Your raw material will come in the form of a large spool of sheet metal containing a strip of steel hundreds of meters long. You will need an unspooler to feed steel off the spool and a straightener to take the curvature out of the steel strip. Then you need either a punch press or a shear to cut the sheet metal blanks to size and trim their corners. To put ripples or corrugations into the cut blanks, you will need a roller die or a rolling mill. To put a folded edge onto the sides of the blank you will need either a bending brake or a set of progressive dies. To bend the fenders into their final curved shape you will need a sheet metal press and to smooth out any resulting ripples you will need an ironing press.
To attach the mounting brackets you will need an electric spot welder. Finally, you will need either an electrostatic spray booth to paint them or a powder coating rig.