Cooling cold end

[paoletto 3]

Hi, so i have a problem with one filament: somehow it's the same brand of PLA i always used and that always worked well with the UM3, this time with a different dye (bronze).
Somehow it prints different, and it's visible already in the initial pooping (print blob), where the blob with this one looks very melted together, while with other filaments it becomes a small cone with all layers.

Well anyway, the problem with this one seems to be that is very heat conductive, and it expands up until the bowden tube, inevitably causing jamming.
i tried to reduce retraction up to 1.5mm that somehow seems to work with not too long prints, but i would like to know if there is a more robust solution.
Is there any way to increase the cold end cooling so that the heat doesn't get all the way back along the cold end and make the filament eventually expand?

Thanks

Edited June 12, 2022 by paoletto

[Enigma_M4 123]

Hi,

to your main question: afaik the print core cooling is controlled by firmware only. The fan runs 100% when one core is hotter than 60°C and is off at 59°C and below.

If this material is so heat conductive, it possibly can (must?) be printed at lower temp. Here possibly doing a temp tower for examining the coldest possible print temperature could be reasonable?

Regards

[GregValiant 1,408]

@paoletto is that a "silky" filament?

 

[paoletto 3]

Hi, no it's not silky, it's "metallic" looking PLA, like the one i had best results with (gold, and also white and to some extent black).
However it seems to behave quite differently (other colors also gave me issues, such as orange with which UM3 was consistently underextruding).
I tried to lower temp from 196 i used for gold to 188, but i still got the jamming. Recommended temp seems to be the same for all other PLAs of this kind (metallic or not): 170-210
I also feel like tower won't help because it seems jamming starts to happen after a while (like an hour into the print).
As if the cold end needs to warm up properly too.

So i suppose no way to change that cold end temp threshold?