On-line monitoring method for electrode invalidation during spot welding of zinc-coated steel

In the process of spot welding of zinc-coated steel, because of the existence of zinc coat, the electrode invalidation is accelerated greatly, which causes unacceptable welding quality. A collecting system is developed with a C8051F020 microcomputer as the controlling core, which is used to collect such parameters as welding current, supply voltage, dynamic resistance, etc. Through the comprehensive processing, the whole variety trends of those parameters are obtained. Finally, an on-line monitoring method is given through the relationship between electrode wear and welding parameters, which is valuable for the industrial production.