Longer weld spots

Some seams look towards the end like the welding spots got longer

Cause:

1. Welding pressure:
        Is the welding pressure mechanically always guaranteed?
    
2. Upper roller:
        is the upper roller touching the Z-bar?
    
3. Lower welding roller:
       Is the lower welding roller too low?
       Welding center must be in the center of Z-bar!
    
4. WEC-O3 circuit board:
        Change the existing with a new one.

Attention: Make sure all jumpers and all little blue potentiometers are in the same position!