Please tell us how to control the quality of resistance welding.

If spot welding is performed continuously, electrode tips will wear and their diameter of contacts with the object to be welded will gradually expand.Spot welding requires a small diameter of electrode tip and consistent current density in the welded area as described above. Therefore, the tip dressing cycle should be pre-determined and managed.Commercially available dressers and lathes are used to dress electrode tips.
In addition, new devices are being introduced to the market such as control devices equipped with a communication function to send the weld results to PCs as well as control devices that can judge quality of tip dressing. More reliable quality control can be achieved with these latest devices.
In the case of projection welding, the parallelism of upper and lower electrodes and the parallelism of the contact face of the welded object and electrodes are crucial, and they will affect weld quality.Electrodes are re-shaped by lathes or milling machines.With the projection welding, the rise of welding current would greatly affect the weld quality. A type of control devices that can precisely control the rise of the current is also available in the market.
In the case of seam welding, a shaping tool is generally incorporated into the unit.