Progress of Precision Engineering and Nano Technology

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Authors: Yan Hua Zou, Takeo Shinmura
Abstract: This paper describes a new efficient internal finishing process for a thick tubing (10~30mm in thickness), by the application of a magnetic field-assisted machining process using a magnet tool. Because a stronger magnetic force can be generated than conventional magnetic abrasives, it makes the internal finishing of thick non-ferromagnetic tubing possible. Moreover, in order to obtain a high-quality surface, this process method was developed using magnetic particles magnetically attracted on the magnet surface. This paper characterizes the processing principle and advantages of this process. Then, the mechanism of this finishing process was examined by a plane model experiment. It was clarified that the magnetism and shape of a magnetic particle influence realization possibility of this processing method, and it also influence the finishing characteristics.
Authors: Hui Feng Wang, Guang Lin Wang, Ze Sheng Lu
Abstract: Aiming at the ultra-sophisticated combined working machine tool that was developed, the motion style of the machine tool when abrasive machining a sort of inward-curving-parabolic shape optical aspherical surface device is analysed, according to the equation of the machined part’s surface, the relative movement locus between the cutter and the machined part can be established while using a spherical grinding wheel as grinding cutter. The caliber of the paraboloid that to be processed is analysed, and the grinding wheel's installation angle is chosen, as well as the cutting speed of the cutting spot is analysed, the abrasive model in ideal condition is analysed, the basis is based for error compensating.
Authors: Xin Chen, Z.H. Zhong, Q.Y. Wang
Abstract: A series of experiments is carried out on the characteristics at the wedge bond interface. Bond lift-off characteristics are studied by using Scanning Electron Microscope with EDS-test. The characteristics of input impedance of PZT transducer are analyzed by the driving electric signal measured by Oscilloscope. Results show that the pattern of partially bonded material at the interface of ultrasonic wedge bonds exposed by peeling underdeveloped bonds simulates a torus with an unbonded central region. For the same machine variables, the input impedance and transforming power of the first wedge bond are greater than that of the second wedge bond. Some conclusions drawn by analyzing the input impedance and the power of PZT consist with the results gotten by testing microstructures at the interface.
Authors: Guan Xin Chi, Shi Chun Di, Guo Hui Cao, Zhen Long Wang
Abstract: This paper analyzes the cause of overshoot and retarded response in controlling piezoelectric ceramic motor with PMAC card in micro WEDM. The model of start-stop control is presented, and the servo control card with start-stop control is also developed. The model reserved the advantages of traditional PID control, and overcome the problems of overshoot and retarded response. It has been verified by machining that system overshoot is less than 3 pulses and response time is less than 1 second.
Authors: Jian Jun Ding, Zhuang De Jiang, Bing Li, Jun Jie Guo
Abstract: Rapid reverse technology is one of the key technologies with which the enterprises develop new product and occupy the market rapidly. How to realize the reverse measurement and CAD geometry reconstruction rapidly and accurately is always the most important focus for the researchers. Based on the laser scanning technology, the realization principle of the laser line scanning measuring system is presented and the approaches to improve the precision are also analysed in the paper. The self-adaptation adjustment of the probe position can move the light knife image to the optimal imaging area of the CCD according to the calibration result, which will ensure the measurement precision of the CCD image. With the inner velocity loop and outer position loop feedback control, the simple axis position precision of the mechanical system can be controlled within 5um. In order to pick up the points of the light knife centre rationally and exactly, the reconstruction-disperse iteration algorithm is put forward. After processed by different iteration times, the optimal points can be obtained. The reconstruction method of curve and surface based on NURBS is also given. The paper presents the application and realization of the system at last, which realizes the curve and surface measurement with high precision.
Authors: N. Geng, Xing Fu, H.X. Li, X.C. Ni, Xiao Tang Hu
Abstract: A 775nm femtosecond laser is applied to single crystal silicon by direct-write processing in air. A series of holes are drilled with 150fs duration pulses, various numbers of laser pulses and laser fluences on silicon wafer. Different laser parameters and material properties influence the size of fabricated holes. The diameter and depth of holes are gradually enlarged with the increase of laser fluence and pulse number. The periodic ripple structure on silicon surface is found and explained at the same time.
Authors: J.S. Jeon, S. Hyun, Young Shin Kim
Abstract: Finite-element methods are used to study non-adhesive, frictionless rough contact of elastic and plastic solids. Roughness on the contact surfaces is realized by self-affine fractal. True contact area between spherical rough surfaces and flat rigid surfaces rises in power law as the external normal load increases. The power exponent is sensitive to surface roughness as well as the curvature of spherical geometry. Surface contact pressures are analyzed and compared for elastic and plastic solids. The distribution of local contact pressure is significantly dependent on the surface roughness and the yield stress of plastic solids.
Authors: Chun Hua Ju, Yi Xie
Abstract: Surface roughness is an important quality characteristic in grinding. Measurement of surface roughness by means of mechanical stylus is widely done in metrology. In this paper, a new machine vision system has been utilized to quantify the surface roughness of machined surfaces (ground and milled). Compared with other measurement methods, it is accurate, quick and credible. This system is mounted on the grinding machine and automates the measurement process by using computer control to automatically position the CCD and capture digital images of machined surfaces between grinding cycles. It was proposed that the proportional formula was used in calibrating this system, and calibration precision meets application requirement. Not only the statistic character of gray image but also which of edge image were calculated out. These characters include the mean value of pixels (Mean), standard deviation (σ), maximal value (Max) and minimal value (Min), the number of pixels on the examine line(Count), etc. It was found out that the standard deviation value σ of the gray image could express the surface roughness most. The correlation between σ and Ra is established by interpolating σ value used Lagrange interpolation law, and the σ value is converted into Ra value through the calculation procedure finally.
Authors: Hyun Seop Lee, Boum Young Park, Sung Min Park, Hyoung Jae Kim, Hae Do Jeong
Abstract: Chemical mechanical polishing (CMP) has become the preferred technology to achieve global planarization of wafer surfaces. Especially in oxide CMP, mechanical factors have a greater effect on the removal rate than chemical factors. So, the effects of mechanical parameters in CMP can be expressed as friction force and heat caused by friction. The friction force can be evaluated by a CMP friction force monitoring system and process temperature can be obtained by an infrared rays (IR) sensor. Furthermore, friction energy can be calculated from the friction force monitoring system. In this paper, research on the correlation between frictional and thermal characteristics of SiO2 slurry and CMP results was conducted. This data, which was obtained by using integrated monitoring system for CMP, will lead to the efficient prediction of CMP results.
Authors: Wei Min Pan, Ji Shun Li, Y. Lei
Abstract: Precision measuring techniques have been developed interdependently with the techniques of design and manufacturing in the history. Computer aided inspection plays a very important role in modern manufacturing industry. On account of the CMM (Coordinates Measurement Machine) being applied widely and the precision model inspection concept coming true, it is possible to implement the digital inspection of the spiral bevel gear on the CMM. In this paper the framework of the spiral bevel gear digital inspection based on the integration of CAD/CAM/CMM is put forward. The key techniques of the scheme are investigated, which consist of exact modeling of spiral bevel gear based on manufacturing process, datum matching of CAD model and CMM inspection, CMM Inspection path planning, reconstruction of the tooth surface based on the CMM inspection results, Analysis of the deviation between the real gear tooth and CAD model, adjusting strategy of machining parameters.

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