Recently, much interest is being taken in method to protect the copyright of digital data and preventing illegal duplication of it. However, in the area of CAD/CAM and CG, there are no effective ways to protect the copyright of the 3D geometric models. As a first step to solve the problem, a new digital watermarking method for 3D polygonal models is introduced in this paper. Watermarking is one of the copyright protection methods where an invisible watermark is secretly embedded into the original data. The proposed watermarking method is based on the wavelet transform (WT) for the polygonal model. The watermark can be embedded in the large wavelet coefficient vectors at various resolution levels of the transformed model. The method makes the embedded watermark imperceptible and invariant to the affine transformation. And also makes the control of the geometric error caused by the watermarking reliable. Finally, the effectiveness of the proposed watermarking method is shown through several simulation results.

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The study deals with a new practical fabrication method of various end mills, based on 3D-CAD/CAM. End mills with arbitrary tool shapes, which are generally difficult to produce, are strongly required in terms of upgrading machining accuracy and efficiency. Thus, our tool grinding CAD/CAM system was already reported, and showed the potentials of producing end mills with arbitrary tool shapes though it was not suitable for practical use. To put them to practical use, the system was improved, taking account of a grinding method of primary flank, a design of cutting edge shape and five-axis NC data generation. As a result, the system allows to produce practical end mills with arbitrary tool shapes. In addition, it is found that end mills fabricated by the system have enough shape accuracy, compared with commercially available ones.

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This paper presents a new optical measurement method for evaluating small defects on a silicon wafer surface by detecting the intensity distribution, "Laser Scattered Defect Pattern(LSDP), " corresponding to the superposition of scattered light from a defect and reflected light from a surface. In order to verify the feasibility of application of this optical measurement method to in-process measurement, the experimental measurements were carried out by identifying the LSDPs with the standard particles on the silicon wafer surface which had been observed by SEM. It was found that this method makes it possible to measure the small defects and contaminations with size of submicron order and has the possibility of discriminating the different kinds of ones.

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High precision, long stroke linear stage which will be applied to fine delay line for long baseline optical stellar interferometer is being developed. Requirements of the liner stage are precision less than ±λ/40 of movement jitter in an integration time of about 5ms at stage velocity of 0-30mm/s, such a low residual error during 10 minutes interval by closed loop control, and longer than 10m stroke. In this paper, driving mechanism (motors, micro-stepping technique and gears) and isolation method for high frequency vibration with rubbers are studied in order to provide high performance of the linear stage. The linear stage consists of an optics cart and a micro-stepping motor cart moving on stainless steel poles. The stage movement jitter of 8.3nm RMS in 5ms duration was achieved with the best selection of parameters even at the stage velocity of 30mm/s without closed loop control. This performance is enough to use practically as an 800m baseline optical interferometer. It is expected that the performance will become better than at present when a servo control is applied. Furthermore, the rubber isolator will possibly introduce a simpler control architecture of the delay line system.

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Due to the advancement of micromachine technology, development of measuring method for both profile and dimension of microparts has been strongly demanded. One of the methods available for this is a small three-dimensional profile measuring apparatus with microprobe. For this purpose, fabrication technology of probes that have optimal shape for individual part measurement must be developed. In this research, micro electrical discharge machining which has extremely small machining force and is applicable for fabrication of various type probes, has been used. X type and X-Z type probes which are installed to the small three dimensional profile measuring apparatus based on principle of STM (scanning tunneling microscopy) are made by proposed method using micro die-sinking electrical discharge machining. The relation of electrode and probe profile and measuring results obtained by the probe fabricated are described also.

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An analysis method of the damping characteristics for electrostatically driven torsion micro actuators which have deep grooves on their electrodes is described. The damping force is caused by viscous friction (squeeze action) of the gas film between a moving mirror plate and the electrodes. The grooves decrease the damping force and enable the moving plate to be driven at high speed and low driving voltage. To calculate the damping force correctly, it is required to consider the viscous friction not only on the moving plate and electrodes, but also on the side walls of the grooves. For that purpose, the idea of hydraulic mean depth is introduced and is applied to Reynolds equation. The calculated damping force shows good agreement with the measured damping force of the developed torsion mirror actuator for optical heads.

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This paper deals with lateral spacing parameters of the three-dimensional surface topography data. To begin with, the method for calculating the mean surface wavelength was introduced being based on auto-correlation analysis for the virtual surface composed of orthogonal sine waves. By applying this technique to measured data, a fairly good correlation was obtained between the mean surface wavelength and lateral spacing of adjacent asperities. Additionally, the method for deciding the calculation region of the local slope and the summit shape was developed and the necessary condition for sampling interval was shown.

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In the field of the roundness measurement, the 3-point method is used as the typical software datum to achieve high accuracy beyond the radial motion error of the axis. Furthermore, the 3-point method is applied to the radial motion measurement using compensation procedure. Many papers have reported the characteristics of the 3-point method for the roundness measurement. On the other hand, the characteristics of the 3-point method for the radial motion measurement is not clear. This article proposes a novel 3-point method for the radial motion measurement based on the weighted addition and inverse filtering. The transfer function of the 3-point method for the radial motion measurement is the same that the roundness measurement. Influence of the random error of the 3-point method is low. Influence by the setting angle error of the displacement sensors is large at high spatial frequency domain.

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The crystallographic orientation dependence of the machinability of single-crystal silicon was studied by molecular dynamics (MD) simulation in the turning process of single-crystal copper from the standpoint of slip deformation behavior. Slip deformation occurred with minimal damage to the work material, as the material removal process was governed by activated slip systems parallel to the turned surface. On the other hand, as other non-parallel slip systems contributed to slip deformation, the turning process advanced with greater damage such as crystal rotation or change in crystal orientation. This agrees with previous experimental results showing that better surfaces were obtained on the (111) wafer than on the (001) wafer at the same depth of cut. MD analysis also revealed that, as slip systems existing on intersecting slip planes were activated simultaneously, glide was restricted in each plane due to their interaction. This in-dicates that ductile-brittle transition is highly dependent, not only on the number of activated slip systems and the amplitude of their Schmid factor, but also on how each slip system is arranged geometrically. Such slip deformation behavior makes it clear why ductile-regime turning can be realized more easily by turning along the [112] direction on the (111) wafer than by turning along the [112] direction.

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In automated manufacturing processes, it is indispensable to have the ability to monitor and diagnose automatically the faults occurring in machining processes. To realize such ability, it is important to develop a pattern recognition from the measured value of the state to give correct judgment of the normality. This paper presents a new recognition process based on Mahalanobis distance. The distance is calculated with the so-called Mahalanobis Space that is constructed by characteristics derived from only the normal states' wave patterns of cutting vibration. The "differential and integral" characteristics were picked up from the wave patterns. Experimental result shows that an on-line monitoring with high sensitivity can be realized. And, a method to progress the sensitivity keeping the high speed processing was examined using Genetic Algorithm (GA).

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Laser forming is a metal forming process by thermal stresses under laser irradiation without an external force exerted to material. The process has a high possibility as a rapid proto-typing, because the process does not need any die or punch in a metal forming process. Three dimensional thermal elastic-plastic analysis on a stainless steel plate during laser scans was done by the finite element method. The temperature, stress and plastic strain distributions in a plate were obtained analytically as well as the deformation of a plate. The simulated bending angle of the plate was compared with experimental results. It is clarified that the bending of a metal plate is produced by compressive stresses due to a local expansion on a laser-irradiated area.

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A novel plasma etching technique has been developed for improvements of etching rate and aspect ratio. So far, etching characteristics are improved mainly by controlling plasma particle anisotoropic movements, gas components and thermal conditions etc. Against this backdrop, a substrate vibration mechanism is proposed to enhance the relative movement of the substrate in plasma particles and promote a better gas stirring. This paper describes the principle of the mechanical vibration assisted plasma etching, basic construction of the reactor and some evaluations of the vibration assisted etching. A prototype reactor has been constructed by using a stacked piezoelectric resonator with a resonant frequency of 2.9KHz and a maximum vibration amplitude of 19.2 μm. Si chips with a grid patterning are used for the evaluation of etching characteristics in SF₆ gas. The results indicate usefulness of the new technique in silicon trench etching for SiO₂ and chromium masks.

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Variation in the preferred orientations of Titanium Nitride (TiN) thin films with various experimental conditions (N/Ti transport ratios, N ion incident angles, film thickness and substrate temperature) were investigated. These films were formed on Silicon (100) wafers by ion-beam-assisted deposition with the nitrogen ion energies of I keV. The preferred orientation of TiN films changed from (111) to (200) as the N/Ti transport ratios and the ion incident angles increased. It is considered that this phenomenon is caused by the selective damage of crystal growth due to the energy of bombarding particles. On the other hand, the increase of film thickness led the preferred orientation of the TiN (200) film to (200) plus (220) orientation. Furthermore, this orientation changed to (200) again with the heating of the substrate during film preparation. It is considered that these phenomena are caused by the minimization process of the overall energy. So, the heating of the substrate is useful for synthesize of thick TiN (200) films.

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Steel balls set into the bearings are finished with conventional ball lapping machine which uses a couple of flat and V-groove lapping plate. Conventional lapping method, however, needs so long machining time. Present study focuses on efficient lapping method using spin control lapping macine which V-groove lapping plate is separated into two parts and three plates are able to rotate independently. Spin angle θ of steel ball is rotated by force during lapping to promote finishing efficiency. Experiments show that spin angle rotation have great effect on finishing characteristics such as a stock removal, decrease of deviated diameter and surface roughness of ball. Lapping carried out at fixed angle of θ indicates that finishing modes change drastically at 45 degree, which is responsible for efficiency of machining of ball.

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The grain edge shape plays an important role in cutting ability. In order to examine the grain shape, bulk density test has been carried out as a standard test so far. However, it does not give any microscopical information for evaluating the grain edge shape. Hence microscopic evaluation of grain edge shape must be taken into consideration for better abrasive machining. To solve this problem, it was suggested in the previous paper that the fractal dimension could be used to characterize the complexity of grain edge geometry. In the present paper the role of fractal geometry of abrasive grain in lapping is evaluated. When grains of low fiactal dimension are supplied in lapping, stock removal increases in compare with using high fractal dimension. It is because grain surface consists of large and sharp edges. When grain surface consists of micro edges and has a large f actal dimension, the surface finish becomes better. Based on the results, the fractal dimension that characterizes the grain edge geometry can be a better index of cutting ability.

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OD-Blade slicing method using low-frequency vibration and air-mist working fluid has been developed to improve the slicing characteristics and decrease a quantity of the supplied working fluid for environmental integrity. This method is applying the vertical vibration to the workpiece and supplying a small quantity of the working fluid at high speed to the machining region used by the compressed air. Especially, this paper elucidates the effect of vibration applied to the workpiece on its slicing characteristics experimentally. As the results, with an air-mist working fluid for OD-Blade slicing, the applied vibration is indispensable to keep the good slicing characteristics. Not only the grinding force is decreased, but also the grinding ratio is improved by means of increasing the applied vibration amplitude. Furthermore, in the case of supplying the air-mist working fluid, the wafer waviness in the non-vibration slicing is deteriorated by the compressed air. However, that of the vibration slicing shows a considerable improvement.

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A micro-photoforming whose unit laminated layer is made by a spinner is proposed. A high resolution of 2 μ m was confirmed to solidify a visible light curable resin using a DVD optical head. A 30 μ m diameter shuttlecock optical rotator was fabricated to indicate the possibility of 3D microstructures.

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