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.

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.

A welding apparatus includes a movement assembly for at least one electrode configured to which can be passed through by current for the execution of welding treatments. The assembly includes at least one cylinder and at least one stem which rigidly supports the electrode; the stem is at least partially accommodated in the cylinder and is coaxially movable with an alternating straight motion along the longitudinal axis of the cylinder, in order to press the electrode against the parts to be welded with a corresponding welding force.

A device for measuring the welding force is also provided, which has a plate, which is stably interposed between the stem and the electrode with the respective faces arranged at right angles to the longitudinal axis, and a plurality of deformation sensors accommodated in through slots provided in the plate and distributed along an imaginary circumference which is centered along the longitudinal axis.

An example diagnosis system determines a state of a target device that includes a work apparatus. The diagnosis system includes circuitry that is configured to acquire first data generated in response to operating the work apparatus at a first pressure, configured to acquire second data generated in response to operating the work apparatus at a second pressure, configured to calculate a feature quantity indicating a relation between the first data and the second data, and configured to determine the state of the target device based on the feature quantity.

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.

A method for adaptive control of the traveling electrode of a spot welding gun includes causing the traveling electrode of the welding gun to move at a first speed when performing a welding (working) cycle and to switch to a second speed at a point, the coordinate of which is calculated based on the point of contact of the coordinate of the electrode obtained at the configuration cycle performed before the working cycle. The method allows for a reduction in welding cycle time.

A method and/or a system estimate a quality of a weld. For example, a weld information algorithm may be generated based on, for each of a plurality of welds, at least two of a first maximum weld force parameter, a minimum weld force parameter, or a second maximum weld force parameter. The weld information algorithm may be used to estimate the weld quality of a particular weld based on weld information obtained for that weld.

A spot welding apparatus includes a spot welding gun and a welding gun control apparatus. The welding gun control apparatus includes a pressurizing force control part controlling the pressurizing force, a position control part controlling the position of at least one electrode, and a determination part determining whether or not the welding is performed in a normal state. The position control part controls an electrode drive motor so as to hold the electrodes, after the supply of the electric current is started, at positions when the initial pressurizing force is applied before the electric current is supplied. The determination part acquires the pressurizing force and determines whether or not the welding is performed in a normal state based on change tendency in the pressurizing force.

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 method for resistance welding includes performing a plurality of resistance welding processes during which welding electrodes are pressed against respective welding spots of respective workpieces. The welding electrodes are energized with a respective welding current for each of the plurality of resistance welding processes, and for each of the plurality of resistance welding processes, a respective at least one characteristic value that characterizes a quality of the welding is determined. A statistical analysis of the determined at least one characteristic value for each of the plurality of resistance welding processes is performed, and based upon the analysis, an adaptation of the prescribed welding parameters is determined.