Abstract: 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.

Abstract: An equalizing mechanism of a welding apparatus connects an apparatus body and a fixed bracket, and includes a fixed member on the fixed bracket, and a pressure shaft on an apparatus body close to a bottom face of the fixed member. A cutout is at a position facing the fixed member A movable member on the apparatus body accommodates the fixed member. A restrictive member located by side faces of the fixed member and the movable member restricts relative movement thereof to a direction parallel to the pressure shaft. A driven lever is supported by a front portion of the fixed member to abut on an inner front face of the movable member at one end and abut on the pressure shaft at an other end. A spring between a back portion of the fixed member and an inner back face of the movable member presses the two members to move away from each other.

Abstract: A welding process for the welding of aluminium includes a force sensor measuring a force between two welding electrodes on aluminum elements to be welded and transmitting its measured values to a welding control. Until the elapse of a set welding time, the welding control calculates and stores at least one absolute value and/or at least one increase in the measured force. The welding control compares the measured absolute value and/or the increase in the measured force with a reference value and/or a reference curve and calculates a control deviation from the comparison. After the elapse of the set welding time, the welding control subjects the welding electrodes to a constant current during a welding time extension that follows the set welding time, dependent on a magnitude of the control deviation that is measured at the point in time of the elapse and/or during the set welding time.

Abstract: A spot welding apparatus includes a robot, a spot welding gun, and a controller. The spot welding gun includes a gun arm, a fixed electrode, a movable electrode, and a gun-dedicated motor. The fixed electrode is fixed to the gun arm. The movable electrode is disposed on the gun arm at a position opposite a position at which the fixed electrode is disposed. The gun-dedicated motor is configured to move the movable electrode. The controller is configured to output a position command to the gun-dedicated motor so as to control the gun-dedicated motor to move the movable electrode, configured to control the fixed electrode and the movable electrode to hold a to-be-welded object under pressure between the fixed electrode and the movable electrode, and configured to subject the to-be-welded object to spot welding.

Abstract: A weld gun system for detecting the orientation of a weld nut relative to the metallic component to which it is to be welded prior to welding is disclosed. The system includes a lower electrode having a weld location pin, an upper electrode having a central circular recess formed therein, a fluid supply fluidly connected to the central circular recess of the upper electrode, and a pressure switch also fluidly connected to the central circular recess of the upper electrode. Once the weld nut is captured between the electrodes the fluid flows from the fluid supply into the central circular recess of the upper electrode. If the weld nut is in proper orientation the fluid continues to flow to the pressure switch and the weld occurs. If the weld nut is not in proper orientation the fluid does not flow to the pressure switch but is instead vented from the central circular recess and the weld does not occur.

Abstract: An improved method for executing a flash butt weld to join first and second rail segments includes applying a voltage to the first rail segment and the second rail segment to establish a voltage difference between the first and second rail segments. The rail end faces are brought into contact, resulting in an electrical current between the first rail end face and the second rail end face, resistively heating material at the interface. As material burns off at the interface, the power consumed at the rail end interface as a function of rail displacement is periodically sampled. If the comparison indicates that the power per unit of rail displacement is not increasing from sample to sample, the burn-off process is terminated. In a further aspect, if the power per unit of rail displacement exceeds a predetermined threshold, the burn-off process is terminated.

Abstract: A welding apparatus includes a first electrode tip; a second electrode tip opposing the first electrode tip; and an electrically conductive part which is provided so as to be freely interposed between the second electrode tip and a work and ensures electrical conduction between the second electrode tip and the work when the electrically conductive part is interposed between the second electrode tip and the work, the electrically conductive part including an electrically conductive member one side of which opposes the work with a presence of a void space from the work when the electrically conductive member is interposed between the second electrode tip and the work, and against which the second electrode tip is abutted on another side thereof, and a pair of electrically conductive abutment members which are provided integrally with the electrically conductive member in such a manner as to extend toward the work, and distal ends of which are abutted against the work, a position of abutment of the electrically

Abstract: A system and method for controlling a piston-cylinder assembly of a welding apparatus, the piston-cylinder assembly including a plurality of pressure chambers, wherein the piston-cylinder assembly is operatively coupled to at least one welding electrode of the welding apparatus so as to effect movement of the electrode in a pre-stroke and weld motion, comprises: connecting to a first port of the piston-cylinder assembly a first fluid pressure, the first port in communication with a first pressure chamber so as to effect the pre-stroke motion of the electrode; and connecting to a second port of the piston-cylinder assembly a second fluid pressure, the second port in communication with a second pressure chamber so as to effect the weld stroke motion of the electrode, wherein the second fluid pressure is different from the first fluid pressure.

Abstract: Spot welding system including a welding gun with an electrode pair actuated by a servo-motor, a robot carrying the welding gun or objective workpieces and operating to change an relative positions and orientations of the welding gun and an workpieces, and a gun motion controller controlling the servo-motor to actuate the electrode pair. The gun motion controller includes a motion commanding section outputting motion commands to the servo-motor in accordance with a speed set-value designating a closing speed of the electrode pair, and a set-value adjusting section automatically adjusting the speed set-value to an appropriate value.

Abstract: An arrangement of a stress transducer (8) mountable on one arm (31) of welding pliers, wherein an insert (10) is positioned between the arm (31) of the pliers and the stress transducer (8). A method for mounting said stress transducer is also provided.

Abstract: A production line method of resistance welding comprising the steps of contacting a metal sheet with an electrode having an initial contact surface area at a force to provide a pressure to the metal sheet; applying a current though the electrode to the metal sheet; measuring dimensional changes of the electrode; correlating dimensional changes in the electrode to changes in the initial contact surface area; and adjusting the force to compensate for the changes in the initial contact surface area of the electrode to maintain pressure to the metal sheet. The force may be adjusted by stepping the force to maintain pressure to the faying surface of the metal sheet to be welded. By maintaining the pressure at the faying surface the life cycle of the electrodes may be increased without forming discrepant welds.

Abstract: A welding gun assembly including a housing that defines a first chamber and a second chamber. The assembly also includes a first piston moveably disposed in the first chamber and a second piston moveably disposed in the second chamber. The assembly includes an intensifying rod that can move at least partially into the first chamber due to movement of the second piston within the second chamber. The assembly includes a controller with a pressure sensor operable to detect pressure within the first chamber. The controller is operable to increase pressure within the first chamber up to a predetermined extension pressure while the intensifying rod is disposed outside of the first chamber. The controller is further operable to increase pressure within the second chamber to thereby move the intensifying rod into the first chamber to thereby increase pressure within the first chamber above the predetermined extension pressure.

Abstract: A process and a device for controlling the pressing force of the electrodes [of an] electrode holder driven by means of an electric motor, especially of an industrial robot, during the welding operation characterized in that the motor position is controlled or that a means for controlling the position of the electric motor is provided.

Abstract: The present invention provides a servo driven spot welder where an electric servo actuator moves at least one of two electrodes to and away from the workpiece. The servo driven spot welder includes a controller that allows accurate control of the position of one of the electrodes such that fine adjustments may be made during the welding event. A power source is provided in communication with the actuator, the controller and the electrodes whereby the controller controls the delivery of power to the actuator for movement and to the electrodes for welding. A sensing device is provided between the servo drive and the electrode for sensing the load on the electrode during the welding event. The sensing device senses when a weld nugget forms on the workpiece and expands to cause an increase in the load and then becomes plastic to cause a decrease in the load.

Abstract: A welding head for connecting weld members by resistance welding includes an infeed cylinder having a piston rod, an electrode movable via the cylinder; and a sensor arranged between the piston rod of the infeed cylinder and a readjusting spring for the rapid readjustment of the electrode. The sensor is clamped in place between contact means in a sleeve-shaped or tubular drive shaft mounted in a housing.

Abstract: A weld gun includes internal, external and structural devices that dissipate heat generated at electrode tips without requiring a continuous external source coolant. The internal devices utilize heat pipes within the electrodes to transfer heat to secondary heat removal features. A heat capacity on the weld gun contacts external heat sinks to directly conduct heat away from the weld gun after a completed weld cycle. Alternatively, the heat sink, the heat pipe and the secondary heat removal features are combined structurally on the weld gun arm by forming the arm from a plurality of plates separated by an air gap.

Abstract: A method of and device for automatically setting and updating a reference position of a welding tip of a servo spot welding gun to automatically compensate displacement of a distal end of a welding tip by abrasion thereof. A movable welding tip is moved towards a stationary welding tip to press the stationary welding tip until an estimated disturbance load reaches a fist threshold, and then moved in reverse direction away from the stationary welding tip until the disturbance load is reduced to a second threshold. The position of the movable welding tip when the disturbance load is reduced to the second threshold is set and updated as the reference position of an axis of the movable welding tip. The first threshold is set to be greater than a frictional force exerted on the axis of the movable welding tip in the motion towards the stationary welding tip, and the second threshold is set to be equivalent to the frictional force.

Abstract: The welding gun includes an electrically driven welding clamp comprising a fixed indexed arm and a mobile arm, respectively provided with an electrode, and a device for indexing and de-indexing locking and releasing the clamp movement relative to the welding plane. The device for indexing and de-indexing includes a mechanical device arranged to ensure the locking and the releasing of the clamp movement, while the clamp is opening/closing, by the action of an electrical device controlling the opening and closing of the clamp.

Abstract: The present invention relates to an improved resistance weld-based gun assembly for use in an electric welding system without a need for plant-provided air and water-cooling circulation systems. In one aspect of the invention, a resistance-based force controller measures the resistance of a secondary circuit of the weld gun, the combined resistance of the secondary circuit in parallel with the circuit formed by the workpieces and opposing electrodes when sandwiched between the electrodes, and calculates the resistance of the workpieces. The measured resistance is compared to a predetermined resistance and the sandwiching force of the electrodes incrementally adjusted until the resistance of the workpieces is acceptable. The invention also relates to a closed loop coolant system having a coolant line, a coolant contained within the coolant line, a heat exchanger, and a mechanical coolant pump. One possible pump comprises an elastic bladder dependent upon the state change of the coolant.

Abstract: An intelligent welding gun is provided with a fixed side sensor in a fixed side portion. The mechanical impedance of the fixed side portion is kept small, which permits the mechanical impedance to be set in a range where the fixed side sensor can effectively detect at least one of a position of a fixed side welding tip and a pressing force imposed on the fixed side welding tip. The fixed side sensor and a moving side sensor constitute a redundant sensor measurement system. Various kinds of methods conducted using the above welding gun include a method of calibrating a sensor (including calibration of a reference point and a gain), a control method of suppressing a welding expulsion, a re-welding feedback control method, a control method of a welding strength, a control method of reducing a clearance between workpieces, a method of correcting a welding robot track, and a method of managing a positional accuracy change at a welding point.

Abstract: A pressure regulator system for a pneumatically- or hydraulically-actuated weld head. The weld head includes a switching valve comprising several ports: an inflow port attached to a source of pressurized gas, preferably air; an exhaust port; a first line port; and a second line port. Two-way valves are provided on the first line port and the second line port. A valve sensor connected to a switch for determining weld force in the weld head is connected to means for simultaneously closing the first line port valve and the second line valve port when a desired weld force is attained between one or more electrodes and a workpiece, thereby maintaining a constant, maximum pressure in the cylinder and consequently maintaining the desired weld force between the electrode(s) and the workpiece during the welding operation.

Abstract: Resistance welding device of the type comprising two welding electrodes (21, 31) that are displaceable in relation to one another and can clamp between them the sheet metal to be welded. One of said electrodes (31) is connected to driving means formed by a screw-nut mechanism (8, 9) operated by an electric motor (6), said driving means being connected to electronic control means (7) capable of controlling the force with which the electrodes (21, 31) clamp said sheet metal to be welded by controlling the supply current of the electric motor (6). The device of the invention is characterized in that said screw-nut mechanism transmitting the force of the motor (6) to the electrodes (21, 31) is highly efficient and reversible, and in that said electronic means (7) control the clamping force of said electrodes by a closed control loop using the value of the supply current passing through the electric motor (6).

Abstract: The present invention is an improved welding technique that provides real-time control of the servo valve to account for the changing conditions of the parts being welded. The present invention may be implemented within any electrical welder having at least one movable platen for carrying a part to be welded, at least one hydraulic cylinder coupled to the movable platen, the hydraulic cylinder having a first chamber and a second chamber, and a servo valve coupled to the hydraulic cylinder. The present invention includes means for making instantaneous pressure measurements within the first and second chambers of the hydraulic cylinder. Also included is a force control module that reacts to the pressures within the first and second chambers to control the servo valve. The force control module receives the instantaneous pressure information from the first and second chambers of the hydraulic cylinder and determines whether the platen is moving and how far the servo valve is from its target force.