Papers by Author: Dong Kai Jia

Abstract: In the detection process of the ball detector, surface can not unfold effectively, which brings about that the camera can not capture the image which we want, resulting in a high rate of defect and at a low efficiency in the test with the ball detector. In order to solve this problem, the optimized design on the mechanical control parts of the expansion organization was carried out, besides, kinematics analysis model the expansion organization and a motor control timing schedule were created by ADAMS, enabling expansion process consistent with the mathematical modeling. To a certain extent the optimization results improve overall performance of the system, which plays a guiding role in the improvement of the system.

Abstract: In this paper, FEM is used to simulate the three stages of catastrophic shear occurrence, expansion and shear band formation when serrated chips are formed under adiabatic shear behavior in high-speed machining of hardened steel GCr15 with PCBN tool. By comparing data of simulation and experiment on chip morphology characters, it is indicated that they are in good accordance. Hereby, the author has analyzed strain and temperature distribution in adiabatic shear band, and dynamic characters of cutting force . The research results show that adiabatic shear band begins from tool tip and extends to workpiece free surface, and it is characterized by large strain and high temperature. In addition, it results from adiabatic shear behavior that cutting force waves regularly in a numerical range.

Abstract: A 3D model is established in this paper to simulate cutting process of PCBN tool cylindrical cutting hardened steel GCr15 using ABAQUS/Explicit. The model effectively overcomes serious element distortions and cell singularity in high strain domain caused by material large deformation by adopting shear failure criteria and element deletion criteria. In this study cutting force, cutting temperature, surface residual stress field as well as side flow are forecasted of hard cutting process with chamfering tool preparation. It shows that satisfactory results could be obtained by FEM. The simulation results provide theoretical basis for studying hard cutting mechanism and selecting the best cutting condition in practical.