Abstract: A method for laser welding of a bipolar plate for a fuel cell is provided. The bipolar plate includes two metallic plate parts. The method includes producing at least one continuously enclosing first weld seam with a first seam width, and producing at least one second weld seam with a second seam width. The second seam width is at least 10% greater than the first seam width.

Abstract: A method for welding bar-type conductors includes arranging at least two bar-type conductors in partially overlapping fashion, and welding the at least two bar-type conductors to one another by using a processing laser beam. The processing laser beam traverses a welding contour relative to the bar-type conductors. The traversing of the welding contour includes an initial phase, a main phase and an end phase. In the initial phase, in a partial region of a beam cross section of the processing laser beam, an intensity of the processing laser beam, which is spatially averaged over the partial region, is increased over time. In the main phase, the spatially averaged intensity, which is achieved at the end of the initial phase, is kept at least substantially constant over time. In the end phase, the spatially averaged intensity, starting from the intensity at the end of the main phase, is reduced over time.

Abstract: A method for laser welding includes arranging two bar-type conductors next to one another with a partial overlap, and welding the two bar-type conductors to one another using a processing laser beam. A weld bead is formed on a common base surface of the bar-type conductors. During the welding, the processing laser beam is guided so that a welding contour is placed relative to the bar-type conductors. An advancing rate of the processing laser beam along the welding contour is selected such that the weld bead has a non-liquid oxide skin inside which liquid bar-type conductor material accumulates. The non-liquid oxide skin is partially broken open by the processing laser beam only on an upwardly facing end face of the weld bead, and remains undamaged in a surrounding region of the weld bead that extends downward from the upwardly facing end face and around the entire weld bead.

Abstract: A method for laser welding two workpieces includes arranging a first workpiece of a thickness D1 and a second workpiece of a thickness D2 on top of one another so that the first workpiece and the second workpiece overlap in a region of overlap. Each of D1 and D2 is 400 ?m or less. The method further includes melting, using a laser beam guided along a weld seam, a material of the first workpiece over an entirety of the thickness D1 and a material of the second workpiece over only a partial thickness TD of the thickness D2 in the region of overlap, from a side of the first workpiece. The laser beam generates a vapor capillary that extends to a capillary depth KT into the first workpiece or into the first workpiece and the second workpiece, where 0.33*EST?KT?0.67*EST, with EST being a weld depth EST=D1+TD.

Abstract: A method for stripping a rod-shaped conductor using laser radiation is provided. The rod-shaped conductor includes an electrically conductive core and a coating that is at least partially transparent to the laser radiation. The method includes traversing the conductor for a first time with at least one laser beam to at least partially reduce transparency of the coating, and traversing the conductor for a second time with the at least one laser beam to at least partially reduce adhesion of the coating.

Abstract: A method for monitoring and/or controlling in a closed loop a laser welding process for welding together two workpieces of metallic material includes, during the laser welding process, scanning a melt pool and/or a melt bead using an optical coherence tomography (OCT) measurement beam in at least one line scan, determining an actual geometry of the melt pool and/or the melt bead based on the at least one line scan, and setting at least one welding parameter controlled in the closed loop based on a deviation of the actual geometry from a target geometry of the melt pool and/or the melt bead.

Abstract: A method for monitoring an attachment area during laser welding of bent bar-type conductors containing copper, includes the steps of arranging a first bar-type conductor relative to a second bar-type conductor in partially overlapping fashion and welding the first and second bar-type conductors to one another using a processing laser beam, the welding including forming a weld bead interconnecting the bar-type conductors to one another. After the welding, at least one measurement variable is measured on at least one portion of the weld bead, wherein the at least one measurement variable changes with the temperature of the weld bead as a function of the time during a cooling down of the weld bead. A parameter depending on a heat capacity of the weld bead is determined from the at least one measured measurement variable, and the attachment area qualitatively or quantitatively determined from the parameter.

Abstract: The disclosure relates to methods and apparatuses for controlling a cutting process in which a workpiece is cut by a high-energy beam. A process light signal is detected emanating from an interaction region of the high-energy beam with the workpiece in a first wavelength range (??1), in which at least one metallic constituent (Fe, Cr) of the workpiece has at least one emission line, and in a second wavelength range (??2), which differs from the first wavelength range, in which continuum radiation of the workpiece without emission lines is detectable. Vaporization of the at least one metallic constituent (Fe, Cr) is monitored on the basis of an intensity of the process light signal detected in the first wavelength range (??1) and on the basis of an intensity of the process light signal detected in the second wavelength range (??2).

Abstract: A device for monitoring, in particular for closed-loop control, of a thermal cutting process carried out on a workpiece. The device includes a focusing unit for focusing a machining beam, in particular a laser beam, onto the workpiece for the formation of a kerf on the workpiece. The device also includes an image acquisition unit to generate at least one image of a region of the workpiece, and an evaluation unit configured to determine, based on the at least one image, at least one measured variable for the course of the gap width of the kerf in a thickness direction of the workpiece. The invention also relates to an associated method for monitoring, in particular for closed-loop control, of a thermal cutting process carried out on a workpiece.

Abstract: A method for joining busbars includes reshaping a raw laser beam to obtain a reshaped laser beam. The reshaped laser beam comprises a core focus portion and at least one ring focus portion. The core focus portion and the ring focus portion are coaxial with respect to one another. The ring focus portion surrounds the core focus portion. The method further includes directing the reshaped laser beam to a plurality of busbars to weld the plurality of busbars to one another along at least one weld seam.

Abstract: A method for laser welding of a workpiece includes welding at a corner joint of two workpiece parts of the workpiece by a welding laser beam to create an aluminum connection between the two workpiece parts, and feeding an output laser beam into a first end of a multiclad fiber to generate the welding laser beam. The multiclad fiber comprises at least a core fiber and a ring fiber surrounding the core fiber. A first portion LK of a laser power output of the output laser beam is fed into the core fiber, and a second portion LR of the laser power output of the output laser beam is fed into the ring fiber. A second end of the multiclad fiber is reproduced on the workpiece. The method further includes welding the workpiece by deep welding.

Abstract: A method for processing a foil comprising lithium includes irradiating the foil with a laser beam having a wavelength of between 200 nm and 1 ?m.

Abstract: A method for laser soldering includes selecting a copper-containing material as a filler material, supplying the filler material at a butt joint of two components, and melting the filler material in a main process zone by means of laser radiation in an advancement direction. The filler material in the main process zone is melted by means of laser radiation of a wavelength ?H in the blue or green spectral range with 400 nm??H?600 nm.

Abstract: A method for laser welding a multiplicity of foils onto a carrier includes arranging the foils one on top of the other to provide a foil stack, folding the foil stack to provide a folded region of the foil stack that protrudes up from two side regions of the foil stack, pressing the side regions against the carrier, and pressing together the side regions toward the folded region. The method further includes welding the foils to one another and to the carrier by directing a laser beam onto the folded region and moving the laser beam along the folded region.

Abstract: A method for joining copper hairpins includes providing at least two ends to be joined to one another of the copper hairpins, and joining the copper hairpins. The copper hairpins are joined by laser beam welding with a machining beam having a wavelength of less than 1000 nm.

Abstract: A method is provided for monitoring a laser welding process for welding two workpieces of metallic material, particularly copper or aluminum, preferably bar conductors, by using a laser beam, particularly for monitoring a plurality of identical laser welding processes for welding two identical workpieces with the same laser power and the same welding duration of the laser beam. During the welding, the laser beam is directed onto adjacently disposed end faces of the workpieces to melt a fusion spot at the end faces then solidifying to form a weld bead. During the welding, the solidification duration from turning off the laser beam until solidification of the fusion spot is determined, the determined solidification duration is compared with a setpoint solidification duration predetermined for pore defect-free welding, and if the determined solidification duration falls below the predetermined setpoint solidification duration, the solidified weld bead is classified as defective.

Abstract: A hairpin welding method welds wire ends of at least two copper wires, arranged flush next to one another, to one another by a laser beam. The laser beam is generated with a beam cross section that impinges on the wire ends at an end side and has a round core region and a ring region surrounding the round core region. A ratio of an external diameter of the ring region to a diameter of the core region is between 7:1 and 2:1. A ratio of a laser power in the core region to a laser power in the ring region is between 10:90 and 70:30.

Abstract: A device for monitoring, in particular for closed-loop control, of a thermal cutting process carried out on a workpiece. The device includes a focusing unit for focusing a machining beam, in particular a laser beam, onto the workpiece for the formation of a kerf on the workpiece. The device also includes an image acquisition unit to generate at least one image of a region of the workpiece, and an evaluation unit configured to determine, based on the at least one image, at least one measured variable for the course of the gap width of the kerf in a thickness direction of the workpiece. The invention also relates to an associated method for monitoring, in particular for closed-loop control, of a thermal cutting process carried out on a workpiece.

Abstract: The disclosure relates to methods and apparatuses for controlling a cutting process in which a workpiece is cut by a high-energy beam. A process light signal is detected emanating from an interaction region of the high-energy beam with the workpiece in a first wavelength range (??1), in which at least one metallic constituent (Fe, Cr) of the workpiece has at least one emission line, and in a second wavelength range (??2), which differs from the first wavelength range, in which continuum radiation of the workpiece without emission lines is detectable. Vaporization of the at least one metallic constituent (Fe, Cr) is monitored on the basis of an intensity of the process light signal detected in the first wavelength range (??1) and on the basis of an intensity of the process light signal detected in the second wavelength range (??2).