul 19, 2015 5:30 pm

Re: Catastrophic failure

Post by Farris » Sun Jun 05, 2016 12:29 pm

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.

idiot
Posts: 122
Joined: Thu Jul 02, 2015 7:53 am

Re: Catastrophic failure

Post by idiot » Thu Jun 09, 2016 4:34 pm

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?

Post Reply