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.

A highly corrosion-resistant spot weldment can be produced at low cost without occurrence of prominent protrusions and the like on the surface. The spot weldment is joined by a nugget formed inside stacked sheet materials through bringing a pair of electrodes arranged opposite to each other into pressure contact with the stacked sheet materials from outside and energizing the stacked sheet materials from the electrodes. The nugget has a diameter that is ≥4√t (t: thickness of sheet material) and a flattening level of 3.5 to 8, which is a ratio of diameter to thickness. Both outer surface parts of the sheet materials are free from protrusions formed due to bulging of molten metal. Even when the electrodes are made of a copper alloy, the increased amount of Cu in the outer surface parts is 0.2 mass % or less with respect to the component composition before spot welding.

The invention relates to a spot welding cap changer (1) with a cap puller (2) and two cap magazines (3, 3A), the cap puller (2) having a gripper (20) with spring-loaded, pivotable jaws (21, 22), which in response to a turning and axial pulling-off movement detaches a spot welding cap (K) of a pincer spot welding head introduced into it from a shaft of the pincer welding head in such a way that it is clamped to prevent it twisting, and the cap magazines (3, 3A) holding spot welding caps respectively in a round cap carrier (31) such that they are circularly arranged in a directed and oriented manner and are respectively transported individually one after the other into an access position against a stop (32) by an advancing force (P).

The invention relates to a spot welding cap changer (1) with a cap puller (2) and two cap magazines (3, 3A), the cap puller (2) having a gripper (20) with spring-loaded, pivotable jaws (21, 22), which in response to a turning and axial pulling-off movement detaches a spot welding cap (K) of a pincer spot welding head introduced into it from a shaft of the pincer welding head in such a way that it is clamped to prevent it twisting, and the cap magazines (3, 3A) holding spot welding caps respectively in a round cap carrier (31) such that they are circularly arranged in a directed and oriented manner and are respectively transported individually one after the other into an access position against a stop (32) by an advancing force (P).

A welding portion inspection system includes a sensing head, and first and second electrodes that are disposed a predetermined distance from each other at one side of the sensing head, where front end portions of the first and second electrodes contact both sides of a welding portion to apply current such that a temperature of the welding portion is heated, and an infrared camera is disposed on the sensing head and detects a temperature distribution of the welding portion.

One aspect of the present disclosure is a resistance spot welding apparatus for welding a workpiece made of layered metallic plates. The resistance spot welding apparatus includes a first electrode; a second electrode arranged such that the workpiece is interposed between the first electrode and the second electrode; and a pressure mechanism that applies pressure to the first electrode towards the first metallic plate by air. The pressure mechanism includes a piston coupled to the first electrode; a cylinder having an inner space that accommodates the piston; a first ventilation unit that supplies the inner space with air for applying pressure to the first electrode; and a second ventilation unit that discharges air from the inner space as pressure is applied to the first electrode. At least one of the first ventilation unit or the second ventilation unit includes two or more air passages that communicate with the inner space.

The invention relates to a spot welding cap changer (1) with a cap puller (2) and two cap magazines (3, 3A), the cap puller (2) having a gripper (20) with spring-loaded, pivotable jaws (21, 22), which in response to a turning and axial pulling-off movement detaches a spot welding cap (K) of a pincer spot welding head introduced into it from a shaft of the pincer welding head in such a way that it is clamped to prevent it twisting, and the cap magazines (3, 3A) holding spot welding caps respectively in a round cap carrier (31) such that they are circularly arranged in a directed and oriented manner and are respectively transported individually one after the other into an access position against a stop (32) by an advancing force (P).

The invention relates to a spot welding cap changer (1) with a cap puller (2) and two cap magazines (3, 3A), the cap puller (2) having a gripper (20) with spring-loaded, pivotable jaws (21, 22), which in response to a turning and axial pulling-off movement detaches a spot welding cap (K) of a pincer spot welding head introduced into it from a shaft of the pincer welding head in such a way that it is clamped to prevent it twisting, and the cap magazines (3, 3A) holding spot welding caps respectively in a round cap carrier (31) such that they are circularly arranged in a directed and oriented manner and are respectively transported individually one after the other into an access position against a stop (32) by an advancing force (P).

A weld wheel cleaning system is provided to clean or remove a layer of embedded material and other debris produced from welding from the working surface of a weld wheel. Such a weld wheel cleaning system includes a cleaner with an abrasive material positioned on an outer surface of the cleaner. The cleaner is positionable adjacent to the weld wheel such that the abrasive material is aligned with the working surface of the weld wheel. An actuator can be used to selectively actuate the cleaner with a force sufficient to remove the layer of embedded material from the working surface of the weld wheel with the abrasive material. The debris from the cleaner can be removed by a vacuum.

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.