Papers by Author: Yu Fu Li

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Authors: Fu Gang Yan, Cai Xu Yue, Xian Li Liu, Yu Fu Li, 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.
Authors: Tao Chen, Yi Wen Wang, Yu Fu Li, C.J. Yang, Xian Li Liu
Abstract: In this paper, cutting experiment and FEM simulation are combined to investigate the effect of various chamfered edge geometries on cutting force and cutting temperature distribution when hardened steel GCr15(HRC60+2) is machined with PCBN tool. The research results indicate that radial force and main cutting force increase with the enlargement of chamfer angle, and especially, radial force rises more significantly, but radial force is less than main cutting force during the entire cutting process. Cutting temperature also gradually rises as chamfer angle increases, and moreover, it is maximized on the chip-tool interface in a place of 0.1-0.2mm distant from nose.
Authors: Jing Shu Hu, Yuan Sheng Zhai, Fu Gang Yan, Yu Fu Li, Xian Li Liu
Abstract: In the cutting process, cutting force is one of the important physical parameters, which affects the generation of cutting heat, tool life and surface precision of workpiece directly. In this paper an orthogonal design of experiment and subsequent data is analyzed using high speed finish hard cutting GCr15 whose hardness is 65HRC. Cutting speed is 200-400m/min, to study the influence of cutting parameters on cutting force, cutting force empirical model has obtained from least square method.
Authors: Xian Li Liu, Chun Ya Wu, Yi Zhi Liu, Fu Gang Yan, Yu Fu Li, Peng Wang
Abstract: Aiming at different grinding surfaces of hardened bearing steel GCr15, this paper made experimental research on detection method of surface roughness based on image technique. Adopting cold light source and five kinds of LED light sources, such as low-angle light, collimated light and coaxial light, we analyzed image characteristics of grinding surface under different processing conditions and found that there was a good correlation between standard deviation of gray variance and roughness of grinding surface. In comparison with the results from traditional surface roughness measuring instrument, we gained the corresponding relation between different grinding surface roughness and standard deviation of image gray variance. It was proved by calculating that they have a good correlativity.
Authors: Yu Wang, Peng Wang, Hong Min Pen, Yu Fu Li, Xian Li Liu
Abstract: Experiment of hard cutting GCr15 with PCBN cutting tools, the influence of tool’s inclination angle and cutting parameters (cutting speed and feed speed) on cutting forces and cutting temperature are studied. A three-dimensional finite elements model using the commercial software Deform 3D 5.03 is developed. The friction between the tool and the chip is assumed to follow a modified Coulomb friction law and the adaptive remeshing technique is using for the formation of chip. The workpiece material property is a function of temperature, strain, and strain rate in the primary and secondary shear zones. Finite element method is used to simulate three-dimensional precision cutting, including orthogonal cutting and oblique cutting. The cutting forces and back forces are slightly changed by tool’s inclination angle. However, in high cutting speed, the cutting force decrease as the tool’s inclination angle increase, while the cutting temperature increase as the tool’s inclination angle increase. The simulation results are compared with experimentally measured data and found to be in good agreement to some extent.
Authors: Er Liang Liu, Yu Fu Li, X.Z. Wang, Fei Xiao, Xian Li Liu
Abstract: In the process of turning high-temperature and high-strength steel, it is an effective method for chip breaking with complicated groove insert. In this paper, chip breaking mechanism is analyzed using the coated complicate groove insert for cutting high-temperature and high-strength steel. The model of chip curl radios is constructed though analyzing the effect of complicated groove insert on chip formation. The mathematical formulation of chip section profile coefficient is built through analyzing influential effect of complicated groove on chip section profile. The chip breaking model is developed according to chip-breaking criterion. Finally, a full experimental validation of the model is presented for chip breaking when the workpiece is high-temperature and high-strength steel, 2.25Cr-1Mo-0.25V. The tested results show the chip breaking model is reasonable, and the optimization cutting parameters are obtained.
Authors: Wei Ji, Xian Li Liu, Yu Fu Li, Tian Yu Ma, Da Wei Sun
Abstract: This paper researched experiment results and analysis of PCBN insert turning nickel-based HSTR GH 4169. According to the curves and pictures, discuss the relationship of cutting parameters (cutting speed, feed and cutting depth) and some indexes (cutting force, cutting temperature and surface roughness). In addition, observed chip burr patterns, tool wear types and white layer statuses, and quantitatively analyzed their factors from the perspectives of cutting force and temperature, and put forward corresponding measures. The studies above were based on future research of quantification.
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