Strange black marks

[ro_balboa 0]

Hello,

I am having strange black marks on my print (it looks like black grid inside materials). I am using transparent white fillament (inofil3d). I am printing 2 shells (0.8 nozzle)

It always apperas on the same spots (on every print of this kind).

Do you have any idea what that could be? what should I try to avoid this?

Thank you!

[gr5 964]

The vertical lines?

The darker areas - I assume that is light coming through? If so those are probably where the print is thicker. Could those be infill? Look at the print in layer view in cura to see if that is infill. Or maybe those are the corners of each segment - a circle in CAD is broken up into triangles and then those are sliced into line segments. Those darker areas could be where the printer slows down at each vertex. You could lower the print speed to about 30mm/sec and then it should be at a constant speed (no slowing down at each vertex) to see if that helps.

The horizontal dark areas would be where the Z axis had a slight error and was off on that layer such that the layer is slightly thicker. That is harder to fix but also more difficult to see alread. But the first thing to try to fix the horizontal bands would be to clean the z screw and re-apply new grease.

[ro_balboa 0]

Thank you, I'll try everything as suggested.