Abstract: A method of spot welding a workpiece stack-up that includes a steel workpiece and an aluminum alloy workpiece involves passing an electrical current through the workpieces and between welding electrodes that are constructed to affect the current density of the electrical current. The welding electrodes, more specifically, are constructed to render the density of the electrical current greater in the steel workpiece than in the aluminum alloy workpiece. This difference in current densities can be accomplished by passing, at least initially, the electrical current between a weld face of the welding electrode in contact with the steel workpiece and a perimeter region of a weld face of the welding electrode in contact with the aluminum alloy workpiece.

Abstract: A method of resistance spot welding a workpiece stack-up. The workpiece stack-up includes at least a steel workpiece and an aluminum workpiece. The method involves attaching a steel plate to the steel workpiece at a weld-site of the workpiece stack-up, passing electrical current between a first welding electrode and a second welding electrode at the weld-site, and terminating passage of electrical current between the first and second welding electrodes in order to form a weld joint. The steel plate serves to stiffen the weld joint.

Abstract: An additive manufacturing system includes a powder delivery system, an area scanning laser, a build chamber, and a controller. The powder delivery system provides a predetermined amount of powder material to the build chamber, and includes a material dispenser, a dispensing head, and a scraper. The scanning laser selectively sinters the powder material, and includes a mirror galvanometer for raster scanning. The build chamber has an annular configuration, and includes an inner annular wall that defines a central portion disposed inward of the build chamber. A portion of the delivery system and the laser are located in the central portion. The chamber continuously rotates under the head and under a sintering zone generated by the laser as the delivery system continuously dispenses the material. The laser continuously raster scans the material at the sintering zone in a raster pattern to sinter a layer of material directly to a preceding layer.

Abstract: A welding electrode includes a weld face that has a convex base weld face surface and a plurality of ringed ridges that are radially spaced apart on the base weld face surface and surround a central weld face axis. The plurality of ringed ridges including an innermost ringed ridge and an outermost ringed ridge. The innermost ringed ridge is located closest to the central weld face axis and rises above a central portion of the base weld face surface, and the outermost ringed ridge is located farthest from the central weld face axis and rises above an outer peripheral portion of the base weld face surface. At least one of the plurality of ringed ridges is a discontinuous ringed ridge.

Abstract: A workpiece stack-up that includes at least a steel workpiece and an aluminum-based workpiece can be resistance spot welded by employing a multi-stage spot welding method in which the passage of electrical current is controlled to perform multiple stages of weld joint development.

Abstract: A method of laser welding a workpiece stack-up (10) of overlapping steel workpieces (12, 14) involves heat-treating a region (64) of the stack-up (10) followed by forming a laser weld joint (66) that is located at least partially within the heat-treated region (64). During heat-treating, one or more pre-welding laser beams (68) are sequentially directed at a top surface (20) of the workpiece stack-up (10) and advanced along a pre-welding beam travel pattern (70) so as to reduce an amount of vaporizable zinc within the stack-up (10). Thereafter, the laser weld joint (66) is formed by directing a welding laser beam (82) at the top surface (20) of the workpiece stack-up (10) and advancing the welding laser beam (82) along a welding beam travel pattern (84) that at least partially overlaps with a coverage area of a pre-welding beam travel pattern (70) or a shared coverage area portion of multiple pre-welding beam travel patterns (70).

Abstract: A method of joining workpieces includes the steps of bringing a first workpiece and a second workpiece together, induction heating a susceptor material, and pressing the workpieces together. Each workpiece may include a thermoplastic material, and the workpieces are brought together at a joint interface so that a protrusion of the first workpiece is aligned with a receptacle of the second workpiece. The susceptor material is in contact with the thermoplastic material of the first workpiece during heating such that the thermoplastic material of the first workpiece softens. The step of pressing is performed while the thermoplastic material of the first workpiece is softened, thereby reshaping the first workpiece where the susceptor material is in contact with the thermoplastic material of the first workpiece. The protrusion is deformed to form an interlock with the receptacle at the joint interface.

Abstract: A probe for detecting discontinuities includes: a body portion; a head portion; one or more inductor coils located in the head portion and configured to: receive power from a power source; when power is received, induce an eddy current in a joint where a first metal component is joined with a second metal component; based on the induced eddy current, output a signal indicative of an inductance of the one or more inductor coils; and a plurality of positioning devices configured to maintain the one or more inductor coils approximately a predetermined distance from the surface.

Abstract: A method of resistance spot welding a workpiece stack-up that includes a steel workpiece and one or more aluminum workpieces involves locally stiffening the steel workpiece to resist steel workpiece deformation. The local stiffening of the steel workpiece is achieved by incorporating an electrode receiving wall into the steel workpiece along with one or more integral elevated portions of the steel workpiece that are disposed at least partially around the electrode receiving wall. The electrode receiving wall includes an electrode-contact surface and an opposed interface contact surface. During welding, a weld face of one welding electrode is pressed against the electrode-contact surface of the electrode receiving wall of the steel workpiece, and electric current is momentarily passed between that welding electrode and another welding electrode on the opposite side of the workpiece stack-up to form a weld joint that bonds to the interface contact surface of the electrode receiving wall.

Abstract: A method of resistance spot welding a workpiece stack-up that includes an aluminum workpiece and an overlapping adjacent steel workpiece so as to minimize the thickness of an intermetallic layer comprising Fe—Al intermetallic compounds involves providing reaction-slowing elements at the faying interface of the aluminum and steel workpieces. The reaction-slowing elements may include at least one of carbon, copper, silicon, nickel, manganese, cobalt, or chromium. Various ways are available for making the one or more reaction-slowing elements available at the faying interface of the aluminum and steel workpieces including being dissolved in a high strength steel or being present in an interlayer that may take on a variety of forms including a rigid shim, a flexible foil, a deposited layer adhered to and metallurgically bonded with a faying surface of the steel workpiece, or an interadjacent organic material layer that includes particles containing the reaction-slowing elements.

Abstract: A method of joining a first workpiece substrate and a second workpiece substrate is disclosed in which a local mold tool is positioned into contact with the first workpiece substrate and the second workpiece substrate. The local mold tool defines a mold cavity and encloses an edge portion of the first workpiece substrate and an edge portion of the second workpiece substrate such that the edge portion of the first workpiece substrate and the edge portion of the second workpiece substrate are contained within the mold cavity. Once the local mold tool is positioned, a liquid polymer molding compound is injected into the mold cavity. The liquid polymer molding compound is hardened in the mold cavity into a polymer joint that adheres the edge portion of the first workpiece substrate and the edge portion of the second workpiece substrate together.

Abstract: A method of joining workpieces includes the steps of bringing a first workpiece and a second workpiece together, induction heating a susceptor material, and pressing the workpieces together. Each workpiece may include a thermoplastic material, and the workpieces are brought together at a joint interface so that a protrusion of the first workpiece is aligned with a receptacle of the second workpiece. The susceptor material is in contact with the thermoplastic material of the first workpiece during heating such that the thermoplastic material of the first workpiece softens. The step of pressing is performed while the thermoplastic material of the first workpiece is softened, thereby reshaping the first workpiece where the susceptor material is in contact with the thermoplastic material of the first workpiece. The protrusion is deformed to form an interlock with the receptacle at the joint interface.

Abstract: A fused filament deposition head is employed for depositing filament materials on workpieces to join the workpieces together. The workpieces can be of an automotive application, aerospace application, or something else. The fused filament deposition head, in an example, has a feed end, a dispensing end, and a heater. The feed end introduces more than one filament in the fused filament deposition head, as demanded in the larger application. The dispensing end delivers materials of the filaments to the underlying workpieces. The materials are delivered together. The heater serves to heat the filaments as they travel through the fused filament deposition head. The filaments can include a filament having a core portion of liquid-crystal polymer material.

Abstract: A composite fusion filament is disclosed that includes a polymer encasement and one or more mesogenic reinforcement bodies contained within the polymer encasement. The polymer encasement is comprised of a thermoplastic polymer, which has a melting temperature, and each of the one or more mesogenic reinforcement bodies is comprised of a thermotropic liquid crystal polymer, which has a clearing temperature. The melting temperature of the thermoplastic polymer included in the polymer encasement is less than the clearing temperature of the thermotropic liquid crystal polymer included in the one or more mesogenic reinforcement bodies. Additionally, the thermotropic liquid crystal polymer of each mesogenic reinforcement body has a plurality of organized crystalline fibrils that are aligned lengthwise along a longitudinal axis of the polymer encasement. A method of using the composite fusion filament to form a bond with a substrate that includes a thermoplastic polymer is also disclosed.

Abstract: A spot weld may be formed between an aluminum workpiece and an adjacent overlapping steel workpiece with the use of opposed spot welding electrodes that have mating weld faces designed for engagement with the outer surfaces of the workpiece stack-up assembly. The electrode that engages the stack-up assembly proximate the aluminum workpiece includes a central ascending convex surface and the electrode that engages the stack-up assembly proximate the steel workpiece has an annular surface. The mating weld faces of the first and second spot welding electrodes distribute the passing electrical current along a radially outwardly expanding flow path to provide a more uniform temperature distribution over the intended spot weld interface and may also produce a deformed bonding interface within the formed weld joint. Each of these events can beneficially affect the strength of the weld joint.

Abstract: A welding electrode and a method of using the welding electrode for resistance spot welding are disclosed. The welding electrode includes a body and a weld face. The weld face includes a central dome portion and a shoulder portion that surrounds the central dome portion and extends from an outer circumference of the weld face upwardly and radially inwardly to the central dome portion. The central dome portion has a series of radially-spaced ringed ridges that project outwardly from a base dome face surface. The series of radially-spaced ringed ridges on the central dome portion includes an innermost ringed ridge and an outermost ringed ridge. The outermost ringed ridge on the central dome portion has a radial inner side surface and a radial outer side surface. The radial outer side surface extends below the base dome face surface down to the shoulder portion of the weld face.

Abstract: A series of many electrical resistance spot welds is to be formed in members of an assembled, but un-joined, body that presents workpiece stack-ups of various combinations of metal workpieces including all aluminum workpieces, all steel workpieces, and a combination of aluminum and steel workpieces. A pair of spot welding electrodes, each with a specified weld face that includes oxide-disrupting features, is used to form the required numbers of aluminum-to-aluminum spot welds, aluminum-to-steel spot welds, and steel-to-steel spot welds. A predetermined sequence of forming the various spot welds may be specified for extending the number of spot welds that can be made before the weld faces must be restored. And, during at least one of the aluminum-to-steel spot welds, a cover is inserted between the weld face of one of the welding electrodes and a side of a workpiece stack-up that includes the adjacent aluminum and steel workpieces.

Abstract: A method of resistance spot welding a steel workpiece and an aluminum or aluminum alloy workpiece, and a welding electrode used therein. In one step of the method a workpiece stack-up is provided. The workpiece stack-up includes a steel workpiece and an aluminum or aluminum alloy workpiece. Another step of the method involves contacting the aluminum or aluminum alloy workpiece with a weld face of the welding electrode. The welding electrode has a body and an insert. The insert is composed of a material having an electrical resistivity that is greater than an electrical resistivity of the material of the body. The weld face has a first section defined by a surface of the insert and has a second section defined by a surface of the body. Both the first and second sections make surface-to-surface contact with the aluminum or aluminum alloy workpiece amid resistance spot welding.

Abstract: A method of resistance spot welding a workpiece stack-up comprising overlapping first and second steel workpieces is disclosed, wherein at least one of the steel workpieces comprises an advanced high-strength steel substrate. The workpiece stack-up is positioned between a pair of opposed first and second welding electrodes. A cover is disposed between at least one of the first steel workpiece and the first welding electrode or the second steel workpiece and the second welding electrode at an intended weld site. The workpiece stack-up is clamped between the first and second welding electrodes at the weld site such that at least one of the weld faces of the first and second welding electrodes presses against the cover. The first and second steel workpieces are welded together by passing an electrical current between the first and second welding electrodes at the weld site.

Abstract: A method of laser welding a workpiece stack-up that includes two or three overlapping aluminum alloy workpieces involves constraining a free end of an overlapping portion of a first aluminum alloy workpiece against movement away from an underlying second aluminum alloy workpiece to counteract the thermally-induced forces that cause out-of-plane deformation of one or more of the aluminum alloy workpieces during laser welding. Such constraint of the free end of the first aluminum alloy workpiece may be accomplished by clamping, spot welding, or any other suitable practice. By constraining the free end of the first aluminum alloy workpiece, and thus inhibiting out-of-plane deformation of the aluminum alloy workpieces when laser welding is practiced in a nearby welding region, the occurrence of hot cracking is minimized or altogether eliminated in the final laser weld joint.