MFDC - An energy efficient adaptive technology for welding of thin sheets

Resistance spot welding systems which are based on medium-frequency inverters are recently gaining in importance and are being used for welding of steel sheets for automotive sector. This paper focuses on deriving out the energy efficiency of the Medium Frequency Direct Current (MFDC) technology over AC power source. MFDC have been chosen for the study due to its improved consistent power factor, optimum response, process friendly and precise weld control. The experimental trials have been conducted for both AC and MFDC in Carbon silico manganese alloy - the recent developed new steel sheet by the steel manufacturers. The result showed that the energy input taken by the MFDC for nugget formation is less compared to that of alternating current. Design of Experiments was used to explore the relationship between several explanatory parameters and a response parameter, to obtain an optimal response. Weld lobe have been generated with the experimental data and it was ensured that energy efficient MFDC systems has wider welding lobes at lower weld current levels as compared to AC systems.