DYNAMIC ESTIMATION OF FULL PENETRATION USING GEOMETRY OF ADJACENT WELD POOLS

Control of weld penetration is currently one of the most important and crucial research issues in the area of welding. The weld pool can pro vide accurate and instantaneous information about the weld penetration , however, the establishment and confirmation of the correlation betwe en weld pool and weld penetration require numerous accurate measuremen ts and suitable geometrical modeling of weld pool. A normalized model is proposed to characterize the weld pool two-dimensionally. More than 6,000 weld pools are measured from experiments using a developed real time weld pool sensing system. A data analysis shows that the weld pen etration is correlated with the weld pool which is specified by the th ree characteristic parameters proposed in the study. However, the corr elation is nonlinear. To approximate the complicated nonlinearity, neu ral networks are used. Comparative modeling trails show that the weld penetration can be more accurately calculated if the adjacent weld poo ls are also used. This implies that the correlation between the weld p enetration and weld pool is dynamic. Hence, an on-line nonlinear dynam ic estimation system is developed to estimate the weld penetration.