`Automotive spot-weld electrode wear improvement (1980–1990)`

Galvanized steel adoption in automotive sheet collapsed copper electrode tip life from 8 hours (one shift) to under 1 hour. Ford imposed a 2,000-weld spec on steel suppliers — sized so that tip changeout could happen on the 15-minute coffee break. Illustrates the "one shift" productivity barrier.

When you don't have that — for example, in spot welding of automobile sheet, when they went to galvanized steel, the zinc would react with the copper electrode tips. They could use copper tips that would last a whole shift on the automotive assembly line — eight hours. When they went to galvanized steel, they couldn't even get an hour, which meant they had to stop the line and have some guy go in and change the tip. What Ford wanted was 2,000 welds, because that would be the break after two hours. So Ford had a spec of 2,000 spot welds — the steel company had to supply a steel with galvanizing that would last for 2,000 spot welds. That was the Ford spec back in the early 1980s. The reason: while everyone else was having their fifteen-minute coffee breaks, a mechanic could go in and change the tips. You have to look at the whole system.