An empirical examination of the thickness profile formation of twin-roll-cast magnesium strips

The recently developed technology of twin-roll-cast (TRC) magnesium strips permits an efficient production of magnesium sheets, primarily for the automotive industry. The focus of the paper is to develop a structural equation model explaining the variance of the thickness profile formation. Hence, the complex and partially unknown relationships between twin-roll casting process parameters and the thickness profile formation are analyzed using latent variables, e.g. the deformation resistance, length of contact arc, etc., which consist of several observed parameters. The fundamental process variables and their effect on the thickness profile formation during twin-roll casting are investigated and evaluated by partial least squares structural equation modeling (PLS-SEM) - a statistical method that fits networks of constructs to empirical data. The results of the predictive modeling technique allow an approximation of the existing interrelationships between thickness profiles, rolling force as well as processes in the roll gap which are typically difficult to measure directly using sensors. In this context, it was identified that the thickness profile variation is primarily caused by the forming force, which is mainly driven by the length of contact arc. Moreover, implications for the control of the thickness profile are derived.