Welding system and method

A method of resistance spot welding, comprising:

• providing a first workpiece having a use surface in an abutting relationship to a second workpiece having a concealed surface;
• positioning a first electrode of a first class in physical contact with the use surface;
• maintaining the first electrode in contact with the use surface;
• maintaining a second electrode of a second class in contact with the concealed surface;
• measuring a signal representative of at least one of a contact force between the electrodes and the workpieces or time;
• for at least a pre-selected amount of time or a pre-determined contact force value is exceeded;
• applying a pre-determined current by the electrodes for at least a pre-selected amount of time or a pre-determined contact force value is exceeded to form a weld nugget between the first workpiece and second workpiece;
• so that a lesser portion of the weld nugget is formed in the first workpiece and a greater portion of the weld nugget is formed in the second workpiece;
• wherein a depression formed on the use surface has a lesser depth than a depression formed on the concealed surface.

An article of furniture providing a concealed surface having a greater depression and a use surface having a lesser depression that is not substantially visible to the unaided eye and produced by a processes of resistance spot welding, comprising:

• measuring a signal representative of a contact force of at least two electrodes of different classes against the use surface or the concealed surface;
• applying a pre-selected amount of current by the electrodes after a pre-determined contact force is exceeded;
• forming a lesser portion of a weld nugget in the first workpiece and a greater portion of the nugget in the second workpiece;
• wherein the greater depression in the concealed surface has a depth greater than the depth of the lesser depression in the use surface.

A method of resistance spot welding, comprising:

• providing a first workpiece having a use surface in an abutting relationship to a second workpiece having a concealed surface;
• positioning a first electrode of a first class in physical contact with the use surface;
• maintaining the first electrode in contact with the use surface;
• maintaining a second electrode of a second class in contact with the concealed surface;
• measuring a signal representative of at least one of a contact force between the electrodes and the workpieces or time;
• applying a pre-determined current by the electrodes for at least a pre-selected amount of time or a pre-determined contact force value is exceeded to form a weld nugget between the first workpiece and second workpiece;
• controlling the growth of the weld nugget by using a first material composition for the first electrode and a second material composition for the second electrode at least two different classes of electrode material;
• so that a lesser portion of the weld nugget is formed in the first workpiece and a greater portion of the weld nugget is formed in the second workpiece;
• and
• wherein a depression formed on the use surface has a lesser depth than a depression formed on the concealed surface.