Generally, when 3D printing, you want the outside surface to be as smooth as possible.
The only exception to this should be patterns that you have explicitly designed.
A tell-tale sign of this issue is repeating patterns on the outer shell that align with your infill pattern.
Infill overl4ap controls how much the infill material overlaps with the outer shell.
A value of 15-30% is typical.
Try thickening the shell by simply doubling the shell thickness.
Tip: The shell thickness should be a multiple of the nozzle size.
If it isnt, the printer cant accurately reproduce the instructions its given.
The results of this can vary between devices as some may round down and others round up.
If this setting is wrong, it can also cause a range of other issues throughout your entire print.
Your slicing software should allow you to configure the shell to print before the infill.
Go through the manufacturers recommended calibration process.
