Advances in Abrasive Technology IX

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Authors: J.D. Yang, Q. Liu, C.L. Tian, J.W. Guo, Y.H. Feng
Abstract: This paper discusses a new lapping ellipsoid method, which combines high-speed lapping technology with solid abrasives and lapping tool bending method. In this method, a bending moment is acted on lapping tool with solid abrasives, which makes it bend to form a shape on its working surface, which is the same as generant of workpiece shape. This kind tool is used in forming lapping on a high speed lapping machine. With the development of science and technology, the requirements for optics systems become higher and higher, e.g. good quality of imaging, little loss light energy, small size and light weight etc. It is difficult to reach above requirements by using traditional sphere lens/mirrors in optics systems. Aspheric optics elements can be used to solve these problems. In optics systems, by using aspheric optics elements, the number of optics elements can be reduced, the system structure can be simplified, the weight and size of the system can be reduced, light energy loss can be reduced too, imaging errors can be avoided and imaging quality can be improved. Ellipsoid is a kind of surface being used widely within all kinds of aspheric surfaces. The main purpose of this paper is to introduce a method of lapping this kind of surface at high speed.
Authors: Yong Kang Zhang, De Jun Kong, Y.H. Fu, Jin Zhon Lu, Ai Xin Feng, Xu Dong Ren
Abstract: The diesel engine cylinder was processed by laser honing (LH) device, the structure morphology was observed with scanning electric mirror (SEM), and lubricant consumes and wear performances were measured, at the same time the mechanism of LH and effects of laser parameters on LH results were analyzed. The experimental results are shown that LH is a kind of phase transformation treatment by laser, which processes a hardening belt in the certain distributing form on the work-piece surface, and forms the hardness distribution of soft and hard material alternatively; LH may lower the engine oil consumes 30%-60%, and reduce the pollution of the catalyst machine, and lower the grain let of the engine oil 25%-30%. LH intentionally machines the grain cave, which has the certain angle, depth, and width etc.. The surface microcosmic sculpting has the lubricating function for usage process, and storage and transport lubricant, which improves the rubbing condition, then lower the part wear and increase the other performances. The short-wave laser is more applicable to the LH process, which improves the lubrication condition, and increases the service life of the engine and the efficiency, and lowers the engine oil consumes.
Authors: Vu Ngoc Pi, A.M. Hoogstrate
Abstract: This paper introduces a new and comprehensive study on cost optimization of abrasive blasting systems. In the study, the effects of many parameters such as nozzle diameter, air pressure, efficiency, cost components as well as the effect of the nozzle wear on the cleaning cost were investigated. A new model for calculation of the optimal exchanged nozzle diameter (called “optimal diameter”) was proposed. With “optimal diameter” a new and effective way of using and making blasting nozzles was proposed and both the cleaning cost and the cleaning time can be reduced significantly.
Authors: Chuan Zhen Huang, Rong Guo Hou, Jun Wang, X.Y. Lu, Hong Tao Zhu
Abstract: Three dimensional simulation of the velocity field of solid-liquid two-phase flow inside the abrasive water jet nozzle was studied by the computational fluid dynamics software (CFD). The complicated velocity field and vectorgraph of the flow in the abrasive water jet nozzle was obtained. In the course of the simulation, the Syamlal-O’Brien model was used to decide the inter-phase drag exchange coefficient. The velocity vectorgraph simulation results indicate that the highest flow speed is occurred at the inlet of the mixing chamber and the flow speed is gradually decreased along the direction of the nozzle axis and got to the lowest speed at the outlet of the nozzle. And also the flow speed in the cross section of the mixing chamber is gradually reduced along the radial direction of the cross section and got to the lowest speed in the verge of the chamber. The comparison of simulation result for the velocity field of water and abrasive exhibits that the velocity of water in the mixing chamber is three or four times higher than that of abrasive.
Authors: Yan Xia Feng, Chuan Zhen Huang, Jun Wang, X.Y. Lu, Hong Tao Zhu
Abstract: The surface characteristics of Si3N4 ceramics milled with abrasive waterjet milling technology is studied. The milled surface characteristics and the effect of process parameters on milled surface roughness are analyzed. The results show that the milled surface roughness ranges between 0.55 and 1.1um at the milling conditions under consideration and is changed with the change of process parameters. The milled surface roughness will be significantly decreased at the milling conditions of lower water pressure and larger lateral spacing. The effect of nozzle traverse speed on milled surface roughness is complex, but a traverse speed of 1000mm/min is the optimum speed for AWJ milling Si3N4 ceramics. The milled surface roughness first decreases then increases with an enhancement of standoff distance from 10mm to 30mm, and it also significantly decreases with the increase in abrasive mesh. Therefore, the medium standoff distance of 20mm and finer abrasive are the optimum conditions for AWJ milling Si3N4 ceramics with the process parameters under consideration.
Authors: Y.B. Cao, X.P. Xie
Abstract: Based on Back-Propagation neural network and Dempster-Shafter evidential reasoning, a fuse classification method for identifying wear particles is putted forward. Firstly, digital wear debris images are dealt with images processing methods. Then from the wear particles images, wear particles characters can be obtained by means of statistical analysis and Fourier analysis. Later, an integrated neural network made of two sub-neural networks based on statistical analysis and Fourier analysis is established, and some typical wear particles features as training samples are provided. After each sub-BP neural network has been trained successfully, the preliminary diagnosis of each sub-neural network is achieved. By using of the dempster-shafter evidential reasoning, the finial fusion diagnosis results are obtained. In the end, a practical example is given to show that the fusion results are more accurate than those with a single method only.
Authors: Da Ping Wan, De Jin Hu, Li Ming Xu, Hai Feng Wang, X.D. Yao
Abstract: This research is to investigate the dynamic characteristics of the grinding process. A kind of robust grinding wheel reciprocating arrangement is schemed out, which realizes the precise point-grinding machining. The grinding wheel reciprocating movement is driven by a linear motor to replace the traditional crank or hydraulic pressure drive device. Based on the time series method, the modal experimental analysis technique has been adopted in this paper. By acquiring acceleration signals of multiple positions of the grinding wheel slide, the dynamic characteristics are analyzed and the modal parameters of the structure are identified by virtual analysis program. The boundary condition of the finite element model is adjusted for optimizing its dynamic characteristic. The equivalent substructure is created and modified in order to improve the surface grinding quality. This study has got satisfying results. The grinding wheel movement realizes the self-regulation control and reduces the surface waviness and roughness during high speed point-grinding operation.
Authors: Kazushi Minaki, Koichi Kitajima, Yu Nakahira, K. Minaki, Moriyasu Izawa, Katsuji Tosha
Abstract: Recently, wet blasting is generally used such as liquid honing and water jet machining in surface before plating of stainless steel. The outstanding feature of wet blasting is to prevent generation of static electric charge, to use micro abrasive grain, and to have cushioning for workpiece. On the other hand, the disadvantage of wet blasting is to generate corrosion of equipment and liquid waste under processing. Moreover, the using abrasive grain is available on a limited basis. In particular, improvement disposal of liquid waste under processing is crucial in the near future. This paper makes proposal for improvement of surface texture by utilizing dry blasting, and it conducts improvement of surface texture about martensite stainless steel (SUS420J2 In JIS), which is used in material for scale. In the previous report, it has been cleared that relationship between surface texture and wettability. In this report, adhesion of plating was measured by scratch test. As a result, it was cleared that availability of adhesion evaluation by utilizing wettability.
Authors: J.H. Liu, Zhi Jian Pei, Graham R. Fisher
Abstract: The majority of integrated circuits are built on silicon wafers. To manufacture high-quality silicon wafers, a series of processes are needed. After a wire sawing process slices silicon ingots into wafers, grinding processes can be used to flatten the sliced wafers. This paper reports three experimental investigations on wafer grinding. The first investigation was to study the effectiveness of soft-pad grinding in removing the wire-sawing induced waviness. The second was to explore the capability of grinding in achieving super flatness. The third was to study the effects of grinding parameters on wafer flatness.
Authors: Sumio Kamiya, Hisao Iwase, Tetsuya Nagaike, Li Bo Zhou, Hiroshi Eda, Shun-ichiro Kimura
Abstract: The single crystal of Si is still one of the most important candidates among other materials including Single crystals of SiC, GaN, C(diamond) or compound semiconductors. The innovative process as called CMG(Chemo-Mechanical-Grinding) for Si wafer has been recently developed which is different from conventional CMP(Chemo-Mechanical-Polishing ) process. The CMG process can be done under dry conditions using CeO2 based solid bulk abrasives. The microstructures for surface and subsurface of Si single crystal after CMG process were analyzed using TEM/EDX, AFM, MFP-3D Microscope. The mechanism of CMG process was also investigated by X-ray diffraction and ICP chemical analysis using products by chemical reaction between Si and CeO2 abrasives. The results showed that Si single crystal after CMG had, 1) no defects even Si lattice revel or mechanical imperfections,2) better surface roughness as compared to CMP process. The CMG mechanism concluded that CeO2 reacted with Si producing Ce-Si-O amorphous phase.

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