Welding process does not start or starts too early

Problem:

• Welding process does not start or starts too early before the welding rollers are closed and burns a hole in the can.

Possible Cause:

• Wrong signal of welding pressure switch. The start of welding current and transport is activated by a digital pressure switch S31 installed on the air regulator for welding pressure. If the welding rolls close and the digital pressure switch reach the programmed value the welding does start.

Check:

• Is the setting of welding pressure correct?
• Does the welding pressure cylinder work fine? Does it open and close smoothly?
• Does the welding pressure switch work properly? The switch must switch on when the welding pressure is between 1.5 and 3.0 bar.