What printing problem could be this?

Sliced with Cura 2.3.0
0.2mm resolution
100%Flow
0.4 mm nozzle, 4 perimeters
10% infill with 10% overlap
205/55 degree, PLA
Z seam alignment: back
Devil design brand new spool 1.75mm filament.
So, what could be the problem?

It could be several things:

Uneven filament diameter.
"Wet filament" or trapped air inside the filament, it will pop as it gets extruded, or steam if wet.
Extruder idler shaft has some play.
If bowden setup, the serpentine effect inside the tube can create irregular pressure at the nozzle.

I will test other filament first and see if repeats, if persist then check your extruder setup.
Also you can lower your temperature to 195, the filament will be more "stable" but you will have to print slower.

Edited 1 time(s). Last edit at 04/08/2017 10:11PM by ggherbaz.

I use an original e3dv6 and I never printed with 195. I have a bowden tube setup and it will make too muck pressure on it and the extruder will skip. I'll tight up the idler on the shaft and see what i get. How can I avoid irregular pressure inside the tube in this case? I'm thinking that maybe the extruder spring also is not tight up correctly so the extruder gear slips slowly on the filament and I can't hear it.

Measure the inner diameter of the tube, if more than 2mm then put a new one, if you use high quality filaments you can even use a 1.8mm tube but it might jam if filament isn't even enough.

The only real way to minimize the serpentine effect and reduce irregular pressure is to shortened as much as possible, reduce retraction and use a powerful extruder that have good amount of torque and good grip.

I use e3d v6 too and printing at 195 degrees isn't a problem as long as you don't go faster than 30~40mm per sec. Some PLA filaments need to be printed at lower temperatures and although 205 isn't too hot it is on the upper end for PLA , at those temperatures the plastic is more liquid and tend to create those effects shown in your photos at lower temperatures the consistency of the plastic is more malleable and will keep more it's shape and will help creating a back pressure to compensate for the bowden tube.

Edited 1 time(s). Last edit at 04/09/2017 08:26PM by ggherbaz.

Yeah... I got it. My bowden tube is 50cm long and I can't cut it shorter than this is my system. Thaks for advices. And by the way, I decrease the numbers of perimeters from 4 to 2 and I get a better result.