Method and device for monitoring and/or controlling a flow-drilling and thread-forming process

A method for monitoring or regulating a flow-drilling and thread-forming process in which a joining element having a threaded portion is driven with a rotational speed, a torque, and a feeding force over a penetration depth into and through a workpiece, the method comprising:

• a) forming at least one process variable based on an energy expended for performing the process or an auxiliary value derived therefrom;
• b) comparing the at least one process variable to at least one comparison value for the performance of the process;
• and
• c) outputting a control or display signal dependent on said comparison in order to indicate a proper or faulty running of the process or to control the process depending on the comparison.

A joining device comprising:

• a control unit configured to control one or more components for performing a flow-drilling and thread-forming joining process in which a joining element having a threaded portion is driven with a rotational speed, a torque, and a feeding force over a penetration depth into and through a workpiece, the control unit configured for:
• a) forming at least one process variable based on energy expended for performing the process or an auxiliary value derived therefrom;
• b) comparing the process variable to at least one comparison value for the performance of the process;
• and
• c) outputting a control or display signal dependent on said comparison in order to indicate a proper or faulty running of the process or to control the process depending on the comparison.