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strange build artifacts, how do I avoid them?

Posted: Sun Jul 30, 2017 10:59 am
by mark.gesing
Hi everyone,

I've been having an issue with my prints where I'll get weird features added that make these "strings" which get built up at about 45 degrees to the build direction (build direction indicated with an arrow in the image):

IMG_20170730_103938_LI.jpg


There's nothing strange in the "layers" preview in MatterSlice, but I'm seeing these on most of my prints.
Which settings should I tweak to get rid of this? I've tried increasing retraction, which helped with traditional "stringing" but didn't help with this issue.

Thanks.

Mark.

Re: strange build artifacts, how do I avoid them?

Posted: Sun Jul 30, 2017 8:26 pm
by Xenocrates
Those are usually a sign of imperfect retractions, as there is a little debris on the nozzle, and as it wipes off onto the part, it gradually moves against the build direction as it builds up on the side it approaches from.

Re: strange build artifacts, how do I avoid them?

Posted: Mon Jul 31, 2017 9:14 am
by mark.gesing
Xenocrates wrote:Those are usually a sign of imperfect retractions, as there is a little debris on the nozzle, and as it wipes off onto the part, it gradually moves against the build direction as it builds up on the side it approaches from.

What's the best way to clean a nozzle?
Do I need a tiny reamer?

Re: strange build artifacts, how do I avoid them?

Posted: Mon Jul 31, 2017 4:33 pm
by Xenocrates
no. In this case, a paper towel or bit of leather, while it's at temperature. But to get them to go away, tune your retraction settings, possibly increase the length a little, or increase the non-printing speed.

Re: strange build artifacts, how do I avoid them?

Posted: Mon Jul 31, 2017 9:37 pm
by joe
Xenocrates wrote:Those are usually a sign of imperfect retractions, as there is a little debris on the nozzle, and as it wipes off onto the part, it gradually moves against the build direction as it builds up on the side it approaches from.

I have to disagree. I believe it is temperature issue.

Re: strange build artifacts, how do I avoid them?

Posted: Tue Aug 01, 2017 3:32 pm
by Xenocrates
joe wrote:
Xenocrates wrote:Those are usually a sign of imperfect retractions, as there is a little debris on the nozzle, and as it wipes off onto the part, it gradually moves against the build direction as it builds up on the side it approaches from.

I have to disagree. I believe it is temperature issue.


It really is both. I say retraction because it's filament that has oozed out of the nozzle while it's not supposed to be printing. If you get retraction right, all but the very smallest amount of filament should be withdrawn from where it can drip out, but that requires tuning retractions to temperature. I prefer to advise people to tune retraction, especially for clearer filaments, as the temperature changes can make a big change in the look or strength of the part (And for all I know, they have it tuned right where they want it), but it's not like you're incorrect. Adjusting the temp would also help solve it.

Re: strange build artifacts, how do I avoid them?

Posted: Fri Aug 04, 2017 11:05 am
by mark.gesing
Ok, next time I print, I'll lower the temperature, increase the retraction, and increase the non-build movement speed, thanks.