An electrostatic energy storage welding machine for performing resistance welding while applying pressure to an object to be welded includes: a pair of welding electrodes; an energy storage section including a plurality of energy storage parts; an individual charge circuit for individually charging respective energy storage parts; an individual discharge circuit for individually discharging the respective energy storage parts; a voltage monitor circuit individually monitoring voltages of the respective energy storage parts; an individual voltage stabilization control section for performing control to further charge an energy storage part having deviation in performance in an individual manner to stabilize a voltage of that energy storage part and thereby achieve a set voltage; and an output circuit for outputting power produced by the set voltage stabilized through individual charging and electric current through individual discharging in the energy storage section to apply the electric current between the welding electrodes.

A method of resistance spot welding workpiece stack-ups of different combinations of metal workpieces with a single weld gun using the same set of welding electrodes is disclosed. In this method, a set of opposed welding electrodes that include an original shape and oxide-disrupting structural features are used to resistance spot weld at least two of the following types of workpiece stack-ups in a particular sequence: (1) a workpiece stack-up of two or more aluminum workpieces; (2) a workpiece stack-up that includes an aluminum workpiece and an adjacent steel workpiece; and (3) a workpiece stack-up of two or more steel workpieces. The spot welding sequence calls for completing all of the aluminum-to-aluminum spot welds and/or all of the steel-to-steel spot welds last.

A welding system including a welding electrode, a closed-loop cooling device, and a vent. The closed-loop cooling device is configured to cool the welding electrode. The closed-loop cooling device includes a pump and a water line. The vent is located along a path of the water line. The vent is configured to release air trapped within the water line.

A method of resistance spot welding a steel workpiece and an aluminum or aluminum alloy workpiece, and a welding electrode used therein. In one step of the method a workpiece stack-up is provided. The workpiece stack-up includes a steel workpiece and an aluminum or aluminum alloy workpiece. Another step of the method involves contacting the aluminum or aluminum alloy workpiece with a weld face of the welding electrode. The welding electrode has a body and an insert. The insert is composed of a material having an electrical resistivity that is greater than an electrical resistivity of the material of the body. The weld face has a first section defined by a surface of the insert and has a second section defined by a surface of the body. Both the first and second sections make surface-to-surface contact with the aluminum or aluminum alloy workpiece amid resistance spot welding.

A series of many electrical resistance spot welds is to be formed in members of an assembled, but un-joined, body that presents workpiece stack-ups of various combinations of metal workpieces including all aluminum workpieces, all steel workpieces, and a combination of aluminum and steel workpieces. A pair of spot welding electrodes, each with a specified weld face that includes oxide-disrupting features, is used to form the required numbers of aluminum-to-aluminum spot welds, aluminum-to-steel spot welds, and steel-to-steel spot welds. A predetermined sequence of forming the various spot welds may be specified for extending the number of spot welds that can be made before the weld faces must be restored. And, during at least one of the aluminum-to-steel spot welds, a cover is inserted between the weld face of one of the welding electrodes and a side of a workpiece stack-up that includes the adjacent aluminum and steel workpieces.

An apparatus having a housing, a location pin, a lever and a sensor is disclosed. The housing may be configured to receive a weld head. The location pin may be configured to move linearly in the housing in response to a force between the location pin and a part to be welded. The lever may be rotatably attached to the housing and configured to convert a linear position of the location pin relative to the housing into an angular position of a shaft relative to the housing. The sensor may be coupled to the shaft and configured to generate a value representative of the linear position of the location pin by a measurement of the angular position of the shaft.

A welding electrode is disclosed that includes an electrode welding shell and a blind adapter that are joined together to cooperatively define an internal cavity. The electrode welding shell and the blind adapter may be integrally formed or they may be distinct components that are attached together. The presence of the internal cavity defined by the electrode welding shell and the blind adapter reduces the thermal mass of the welding electrode and slows the rate of conductive heat transfer from the weld face to a cooling fluid, which allows in the center of the weld face to retain heat for a longer duration once current flow through the welding electrode is terminated, thereby positively affecting the spot welding process for particular types of workpiece stack-ups including those that include an aluminum workpiece and an overlapping adjacent steel workpiece.

A moving mechanism brings the rotational axis of each driven rotator into alignment with the rotational axis of a drive rotator, which has an engaging face extending along its rotational axis. Each driven rotator has an engageable face extending along the rotational axis of the drive rotator. Rotating the drive rotator while moving the driven rotator, of which the rotational axis is aligned with the rotational axis, toward the drive rotator will bring the engaging face into engagement with the engageable face.

To accurately make a dressing quality determination based on resistance waveforms, a dressing quality determination method determines the quality of dressing performed for electrodes when resistance welding is performed at a plurality of welding points. This method includes accumulating a known resistance waveform immediately after dressing the electrodes, and a known resistance waveform immediately before dressing the electrodes; creating, by a statistical method, a model for setting a threshold value for dressing quality determination, based on a plurality of known resistance waveforms immediately after dressing and a plurality of known resistance waveforms immediately before dressing; acquiring an unknown resistance waveform immediately after dressing the electrodes; and determining whether dressing is normal or dressing is abnormal by comparing the unknown resistance waveform immediately after dressing with the threshold value for dressing quality determination.

Disclosed is a device for attaching corrective weights to a cylindrical outer surface of a rotor by means of electric resistance pressure welding, including an electrode (1) having a contact surface (20) for application against the rotor and comprising a supporting body (2) and a swinging body (6) having oppositely facing, congruent, spherical bearing surfaces (5, 8) suitable for abutting engagement with each other. The swinging body (6) is movably secured to the supporting body (2) such as to be able to perform limited swinging movements to all sides. A spring (14) arranged between the supporting body (2) and the swinging body (6) enables a gap to be produced between the spherical bearing surfaces (5, 8), whereby the contact surface (20) is in a position to align itself relative to the opposite surface of the rotor prior to pressure application by the welding force.