The present disclosure generally relates to a welding machine adapted for performing a spot welding process on a workpiece, wherein the welding machine is specifically adapted for automatically applying pre-conditioning a welding pulse portion to the workpiece prior to performing the spot welding process. The present disclosure also relates to a corresponding method and computer program product.

A resistance spot welding method includes: performing test welding; and performing actual welding after the test welding, wherein in subsequent current passage in the test welding, current passage is performed by constant current control under a condition: 0.5 ? Vtp/Vtm ? 2.0 when tc<800 ms; 0.5?0.3.Math.(tc?800)/800 ? Vtp/Vtm ? 2.0?0.5.Math.(tc?800)/800 when 800 ms ? tc<1600 ms; and 0.2 ? Vtp/Vtm ? 1.5 when tc ? 1600 ms, and wherein in main current passage in the actual welding, adaptive control welding is performed, and in subsequent current passage in the actual welding, current passage is performed by constant current control under a condition: 0.8.Math.Itp ? Imp ? 1.2.Math.Itp.

Provided are a method and an apparatus for resistance spot welding in which preliminary current application is executed and then main welding is executed in accordance with master patterns of various parameters obtained during the preliminary current application. The main welding is executed under welding conditions of the master patterns, and whether a welding abnormality has occurred and whether the welding abnormality is likely to occur are determined. When the welding abnormality is likely to occur, the welding conditions for the main welding are corrected so as to prevent the welding abnormality. When the welding abnormality is unlikely to occur, the welding conditions for the main welding are corrected so as to match the master patterns.

The current invention is a system and application that provides key insight into the technological processes that encompass a welding calculator apparatus consisting of a calculator casing, an optical rotary encoder in the calculator casing for providing weld length data, a time counter in the calculator casing for providing weld time data and a microcontroller device in the calculator casing for processing weld length data and weld time data, weld travel speed data and heat input data.

A system and method to correct for height error during a robotic additive manufacturing process. One or both of an output current, output voltage, output power, output circuit impedance and a wire feed speed are sampled during an additive manufacturing process when creating a current layer. A plurality of instantaneous contact tip-to-work distances (CTWD's) are determined based on at least one or both of the output current, output voltage, output power, output circuit impedance and the wire feed speed. An average CTWD is determined based on the plurality of instantaneous CTWD's. A correction factor is generated, based on at least the average CTWD, which is used to compensate for any error in height of the current layer.

A no-indentation welding monitoring device may include a pressing force measuring device for measuring a pressing force for pressing a welding target of a welding tip of a welding gun, a voltage measuring device for measuring a voltage applied to the welding tip of the welding gun, and a monitor device for digitizing a welding quality by use of the pressing force and the voltage transmitted from the pressing force measuring device and the voltage measuring device.

A welding installation with a calibration tool is provided in a device for producing container shells. The force exerted by the container shells on the calibration tool is measured and evaluated as information for the overlapping width of the respective container shell. This allows adjusting the calibration tool during configuration of the device and allows the removal of container shells welded with too large or too small overlapping during production of container shells.

Methods and apparatus for detecting a leakage current are disclosed. An example apparatus to monitor a welding-type system includes: a test signal generator configured to output a test signal to a welding-type circuit; and a lock-in amplifier configured to: receive a reference signal based on the test signal; measure a leakage current in the welding-type circuit based on the reference signal; and generate an output signal representative of the leakage current.

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.

A sealing method that uses an electrostatic energy storage welding machine which includes an energy storage section including a plurality of energy storage parts is provided. A method of sealing a liquid inlet port of a power storage device includes burring in advance a through-hole of the liquid sealing port to raise a hole edge of the through-hole into a form of a projection, wherein the liquid sealing port of the power storage device to be sealed with electrolyte contained therein corresponds to an object to be welded; placing a spherical body that is a lid body on the projection; and performing resistance welding between the projection and the spherical body to seal the liquid inlet port.