Effect of Electrode Pressure

The total resistance R between the two electrodes is significantly affected by the electrode pressure, which decreases with the increase of the electrode pressure. At this time, although the welding current increases slightly, it can not affect the reduction of heat production caused by the reduction of R. Therefore, the strength of solder joint always decreases with the increase of electrode pressure. While increasing electrode pressure, increasing welding current or prolonging welding time can compensate for the effect of resistance reduction and keep the strength of solder joint unchanged. This kind of welding condition is helpful to improve the stability of weld strength. If the pressure of the electrode is too low, it will cause spatter and decrease the strength of the solder joint.