Described herein is a single-sided welding head including a first welding electrode and a second welding electrode, where the first and second welding electrodes are carried by a body of said welding head. The first welding electrode is movable relative to the body of said welding head at least along a first coordinate of motion. The second welding electrode is movable relative to the body of said welding head at least along a second coordinate of motion; where said first coordinate of motion is a coordinate of angular motion that develops about a first axis of rotation, and said second coordinate of motion is a coordinate of linear motion that develops along a first axis of translation.