I forgot mention this point
-In case of spot welding each welding cycle consists of several steps usually 1 to 10 steps. Each step is followed by some cooling time and then next step is started and so on. Each step has specified welding current and number of cycles and may or may not have associated forging action. The number of cycles 2-20 mentioned in earlier post applies only for the highest current step and other steps can be upto 100 cyles Thus a spot weldign program looks something like this.

-----------------------------------------------
Step Squeeze Current(%)  Weld   Off     Forge
     Cycles            Cycles  Cycles
-----------------------------------------------
1      45      10          90     10      N
2       -      40          60     15      Y
3       -      80          20     20      Y
4       -      50          55     10      N
5       -      20          80     25      N
6       -      5           90     10      N      
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Thanks & Regards,
Prahlad Purohit