Furry prints ... how to get rid of the hair ...

[ultiarjan 1,223]

Had this before of an larger print with a flat side, on the front.

And now again my print is growing hair.

Have only seen it with the Colorfabb PLA (not pure PLA..) in this case there magenta.

I varied the temp (210, 215, 200) it seems to be a little less at 200 but still there. Printing fairly standard at 40 speed / 0.1 hight.

Any idea what is causing this ? It's only on the front, and more on the right front than the left front....

 

[solid-print-3d 30]

It's only on the front because that's where the print head is jumping the void.

A little more retraction (retraction settings in printers menu), cooler temps, and quicker travel speed to break the strings before they form.

For advanced alternatives, you can change shell thickness to get Cura to make an optimal path around part, you may be able to cut retractions down by tweaking some Cura settings like that. Look at the little blue lines in the slicer to see how "busy" the path is. Try different settings and look at the blue lines (Layer view). Try turning off "enable combing" and see if that helps.

For some reason, on some parts, if I change shell thickness from .8 to .75, it makes a nicer path. Keep in mind that I usually design my models to have walls in multiples of .4mm, so this might not work the same for you, but little tricks like that can get Cura to behave differently for sure.

 

[colorfabb 3]

I varied the temp (210, 215, 200) it seems to be a little less at 200 but still there. Printing fairly standard at 40 speed / 0.1 hight.

 

Hi Arjan,

In the picture I can see that the nozzle isn't clean, there's a noticeable build up of PLA on the outside of the nozzle. This shouldn't be there and might cause the very fine hairs you're seeing. Might be the heater block is leaking, can you see molten PLA on top of the heater block?

What happens if you decrease flow rate to about 95%? And are you seeing the same effect on 0.2mm layer height?

cheers,

Gijs

 

[ultiarjan 1,223]

He Gijs,

was planning on giving you a PM on this one, but you're here already...

The top of the block is clean, so no leaks I guess... I admit the nozzle is rather dirty.

Is it that simple that its just a matter of cleaning? If thats the case it could be an issue on longer prints, as I told you saturday I had it on the "nesspreso cup holder" as well on the front side and this is a longer print (20+ hrs).

I'll clean and try the same model again, keep you posted.

@solid print 3d - Am I right that you think it's "stringing" ? I don't think it is ....

 

[ultiarjan 1,223]

done cleaning, printing a small testcube right now, no sign of furry fibers sofar.... will print the "problem file" with same setting again tomorrow.

 

[gr5 2,267]

Is it retracting at all? Retraction has about 5 parameters but you can see it in layer view. Make sure it is retracting before looking at hardware.

Also retraction amount matters and PLA temp and travel speed. You want fast travel speed - 150mm/sec minimum. But first step is to see if retraction is happening and like mentioned above you can tell for sure in layer view.

 

[gr5 2,267]

See first photo here:

http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/

 

[solid-print-3d 30]

WOW, That's one dirty nozzle. Is that from one print? My dirty nozzle usually turns black. How did you manage to get it coated completely in fresh filament?

Settings man!

I've had prints carry the initial that extrusion booger all over my 5 hour prints... Didn't touch it cuz the print was looking good, but it was odd to see a big glob of filament hanging off the extruder! Still print turned out great.

 

[yellowshark 153]

Makes me wonder if you get Candy Floss filament? Sure would be fun!

That is a hell of a nozzle, never seen that before. If it is not that then I bet you do not have retraction set properly.

 

[DidierKlein 729]

I also get these hairs on some prints, i mainly use Colorfabb Filaments.

It's quite easy to clean so i didn't really bother looking more in depth.

My nozzle looks like yours, it mostly dirty. How do you clean it? I thought that acetone would do the trick but it only cleaned it partially and after a couple of prints it's back to being as dirty as Miley Cirrus :mrgreen:

It's not stringing to me because the thing is very thin like hair and doesn't need as much effort to clean (you can get rid of it by rubbing the print by hand)

 

[gr5 2,267]

Acetone is a good solvent for ABS. Ethyl Acetate is a good solvent for PLA.

I agree with didier - this is probably a filament thing - my filaments don't do this.

 

[pm_dude 27]

I get these type of strings with Colorfabb Woodfill fine. Very light even when printing the UltiRobot. I aso get burned materials from nozzle when using XT which stick on the print :( and is visible due to transparency.

Cleanning the nozzle is the key. Even long prints you can pause and clean when you see some buildup starting.

 

[ultiarjan 1,223]

I cleaned with a tissue after heating up. And with a mini rust brush.

Tried the same print... still same issue... will try same model and settings with um pla later ....

[gr5 2,267]

What is your travel speed? And realize that if you print "at 30%" then that slows down your travel speed also. You want it >150mm/sec to break any strings. But I've never seen this on my own prints so I'm not sure how they are created.

 

[ultiarjan 1,223]

Picture may be not clear as it's from the front but i think travel is not relevant here. Nozzle is just following the outline. Not "jumping a gap"... this is not stringing is also haopens on a flat front.

[gr5 2,267]

this is not stringing is also haopens on a flat front.

 

I can also see it in the picture on the fan shroud! I've just never seen this. It's like cotton candy machine. I should just shut up as I'm ignorant of this issue.

 

[pm_dude 27]

Somebody take note of this date!

[yellowshark 153]

Ditto George's 2nd comment. I just wipe any filament off with a rag when the extruder is heated. I do mean one day to take my nozzles off and give them to my wife, who is a horologist, to give them a nice polish with her myriad of chemicals.

 

[pm_dude 27]

Speaking of nozzle. How resistant is the nozzle to sanding or steel whool? Some burns at 250C can be hard to remove.

[solid-print-3d 30]

Why isn't there any cotton candy on the sides? The sides look great. Just noticed the fan shroud as well. It's as if theres a pin hole in the side of the extruder, where the extruder is putting down the bulk of the filament on the print, and shooting out a liquid like stream through a pin hole or leak. Then the 2 side fans are keeping the cotton candy centered towards the middle as they blow inwards, or the rear fan creates just enough draft to keep the cotton candy facing forward.

I'm just having fun shooting from the hip here.... don't listen to me

 

[solid-print-3d 30]

Speaking of nozzle. How resistant is the nozzle to sanding or steel whool? Some burns at 250C can be hard to remove.

 

Have you tried using a brass wire brush? Works for me removing the tough black carbon. Brass on brass is better than using steel wool or a steel wire brush.

 

[pm_dude 27]

I'll have to try that. Thanks

[DidierKlein 729]

If you look at this print in biggest scale you'll see the furs:

 

It's a print i did a while ago in WoodFill Fine and this pic was taken after a small cleanup

 

[ultiarjan 1,223]

Tested some more this evening, after cleaning the nozzle again... same model/material (colorfabb magenta PLA/PVA) tested at 95 % flow, no effect at all, still a large amount of furr.

Cleaned again (only outside of nozzle) and tried with UM blue PLA, still furry, but a lot less. So I'm beginning to think it's the model (slicing of the model) as main issue, but there's for sure a big difference per material.

Some idea's for further testing (later this week...)

- same model, sliced again, maybe on a different scale...

- same material & setting, different model.

I thingk I'll also do a "full" cleaning of the nozzle first, as I noticed at the start of the print the flow of material was not nicely going straight down, but more on one side, this may have something to do with the nozzle getting dirty so fast....

 

[pm_dude 27]

mind sharing your model to see if it will do the same on other printers? I dont mind testing a print tonight.