Help Me Fix Our Printer  

RE: Help Me Fix Our Printer

Hi Catherine, 
it looks like you have a Mk2 prusa printer... 

that looks quite a mess.  

What filament was it?

you need to remove the blob, however the blob may have damaged your printer... 

so, Step one, turn the printer on...

what does the display show for the extruder and heatbed temperature?

Both should show room temperature.  

if your extruder temperature is very low say 11degrees centigrade, then your thermistor wiring may be broken...!

if your extruder temperature, is the same as the heatbed temperature, then you stand a chance of recovering the situation without too many problems...

where are you located? from the term "last Fall" I am guessing america...

as you are uncertain of the way forward, you may be best to try and find a local expert....

in case you fancy trying to resolve the problem, here is aquick precis of one way forward...   I have a Mk2 printer and recently had a blob of doom... not quite as big as yours, but upsetting, all the same!

assuming the printer is not damaged  (extruder and heatbed both show ambient temperature!)

1, you need to remove the blob... without damaging anything else..., last time I had a blob, I removed the part fan shroud to prevent melting it...

be aware, that the blob might resist removing the fan duct... 

From your pictures, it looks like your extruder is already raised well above the heatbed... 
Please put something non flammable on the heatbed, to protect it...  maybe a  small plate (to catch the waste plastic from the blob...)

2, select the "SETTINGS MENU >TEMPERATURE > EXTRUDER" and set the extruder temperature to the highest temperature that it will attain (About 290Centigrade) as the extruder temperature passes 50 centigrade, the left hand fan should start running, this is normal!

let the printer sit  with the extruder heated,  for a while... and the BLOB should start to heat up from the inside  and soften...  BEWARE IT'S GETTING VERY HOT (Yes I burned my fingers)
as the blob heats it should release itself from the extruder heat block, UNFORTUNATELY it will not easily release itself from the heater wiring or the thermistor wires...   (thermistor wires are incredibly thin and fragile... be careful)

This picture actually shows the OLD style thermistor, YOU probably have a different style thermistor... (But you won't be able to see it yet so don't worry too much)

your heatsink and thermistor should look a bit more like this... (I think your thermistor will be a cartridge type like here)

a sensible person would probably have carefully used a hot air blower to help soften the blob from the outside (whilst NOT heating the ORANGE BITS)...  Or they might have used a hot soldering iron, to carve bits of the BLOB off...
I actually used a kitchen gas lighter to spot heat the blob but that's potentially dangerous and I would not recommend that approach!

the combination of printer heater, and your choice of external spot heater, should cause the bulk of the BLOB, to loosen and drop onto your plate... 

you may have to remove the blob in small chunks / drops of burning hot plastic... 

when you successfully remove the blob, your heatblock / nozzle/ thermistor, will be messy like this... (Mine was)

I used a brass bristle brush, to rub the waste plastic, off the heatblock etc. 

assuming you too are successful, select "PREHEAT > COLDOWN" off the LCD Menu... and watch the temperature of the extruder decline
at about 50 centigrade the left hand fan should shut off...    let the extruder cool to room temperature.
then

3, re fit the part cooling fan...   

4 wait for the next instalment...

regards Joan

RE: Help Me Fix Our Printer

when you get the hot end clean, it's time to consider checking your first layer calibration. 

the  Mk2 had a file called V2 Calibration, for first layer calibration   I didn't like it...    

I prefer to use https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/

there is a Zip file at the bottom of the first post, that contains three test files, one each for PLA, PETG and ABS...    (hopefully the zip file will be attached here as well

Regards Joan

RE: Help Me Fix Our Printer

Wow, thank you so much for the thoughtful post.  In order to remove the filament, we did heat it up, but it was impossible to remove without losing one of the wires.  The filament is also still in the area beneath the fan.  Plus, this is the second time it has happened.  I hate to order new parts, pay to have someone install them, and two weeks later have the same problem.  I am using the Vanilla White PLA 1.75 mm.  I ordered it from Prusa.  Any other thoughts?  I guess I should find a repair person.

RE: Help Me Fix Our Printer

To prepare for the live Z calibration, prepare an SD Card with the test file, for the material that you are going to use... (Probably PLA)

insert the SD Card into the card reader on the left hand side of the printer.

Whilst the printer is cool!   Clean the heatbed...     

there are different opinions on how to do this, 
Prusa have a knowledge base article https://help.prusa3d.com/article/6Gtws6Yqjg-pei-print-surface-preparation

there is a second knowledge base article on Increasing adhesion I will add a link here, but you probably don't need to use this information at this time https://help.prusa3d.com/article/UdxnagXRY7-increasing-pei-adhesion (the last section mentions using acetone...  this is in my opinion, a last ditch option, one of my PEI sheets started cracking after using Acetone... and I am too cost conscious to risk another PEI Sheet checking if this was the cause...)

Clean the bed well, and then DON'T touch it with your fingers!   

once the heatbed is dry, select the correct live Z test file, from the SD Card, using the LCD Menu...     
(At this stage the extruder should still be in mid air, at least 60mm above the heatbed surface.)(Note that for future reference).

there are instructions in the Life Adjust Z, My thread on how to adjust Live Z and How to interpret the results... 
Do your best... 

If you need to run Live again, Please raise the extruder to about 60mm above the heat bed first... 

(Press and hold the LCD Knob for a couple of seconds and you should get the option to raise or lower the extruder by turning the knob...    turn the knob until the display shows z height to be 60mm,)   
NOTE the reason for keeping the start position constant, is, the Mk2 Pinda probe is not temperature compensated nor is it temperature monitored...   if you set live Z, starting from 60mm, and you are happy with the print, the extruder will be about 0.2mm from the bed... if you now start to print a model, the Pinda is much closer to the heat bed during heating, it's temperature will be higher than it was when you started the Live Z print, and the PINDA sensitivity will have changed... resulting in poor mesh bed levelling and poor first layer live Z for the new print...

clear the previous filament build plate, without getting greasy finger prints on the build plate...  and re run the live Z file...    do this until you are happy with the test panel print out... 

once you are happy, you are nearly ready to go with your youngster's model... 

it would be a really good idea to check that you have the latest firmware, which, assuming you do have a Mk2 printer, will be version 3.2.3.
the last option on the printer LCD menu, should show you what firmware is loaded...   

there is a knowledge base article on flashing firmware, here https://help.prusa3d.com/article/r5ByKgVm69-firmware-upgrade-and-flashing

firmware and driver files are available here https://www.prusa3d.com/drivers/

before preparing the model files for printing... Make sure that you have the latest version of Slicer loaded  (I believe it is Prusa Slicer 2.0.0) on your computer, AND, make sure that you have chosen the correct printer profile, in the configuration wizard

once that's done, open slicer,

select the Mk2S profile, 

select your preferred layer height,

select your preferred filament type,

load your model, STL (for the time being let's assume that it doesn't need supports)  and you should see something like this

If you have a mis match between the printer firmware and the slicer firmware, the printer will alert you that there is more up to date firmware available,   If you have accidentally selected the MK3S printer profile, and you are actually using a mk2S printer, then the printer will erroneously report that you have the wrong firmware loaded... be careful, loading the wrong firmware can cause problems!

regards Joan

RE: Help Me Fix Our Printer

I think I covered  most points... 

and whilst I was writing that I noticed there is a knowledge base article on dealing with blobs too... Doh! 

regards Joan

RE: Help Me Fix Our Printer

Hi Catherine,
 
I still use My Mk2,

I always raise the extruder to 60mm as described and have only had one blob in about two years  I was rushing, and didn't watch the first layer go down..   when I got back the blob had occurred....     it may be that nozzle wear caught me out, or the filament was old...    

I cleaned up, re assembled the printer, cleaned the build plate, did live Z, and all is going well again.
thermistors are not very expensive, I  suggest you get two so you have one in stock should you have another blob of doom... (Cut down the time waiting for spares...   might be an idea to get a share heater too... 

 have you tried local suppliers for the thermistor and heater...   might be quicker and less expensive than importing from Prusa.
have you considered learning to repair the printer yourself? could help you understand the printer better...   

I am not sure where you will find a 3D printer repair specialist. have you still got contact with your previous student? 

Prusa can supply spare plastic parts. however if you have somewhere loclly that can print parts, the files are available here

https://www.prusa3d.com/prusa-i3-printable-parts/

maybe a local maker space, Hack Space or Library could help, or Ask on here...   I am in the UK so probably too far away to help sensibly, but for all you know there may be a prusa owner around the corner from your premises... or even a parent with a 3D printer! 🙂

Good luck, 
Joan