MONITORING OF RESISTANCE WELDING

摘要

A method of monitoring the nugget size of the welds produced by a spot welding machine, comprises optically imaging a region of a weld spot onto a transducer (21) after completion of the spot welding process. The transducer (21) produces an electrical signal having a value dependent on the mean intensity and the wavelength distribution of the radiation emitted from the region of the weld spot (18) imaged on to the transducer (21). A computer (24) analyses the electrical signal produced by the transducer (21) to evaluate a weld nugget size indicator value and issue a warning through a visual display module (31) when welds of poor size are being, or about to be produced, so that corrective action can be taken by replacing or dressing the electrodes.