The determination of appropriate welding parameters for spot welding is a very complex issue. A small change of one parameter will effect all the other parameters. This, and the fact that the contact surface of the electrode is gradually increasing, makes it difficult to design a welding parameter table, which shows the optimum welding parameters for different circumstances. However, this table shows target values for the welding parameters. http://www.robot-welding.com/Welding_parameters.htm