I have noticed what I would consider a strange behavior with Cura regarding infill densities. If I use a density of 23% or less the software lays out a nice square pattern rotated 45 degrees from the X and Y axis. Each layer is printed with the material being laid down in both directions of the pattern.
However, on some of my prints I set the infill density higher anticipating a stronger print. Unfortunately I ended up with a weaker print that would fracture more easily along the layer lines. It appears that at densities above 23% Cura is only laying infill material down in one direction per layer. It alternates the direction of the infill on alternate layers. This makes for a poor bond of the infill material and it ends up adding no strength to the part. The part will shear along the layer lines as if there were no infill at all.
I have not tested see if it goes back to printing both directions at some densities. I would expect at very high densities (say 95% and above) alternating directions would be a desirable behavior (just like at the top and bottom thicknesses).
Is there a setting that I am missing in regards to infill? The only one I see are infill density and infill overlap percentage. From what I can find overlap percentage seems to be more for thin wall issues than the actual infill but I don’t know?
Can anyone verify the behavior or more importantly offer suggestions on how to get the infill to be built in both directions at higher densities?