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Popping noise and voids

Posted: Sat Feb 27, 2016 5:43 pm
by PannDemic
So, I have some SeeMeCNC Artic White ABS that is printing at 230°C. As it extrudes, I hear a popping coming from the nozzle and can see the smallest voids in the extrusion.
Any idea what is causing this, and how to remedy it?

I did some searching but found mostly issues with extruders, but this is at the nozzle, seems like a pocket of gas that blows out the soft filament as it is extruded.

Thanks for the great community
Pann

Re: Popping noise and voids

Posted: Sat Feb 27, 2016 5:50 pm
by teoman
Your filament has water in it.

Re: Popping noise and voids

Posted: Sat Feb 27, 2016 6:47 pm
by TheIrishScion
Well, at any rate it's a bit damp. The pops are absorbed humidity in the filament itself, this is why it's so important to keep it in a very very dry place when you aren't using it. If you have a very dry place (enclosed water heater closet for example) you can likely dry it out over the course of a week or two. Sealing it in a bag with some desiccant sachets in a warm place is likely to work even better, if the desiccant is dry to begin with.

Re: Popping noise and voids

Posted: Sun Feb 28, 2016 2:06 am
by PannDemic
Could it be caused by a long retraction distance? It seems to get worse as I continue to chase down the right retraction length. I am now at 13mm of retraction, using an all stock Rostock MAX V2.
I think it might be, I did not have any gaps in my printing artifacts, but now I have both oozing and gaps with these pops. It is also a brand new role, and I live in the desert.

Re: Popping noise and voids

Posted: Sun Feb 28, 2016 2:38 am
by PannDemic
This is what my prints now are looking like. The small pits are gone, and it seems like entire lines of extrusion are missing.

[img]http://i66.tinypic.com/j61vvd.jpg[/img]

Re: Popping noise and voids

Posted: Sun Feb 28, 2016 5:55 am
by nebbian
13mm seems way too high. You might be seeing air bubbles due to severe overretraction, which would fit with the popping noises you're hearing. I would set retraction to 5mm or so, and see what happens.