Print failure - A student's print failed spectacularly. How do I go about cleaning this?  

RE: Print failure - A student's print failed spectacularly. How do I go about cleaning this?

I meant to add a few tags, but hitting enter just posts it. Here's the situation.

A student came in this last week and printed a job. The print failed, however, and this was left to harden. 

I do not know how to clean this large of a mess. Is there a solution anyone can offer?

RE: Print failure - A student's print failed spectacularly. How do I go about cleaning this?

I would turn the printer on, set it to preheat 
then I would us an old soldering iron, to carve the waste material off the outside of the blob of doom. 

BE VERY CAREFUL. the thermistor, has very fragile wires attached, it you try to pull the blob off the hotend, YOU WILL BREAK the thermistor wires. 

if the printer reports error MINTEMP, then these wires are already broken. 

regards Joan

RE: Print failure - A student's print failed spectacularly. How do I go about cleaning this?

Thank you for your reply. 

I did not have a soldering iron, so I took to a secondary action. I heated the extruder up to the highest temperature preset to see if I could melt the filament.

Turns out, that was not effective. Though it did soften and melt the majority of the filament present, I believe the wires got damaged in the process of heating or from my attempt to dislodge the blob. As I moved the loose blob around gently to dislodge it, I saw a few sparks and some smoke. I immediately shut down the unit and moved it to a safe location in case it tried to combust. 

On Monday, I will see if I can salvage any of the extruder. I believe the stepping motors are intact, as well as a majority of the upper assembly.

In the case that the extruder assembly is shot and we need a replacement, should I open a ticket with you all and request it there? or do you have a way I could just order it if needed?

Thank you for your help. I wish I had a soldering iron on hand! haha

RE: Print failure - A student's print failed spectacularly. How do I go about cleaning this?

Hi William, 
whilst I have Moderator status, I am a mere user of the forum like yourself. so I cannot respond on behalf of Prusa Research. 

the thermistors are relatively cheap items so I would consider ordering two thermistors and one heater cartridge. 

If you disassemble the  extruder assembly and take the extruder out of the printer, you can disassemble it more easily with the help of heat resistant gloves, and maybe a hot air gun, or maybe even a domestic oven, 
Heat up the heat block, then loosen the thermistor grub screw, and poke the thermistor cartridge out with an allen key. 

insert the new thermistor, clamp gently with the grub screw then re assemble the extruder

thermistors are available  from prusa themselves, https://www.prusa3d.com/product/hotend-thermistor-e3d/

from e3d online,  https://e3d-online.com/products/prusa-specific-thermistor-mk2-mk3?_pos=1&_sid=1cdfb8cae&_ss=r

and from e3d resellers.  https://e3d-online.com/pages/resellers

I suggest two thermistors and a heater so that if you break the heater whilst repairing the thermistor, you already have one on hand, and if all goes well, you will have a thermistor and heater for the next time a student causes a Blob of Doom!

regards Joan

RE: Print failure - A student's print failed spectacularly. How do I go about cleaning this?

Online we often refer to this type of failure as a "blob of death".  They are often created by a first layer failure that peels away the filament from the print bed. To avoid them most of us watch the first layer going down closely.

YM 'Blob of doom' - search for that phrase to see how others have dealt with them.

Cheerio,