A first principle model for closed-loop gap bridging of remote laser welding of aluminium components

Abstract

Remote Laser Welding (RLW) has been successfully deployed for Steel products, particularly doors, closures and hang-on parts with overlap seam welding configurations. The growing demand for light-weight body structures has created interesting opportunities to apply RLW to fillet welding with application to Aluminium components. However, seamless migration from seam welding of Steel to fillet welding of Aluminium is limited by the following challenges: weld seam tracking capability to compensate trim edge variations; hot cracking resulting from the interaction between material chemistry and heat dissipation; form error variations leading to unwanted part-to-part gaps, which in absence of filling material can be bridged only by autogenous material.This paper focuses on the aspect of the part-to-part gap bridging and proposes a model to select and adjust welding process parameters to control the volume of molten pool, and achieve gap bridging. The proposed model is based on the observation that gap bridging is impaired by five distinct failure modes. Each mode is modelled by first-principle energy balance criteria. Selection of welding parameters is presented by a set of gap bridging capability charts which helps to prevent failure modes, and select feasible weld process parameters.