A joining apparatus for panel sheets and a joining method for panel sheets using the same are provided. The joining apparatus includes an element punching device which stores and supplies elements according to a specification of a panel sheet and inserts the element into a first panel sheet among different types of panel sheets. Additionally, a welding device resistively welds a part of the first panel sheet into which the element is inserted by the element punching device.

A method for welding a stack of sheets having a plurality of sheets of different materials is provided. In an aspect, the stack of sheets includes an aluminum sheet and a galvanneal steel sheet. In an aspect, the method includes resistively spot welding the galvanneal sheet to a hot-stamped steel sheet placed between the aluminum sheet and the galvanneal sheet, the sheet of hot-stamped steel including stress relief sections. The method further includes placing a metal foil on the aluminum sheet and vaporizing the metal foil to project portions of the aluminum sheet through the stress relief sections of the hot-stamped steel sheet to weld the portions of the aluminum sheet to the galvanized steel sheet. In another aspect, the method includes placing the metal foil on a raised portion of the aluminum sheet and projecting the raised portion of the aluminum onto the galvanneal steel sheet.

A welding process for the welding of aluminum includes a force sensor measuring a force between two welding electrodes on aluminum elements to be welded and transmitting its measured values to a welding control. Until the elapse of a set welding time, the welding control calculates and stores at least one absolute value and/or at least one increase in the measured force. The welding control compares the measured absolute value and/or the increase in the measured force with a reference value and/or a reference curve and calculates a control deviation from the comparison. After the elapse of the set welding time, the welding control subjects the welding electrodes to a constant current during a welding time extension that follows the set welding time, dependent on a magnitude of the control deviation that is measured at the point in time of the elapse and/or during the set welding time.

A laminate structure and method of welding the laminate structure is provided. The laminate structure includes a first metal sheet having a first thickness, a second metal sheet having a second thickness, and an adhesive core made of an adhesive material also described as a viscoelastic adhesive material. The adhesive core is disposed between and bonded to the first and second metal sheets. The first and second metal sheets are made of an aluminum based material. The adhesive core includes a plurality of electrically conductive filler particles dispersed in the adhesive materials. The filler particles are made of a first filler material and at least a second filler material which is a different material than the first filler material.

A laminate structure and method of forming is provided. The laminate structure includes a first metal sheet having a first thickness, a second metal sheet having a second thickness, and an adhesive core having an adhesive thickness. The adhesive core is disposed between and bonded to the first and second metal sheets. The first and second metal sheets are made of an aluminum based material and the adhesive core is made of an adhesive material also described as a viscoelastic adhesive material. The laminate structure is configured such that a ratio of the sum of the first and second thickness to the adhesive thickness is greater than either to one (8:1). The laminate structure including the viscoelastic adhesive core is characterized by a composite loss factor at 1,000 Hertz which is continuously greater than 0.1 within a temperature range of 25 degrees Celsius to 50 degrees Celsius.

A self-piercing riveting system includes a localized melting system that locally melts a target location on a metal substrate and a driver that drives a rivet into to the metal substrate after the target location is locally melted. A method of forming a joint with a self-piercing riveting system includes locally melting a target location on the at least two metal substrates. The method also includes driving a rivet into the target location, optionally with a driver, after locally melting the target location such that the rivet pierces the at least two metal substrates at the target location.

This spot welding method for an aluminum material comprises: a processing step in which, in a plan view, a circular emboss expanded in a direction of superposition on a second aluminum plate side is formed at a position-to-be-welded of a first aluminum plate; an arrangement step in which positions-to-be-welded are superimposed while the expansion side of the emboss faces the second aluminum plate, and the positions-to-be-welded are arranged between a pair of electrodes; a pressing step in which the superimposed aluminum plates are pinched between the electrodes, and a central side excluding a peripheral edge of the emboss is pressed; and an electrification step of performing pressing and electrification. An electrode having a tip diameter larger than the diameter of a root part of the expansion part of the emboss is used.

A resistance welding apparatus includes a welding tool with a welding electrode configured to contact a component. A welding transformer is configured to feed an electric current to the welding tool and a control device is configured to control a polarity of welding transformer by transmitting polarity information to the welding transformer such that a polarity of the welding transformer is switchable. A circuit including two transistors is operably connected in series between the welding tool and an output of the welding transformer and a polarity one of the transistors is rotated relative to the other transistor, such that a polarity of a welding voltage at the welding electrode is switchable with the switching of the polarity of the welding transformer, and such that a polarity of a welding current at the welding transformer is switchable with the switching of the polarity of the welding transformer.

A welding assembly may include a current generator, a first electrode electrically coupled to the current generator, the first electrode including a first engagement surface, a second electrode electrically coupled to the current generator, the second electrode including a second engagement surface and a width-determining fixture positioned between the first electrode and the second electrode to define a welding volume.

A workpiece stack-up that includes at least a steel workpiece and an adjacent and overlapping aluminum workpiece can be resistance spot welded by a multi-stage spot welding method. The multi-stage spot welding method involves initially forming a weld joint between the steel and aluminum workpieces. The weld joint extends into the aluminum workpiece from the faying interface of the two workpieces and includes an interfacial weld bond area adjacent to and joined with the faying surface of the steel workpiece. After the weld joint is initially formed, the multi-stage spot welding method calls for remelting and resolidifying at least a portion of the weld joint that includes some or all of the interfacial weld bond area. At least a portion of the resultant refined weld joint may then be subjected to the same remelting and resolidifying practice, if desired. Multiple additional practices of remelting and resolidifying may be carried out.