The measurement of machined-part strain fields induced by the cutting process remains a challenge because of the presence of highly intensive and localised strains. In this study, a high-speed double-frame imaging device with pulsed laser lighting is used in order to obtain sharp and highly resolved images during orthogonal cutting tests performed in an aluminium alloy. The displacement fields are then measured using a global Q4-digital-image-correlation (DIC) method and several strategies, facilitating calculation of the total displacements due to the cut, along with the residual strains in the machined part. Numerical procedures are developed to manage the removed material that disturbs the DIC. An automatic primary shear angle detection procedure using DIC is also proposed. Five different markings, which are produced via chemical etching and micro blasting, are applied to the observed surfaces. Their effects on the kinematic fields and the uncertainties are then studied. Three surface parameters are proposed as indicators for determining the surface preparation suitability for the DIC. The repeatability of the kinematic fields induced during the cutting process is studied, because of the ease with which testing can be performed. Finally, the plastically deformed layer engendered by the cutting process is measured using the calculated residual strains.

In the case of hard machining of steels, negative rake tools generate compressive deformation and high temperature under the cutting edge, leading to phase transformation or "white layers". The resulting surface integrity can be predicted by numerical simulations which may be validated by comparing simulated and measured strain fields. Recent high speed imaging devices have facilitated strain field measurement by Digital Image Correlation (DIC), even at high strain rates. However, the analyse is generally restricted to the primary shear zone and not to the workpiece under the machined surface. For this study, a double-frame camera and a pulsed Nd:YAG laser, generally used in the field of fluid mechanics, have been employed to record images during an orthogonal cutting operation of a hardened steel. The effect of the rake angle and the edge preparation of c-BN tools on the subsurface displacement field, which has been experimentally investigated by using DIC, are presented in this paper together with an analysis on the origins of the strains. The results of these measurements will be used to validate cutting numerical simulations or to improve hybrid modelling of surface integrity.