Material removing mechanism for mechanical lapping of diamond cutting tools

The material removing mechanism for mechanical lapping of diamond cutting tools was illuminated at the atomistic scale. In lapping process, phase transformation of the lapping region was the main reason for the material removal. Thus a three-dimensional model of a specimen of the diamond monocrystal and rigid diamond grit was built with the aid of the molecular dynamics(MD) simulation. The force between all of the atoms was calculated by the Tersoff potential. After that, lapping with a certain cutting depth of 1.5 lattice constants was simulated. By monitoring the positions of atoms within the model, the microstructure in the lapping region changes as diamond transformed from its diamond cubic structure to amorphous carbon were identified. The change of structure was accomplished by the flattening of the tetrahedron structure in diamond. This was verified by comparing the radial distribution functions of atoms in the lapping and un-lapping regions. Meanwhile, the debris produced in lapping experiment was analyzed by XRD(X-ray diffraction). The results show that the phase transformation happens indeed.