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.

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.

A resistance spot welding method able to form a welded joint having delayed fracture resistance, comprising, in order, a step of applying a pressing force P1 (kN) to the plurality of steel sheets by welding electrodes while supplying a supplied current I1 (kA), a step of, while applying the pressing force P1, supplying a current Ic (kA) during a cooling time tc (s), a step of repeating two times or more a pressure force raising and lowering cycle of supplying a supplied current I2 (kA) to the welding electrodes while applying a pressing force P2 (kN) to the plurality of steel sheets by the welding electrodes during a pressing time tf (s), then immediately applying a pressing force P3 (kN) during a pressing time ti (s), a step of applying the pressing force P2 during the pressing time tf, and a step of releasing the pressing force and ending the supply of current, satisfying 0Ic<I1, 0.3I2/I1<1.0, P2/P11.2, P3<P2, and ti0.2.

A control apparatus for a welding tool includes a determination module for determining a normalized displacement signal, in which a deflection of a tong-shaped tool, due to an effect of a mechanical force generated on the tool during a work process using the tong-shaped tool, is compensated for. The control apparatus further includes a force regulation module for regulating a progression of the force which the tong-shaped tool applies to at least one component during the work process on at least one component. The force regulation module is configured to regulate the progression of the force during the work process based on the normalized displacement signal.

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.

To provide a spot welding system capable of shortening a cycle time of spot welding. A robot controller measures a time between a transmission time of a welding command signal to a welding machine and a reception time of a welding completion signal, after determining completion of pressuring by a spot welding robot, and subtracts a predetermined welding time from the measured time, thereby calculating a communication delay time between the robot controller and the welding machine. A spot welding system advances transmission timing of the welding command signal and the welding completion signal by the calculated communication delay time.

Disclosed are weld electrode plugs with polymeric inserts for loss-of-cooling detection, methods for making or for using such weld electrode plugs, and electric welding systems equipped with loss-of-cooling detection plugs. A disclosed loss-of-cooling detection assembly includes a plug that attaches to the weld shank of a welding system such that the plug fluidly couples to a coolant bore within the shank. The plug includes a plug body with a clearance hole extending therethrough. An insert detachably mounts to the plug such that the insert fluidly seals the clearance hole. This insert is fabricated from a polymeric material, such as a shape memory polymer, that alters a physical property, such as shape/size, of the insert responsive to changes in temperature and/or pressure of coolant fluid in the shank's bore. When this physical property is altered, the insert unseals the clearance hole causing a detectable leak of fluid from the shank.

Shifts of a reference point C in a robot coordinate system among three postures of a seam welding apparatus 10 are found, and calibration data is obtained (STEP 1). Correction data is found from the calibration data based on deformation of elastic units 22a due to weight of the seam welding apparatus 10 in accordance with the posture of the seam welding apparatus 10 relative to a robot 20 (STEP 5). Teaching data is corrected based on the correction data (STEP 6).

In the indirect spot welding apparatus, a lower limit in a stable pressing force region where the pressing force of the spot welding electrode against the metal sheets can be controlled within a tolerance of 10% ranges from 70 N to 200 N and an upper limit in the stable pressing force region ranges from 800 N to 2000 N, and an overshoot OS(%)=(PLAL)/AL100 of the pressing force occurring when the spot welding electrode is pressed against the metal sheets is controlled to be 10% or less.

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.