Papers by Author: Shu Yi Ji

Abstract: Tool wear plays an important role in cutting process research. It affects the quality of machined surface and cutting parameter to a great extent, such as cutting force, cutting temperature and cutting quiver. In order to predict tool wear in hard cutting process by using FEM method, the character of tool wear during cutting process is presented firstly, and Usui’s tool wear rate model is introduced. Then the FEM model for steady state cutting process using Abaqus is established. FEM model describes the workpiece material characteristic accurately for the process of PCBN tool cutting GCr15 by adoptiving Johnson-Cook constitutive model. Simulation results of steady cutting process offer foundation to simulate tool wear.

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.

Abstract: A new low cost high performance PMMA micropump, developed for microfluidic system, is presented. According to the orifice flow theory, a diffuser/nozzle structure is fabricated with precision milling process, and packaged with the film-sealing at the condition of thermal bonding process. The size parameter of the diffuser/nozzle structure is 2.5mm *150µm, 8° conical angle, the volume of PMMA micropump is 14×14×2.5 mm3. And experimental results show that the PMMA micropump can produce a maximum back pressure of 1906.1Pa and a maximum flow rate of 564µL/min under 220 V, 500Hz squired wave power supply.