Briefly describe the principle of operation of resistance spot welding and give one example of where it is typically used. - Leaving Cert Engineering - Question b - 2021

Resistance spot welding is a welding technique that joins work pieces through the application of heat generated by a high electric current flowing through the contact points. When the electrodes apply force to the work pieces, the current flows through these contact points, causing localized melting of the material. This melting forms a small weld pool called a 'nugget', which solidifies under the applied pressure, resulting in a strong joint. The combination of time, pressure, and current affects the formation of a reliable weld, with these parameters dependent on the work piece materials and electrode dimensions.