Advances in Materials Manufacturing Science and Technology

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Authors: Guo Sheng Geng, Jiu Hua Xu, Ying Fei Ge, Yu Can Fu
Abstract: A series of experiments were carried out on normal and high speed milling of a high strength titanium alloy (TA15). TA15 is a close alpha titanium alloy strengthened by solid solution with Al and other component. It is often used to make large structural parts in airplane and welded parts subject to heavy load. The tool life of several typical types of cutter commonly used in the milling of titanium alloy was studied by the orthogonal experiment design method. After multi-element regression analysis, the empirical equation of the tool life was stablished. The milling force and temperature were measured under different cutting conditions and tool wear status. The knowledge is useful to further understand and analysis of the cutting mechanism, machining quality and tool wear. The study on the machined surface integrity includes the following content: surface roughness, metallographic examination, work hardening and residual stress.
731
Authors: G. Wang, K. Liu
Abstract: Laser cutting process plays a key role in obtaining accurate parts in Laminated Solid Manufacture. Conventional laser cutting machine adopts motion control scheme. For further improving the cutting accuracy, dynamic factors are to be taken into account. The dynamic compensation scheme is proposed. The method combines the advantages of close-loop position control and computed torque control. Different from other presented schemes, the method is not model-based. A multilayer neural network is employed to realize the inverse mechanic dynamics. The complicated dynamic parameter identification problem becomes the learning process under supervision. Experiments have been conducted to verify the proposed method for improving the laser cutting accuracy.
736
Authors: Qin He Zhang, Ru Du, Jian Hua Zhang, J.Y. Yang, Sheng Feng Ren
Abstract: A new machining method, ultrasonic vibration aided electrical discharge machining (UEDM) in gas, is proposed in this paper. It is shown that electrical discharge machining with ultrasonic vibration aid can be achieved well in gas medium. In the process of UEDM in gas, the tool electrode is formed to be thin-walled pipe, high pressure gas medium is supplied from inside, and ultrasonic vibration is applied to workpiece. The property of ultrasonic is introduced. The same to other sound waves, ultrasonic have the characteristics of reflecting, refracting, intervening and resonance. The mechanism of elastic pole keeping in resonance with ultrasonic transferring from one end to the other end is explained with characteristics of ultrasonic. During the process of UEDM in gas, ultrasonic vibration of workpiece can improve the machining process. The theories of ultrasonic vibration increasing materials removal rate (MRR) are introduced. One theory is that the adhere strength between the metallic liquid drops and workpiece is not enough for the accelerative vibration, so metallic liquid drops will be ejected off easily. Another theory is that ultrasonic vibration increases the number of the effective discharge.
741
Authors: Ai Xin Feng, Yong Kang Zhang, H.K. Xie, Lan Cai
Abstract: The interfacial adhesion between thin film and substrate is often the predominant factor and chief target in determining the performance and reliability of thin film/substrate system. A new technique of laser scratch testing technique has been presented by the authors of the article to characterize the interfacial adhesion between film and substrate, which synthesizes the advantages of traditional scratching technique and laser measure technique. The failure procedure is studied detailedly in the article. On different failure step of the film/substrate system, there are different characteristic s of stress and strain, as well as the characteristic of thermal lensing effect, which can be used as the distinguishing rule of the bonding state of the film/substrate system.
746
Authors: Wan Sheng Zhao, Yu Fang, Zhen Long Wang, L.H. Li
Abstract: This paper describes a new surface modification method by Electrical Discharge Machining (EDM) to create a hard ceramic layer on the workpiece. When a kind of metallic material that makes hard carbide is used as an electrode of EDM, hard ceramic layer can be deposited in a certain condition in the process of EDM. In this paper, characteristics of the layer and the application of this method to cutting tools are discussed. First, the principle of this surface modification method is shown. Secondly, the characteristics of the layer are studied in detail. Through the discuss of wear characteristics of the electrode and formation characteristics of the layer, it can be found that there are some distinct differences between the traditional EDM technology and this new EDM surface modification method. Thirdly, the micro-hardness test of the layer at the different distance from the base metal is carried out. It shows that there is a hard area also under the surface of base metal. At last, as an application of EDM surface modification method, cutting test of cutting tools is done, and it confirms that the life of the cutting tool by EDM surface modification is much longer than that of without layer.
750
Authors: S.T. Huang, Jing Feng Zhi, Hao Bo Cheng, W. Zuo
Abstract: This paper presents the design and implementation of a robust motion control structure for linear servo units used in noncircular machining. Compared with ball/screw driven system, the controller of the linear motor driven system must provide a high level of disturbance rejection performance, as the system is more sensitive to force disturbances and parameter variations. Thus, in this paper, a robust feedback controller based on disturbance observer is applied to enhance the stiffness and robustness. A magnitude and phase regulating control scheme (MPRC) is proposed to improve the system tracking accuracy, and a simple error feedforward compensator (EFC) further reduces the feedforward control error that result from inaccurate frequency response data. The effectiveness of the proposed controller is demonstrated by experiments.
755
Authors: L.G. Guo, He Yang, Mei Zhan, Heng Li, L.Y. Li
Abstract: A simple and efficient method has been proposed in order to determine the dynamic speed boundary condition caused by the guide rolls for developing the 3D-FE model of cold ring rolling process rapidly. The concept of the motion track of guide rolls has been put forward firstly and an optimal motion track and track type are given by simulation. Meanwhile, an effect of the guide rolls on the ring tilting and ring circularity was simulated and analyzed. The result shows that the simulation results are in good agreement with experiment results from the literature.
760
Authors: Yi Min Zhang, Xiu Li Lin, Xiao Dong Wang, Guang Qi Cai
Abstract: One of the important factors resulting in the high-speed machinery performance is its machine tool dynamic characteristic. It will directly influence the final manufacturing capability of the machinery and it is also the important criterion of evaluating machinery performances. Especially, the dynamic characteristic of spindle assembly has large effect on manufacturing capability of machinery. So it is very important both analyzing dynamic-static characteristic of the spindle assembly and machine tool of high-speed machinery and studying the effect to machinery function. Using Finite Element Analysis software did a Finite Element Analysis of spindle assembly of the high-speed machine tool, and some experiments are done to validate the result the Finite Element Analysis results.
765
Authors: D.Z. Liu, M. Liu, Pei Si Zhong
Abstract: Product development process analysis and reengineering are the basic for enterprise to put CE into practice. The characteristics of concurrent PDP are analyzed and compared with the traditional PDP. The basic requirements, methods and steps of PDP analysis, improvement and reengineering for CE are presented. The process model for PDP analysis and reengineering is built. According to the actual PDP in Qiqihar Railway Rolling Stock Company in China, the process for the grain rolling stock development is analyzed and improved, and the result is satisfactory.
770
Authors: Y. He, Zheng Qiang Yao
Abstract: End mills are very widely used in machining metal. In this paper, based on analysis of three different end milling indexable inserts with 3-D chip breaker, the influence of different chip breaker on cutting force, chip deformation and machined accuracy are studied by comparative experiments. The results show that the cutting effect of end mills with indexable inserts can be improved by optimization of 3-D chip breaker and suitable for different machining condition.
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Showing 151 to 160 of 186 Paper Titles