Abstract: Methods and devices for controlling a mechanical joining or forming process, in particular friction drilling in thin-walled materials, apply several reverse pulses acting on a process parameter to bring the course of an actual curve of the parameter more into line with the course of a predetermined nominal curve of the process parameter. The number and length of the reverse pulses and the length of the intervals between the pulses are determined as a function of at least one immediately detectable variable associated with the process parameter.

Abstract: A method and a device are provided for simplifying a flow-hole screw process, in which the difference between a process parameter and its smoothed value is employed as a criterion for changing said process parameter or another process parameter in order in particular to be able to determine the changeover point between hole forming and thread forming.

Abstract: A method and device are provided for simplifying a flow-drill screwing process. Based on work performed during the process, a process variable E is formed. This variable is compared to analogously formed comparison values in order to be able to determine the proper or faulty running of the process.

Abstract: Methods and devices for controlling a mechanical joining or forming process, in particular friction drilling in thin-walled materials, apply several reverse pulses acting on a process parameter to bring the course of an actual curve of the parameter more into line with the course of a predetermined nominal curve of the process parameter. The number and length of the reverse pulses and the length of the intervals between the pulses are determined as a function of at least one immediately detectable variable associated with the process parameter.