A one-side spot welding device includes a base which is formed in a cylindrical shape, a welding head and a welding tip. The base has a push rod operable in an upward and a downward direction with respect to the base and has a slide groove in an upper inner circumferential surface thereof. The welding head is installed at an upper side of the base so as to be slidable in a radial direction and equally divided in a circumferential direction so as to include a plurality of unit welding heads in close contact with one another. The unit welding heads are capable of being spaced apart from one another in the radial direction by the push rod. The welding tip is formed in a cylindrical shape so as to be configured at an outer circumference of the base, operates in an upward and a downward direction and is capable of applying welding electric current to the welding head.

A welder having first and second electrodes configured to clamp and weld a fastener to a workpiece at an opening in the workpiece, wherein the first electrode is configured to move in a direction transverse to a clamping direction to center the fastener with the opening. The welder can carry out a method of aligning and welding an internally-threaded nut to a panel at an opening in the panel. The method includes the steps of: centering the opening in the panel relative to a first electrode using a tapered guide pin that extends into the opening; centering the nut relative to the opening using the tapered guide pin; clamping the nut and panel between the first electrode and a second electrode; and welding the nut to the panel by passing current through the nut and panel from one of the electrodes to the other electrode.

A one-side spot welding device includes a base which is formed in a cylindrical shape, a welding head and a welding tip. The base has a push rod operable in an upward and a downward direction with respect to the base and has a slide groove in an upper inner circumferential surface thereof. The welding head is installed at an upper side of the base so as to be slidable in a radial direction and equally divided in a circumferential direction so as to include a plurality of unit welding heads in close contact with one another. The unit welding heads are capable of being spaced apart from one another in the radial direction by the push rod. The welding tip is formed in a cylindrical shape so as to be configured at an outer circumference of the base, operates in an upward and a downward direction and is capable of applying welding electric current to the welding head.

One aspect of the present disclosure provides a method of manufacturing an orthopedic prosthesis. This particular method includes providing a porous metal layer (22) positioned against a metal substrate at an interface between the porous metal layer and the metal substrate. Additional steps include providing an electrode (132) and providing an intermediate element or coating positioned between and in contact with the electrode and the porous metal layer where the intermediate element includes tantalum in contact with tantalum of the porous metal layer. In a further step, an electrical current is directed to the interface between the porous metal layer and the metal substrate to bond the porous metal layer to the metal substrate.

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.