Papers by Author: Xue Feng Bi

Abstract: Tool wear is a significant research field in metal cutting because it affects not only the tool cost and replacing time, but also the productivity and surface quality. Tool wear monitoring is a key technology in tool wear research. A series of turning tests with different cutting time are implemented. Cutting power in cutting process is acquired by a power senor and crater wear value after cutting is measured. Time domain analysis of power data indicates that root mean square increases and kurtosis approaches to 0 with crater wear increase in turning process.

Abstract: Micromold manufacturing technology is very important for the mass production of micro parts. In this paper, modeling of micromold is established in 3D software firstly. The 3D modeling is input into machining simulation software Master CAM to simulate machining process. The machining parameters and cutting tool path are optimized in machining simulation. Machining G code of micromold obtained from post-process program of Master CAM is input into HMI system of Micro Machine Tool (MMT), and hence the micromold will be machined precisely in MMT.

Abstract: Wear modeling makes it possible to predict the evolution of wear profile and explain wear mechanism from process variables, such as temperature, pressure and sliding velocity etc. A composite crater wear model considering adhesive and diffusion wear is established by means of experiment and modeling in conventional speed machining. A series of cutting tests are performed to obtain wear profiles and corresponding process variables. The constants in wear model are fitted by regression analysis with crater wear tests. This crater wear model shows a good predictive capability in conventional cutting speed.

Abstract: Chip velocity is a crucial parameter in metal cutting. The continuous variation of chip velocity in primary shear zone can not be obtained from conventional shear plane model. Therefore a general streamline model was used to investigate the distribution of chip velocity field in metal cutting. This paper also verified the continuity of plastic flow in metal cutting by tracing the variation of particle area. The velocity of chip material was calculated from the mathematical expression of streamline model. The velocity results were compared with conventional shear plane model.

Abstract: In order to investigate that shields have the effect on the thermal equilibrium of CNC machine tool, this paper applies the theory of heat transfer and finite element analysis to analyze the thermal characteristics of CNC lathe CK40A/1000. By ANSYS software, the temperature distributions of spindle engine, headstock and bearing at thermal equilibrium with/without shields are obtained. By analyzing thermal equilibrium patterns and experiments, the temperature of spindle bearings with shields are 3-4 higher than without shields at thermal equilibrium. And shields have less influence on the temperature gradient of tool inner thermal sources.

Abstract: The tool-chip contact length, as an important parameter controlling the geometry of tool crater wear and understanding chip formation mechanism, is widely investigated in machining. The aim of this paper is to study the influence of chip curl on tool-chip contact length by means of experimental observations with high cutting speed. The relationship between tool-chip contact length, chip radius of curvature and uncut chip thickness was investigated. Experimental results show the effect of increasing spiral chip radius on tool-chip contact length with low uncut chip thickness in high speed machining.

Abstract: The streamline method was used to investigate the plastic strain rate in machining. The streamline function presented in this paper is a general equation with three parameters controlling the complex variation of flow line shape. Velocity and deformation field were obtained by streamline analysis. The validation of this model was conducted by comparing with other experimental results published. It shows that the streamline model presented in the paper can be applied to the evaluation of strain rate in machining.