Papers by Author: D.W. Yu

Abstract: The cutting zone temperature is the basic cutting process physical parameter, how to obtain it accurately is a problem over the years. In the paper, a method combined the artificial thermocouple method with thermal conduction reverse seeking method was proposed. The thermocouple can track the temperature history curve of the tool measured point. Then the tool and cutting process heat conduction models were built up in the ANSYS and AdvantEdge FEM respectively. According to the simulation results, the corresponding relationship between the rake face temperature and the measured point temperature and the shear slip face temperature can be solved. So the first and second deformation zone average temperature was obtained. Shown as the research results, the method proposed in the paper can obtain the small cutting zone temperature effectively. It provides technical support for the study of cutting process deformation and friction behavior.

Abstract: This paper proposes a method of determining the constitutive equation parameters of a Japanese type of alloy steel (SCM440H) for Finite Element Analysis (FEA) of orthogonal cutting, involving pressure bar experiments, orthogonal metal cutting experiments and FEA inverse identification. First, Split Hopkinson Pressure Bar (SHPB) experiments combined with Quasi-Static pressure tests were conducted, and after analyzing and processing the experimental data, one set of original constitutive constants was obtained; in the mean time, orthogonal cutting experiments were also performed to collect the cutting force data. Then the original constants were put into FEA software to simulate the cutting process. But comparison between the orthogonal cutting experimental and the simulation results revealed the inadequacy for the constants to predict cutting forces. To address this problem, an inverse identification method was employed to optimize the constants iteratively. And after a certain number of iterations, the ideal parameters for FEA of the orthogonal cutting process were finally determined.

Abstract: This paper provides heat transfer modeling analysis and parameter optimization for wafer system of laser annealing equipment. Heat transfer models are established at axial and radial directions. With the help of programming calculation, the relation between heat flux of radiation and distance of adjacent layers can be analyzed. In order to minimize heat transfer interference on the motor system, optimized parameters are selected. Performance of certain selection is verified by FEA simulation and experiment data.

Abstract: This paper provides the methodology on analyzing the dynamic characteristic of machine tool in consideration of joint parameters. To ensure the dynamic model is available for further study, modal experiment for vertical machining center is involved. The machine tool is divided into several parts and connected with spring and damping for substructure modeling. Particularly, the bolt-fixed joint is an example for the joints modeling. Based on the dynamic model, simulation of modal analysis and harmonic response are carried out. Besides, method of optimization design of column and milling box is given to improve the performance, which is proved to be feasible in harmonic response.

Abstract: A feeding table system is set up to meet the need for high motional precision and super-slow speed in micro-electron discharge machining (micro-EDM). It is composed of a resonant piezoelectric ceramics motor, a linear bearing and a linear encoder . It features high accuracy due to the application of linear driving, closed-1oop feedback and elimination of abbe’s errors. The characteristics of fine motion , slow speed and load capability are investigated. The results of the experiments show that the stable fine motion of this system can be as little as 100 nanometer and its speed can be as slow as 0.5 micron per second which is proper for feeding table of micro-EDM.

Abstract: In non-abrasive cryogenic polishing, ice disk is used as polishing tool .The effects of ice disk characteristics by different water quality on surface roughness of machined parts are investigated. Non-abrasive cryogenic polishing is a plastic transfiguration process based on brittle-plastic transition theory. During machining, higher micro peaks become lower and the number of micro peaks increases which results in lower roughness. Experiments are done to attest to the process.