Papers by Author: Pei Quan Guo

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Authors: Shou Ren Wang, Pei Quan Guo, Hong Yan Wang, Min Wang
Abstract: Owing to two phases are continuous and penetrated each other, Interpenetrating composites exhibit good abrasive wear properties, can be an attractive candidate for structural and functional materials. Specifically, the abrasive wear model of IPCs is an important topic in the field of tribology. In present work, the model has been proposed according to the mixing rule. Many factors such as special topology structure characteristic of reinforcement, hardness and elastic module are discussed in this model. One kind of Al2O3/Mg composite with different volume content was fabricated and many test data of friction wear were obtained. These data validate the correctness and universality of model.
Authors: Shou Ren Wang, Li Ying Yang, Ru Ma, Pei Quan Guo
Abstract: The flow stresses of AZ41M and ZK 60 wrought magnesium alloys under the deformation conditions of twin rolling casting and hot compression (TRC-HC) at different temperature and strain rates were studied. The deformation behavior and failure mechanism of them were discussed. The microstructure evolutions were analyzed by OM and EBSD technique. The results indicated that AZ41M and ZK 60 have different strain-stress curve under the same conditions. Working hardening results in occurrence of cracks in or around the shear bands. The recrystallized, equiaxed and fined grains in shear bands attribute to recovery and recrystallization, grains refinement causes local working hardening as well as decreases of crack tip driving forces. The stresses concentrate in shear bands causing cracks initiation and propagation. Casting defects to be the nucleus of cracks is another failure mode. With the increases of strains, dislocations rearrange forming sub-grains, the low angle grain boundaries (LAGBs) continuously evolved into high angle grain boundaries (HAGBs).
Authors: N. Fan, Pei Quan Guo, Xian Chi, Z.H. Gao
Abstract: Cutting tool wear has relation with the cutting forces. By way of signal processing, the power spectrums of cutting forces in different tool wear stages are analyzed in the present paper. It is proved that several characteristic frequencies exist within a wide frequency range during the cutting process as long as cutting process parameters keep constant. The power value of the characteristic frequency increase with the increase of tool wear. Thus, the tool wear could be predicted by the changes of characteristic frequencies and their power values.
Authors: Pei Quan Guo, Chuan Zhen Huang, W. Wang, N. Fan
Abstract: According to the analysis of engagement between indexing roller and cam contour as gear indexing cam mechanism operating and milling process as contour being machined, three kinds of surfaces, cam’s contour, the surface swept by roller’s axis during engagement and the surface swept by cutter’s axis in milling process, are equidistant surfaces. Based on isometric theory, the approaches to determine tool path and to calculate NC program coordinates for inequi-diameter milling have been developed. The architecture of computer aided programming software for inequi-diameter milling was illustrated. Practical example of inequi-diameter milling NC codes was presented. In inequi-milling process, NC program can be updated to adapt the change of cutter diameter in time. So, cutter’s life can be prolonged, the cost of cutter can be cut down.
Authors: Pei Quan Guo, Shou Ren Wang, Huan Yong Cui
Abstract: The study reports a new surface formation technology during manufacturing process of parallel indexing cam mechanism, ion beam sputtering deposition, in which the operation temperature can be controlled below the limitation of phases exchanging or at room temperature. Phase exchanging deformation can be avoided and the shape accuracy and dimension accuracy can be improved compared with surface quenching process. The microstructure and properties of TiAlN/AlN composite film deposited on the profile surface of cam (made of 45 steel) by ion beam sputtering deposition were discussed. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM) analysis has been used to characterize film’s microstructure and properties. The micro-hardness and adherence grade were tested.
Authors: Pei Quan Guo, Chuan Zhen Huang, Jin Ping Shi, Xiao Xia Li
Abstract: Geometrical model of virtual machining system was introduced. Based on the analysis of the machining system, it was divided into workpiece subsystem and tool subsystem. Dynamic models of subsystems have been established by means of simplification of machining system. Dynamic analysis and simulation have been done. Model of virtual machining system is the combination of geometrical model and dynamic model. Based on the dynamic analysis and simulation of virtual machining system, conclusion was drawn: (1) In cutting process, as cutter feeds into cutting zone, vibration appears and becomes stronger and stronger. As cutter tends to leave cutting zone, vibration becomes weaker and weaker and disappears finally. The most violent vibration occurs as cutter has engaged into cutting zone and as cutter tends to leave cutting zone. (2) As machining corresponding to dwell of indexing plate, dynamic response is smooth and steady. (3) Vibration will attenuate sharply after cutter leaving cutting zone. The operation of virtual machining system accords with the appearance in real machining process. Properties of product model are very close to those of real machined cam.
Authors: Xiao Qin Wang, Xing Ai, Jun Zhao, Pei Quan Guo
Abstract: Ti6Al4V is a difficult to machine alloy with low cutting efficiency and server tool wear. A series of orthogonal turning tests with CBN (Cubic Boron Nitride) in higher speed scale was carried out on a CA6140 lathe. The experiential functions of tool life based on orthogonal experiment were developed. The tool wear morphologies were examined by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS), adhesion, diffusion and micro-chipping were the major wear mechanisms of CBN tool. Finally, the cutting parameters of CBN tool in Ti6Al4V dry turning were optimized based on tool life-efficiency contour analysis, in same cutting efficiency, the higher cutting speed and small depth of cut are the better selection, it means that utilization of CBN tool enables the high cutting speed turning of Ti6Al4V.
Authors: Pei Quan Guo, Shou Ren Wang, Jin Ping Shi, N. Fan, W. Wang
Abstract: Cutting force model for flat end milling and dynamic model of cam milling system were established based on the analysis of machining system for parallel indexing cam contour milling. Solution for dynamic performance of this kind of milling system has been introduced. A system, consisting of NC milling machine SK1632K3, tooling and workpiece, has been taken as example to analyze how cutting speed, feeding, or processing redundancy influence the dynamic performance of machining system. Furthermore, milling error of cam contour has been evaluated corresponding to different machining parameters. Simulation and analysis results are very close to practical manufacturing situation.
Authors: Hong Yan Wang, Xue Feng Yang, Pei Quan Guo
Abstract: Two machining methods for non-circular isometric profile are introduced. The profile modeling technology and the numerical control technology are analyzed. The dynamic property of in a series profile modeling technology system is revealed, and the design principle for in a series profile modeling technology system is put forward, the value range of damping ratio is instanced at near 0.7. The turning machining system adopting linear servo motor as drive element is brought forward.
Authors: Ning Fan, Hang Liang, Pei Quan Guo
Abstract: Cutting force collected by experiment is transformed by continue wavelet in order to overcome the disadvantage that signal processing analyzes single variable. The eigenvector which can reflect tool wear state is extracted from scale-energy matrix based on analysis, and BP neural network is established to predict tool wear. Trained network is used for prediction by unknown sample. Results show that this method can identify and diagnose accurately tool wear state.
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