Glass like drops coming out from the extruder  

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Lvet
 Lvet
(@lvet)
Estimable Member

Hello,

With a Prusament PLA filament spool specifically, I have these strange glass like ball coming to from the extruder, ruining prints.

I cleaned thoroughly the extruder, both the inside (with cold pulls) and the outside.

Did you ever see this? (see picture)

Might it be a problem related to the filament quality?

Posted : 23/12/2020 8:27 pm
jsw
 jsw
(@jsw)
Noble Member

Well, it looks like the blobs may be old and at least partly scorched, so I would say it's either 'boogers' hanging on to the nozzle area (hopefully) which can easily be brushed away prior to starting the print, or else leakage from around the threads.

Inspect the nozzle and heatblock area carefully to see where the unwanted filament is coming from.

Posted : 23/12/2020 9:01 pm
mGoleta
(@mgoleta-2)
Eminent Member
Lvet
 Lvet
(@lvet)
Estimable Member

Hello and thank you for your answers.

I inspected carefully the extruder, and while the heater block is clean, I noticed many particles of old filaments trapped in between the thermistor wires. (My last spaghetti monster was huge).

I am considering disassembling completely the extruder in order to clean everything thoroughly.

@jsw, in a previous post you mentioned that you rebuild the extruder assembly using polycarbonate parts. In hindsight was it a good upgrade? I am temped to do the same.

This post was modified 2 months ago by Lvet
Posted : 25/12/2020 8:46 am
mGoleta
(@mgoleta-2)
Eminent Member

I have not reprinted the extruder assembly in PC so I do not know.  My fan shroud is printed in ASA and the rest is PETG.  These are what PRUSA uses when they make the extruder assembly.  I think if you are printing a lot of high temperature plastics like ABS (260C),ASA(260C), PC(275C), I think it would be reasonable to at least print the fan shroud in PC.  PC has a tendency to wrap like ABS so printing in a enclosure to reduce air drafts is really recommended.  It is also very hygroscopic so it may require oven drying before printing.

https://www.help.prusa3d.com/en/article/printable-parts-for-original-prusa_1824#settings

https://www.help.prusa3d.com/en/article/polycarbonate-pc_165812

 

Posted : 25/12/2020 6:41 pm
Lvet
 Lvet
(@lvet)
Estimable Member

@mgoleta-2 I print a lot of mechanical parts in Nylon and PC, so I often heat the nozzle close to the maximum allowed temperatures. Recently I started to print with Prusament PC blend, that requires slightly lower temperatures.

While PC is definitely the right material for the fan shroud, I don't know if it's worth to reprint the full extruder assembly in PC. I will give it a try and check if it has advantages or not.

With the 3d printing hobby, the best acquisition I made so far, (apart from the Prusa MK3S), is a filament dryer. I bought the https://www.printdry.com/product/printdry-filament-dryer/ but there is a newer version out. I live just next to the seafront and the humidity is extremely high. Drying the filament before printing improved dramatically the quality of my prints.

 
 
Posted : 26/12/2020 5:22 pm
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