DIC in machining environment, constraints and benefits

Abstract

The manufacturing of structural aluminum alloy parts used in aeronautics requires several steps of both forming processes and heat treatments before final machining. Some of the process steps will generate residual stresses and some will reduce residual stresses. For highly alloyed thick aluminum plates and closed-die forging parts, the material removal during the machining of complex geometries will release residual stresses and it can lead to part distortion. This work aims at providing a reliable experimental technique measuring the part deformations during machining process to validate a robust predictive numerical method. The backbone of the technique relies on digital image correlation (DIC). Indeed, the use of DIC as a measurement means allows a nondestructive control of part deformations during machining, which is interesting and difficult to achieve by other measurement techniques. Moreover, DIC allows a full field measurement in one shot that is faster than other available measurement tools. However, experimentation need to be realized to validate the use of DIC in a machining environment. This work discusses more particularly the relevance, the reliability and the feasibility of DIC in the machining environment. The potential offered by the machining center for the calibration of the proposed Global-DIC procedure is also investigated.