Patent DE-102011122513-A1 (DE)
Title: Operating resistance welding apparatus with welding tongs, drive train and mechanical shaft for positioning welding electrodes on workpiece, by selecting signal of drive train to be measured, and measuring selected signal at first time
Inventor: VOELKER WILLI
IPC: B23K11/25
Filed: 2011-12-29
Abstract: The method of operating a resistance welding apparatus with welding tongs, drive train comprising a controller and a linear drive with an electric motor and with a mechanical shaft for positioning welding electrodes on a workpiece, comprises selecting a signal of the drive train to be measured, measuring the selected signal at a first time, where a measuring result is stored in the form of reference data, and further measuring the selected signal compared with the measured signal of the drive train using the reference data during a first time and then analyzing a known variation. The method of operating a resistance welding apparatus with welding tongs, drive train comprising a controller and a linear drive with an electric motor and with a mechanical shaft for positioning welding electrodes on a workpiece, comprises selecting a signal of the drive train to be measured, measuring the selected signal at a first time, where a measuring result is stored in the form of reference data, and further measuring the selected signal compared with the measured signal of the drive train using the reference data during a first time and then analyzing a known variation. The analysis is performed with regard to friction ratios, mechanical backlash and/or a rigidity of the components of the drive train. A motor current, a motor speed and/or a motor temperature of the motor is used as signal. A parameter of a first frequency response of the drive train is selected as signal. An amplitude, a phase and a resonance frequency of the frequency response is selected as parameter. The drive train is pressurized with a nominal frequency response for the creation of the frequency response. A first tolerance threshold is stored and taken into consideration. A second tolerance threshold is stored, and forms an envelope curve together with the first tolerance threshold, where the envelope curve is taken into consideration. The consideration is carried out cyclically. A number of cycles is adjusted by operating the resistor welding apparatus. The plant takes place during the operation of the resistor welding apparatus. The signal to be measured is recorded by a digital oscilloscope function, and is stored as reference data. One of the process steps is started by freely definable trigger signals produced by the drive controller. A trigger threshold of the trigger signal is adjusted. A sensitivity standard value is stored, and is included in the analysis. Characteristic parameters are taken into account for the resistance welding apparatus during the consideration. A diagnostic message is passed onto the operator of the device by a data network and/or a control terminal. The diagnostic message is generated with respect to effects of deviations on a quality of the welding operations to be performed under the consideration of the analysis. An independent claim is included for a resistance welding apparatus.