Serrated Chip Morphology and Comparison With Finite Element Simulations

The complexity of chip formation in machining processes stems from the confluence of several physical phenomena — mechanical, thermal, and chemical — occurring at very high strain rate. The prediction of chip morphology depends on a fundamental understanding of these phenomena and is of industrial importance for cutting force prediction and surface integrity control. Our paper focuses on characterizing the chip morphology of serrated-chip (saw-tooth shape chip) and discusses the physical phenomena accompanying the serrated-chip formation according to finite element modeling (FEM) simulations. The paper presents a bibliographic review and an experimental study of chip formation. The experimental study, based on metallographic analysis of chip morphology and hardness measurements, focuses on machining of American Iron and Steel Institute (AISI) 4340 steel alloy. Two finite element software packages were used to simulate chip formation under orthogonal cutting conditions. The FEM results are compared with the hardness measurements, and the chip morphology characterization method used to support the simulations is discussed.