The main idea in this paper deals with the importance of smart machining improvement by introducing physical based understanding. The case of chip formation, in hard turning, is treated via the existence of a direct relationship between serrated-chip morphology simultaneously with force component signals (resulting from a high frequency acquisition) and with the width of facets detected on a workpiece machined surface. The forces component variations can reach several tens of Newton. The shear segmentation of the chip is a high frequency phenomenon. Because it can excites machine-tool, induces insert wear and affects surface integrity, this phenomenon has to be understood and controlled by the smart machining devices. The paper is a contribution by considering an experimental and a numerical approach.