New discoveries of stress fluctuations at the tool-chip interface and sticking tool tendency in metal cutting processes

Addressing the issue of sticking tools during the metal cutting process is crucial for enhancing cutting efficiency and ensuring industrial safety. This study employs molecular dynamics (MD) simulations to investigate singlecrystal SiC tools and 27 different grain orientations of single-crystal pure metal workpieces (Ni, Cu, Co, and Fe). MD models were established to simulate the nanocutting and tool retraction processes. This study revealed a new phenomenon of stress fluctuations at tool-chip interfaces and proposed a new theory on the relationship between stress fluctuations and metal sticking tool tendencies. Research indicates that during nanocutting, the normal stress distribution at the tool-chip interface of different materials exhibits the same periodic fluctuation (T = 0.5a, where a is the tool lattice constant). The greater the stress fluctuation is, the greater the sticking tool tendency. By fitting the results for 27 workpieces, an approximate relationship was established. For metals with the same lattice type, such as FCC-structured Ni and Cu, the stress fluctuation and sticking tool tendency are both greater when the cutting orientation is (111)[110], and the chip morphology and temperature distribution are similar. Through the analysis of lattice transformation, atomic shear strain, and temperature field, this study explored the microscopic mechanisms and thermomechanical theories underlying the new findings of stress fluctuations and sticking tool tendencies. The stress fluctuation distribution at the tool-chip interface is a new discovery that differentiates nanocutting from traditional processing models. Future research can further investigate the cutting behavior of complex materials under complex conditions, which will help to further elucidate the mechanism of sticking tools during processing.