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Clancey

Causes for 'fluffy' prints.

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Has anyone got a quick check list, or guide to solving fluffy prints?

They're ok, I wouldn't call them bad quality by any means, they're just a little fluffy. I'm guessing the material is tearing slightly as the bead is being layed, but I don't have a clue if this is too hot, too cold, too fast, too slow etc.

I could spend a day testing everything. Anyone have any tips, or at least an order to approach this from?

Thanks.

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I guess by "fluffy" you mean: sort of hairy, but not with thick strings, but rather very thin hairs?

As far as I have seen on my printers, there are two main causes for strings and hairs:

- Strings (=rather thick wires) come about when the nozzle leaks while traveling over a gap, and it leaves a string behind, or the leaking drop gets deposited on the side of the next object upon reaching that.

- Hairs (=very thin) come about when there is a bit of overextrusion, or when molten material accumulates on the outside of the nozzle. And then, as the nozzle passes along the model, this molten material sags down, touches the already printed parts, gets very lightly attached and leaves a hair behind when it is pulled away by the nozzle.

Both happen more when the printing temp is rather high. So printing cooler and slower (=less pressure in the print head) usually helps. Some colors and materials have this more than others. This is what I have seen, but of course there may still be other causes too.

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Pictures would help us deduce what "fluffy" means :)

I put a lot of hours on my Ultimaker 2+ in the year I have had it.

No changes to the PLA profile and hairs started turning up (click on picture to see them)

hairs.thumb.JPG.3d52e87343b2efdfb5e8016defd8ad74.JPG

I bought a replacement nozzle from my friends at PrintedSolid.com

Been printing all weekend and no more hairs turning up

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...

I put a lot of hours on my Ultimaker 2+ in the year I have had it.  

No changes to the PLA profile and hairs started turning up  (click on picture to see them)

...

I bought a replacement nozzle from my friends at PrintedSolid.com  

Been printing all weekend and no more hairs turning up

Just out of curiosity: while printing with the old nozzle, did you closely watch what happened exactly, so why the hairs occured in your case? I am trying to understand, if an worn out nozzle would cause this, then why? Is it also the same filament as before?

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just a guess, but i could imagine that these hairs are caused by micro burrs (not sure if this is the correct word) on the nozzle.

did you use filament that contains particles like wood, carbon or any metal? these particles cause the burrs.

another idea: take an eraser and try to deburr the affected nozzle (i do this with the edges of skis).

Edited by Guest

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That nozzle had recently had Ultimaker Polycarbonate got through it and I did 5 Atomic pulls, since the first 3 pulls showed some 'glazed' looking residue in there. Most likely some leftover of the transparent Polycarbonate. The additional pulls came up perfect, so I felt it was as clean as I could get it.

Perhaps the lesson here is, for more exotic filaments, use a dedicated nozzle for those?

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Just out of curiosity: while printing with the old nozzle, did you closely watch what happened exactly, so why the hairs occured in your case? I am trying to understand, if an worn out nozzle would cause this, then why? Is it also the same filament as before?

The hairs are very thin, so it's hard to really spot them as they occur. (So to answer that question better...I did see them as they happened and of course the end result. But no way to really correct them while printing)

If someone want the old nozzle to cut open and put under the microscope, be my guest!

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