A welding quality inspection apparatus for inspecting the welding quality of a plurality of welding parts formed on the material through the upper electrode and the lower electrode of the welding gun includes a position detection unit for detecting a position of the upper electrode, a control unit generating a position table based on a signal detected by the position detection unit during a total welding time of welding the plurality of welding parts of the material, generating first position data for a first welding time and second position data for a second welding time of a spot welding time of each of the welding parts based on the position table, checking whether the welding parts are defective by using the first position data, the second position data, and reference data, and generating result data based on whether the welding parts are detective, and an output unit for outputting the result data.

The seam welding apparatus includes a pair of rotating electrodes, an electrode supporting frame, a distance measuring means, and a controller. The electrode supporting frame supports the pair of rotating electrodes. The distance measuring means is provided on the electrode supporting frame and measures a distance to an edge of the steel plate. The controller controls the robot to adjust a running direction of the rotating electrodes so that a deviation comes into zero when a distance actually measured by the distance measuring means deviates from a predetermined distance. Thereby, it is accomplished that the seam welding apparatus is downsized as well as uninfluenced by the surface state and/or shape of workpiece (steel plate).

A resistance welding control system includes a pair of electrodes, a driving mechanism, and a control device. The control device includes a detector, a determining unit, and a stop controller. The detector is configured to detect a position of a first electrode of the pair of electrodes and a distance from the first electrode to a second electrode of the pair of electrodes in the approaching-separating direction while electricity is being passed between the first and second electrodes. The determining unit is configured to make a determination as to whether predetermined variation has occurred in the position or the distance. The predetermined variation indicates that a temperature of the member to be welded is at a feature point temperature. The stop controller is configured to stop the electricity passed between the first and second electrodes on the basis of a result of the determination.

An apparatus includes a housing, a pin, a mechanism and a sensor. The housing is configured to receive a weld head. The pin is configured to move linearly relative to said housing. The mechanism is configured to convert a position of said pin into a displacement. The sensor is configured to generate a value representative of said position of said pin based on said displacement.

A resistance spot welding device for welding at least two overlapping steel sheets held between a pair of welding electrodes is provided. The resistance spot welding device includes the pair of electrodes, an electrode force gauge that measures an electrode force, and a controller that controls an electric current supply to the electrodes according to the electrode force measured by the electrode force gauge. The controller controls the electric current such that the electrode force F measured by the electrode force gauge after the start of the electric current supply is adjusted to a prescribed value.

An electrode orientation checking apparatus includes a machine stand attached to a seam welding apparatus from which one roller electrode of a set has been removed, a positioning guide and a set of distance sensors that are provided on the machine stand, and a calculating section. A positioning surface of the positioning guide is fixed at a position corresponding to a portion of an outer circumferential surface of the one roller electrode before being removed, the portion lying on a line segment connecting rotational centers of the roller electrodes. The distance sensors are respectively fixed forward and backward of the positioning surface in a progression direction of the roller electrodes. The calculating section calculates data for acquiring a direction of the line segment relative to the stacked body.

An apparatus includes a housing, a mechanism and a sensor. The housing may be configured to receive a weld head. The mechanism may be attached to the housing and configured to convert a position of a location pin relative to the housing into an angular rotation. The sensor may be coupled to the mechanism and configured to generate a value representative of the position of the location pin based on the angular rotation.

A method for checking quality when resistance-welding workpiece includes pressing welding electrodes with an electrode force against a weld spot of the workpieces using an electrode drive and energizing the welding electrodes with a welding current for a duration of a welding time in order to liquefy a surface of the workpieces. The method further includes determining, at a first time before a beginning of the liquefaction, a first value of a welding electrode parameter identifying a position of one or both electrodes, and determining, at a second time after the beginning of the liquefaction, a second value of the welding electrode parameter identifying a position of one or both electrodes. The method further includes comparing the first value and the second value and, evaluating a quality of the welding process based on the comparison.

A control unit and method for a joining system having at least one joining station, which is designed to join at least one first joining element to a workpiece, determines actual data with respect to a first joining element joined to a current workpiece by the joining station. The control unit and method determine, in accordance with the actual data, a subsequent control instruction for the joining station for joining a first joining element to a subsequent workpiece.

The objective of the present invention is to enable accurate detection of a mismatch during electric resistance welding. This operation monitoring device for high-frequency resistance welding and induction heated welding of an electric resistance welded steel pipe, in which a strip-shaped metal sheet is continuously formed into a cylindrical shape by means of a group of rollers while being conveyed from an upstream side to a downstream side, and in which the two edge portions, in the circumferential direction, of the metal sheet, which are caused to converge into a V-shape, are caused to melt by the application of heat and are caused to abut one another, is characterized by being provided with a means for detecting a mismatch by recognizing a non-uniformity between light-emitting regions of a metal part, on both sides, in the circumferential direction, of the abutting position on an outer surface or an inner surface of the metal plate, on the basis of an image of a region including a V-convergence location, which is a location at which the two edge portions in the circumferential direction converge into said V-shape, and said metal part which is caused to flow out onto the surface of the metal plate by means of an electromagnetic force downstream of the V-convergence location, wherein said image is captured by means of an image capturing device from an outer surface side or an inner surface side of the metal plate that has been formed into said cylindrical shape.