Extruder assembly started smelling like burning plastic after 12-days of no issues
 
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Extruder assembly started smelling like burning plastic after 12-days of no issues  

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Mike S
(@mike-s-2)
New Member
Extruder assembly started smelling like burning plastic after 12-days of no issues

I have an issue with a burning plastic smell that just started on a fairly new Mk3sS that I am almost certain is coming from the extruder assembly but I can't find the cause. I have been printing mostly PETG (Polymaker White and Prusament Orange).

It happens if I heat the extruder and not the bed and the odor is definitely worse right at the extruder. It's enough of an odor I can smell it in the entire house within 10 minutes of printing.

This is ~1 month old Mk3S with approximately 320 hours of printing and it has been working near flawlessly since I built it. Even with the odor the printing is perfectly fine - no issues at all.

The burning plastic issue has been happening for about the past 12-hours of printing.  I've cleaned the heater block and nozzle (wire brush while hot) and made-sure the nozzle is tight (also while hot). Everything looks fine - nothing seems to be overheating and there is no smoke or other visible issue.

Any insight? It's such a bad odor I can't print with anyone else at home.

Thanks

Mike

Posted : 06/01/2021 7:05 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Extruder assembly started smelling like burning plastic after 12-days of no issues
Posted by: @mike-s-2

I have an issue with a burning plastic smell that just started on a fairly new Mk3sS that I am almost certain is coming from the extruder assembly but I can't find the cause. I have been printing mostly PETG (Polymaker White and Prusament Orange).

It happens if I heat the extruder and not the bed and the odor is definitely worse right at the extruder. It's enough of an odor I can smell it in the entire house within 10 minutes of printing.

This is ~1 month old Mk3S with approximately 320 hours of printing and it has been working near flawlessly since I built it. Even with the odor the printing is perfectly fine - no issues at all.

The burning plastic issue has been happening for about the past 12-hours of printing.  I've cleaned the heater block and nozzle (wire brush while hot) and made-sure the nozzle is tight (also while hot). Everything looks fine - nothing seems to be overheating and there is no smoke or other visible issue.

Any insight? It's such a bad odor I can't print with anyone else at home.

Thanks

Mike

Have you checked all 24V contacts (also the Einsy contacts) for corrosion, bad connection or melted cable insulation?

 
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 06/01/2021 10:20 pm
Mike S
(@mike-s-2)
New Member
Topic starter answered:
RE: Extruder assembly started smelling like burning plastic after 12-days of no issues

@karl-herbert

Yes - I checked everything. It's a fairly new build. I can definitely smell the odor on the side of the extruder as the cooling fan turns-on. I don't get any smell until I start heating the nozzle.

I'm also using one of those laser-spot-thermometers to double-check the heat everywhere and nothing looks terribly hot anywhere it's not supposed to be.

I'm stumped - even if there was some residue I would have thought it would have burned-off by now. I hate the thought of taking apart the extruder assembly as I don't even know what I would look for - there's no visible signs of any stuck plastic or leaking.

Thanks for the suggestions.

Posted : 06/01/2021 10:35 pm
Matto
(@matto)
Eminent Member
RE: Extruder assembly started smelling like burning plastic after 12-days of no issues

Is there a leak above the heater block?  They are sometimes very hard to spot, and a slow leak would just burn off plastic on the top of the block.  (Not that I am speaking from experience here.... 🙂  )

Stock Prusa MK3S+ built from kit on 12/2020
OctoPrint, typically print from a drybox, no enclosure yet
Printing proudly since 2011...
Posted : 07/01/2021 3:41 pm
Mike S
(@mike-s-2)
New Member
Topic starter answered:
RE: Extruder assembly started smelling like burning plastic after 12-days of no issues

@matto

That's a very good question - I see nothing at all but I definitely smell it. I am guessing I'm stuck with disassembly of the hot-end assembly to even check for a leak.

How did you spot the issue in your case?

Thanks for the feedback.

Mike

Posted : 07/01/2021 7:01 pm
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