Patent EP-2269760-A1 (EP)
Inventor: MUELLER WILLI
IPC: B23K11/06
Filed: 2010-06-16
Abstract: The method for assessing the applied welding current strength during electrical resistance seam welding of overlap joints of successively following container bodies (6) of production series, comprises welding a first row of the container bodies with a predetermined constant welding current strength by a control of a resistance welding machine during the production, where the row of the container bodies is welded by controlling an individual container body from the production series with welding current strength falling or rising during the seam welding. The method for assessing the applied welding current strength during electrical resistance seam welding of overlap joints of successively following container bodies (6) of production series, comprises welding a first row of the container bodies with a predetermined constant welding current strength by a control of a resistance welding machine during the production, where the row of the container bodies is welded by controlling an individual container body from the production series with welding current strength falling or rising during the seam welding, and testing whether the adjusted constant welding current strength in a predetermined distance to the welding current strength for cold welding and the welding current strength for hot welding and whether the adjusted welding current strength in a range. The position of the adjusted constant welding current strength is periodically determined and recorded for quality security purposes. After welding the individual container body, a changed constant welding current strength is adjusted, lies between the welding current strength of the cold welding and the welding current strength of the hot welding and is selected in dependent of the welding current strengths, where a new constant welding current strength is applied for the row of the container bodies of the production series following to the individual container body. The welding current strength is linearly selected during welding the container body in a falling or rising manner or the welding current strength has two ranges with different rise of the lowering or rising during welding the container body. The electrical energy is determined, in which the welding seam of the welding current and the electric voltage drop for each welding lens or selected welding lens is determined over the welding electrodes. The container bodies have an overlapping width, which changes along the seam. The container bodies are welded with its seam during the welding with lowering or rising welding current strength. The welding current strength is selected greater during the larger overlapping width and smaller during smaller overlapping width. The electrical energy is determined periodically in the container body or two container bodies from the production series during the welding and/or the temperature of the welding is determined based on the electrical energy values and/or the determined temperature values if the welding current strength proceeds the welding of the individual container body to cold and the welding current strength proceeds the welding of the individual container body to hot, and is assessed or changed based on the determination of the flow of the falling or rising welding current strength within the limits. The position of the adjusted welding current strength is recorded for quality security purposes. The electrical voltage drop is determined over the welding electrodes and/or the temperature is measured along the welding seam with an infrared thermometer. An independent claim is included for a welding apparatus for the resistance seam welding of container bodies.