Rough extrusion

Hi,

The extruded PLA from the nozzle is a bit rough. i.e. when i slip it between by two fingers, I can feel the surface is not smooth. What could be the possilbe cause - heat or extrusion speed. From my past reading faster extrusion leads to curling. So is it because the heat being low or high.

PLA - 3mm
Nozzle witdth - 0.35mm
Extrusion spped 400
Heat 200

Thanks

how are you reliably getting 400mm/minute., it just seems incorrect. something like 40 is more tipical of 0.35mm nozzles. we are talking about 3mm feedstock end speed not filiment speed correct?

also post a picture or video, it helps a lot

Edited 1 time(s). Last edit at 11/27/2012 08:56PM by jamesdanielv.

jamesdanielv Wrote:
-------------------------------------------------------
> how are you reliably getting 400mm/minute., it
> just seems incorrect. something like 40 is more
> tipical of 0.35mm nozzles. we are talking about
> 3mm feedstock end speed not filiment speed
> correct?
>
> also post a picture or video, it helps a lot

@james Yes it is 3mm filament. The speed that I am referring to is Extruder speed. Not sure what are feedstock end spped or filament speed. By changing the extruder speed (I am using RepSnapper - attached is the picture) it is changing the rate at which the filament is pushed so I am assuming that is filament speed

It's almost 99% surely heat related.
Some filaments do that when the temperature is too low (or too low for a particular extrusion speed).

Not all of them, though (transparent ones almost never exhibit this).

Agree with the above poster.
All I can add is that cheap filament has shard of old used junk added to it. You can tell when you compare white vs. black. They hide stuff in the black apparently. Once a plastic is molten, it can not be re-molten properly if it is aged. So that begs the question, what is your polymer source?

With white pla I have succeeded at 180C. With black nowadays I'm up to 210.

Simba Wrote:
-------------------------------------------------------
> Agree with the above poster.
> All I can add is that cheap filament has shard of
> old used junk added to it. You can tell when you
> compare white vs. black. They hide stuff in the
> black apparently. Once a plastic is molten, it
> can not be re-molten properly if it is aged. So
> that begs the question, what is your polymer
> source?
>
> With white pla I have succeeded at 180C. With
> black nowadays I'm up to 210.

You can find ball bearings and all sorts of crap in cheap plastic, but you surely are not suggesting its intentional?
It's accidental and allowed to happen due to poor QC.