A tip dresser cutter including a circumferential portion having a circular shape rotatable about an axis of rotation, a center portion located radially inward from the circumferential portion proximate the axis of rotation, and a cutting flute extending radially between the center portion and the circumferential portion. The cutting flute including a leading edge, a trailing edge, a radially inward canted surface extending between the leading edge and the trailing edge. The radially inward canted surface includes a first section extending between the center portion and a first location on the cutting flute and a second section extending between the first location on the cutting flute and a second location on the cutting flute. The second section of the radially inward canted surface including a curved portion that is parallel to a plane of rotation of the cutting flute.

The present disclose provides a method of resistance spot welding that can inhibit Liquid Metal Embrittlement-induced cracking in zinc-coated steel plates irrespective of the plate thicknesses. One aspect of the present disclosure provides a method of resistance spot welding that includes welding a workpiece with a resistance spot welding apparatus. The workpiece includes two or more steel plates in an overlapping state. The two or more steel plates include at least one steel plate coated with zinc. The welding includes causing a cooling rate of a high-tensile steel plate among the two or more steel plates to be higher than a cooling rate of an other steel plate among the two or more steel plates. The high-tensile steel plate has a tensile strength higher than a tensile strength of the other steel plate.

The present disclose provides a method of resistance spot welding that can inhibit Liquid Metal Embrittlement-induced cracking in zinc-coated steel plates irrespective of the plate thicknesses. One aspect of the present disclosure provides a method of resistance spot welding that includes welding a workpiece with a resistance spot welding apparatus. The workpiece includes two or more steel plates in an overlapping state. The two or more steel plates include at least one steel plate coated with zinc. The welding includes causing a cooling rate of a high-tensile steel plate among the two or more steel plates to be higher than a cooling rate of an other steel plate among the two or more steel plates. The high-tensile steel plate has a tensile strength higher than a tensile strength of the other steel plate.

A first electrode coolant path is configured to cool a first welding electrode by liquid coolant flowing from a supply path through the first electrode coolant path to a return path. A second electrode coolant path is configured to cool a second welding electrode by liquid coolant flowing from the supply path through the second electrode coolant path to the return path. Three or more valves are configured to stop or reduce liquid coolant flow through the first or second electrode coolant path and configured to stop or reduce liquid coolant backflow from the return path when the first or second welding electrode is at least partially detached. At least one valve is coupled in the first or second electrode coolant path. A drawback apparatus generates a suction force to draw liquid coolant away from a gap formed when the first or second welding electrode is at least partially detached.

A spot welding apparatus (10) according to the present invention includes: a circular cylindrical cam (12) having an outer circumferential surface, in which a spiral-shaped large lead cam groove (12a) inclined at a steep angle and a spiral-shaped small lead cam groove (12b) inclined at a gentle angle are formed; and a pressurizing shaft (13) including a plurality of rollers (R1, R2) insertable into the respective cam grooves (12a, 12b) and configured to move along an axis of rotation of the circular cylindrical cam (12) when the circular cylindrical cam (12) rotates. When the rollers (R1, R2) are inserted into the large lead cam groove (12a), a roller (R1, R2) located at one end side of a row comes into contact with one of two sides surfaces of the cam groove (12a) and a roller (R1, R2) located at another end side of the row comes into contact with the other one of the two side surfaces of the cam groove (12a), and when the rollers (R1, R2) are inserted into the small lead cam groove (12b), each of the rollers (R1, R2) comes into contact with at least one of one side surface and the other side surface of two side surfaces of the cam groove (12b).

A system and method apparatus for purging liquid coolant from liquid coolant lines providing cooling to welding electrodes in a welding apparatus. The system provides a purging fluid of air at a pressure higher than a pressure of the liquid coolant to be purged. High-pressure air is generated by a centralized compressor and distribution system, a local electric pump, or existing robotic arm movements applied to pump bellows mounted thereon. A variety of placements, tie-ins, and hardware for fluid purging line(s) and its valve(s), for coolant supply(ies) and its valve(s), for coolant return(s) and its valve(s), and for liquid coolant line(s) and its valve(s) allow individual liquid coolant lines to be purged independently, with trade-offs of speed to purge, thoroughness of purge, amount of liquid coolant needed to be purged.

A welding electrode for use in resistance spot welding an assembly of metal workpieces with curved surfaces and closed or open sections is disclosed. The welding electrode includes a body, a weld face at one end of the body, and contoured curvature forming the weld face. The contoured curvature is configured to seat around the curved surfaces of the metal workpieces when the weld face is pressed against the workpieces during a resistance spot weld event. When brought into contact with the curved surface of the workpiece, the electrode has an optimal contact area, which improves the spot weld process by improving the pressure and current distributions.

A welding electrode for use in resistance spot welding an assembly of metal workpieces with curved surfaces and closed or open sections is disclosed. The welding electrode includes a body, a weld face at one end of the body, and contoured curvature forming the weld face. The contoured curvature is configured to seat around the curved surfaces of the metal workpieces when the weld face is pressed against the workpieces during a resistance spot weld event. When brought into contact with the curved surface of the workpiece, the electrode has an optimal contact area, which improves the spot weld process by improving the pressure and current distributions.

A spot welding method including: a main energization step of energizing a pair of opposing electrodes in pressure contact with both outer surfaces of a set of sheets where multiple sheet materials are stacked, thereby to cause melting between facing surfaces of the sheet materials; and a pressing variation step of, prior to the main energization step, causing a pulsation of pressing force applied to the set of sheets from the electrodes. A resin material such as an adhesive or a sealant may be interposed between the facing surfaces of at least a pair of the sheet materials. The period of the pulsation is 0.01 to 0.7 seconds. The amplitude of the pulsation is 10% to 90% with respect to a reference value of the pressing force. The set of sheets may include a first and a second steel sheet, and an aluminum alloy sheet that are stacked in order.

An electrode and a device for resistance spot welding are capable of preventing an occurrence of a surface spatter by using magnetism. The electrode may include a shank and a welding tip mounted to an end of the shank. A magnetic unit is installed on an outer peripheral surface of the shank to form a magnetic field and to form a Lorentz force in a direction of rotation along a circumferential direction of the shank by the magnetic field and a current flowing through the shank.