Description:

Limited-Overlap is designed for continuous treatment lines in which a welded joint of a thickness equal to or double that of the strips is acceptable. L.O.L. is generally preferred to spot welding because of the relative quickness of the operation and the low electrode (wheel) maintenance cost.

The LOL type machine is available in two versions:

1. The standard machine which carries out the resistance seam welding operation in a single movement, on both strip edges with an overlap of approximately 16 mm.
2. The lateral indexing machine which carries out two passes and therefore produces two parallel weld beads on both strip edges with an overlap of 50 mm or  67 mm

LOL welding machines are actuated pneumatically. They are equipped with the positioning and clamping mechanisms enabling the strips to be adjusted and held firmly in place during the welding operation.

WeldMatic welding control systems are designed to produce a continuous weld bead, but the welding current can be interrupted at regular intervals to produce a series of small weld beads over the whole width of the strip. When handling greater thicknesses, there is also the possibility of stopping the rotation of the wheels at regular intervals to produce stronger weld spots over the whole width.

For example, after positioning and clamping, the welding times are:

• for two strips 1100 mm wide and 0.7 mm thick (1 bead): 26 seconds
• for two strips 1540 mm wide and 4 mm thick (2 beads): 114 seconds