Gm Global Technolgoy Operations, Inc.

Robert T Szymanski

Yen-Lung Chen

Mark T Hall

David R Sigler

Blair E Carlson

Sri Krishna Chimbli

Anil Kumar Sachdev

David S Yang

Bradley J Blaski

Xiaohong Gayden

Spyros Pete Mellas

Amberlee S Haselhuhn

Yuri Hovanski

Kenneth A Ross

Mark A Cunningham

Corey C Holupko

Robert L Totten

Gregory A Fischer

A combined stackup apparatus with a perforated interlayer for resistance spot welding is provided. The apparatus comprises a first metal sheet of a first material and a second metal sheet of a second material. The apparatus further comprising a perforated interlayer disposed between the first metal layer and the second metal layer. The perforated interlayer is made of one of the first and second materials. The perforated interlayer has a plurality of perforations formed therethrough. Each perforation has a perforation size of between about 0.1 mm and about 3 mm.

Combined stackup apparatus for resistance spot welding

A bobbin tool is disclosed that includes a top shoulder, a bottom shoulder, and an axial pin that extends between the top and bottom shoulders. The bottom shoulder has an annular shoulder end surface, a back surface opposite the annular shoulder end surface, and a side surface that joins the annular shoulder end surface and the back surface. One or more and radially-extending blades may be disposed on the side surface of the bottom shoulder and/or one or more axially-extending blades may be disposed on the back surface. The one or more blades provide the bobbin tool with an ability to friction stir weld a variable thickness workpiece assembly, axially plunged through the workpiece assembly along an axis of rotation of the bobbin tool, and/or be extracted through the workpiece assembly along an axis of rotation of the bobbin tool.

Friction stir welding bobbin tool

A method of resistance spot welding a steel workpiece and an aluminum or aluminum alloy workpiece together includes several steps. One step involves inserting a cover between the aluminum or aluminum alloy workpiece and an adjacent welding electrode. In another step, the adjacent welding electrode is pressed against cover, and another opposed welding electrode is pressed against the steel workpiece at a weld site. In yet another step, electrical current is passed between the welding electrodes, passed through the cover, and passed through the workpieces in order to initiate and grow a molten weld pool within the aluminum or aluminum alloy workpiece.

Resistance spot welding steel and aluminum workpieces using insertable cover

When a friction stir weld tool penetrates the interface of two workpieces of dissimilar metal alloy materials, the resultant weld of the different alloy materials may produce a weak weld joint. Such weak joints are often experienced, for example, when attempting to form spot welds or other friction stir welds between a magnesium alloy sheet or strip and an aluminum alloy sheet or strip. It is discovered that suitable coating compositions including an adhesive placed at the interface of assembled workpieces can alter the composition of the friction stir weld material and strengthen the resulting bond. In the example of friction stir welds between magnesium alloy and aluminum alloy workpieces, it is found that combinations of an adhesive with copper, tin, zinc, and/or other powders can strengthen the magnesium-containing and aluminum-containing friction stir weld material.

Friction stir welding of dissimilar metals

A pressure-applying device for use with a welding apparatus includes an annular collar, a housing component, a pressure foot, and a motor. The housing component is coupled with the annular collar and selectively rotatable relative to the annular collar. The pressure foot is at least partially located in the housing component and has a discontinuous contact surface for contacting a work piece and has a central opening for accommodating a welding tool, the discontinuous contact surface may have a first and second contact surface that are respectively disposed on substantially opposing sides of the central opening. The motor is coupled to the housing component and is configured to rotate the housing component with respect to the annular collar.

Servo-controlled rotating clamping device for use with a friction stir spot welding apparatus

A welded assembly characterized by improved structural integrity includes a first component disposed along a first plane. The first component includes first and second substantially parallel surfaces, and also includes a channel arranged on the first surface. The welded assembly also includes a second component disposed along a second plane, wherein the second component includes a leading edge. The leading edge of the second component is inserted into the channel of the first component such that an interface is formed between the first and second components. A weld generated on the second surface joins the first component with the second component at the interface such that the assembly is formed. The subject weld may be a friction-stir type of a weld. The subject welded assembly may be a vehicle bumper support. A method of forming such a welded assembly is also disclosed.

Structural integrity welded assembly

A device for use with a welding apparatus, such as a friction stir spot welding (FSSW) apparatus, that maintains work pieces in a generally flat or flush orientation during a welding operation. The device can be mounted to the operable end of an FSSW apparatus so that it exerts a stabilizing force against an upper work piece. The stabilizing force exerted by the device prevents the upper work piece from deflecting when the rotating tool of the FSSW apparatus passes through the upper work piece and penetrates into the lower work piece. In an exemplary embodiment, the device includes a housing component that slidably receives a movable component under the force of a biasing component.

Device for use with a friction stir spot welding (FSSW) apparatus

A method of performing a plurality of friction stir spot welds with a friction stir spot welding (FSSW) system includes measuring a length of a pin of a weld tool of the FSSW system. The length is compared to a first limit to determine if the length is above or below the first limit. Debris is removed off of a tip of the pin when the length is determined to be above the first limit. The length is also compared to a second limit to determine if the length is above or below the second limit. At least one friction stir spot weld is performed on a workpiece when the length is determined to be less than the first limit and above the second limit.

Method of calibrating a friction stir spot welding system

In a Friction Stir Welding process a load, applied through a rotating tool, frictionally heats, plasticizes and commingles selected regions of the workpieces while translating along the length of the joint. The load is supported by an anvil. The applied load inhibits relative motion of the workpiece and conventional anvils due to friction which requires application of higher translation forces and could lead to undesired surface blemishes. Thus conventional practice is to employ bulky, stationary anvils. Compact, moveable anvils comprising freely-rotating or freely moving elements in contact with the workpieces and capable of reducing workpiece-anvil friction are described. Particular benefits of this anvil design are illustrated for the process of assembling inner and outer sheet metal components into an automobile assembly, a portion of which is visible to a vehicle customer.

Anvil with rolling elements for friction stir welding

The present invention provides an apparatus and improved method of friction stir spot welding that assures a predetermined bottom thickness and a reduction in variation in a series of resultant spot welds. The advantage of the present invention lies in that the plunge distance is controlled from the top plane of the anvil against which the bottom thickness is specified, and systematically adjusted to account for changing system parameters, such as, but not limited to, deflection and thermal expansion of the weld gun. The present invention also provides for improved and controlled weld quality through implementation of a dwell operation or dwell operations, whereby weld heat input is manipulated by causing the weld tool to dwell in a dwell region or at a desired depth or depths within the workpiece(s) for a predetermined time interval to achieve desired mechanical properties of the resultant weld joint.

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St. Clair Township, MI, United States of America

Robert T Szymanski