"Hairy" print with U2, Cura14.05-rc2 and Colorfabb PLA standard white.

[codeczombie 0]

Hello, I printed with a brand new PLA from Colorfabb (as mentioned on the title) and it ended up with a good result but with a lot of "suspicious" very thin hairs all around the piece.

Getting rid of those filaments was pretty easy, but I'd like to understand if this is an issue due to a wrong setting or just a regular kind of side effect.

I printed at 220°C/65°C then I lowered a bit to 215°C/65°

I'm now printing ad 210°C and it looks like it's making less "hairs" but it's a different piece so it's not an accurate comparison.

 

[gr5 964]

I never print at .04 layers. Some people love it but I find you get new problems like this. I would look at the blue travel lines in Cura and see if they all had retraction. I suspect it's this parameter here:

Minimal Extrusion Before Retraction: .02mm.

If you do the math, .02mm of 2.85mm filament works out to quite a long trace at .04mm layers. There is a 160X factor for .1mm layers but for .04mm layers it's more than double that or 400X factor. 400X.02 is 8mm trace of filament laid down. So if you have to non-extruding movements with only 8mm filament placed inbetween, the second non-extruding movement WILL NOT USE RETRACTION.

I could be completely wrong on this - it's easy to check with cura layer view. Retraction moves have a little vertical line if it retracts on that move.

Anyway unless you are having problems with your filament getting ground up and prints failing, I would change the .02 to zero. Also min travel from 1.2mm to zero as well.

Also you might have to tune your retraction distance a bit in your filament settings on the printer itself. Maybe increase the retraction distance a little. Not sure.

 

[gr5 964]

Oh - and have you tried .1mm layers? It will probably look just as good except without the hairs, and will print twice as fast.

 

[codeczombie 0]

Thanks gr5, I changed the settings as suggested, also lowered the nozzle temp from 220 to 210, printed the head and found out that some issues are gone, less hairs and bumps.

Later I'll reprint the body (hairy piece) and see what happens, it takes 16 hours so I'll know (and let you know) tomorrow.

For the layer resolution, fact is that I need a supersmooth surface, previously I printed at 0.06 and had to prime and sand too much, I prefer to wait more hours for a print that needs less sanding than having a faster print that will let me lose days on post-production.

One thing I can't stand (but have to accept) are the overhangs, damn, they look so awful.