Method for welding a sphere onto a metal sheet by a welding current between electrodes

A method for welding a sphere onto a metal sheet, the method comprising the acts of:

• picking up the sphere by use of a first electrode;
• pressing a metal sheet and the sphere together, wherein the sphere is pressed against the metal sheet by the first electrode and the metal sheet is pressed against the sphere by a second electrode;
• and
• generating a welding current between the first and second electrodes to weld the sphere and the metal sheet together, wherein:
• the first electrode comprises a face-side having a recess, an act of applying suction to the sphere being carried out such that upon being sucked into the recess a portion of the sphere that is to be welded protrudes from the recess and another portion of the sphere within the recess contacts an inner side of the recess only linearly about a circular periphery of the sphere so as to position the sphere in a defined manner, and
• the act of generating the welding current produces a point weld between the sphere and the metal sheet such that the sphere substantially maintains a spherical shape suitable for use as a joining element of a joint.