Method for monitoring process when joining at least two workpieces by means of press-riveting device having joining clamp, and device having controller designed to carry out such method

Abstract

A method for process monitoring when joining at least two workpieces, which are arranged between a punch and a plug, by means of a press-riveting device having joining jaws, in which a rivet, which is arranged between the punch and a workpiece facing the punch, is pressed into the at least two workpieces by means of the punch in such a way that the rivet is pressed into the at least two workpieces by means of the punch. A force F in the direction of the plug is applied to the punch. In the method, a) for a plurality of joining operations, the total thickness of the joining pliers, the rivet length and the bending constant are respectively detected before joining; b) for a plurality of joining operations, during and / or after the joining, respectively detecting a punch stroke under a defined force, an end force, a stroke end value under the end force, a set stroke of the rivet and a rivet head end position; c) determining an absolute force / stroke window and / or an opposite force / stroke end window of the plurality of engagement operations as a function of the parameters detected in steps a) and b); d) comparing the determined absolute force / stroke window and / or the relative force / stroke end window of at least one further engagement operation with the absolute force / stroke window and / or the relative force / stroke end window of the plurality of engagement operations determined in step c), the at least one further engagement operation being monitored, thus, defects during joining are identified.

Description

technical field [0001] The invention relates to a method for process monitoring during the joining of at least two workpieces by a punch riveting device with joining jaws, and to a device with a controller designed to carry out the method. Background technique [0002] The punch riveting (Stanznieten) method is used to join at least two workpieces, wherein a rivet is pressed into at least two workpieces by means of a punch or a punch tool, wherein the rivet or The workpieces are deformed in a certain way in order to produce a non-positive and form-fitting connection between the workpieces. [0003] Press riveting methods are known from the prior art, in which quality monitoring takes place via the envelope of the force / displacement curve. When joining components made of brittle materials by the punch riveting method, defects such as cracks can appear due to the applied force. The occurrence of this defect here leads to certain short-term fluctuations in the force applied t...

AI Technical Summary

Problems solved by technology

[0007] However, the methods known from the prior art have the disadvantage that, when limiting values ​​are applied to the forces or force gradients required to press the rivet into the two parts to be joined, completely flawless joined parts are excluded. parts

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