My Mini, or Cthulhu? Melting PLA everywhere!  

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Connercbc
(@connercbc)
Active Member

Help me, Obi-wan, you're my only hope!

Hello Prusa community, first time printer owner here, and first time poster.  I need some help troubleshooting my issue.

Please see the picts.  Basically, I came in to check in on my print, to find that it was at 100%, per the display, but only a couple of layers had printed and the hot end looked like the Alien had gotten ahold of it.

I had this problem before, and read the forums here and looked at the Prusa KBase.  I disassembled the hot end and replaced the PTFE tube per the instructions here.  That seemed to work fine and I got a couple of clean prints, then today this happened again.

So my question is - should I do this again?  I'm going to heat up the hot end, clean it well, and trying again.  Any suggestions are welcome.  I love my printer and am having a blast with it, but I feel like I cannot trust it yet.

Thanks y'all - Conner, TX, USA

Posted : 27/09/2020 3:28 am
JoanTabb
(@joantabb)
Moderator

Good morning Conner, 

Obi-wan is On leave for a couple of days, 

Hopefully one of his fellow Jedi will be along shortly! 
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 27/09/2020 8:07 am
Connercbc
(@connercbc)
Active Member

@joantabb

Thanks!  Did my picts show up?  I don’t see them. 

Posted : 27/09/2020 6:13 pm
Robee Shepherd
(@robee-shepherd)
Estimable Member

@connercbc

No they didn't 🙁

Posted : 27/09/2020 9:21 pm
Connercbc
(@connercbc)
Active Member

[gallery ids="49531,49528,49525,49522,49519,49516"]

This post was modified 9 months ago 2 times by Connercbc
Posted : 28/09/2020 1:17 am
Robee Shepherd
(@robee-shepherd)
Estimable Member

Gosh this looks... not good! Thank you for the images.

I think there is a gap between the heatbreak and the nozzle, and the melted filament is leaking out from there.

More experienced people might have better suggestions but I would try:

  • Heat the hotend to 280c
  • Using a wire brush clean the heaterblock but be VERY careful not to damage the wires
  • Leave it for 5 minutes and then wait until nothing is dripping out of the nozzle anymore
  • Remove the nozzle
  • Let it cool down completely
  • Make sure the heatbreak is in properly all the way
  • Warm it up to 280c again
  • Follow steps 24 and 25 here https://help.prusa3d.com/en/guide/how-to-replace-a-heaterblock-heatbreak-mini_122769#122884
  • Re-adjust your MINDA if necessary
  • Check your live-z adjustment in case its nearer the bed now
Posted : 28/09/2020 8:25 pm
Connercbc
(@connercbc)
Active Member

@robee

Thanks robee!  That's what I did the first time around, and what I'm doing again this time.

Posted : 28/09/2020 9:04 pm
Connercbc
(@connercbc)
Active Member

@robee

I have a question about the MINDA height.  When I did the PTFE replacement last time I set the MINDA to the credit card height.  My question is, however, how tightly should the MINDA probe be against the credit card?  I set is so that the probe was touching the card, but you could move the card around pretty freely under the probe.  Do you have any thoughts about how tight that should be?  I'm thinking that might have led to another problem I was having before the PLA blew up, as shown in the pict below.  

 

Posted : 30/09/2020 1:16 am
cwbullet
(@cwbullet)
Illustrious Member

You might need to clean your heat sink and hotend.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 30/09/2020 1:21 am
Crawlerin
(@crawlerin)
Prominent Member

@connercbc

It does not really matter that much, if you set it up to card's height or ziptie height, you will usually get negative Z from range of -1300 to -700. That's what you set during first layer calibration. MINDA triggers metal detection at 2 mm, as long as you are not at an extreme end (0 or -2000) and cannot adjust your Z anymore, you are OK.

You picture looks to me more like your lower right corner is lifting off of bed, or is the object shape like that? If it lifts, it can shift layers above and your nozzle scrapes previous layer.

Posted : 30/09/2020 10:24 am
Connercbc
(@connercbc)
Active Member

@crawlerin

It is shaped like that, but I hear you. Thanks for the explanation re: MINDA probe.

Posted : 01/10/2020 2:14 am
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