Influence of temperature and crystal orientation on tool wear during single point diamond turning of silicon

Abstract

Owing to the capricious wear of cutting tools, ultra precision manufacturing of silicon through single point diamond turning (SPDT) operation becomes a challenging task. It thus becomes non-trivial to understand the contribution of temperature and crystal orientation during the SPDT process in order to suppress tool wear. Molecular dynamics (MD) simulation is an appropriate tool to study nanoscale processes occurring at the femtosecond/picosecond timescale which cannot otherwise be studied experimentally or by the finite element method (FEM). Accordingly, MD simulation has been deployed with a realistic analytical bond order potential (ABOP) formalism based potential energy function to simulate the single point diamond turning operation of single crystal silicon in order to understand the influence of temperature and crystal orientation on the tool wear mechanism. Results showed the strong influence of crystal orientation on the wear resistance of a diamond tool; cubic orientation performed better than dodecahedral orientation. It was also observed that high pressure phase transformation (HPPT) in the cutting zone was accompanied by the formation of dangling bonds of silicon. Under the influence of cutting temperature, the newly formed dangling bonds of silicon chemically combine with the pre-existing dangling bonds on the surface of the diamond tool resulting in the formation of silicon carbide (SiC), the main appearance of which was evident at the tool flank face. Continuous abrasion of the diamond cutting tool with SiC causes sp3–sp2 disorder of the diamond tool. Hence, both these processes proceed in tandem with each other. The mechanism proposed here is in good agreement with a recent experimental study, where silicon carbide and carbon like particles were observed using X-ray photoelectron spectroscope (XPS) technology after machining a silicon wafer with a diamond tool

Influence of microstructure on the cutting behaviour of silicon

“…The implication of this phenomenon is that a more negative inclined tool edge (rake angle) will result in deeper sub-surface damage caused by the formation of such periodically appearing cavities. Notably, the authors have tested several other potential functions under similar conditions [45,46], and it was found that such periodical grooves, which are known from cutting experiments, occur only with the screened empirical bond-order potential. This is a clear indication that the long-ranged screening function applied to the potential helps reproduce the brittle formation of surface cracks correctly.…”

Can a carbon nano-coating resist metallic phase transformation in silicon substrate during nanoimpact?

“…Analytical bond order potential (ABOP) and reactive empirical bond order (REBO) potential functions were used to describe the covalent descriptions of silicon and carbon respectively [12]. The algorithm followed in this work is the same as has been used in the previous investigations [6,[13][14]. Additionally, an automated Dislocation Extraction Algorithm (DXA) [15][16][17][18] was also used to visualize and analyze the atomistic simulation data to identify dislocation lines.…”

Recent Advances in Micro/Nano-cutting: Effect of Tool Edge and Material Properties

“…The accuracy of the potential function used in MD simulation determines the reliability of the simulation results [37]. Lennard-Jones (LJ), Morse and embeddedatom method (EAM) potentials were employed to investigate the effect of interaction potential on the MD simulation of nano-cutting by Oluwajobi et al [38].…”

“…Morse potential is usually used to depict the interaction between the atoms of cutting tool and workpiece materials. Goel et al [37] thought it is not robust enough to describe covalent bond interactions between silicon and diamond. Therefore, the analytical bond order potential (ABOP) proposed by Erhart and Albe [39] is used to describe the interaction within and between the diamond tool and silicon.…”

“…The temperature increase at flank face causes a severe wear between the tool and the elastic recovered workpiece materials and finally affects the generated surface quality [82]. It is identical to the molecular dynamic simulation of the diamond cutting of silicon; the number of atoms at the tool flank face showing an increase in temperature is larger than that at the rake face, especially at the place where the silicon atoms try to recover elastically [37]. Cai et al [108] investigate the temperature in three different zones and find that the temperature near the arc part of the cutting tool edge is larger than that under the flank face of the tool and the zone far from the machined surface.…”