Currently I am testing my 3d printer and i want to know how to

Currently I am testing my 3d printer and i want to know how to improve the print quality specially removing those bold lines.

My slicer configuration is
0.2 mm layer hight
220°c
Perimeter and small primeter speed 30mm
External perimeter speed 70% of perimeter speed
Travel speed 130 mm/s

Filament:
1.75 mm

Thanks in advance

Nozzle size? Printer type?

the lines on the face and back of head are equal distance so it points to a mechanical problem. wobble at the Z axis, loose belts, or wobble in the bearings.

If you are running an I2,(unlickly anymore) I have some really nice x ends that will help.

but yes most def a mechanical issue.

It is a custom printer made by my friends and me … The nozzle is 0.25 mm