A spot-welding system including a spot-welding gun including a movable part including a movable electrode, and a drive part that drives the movable part, a controller that controls the drive part, an applied pressure sensor that measures an applied pressure from the movable electrode of the spot-welding gun, and an own-weight calculator that calculates an own weight of the movable part based on the applied pressure detected by the applied pressure sensor in two different postures of the spot-welding gun that places the movable electrode in different movement directions. . The controller superimposes a dither signal onto a control signal so as to control the drive part in measuring the applied pressure for use in calculating the own weight of the movable part by the own-weight calculator, and after the own weight is calculated, the controller corrects the control signal based on the calculated own weight.

FEA model representing a RSW setup is defined and received in a computer system. The FEA model contains multiple solid elements representing a pair of electrodes and two workpieces. Numerically-calculated heat-power distributions and structural behaviors of the workpieces are obtained by conducting a time-marching simulation using FEA model with a set of time-dependent electrode forces and corresponding set of time-dependent electrical current. An overlapped contact area and corresponding contact center between first and second element contact faces of each of the solid element pairs in contact are determined. Respective elemental coordinates of the contact center in the first and second element contact faces are calculated. Augmented terms for Joule heating effects are added to the overall stiffness matrix for obtaining Joule heat rate power at each contact center, which is then distributed to respective corner nodes of the first and second element contact faces according to respective elemental coordinates.

A stored time variation curve and cumulative amount of heat generated of each step are each used as a target. In the case where a time variation of an instantaneous amount of heat generated per unit volume differs from the time variation curve in any of the steps, a current passage amount is controlled in order to compensate for the difference within a remaining welding time in the step so that a cumulative amount of heat generated per unit volume in actual welding matches the stored cumulative amount of heat generated in the test welding. Further, in the case where expulsion is detected in any of the steps, then in subsequent welding, the cumulative amount of heat generated per unit volume used as the target is reduced, and the current passage amount is adjusted in accordance with the reduced cumulative amount of heat generated per unit volume.

The invention relates to a method for measuring the electrode force on welding tongs. The welding tongs have a first electrode arm with a first electrode and a second electrode arm with a second electrode, said second electrode arm lying opposite the first electrode arm. At least one workpiece is clamped between the electrodes during the welding process. The aim of the invention is to provide a method for measuring the electrode force, said method providing an improved signal quality. The method has the following steps: a) measuring a first force acting on the first electrode, b) measuring a second force acting on the second electrode, and c) adding the measured first force and the measured second force, wherein an electrode force signal transmitted from the welding point to the electrodes is amplified, and an interference force signal introduced into the at least one workpiece from the outside and transmitted to the electrodes is eliminated.

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.

Provided is an evaluation system including: an analog-to-digital converting section comprised of a programmable circuit and configured to convert an analog signal, the analog signal being acquired by a physical quantity acquiring section and indicative of a time-series change of at least one of (i) welding current, welding voltage, or load applied to pieces to be welded and (ii) a displacement, during welding, of a welding head; and an evaluating section configured to determine, based on a digital signal, whether or not the time-series change satisfies a predetermined condition, wherein configuration data for configuring the programmable circuit is arranged to be changeable by a user.

The disclosure relates to a measuring device (1) for automated welding devices, in particular for robot welding tongs with a housing (18); with a holding piece (19); that is affixed inside the housing (18) and insulated against the housing (18) by means of a first insulating ring (2); that has a reception space (22) with a base wall (23) and an affixing appliance (24); and with a load cell (17) that is affixed inside the housing (18) opposite the base wall (23) and that is insulated against the housing (18) by means of a circumferential second insulating ring (5) and an insulating washer appliance (7, 21) located at the front-face side and adjacent to the base wall (23).

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 electronically-controlled electric resistance welding head and method having a support structure and the electrodes located on the same side. The welding head including a ground electrode having an elastic device and a detecting device for detecting a force load on the elastic device on contact with a component to be welded. A welding electrode is movable relative to the ground electrode and the support structure to contact the component to be welded. An electronic control unit is operable to selectively increase the force applied by each electrode when in contact with the component to be welded until respective threshold values are achieved. Current is generated by a transformer for passage to the electrodes.

In the present invention, while a welding current is applied with respect to a laminate body comprising thick metal plates and thin metal plates, a first welding pressure (F1) with respect to the laminate body from an upper tip contacting the metal plate and a second welding pressure (F2) with respect to the laminate body from a lower tip contacting the metal plate are changed relative to each other. Specifically, F1<F2 in a first step which is an initial period of welding, F1=F2 in a second step which is an intermediate period of welding, and F1>F2 in a third step which is a final period of welding.