Method for detecting connecting elements, in particular friction drilling screws, in mechanical joining and forming processes in which an error event in the process was identified

An apparatus including:

• (a) a feed head;
• (b) a receiver connected to the feed head for receiving a connecting element in a loaded position on a carrier component of the feed head;
• (c) a drive arrangement for moving the carrier component along a carrier component stroke in a mechanical joining or forming process sufficient to move the connecting element from a start position to a connected position on a workpiece;
• and
• (d) a control unit for controlling the drive arrangement in the mechanical joining or forming process, the control unit being configured to
• (i) in response to detection of an error event in the mechanical joining or forming process, cause the drive arrangement to move the carrier component toward the workpiece;
• and
• (ii) ascertain whether a connecting element contact point is detected within a predefined permissible tolerance in the movement of the carrier component toward the workpiece.