The welding roll has influence to the overlap, especially with long cans
Cause:
The position of the welding roll (WR) has an influence on the overlap at the beginning and at the end.
WR slightly too high = Overlap at the beginning less
WR slightly too low = Overlap at the beginning constant
WR higher = Overlap at the end better
WR lower = Overlap at the end less
WR lower = Overlap at the beginning less
If you still couldn’t resolve the problem, see related article