Blind Vision for Real-Time Inspection of Spot Welds

Destructive spot weld quality inspection is not practical when considering the high production volumes and testing costs. New non-destructive spot weld characterisation methods employ ultrasonic-based signal analysis for quality assessment of resistance spot welds. Signals obtained in the process of ultrasonic-based non-destructive testing of spot welds are often contaminated by noise. Dramatic temperature variation, electromagnetic noise, coolant water and coupling effect, mechanical noise from servo motors and other moving parts are among the disruptive factors. Detection of desired features and finding the location of important characteristics such as the first echo, backwall and defects inside weld nuggets are the main challenges in ultrasound-based diagnostic signal processing in spot weld quality assessment.