Abstract: A resistance spot welding method can be used to join polymeric and metallic workpieces together and includes the following steps: (a) placing an electrically conductive coating between a polymeric workpiece and a metallic workpiece, wherein the metallic workpiece has a textured surface facing the polymeric workpiece; (b) piercing the polymeric workpiece with first and second electrically conductive pins of a welding electrode assembly; (c) applying electrical energy to the first and second electrically conductive pins so that an electrical current flows through the first electrically conductive pin, the electrically conductive coating, and the second electrically conductive pin in order to at least partially melt the polymeric workpiece and the electrically conductive coating, thereby forming a weld pool; and (d) cooling the weld pool to form a solid weld nugget in order to establish a mechanical interface lock between the solid weld nugget and the textured surface.

Abstract: A resistance spot welding system can join two polymeric workpieces and includes a power supply. The power supply has a positive terminal and a negative terminal. The resistance spot welding system further includes a welding electrode assembly electrically connected to the power supply. The welding electrode assembly includes a housing, a first electrically conductive pin and a second electrically conductive pin. The first and second electrically conductive pins both protrude from the housing. The first electrically conductive pin is electrically connected to the positive terminal of the power supply, and the second electrically conductive pin is electrically connected to the negative terminal of the power supply. The second electrically conductive material is electrically insulated from the first electrically conductive pin. The first and second electrically conductive pins are at least partly made of a material having a hardness ranging between 50 HRC and 70 HRC.

Abstract: A resistance spot welding method can be used to join polymeric and metallic workpieces together and includes the following steps: (a) placing an electrically conductive coating between a polymeric workpiece and a metallic workpiece, wherein the metallic workpiece has a textured surface facing the polymeric workpiece; (b) piercing the polymeric workpiece with first and second electrically conductive pins of a welding electrode assembly; (c) applying electrical energy to the first and second electrically conductive pins so that an electrical current flows through the first electrically conductive pin, the electrically conductive coating, and the second electrically conductive pin in order to at least partially melt the polymeric workpiece and the electrically conductive coating, thereby forming a weld pool; and (d) cooling the weld pool to form a solid weld nugget in order to establish a mechanical interface lock between the solid weld nugget and the textured surface.

Abstract: A resistance spot welding system can join two polymeric workpieces and includes a power supply. The power supply has a positive terminal and a negative terminal. The resistance spot welding system further includes a welding electrode assembly electrically connected to the power supply. The welding electrode assembly includes a housing, a first electrically conductive pin and a second electrically conductive pin. The first and second electrically conductive pins both protrude from the housing. The first electrically conductive pin is electrically connected to the positive terminal of the power supply, and the second electrically conductive pin is electrically connected to the negative terminal of the power supply. The second electrically conductive material is electrically insulated from the first electrically conductive pin. The first and second electrically conductive pins are at least partly made of a material having a hardness ranging between 50 HRC and 70 HRC.