Thanks for the response Mel,
The problem we are having is intermittent failures that we detect by dropping a weight on the stud & it breaks loose. Viewing the samples vary significantly in the amount of weld penetration. It appears we are not controlling the current evenly as we can have one stud with no penetration & the stud next to it can blow a hole through the side of the stud. Occasoinally the stud arcs on to the edge of the hole which also created a poor weld. The machine is a Dorman 250kva model 1-ps-245, volts = 415, freq = 50, valve = 1. We are using a miyach weldtouch controller cy-2108 with settings, tap =7, squeeze=99, weld 1=5, weld2 = 16, weld3 = 34, pulse =1, current = 25, angle = 135, air pressure =2-psi. the material in 2mm zinc coated mild steel.
regards,
Scott.