Temperature measurement during resistance spot welding using a digital camera

In this paper a novel approach for temperature measurement during resistance spot welding is presented. The temperature is calculated using the deformation of the electrode tip. The deformation is measured using a digital camera which acquires a sequence of images. These images are then compared and analyzed using a digital correlation algorithm. The result is the deformation variation over time, which is then converted to temperature versus time. For a comparison a thermocouple was mounted on the same spot of the electrode tip. The comparison of both methods has confirmed the applicability of digital camera for temperature measurement.