bluuebunny/crossref_metadata_2025 huggingface dataset:
Back-Side Thinning of Silicon Carbide Wafer by Plasma Etching Using Atmospheric-Pressure Plasma
Authors: Sano Yasuhisa , Aida Kohei , Nishikawa Hiroaki , Yamamura Kazuya , Matsuyama Satoshi , Yamauchi Kazuto
Published: June 2012

Silicon carbide (SiC) power devices have received much attention in recent years because they enable the fabrication of devices with low power consumption. To reduce the on-resistance in vertical power transistors, back-side thinning is required after device processing. However, it is difficult to thin a SiC wafer with a high removal rate by conventional mechanical machining because its high hardness and brittleness cause cracking and chipping during thinning. In this study, we attempted to thin a SiC wafer by plasma chemical vaporization machining (PCVM), which is plasma etching using atmospheric-pressure plasma. The wafer level thinning of a 2-inch 4H-SiC wafer has been possible without a removal thickness distribution caused by the circular shape of the wafer using the newly developed PCVM apparatus for back-side thinning with a spatial wafer stage.
Estimation System of Accurate Cutting Time Based on Actual Feedrate Identification
Authors: Saito Kosuke , Aoyama Hideki , Sano Noriaki
Published: June 2012

The estimation of accurate cutting time before cutting is important for improving productivity. Estimation of cutting time calculated by length of tool path / command feedrate can easily be obtained in commercial CAM systems because NC programs contain machining information, such as tool positions, feedrate, etc. However, the actual cutting time is longer than cutting time calculated by length of tool path / command feedrate due to acceleration and deceleration which occurs along the tool path. In this study, an estimation system of accurate cutting time based on the control system of the machine tool is proposed. Experiments were conducted to cut complex shapes using the NC machine tool to compare the actual cutting time, estimated cutting time of commercial CAM systems and those of the proposed system. The estimation error of the proposed system was only 2 %, while the estimation error of a commercial CAM system was 51 %.
Smoothing Mechanism of Reaction Sintered SiC in Plasma Assisted Polishing Using Ceria Abrasive
Authors: Deng Hui , Ueda Masaki , Yamamura Kazuya
Published: June 2012

For the finishing of some difficult-to-machine materials, a novel polishing technique named plasma assisted polishing (PAP) was proposed. Ceria abrasive polishing with different electric power plasma irradiation was conducted on RS-SiC surface. Low RF power plasma (8 W) was used, many protrusions were generated which made the surface roughnesses bad (60.93 nm p-v, 5.51 nm rms). In contrast, the height and amount of protrusions decreased when RF power was increased to 12 W, which made the surface roughness better (31.83 nm p-v, 2.63 nm rms). Also, scratches completely disappeared after PAP. To explain the above results, the relationship of oxidation rate by plasma irradiation and material removal rate by abrasive polishing was taken into consideration. The different compositions in RS-SiC have different oxidation rates and levels of hardness. When the oxidation rate is higher than material removal rate, the heterogeneous polishing of RS-SiC is turned to homogeneous polishing of SiO2, and then a flat surface with an oxide layer can be obtained. To prove the above assumption, we firstly oxidized the surface with plasma irradiation for 1 h, and then PAP with a much lower load was conducted on the oxidized surface for 0.5 h. A scratch-free surface with 12.61 nm p-v and 1.45 nm rms was obtained which coincides with the mechanism we propose.
Development of a 3-DOF Mobile Positioning Mechanism with 6 Contact Points
Authors: Yatsurugi Manabu , Fuchiwaki Ohmi
Published: June 2012

In this paper, we describe the design, development and experimental results of a 3-DOF precise inchworm mechanism with six contact points. During the last ten years, we have developed an omnidirectional and holonomic inchworm mechanism to provide flexible, compact, and precise microscopic processing. In a previous mechanism, four piezoelectric actuators connected a pair of U-shaped electromagnets arranged to cross each other so that the mechanism can move precisely in any direction. However, positioning repeatability was made difficult by an inclination of the U-shaped electromagnets. Therefore, we designed a new omnidirectional inchworm mechanism composed of a pair of Y-shaped electromagnets and six piezoelectric actuators to prevent the inclination of the electromagnets. In addition, we explain the drive principle of the newly developed mechanism. Finally, we show the experimental results of the positioning repeatability of translational motions in four directions with a payload.
Robust Production Scheduling Using Autonomous Distributed Systems
Authors: Oike Shunsuke , Tanaka Tomohisa , Zhu Jiang , Saito Yoshio
Published: June 2012

This research proposes a method of production scheduling using autonomous distributed systems. A concrete message protocol is proposed to realize the production scheduling which includes not only Machine but also Human and AGV scheduling. Moreover this method realizes real time scheduling and parallel scheduling. Therefore, a new structure of production scheduling is proposed, which can realize a change of the type of production scheduler to correspond with a type of production system.
Research on the Support and Gravitational Deformation of Large Aperture Primary Mirror of Space Telescopes
Authors: Peng Yang Lin , Dai Yi Fan , Chen Shan Yong
Published: June 2012

The surface figure of the primary mirror in a large aperture telescope is one of the key factors influencing imaging quality. Space telescopes are used in weightless environments, which is different from the ground environment for optical machining and testing. Therefore the effect of the deformation induced by gravity on the imaging quality is not negligible and the mirror support is to be carefully designed to unload the gravity during the course of machining and testing. In this paper, finite element analysis software is adopted to simulate and compare the deformation induced by gravity of a metre-scale aspheric lightweight primary mirror with different support methods and different working conditions. The results are then imported into MetroPro software supplied by ZYGO Corporation, to remove the tilts and rigid body motion of the mirror and calculate the primary aberrations from the deformation. Finally, sensitivity analysis of support deformation is implemented and the principles of mirror support design are summarized. The research is instructive for design, machining and testing of large aperture mirrors.
Chemical and Morphological Analysis of 4H-SiC Surface Processed by Plasma Assisted Polishing
Authors: Deng Hui , Ueda Masaki , Yamamura Kazuya
Published: June 2012

A novel polishing technique combined with the irradiation of atmospheric pressure plasma known as plasma assisted polishing (PAP) is proposed for the finishing of difficult-to-machine materials. In this paper, we mainly focus on the case of 4H-SiC substrate. We used helium-based water vapour plasma to modify the mechanical and chemical properties of the SiC surface. The results of X-ray photoelectron spectroscopy (XPS) measurements indicate that the surface was efficiently oxidized after plasma irradiation, and the main product was silicon oxide. A small amount of silicon oxycarbide was also observed which was identified as the interface oxide. The result of a nanoindentation test revealed that the hardness of oxidized SiC surface decreased by one order of magnitude compared with the unprocessed surface. The decrease of hardness of modified surface enables us to flatten the surface without forming any scratches and subsurface damage by using soft abrasive compared with the base material. We used CeO2 as the abrasive material in PAP, the hardness of which was near to that of the oxidized surface. The microscopic interferometer images of the PAP processed surface showed us that scratches disappeared and surface roughnesses also decreased from 4.410 nm p-v, 0.621 nm rms to 1.889 nm p-v, 0.280 nm rms. From the atomic force microscopy (AFM) images, a step and terrace structure was observed on the surface after PAP, which means that an atomically flat surface was obtained. We conducted reflection high-energy electron diffraction (RHEED) measurement to evaluate the residual strain of the PAP processed surface. The results indicate that the lattice constants approached the ideal value, which meansthat the PAP technique did not introduce crystallographical subsurface damage.
Characteristics of Excimer Laser Ablation for Three Dimensional Machining of PMMA
Authors: Ogura Kohei , Zhu Jiang , Tanaka Tomohisa , Saito Yoshio
Published: June 2012

In this research, machining characteristics of excimer laser ablation for three-dimensional machining of PMMA (Polymethyl methacrylate) is examined. In general, excimer laser ablation of polymeric material has features such as high precision and fine surface quality resulting from a less thermally-affected process, but in an earlier study, a thermal like effect on ablated surface was observed. Therefore, in this research the best machining condition of excimer laser ablation for PMMA by both numerical and experimental approaches was revealed.
Micro EDM by Stray-Capacitance-Coupled Electric Feeding
Authors: Koyano Tomohiro , Kunieda Masanori
Published: June 2012

With the electrostatic induction feeding method which has been developed by the authors to decrease the minimum discharge energy in micro EDM, non-contact electric feeding to the tool electrode is possible, since a pulse power supply is coupled to the tool electrode by capacitance. In this study, the non-contact electric feeding was carried out with stray capacitance only, and hence machining could be carried out without an electric feeder or equipment for electric feeding to the tool electrode. With the stray-capacitance-coupled electric feeding method, since the stray capacitance was significantly small, a discharge current pulse peak of 200 mA and 3 ns in duration was obtained, realizing discharge craters of 0.8 μm in diameter. A micro-hole of 13.5 μm in diameter was drilled successfully in a stainless steel plate with a thickness of 30 μm. In order to change the discharge energy, a capacitor was connected between the pulse power supply and the work piece. Machining results showed that crater diameters can be decreased by decreasing its capacitance. It was also found that smaller crater diameter can be obtained with a lower pulse voltage. Moreover, in order to minimize the discharge energy, the tool electrode was insulated from the mandrel to decrease the stray capacitance. As a result, a discharge current pulse peak of 130 mA and 2 ns in duration was obtained, and the diameter of discharge craters could be decreased to 0.6 μm.
Development of Focusing System for X-Ray Free Electron Laser
Authors: Mimura Hidekazu , Ohmori Hitoshi , Yamauchi Kazuto
Published: June 2012

The X-ray free electron laser (XFEL) is a new type of synchrotron facility, which can produce full coherent light at X-ray wavelength ranges. Its focusing system makes it possible to create an extremely intensive XFEL beam. Long-size focusing mirrors are necessary for this system from the viewpoint of X-ray radiation damage. We established the figuring system with an accuracy at the nanometre level. The focusing mirror has an elliptical curved shape with a length of 400 mm. Figure accuracy with a peak-to-valley height of 2 nm is achieved. The Kirkpatrick Baez focusing system was also designed and developed for two-dimensional focusing at Japanese XFEL.
Ultra Precision Grinding of Wafer Scale
Authors: Hünten Martin , Klocke Fritz , Dambon Olaf , Bulla Benjamin
Published: June 2012

Manufacturing moulds for the wafer-scale replication of precision glass optics sets new demands in terms of grinding tool lifetime and the processes to be applied. This paper will present different approaches to grinding processes and kinematics to machine wafer-scale tungsten carbide moulds with diameters of up to 100 mm and more than 100 single aspheric cavities, each featuring form accuracies in the micron range. The development of these processes will be described and advantages and disadvantages of the approaches derived from practical tests performed on an ultra precision grinding machine (Moore Nanotech 350FG) will be discussed. Finally, a comparison between the developed processes is made where achieved form accuracies and surface topography are analyzed.
Experimental Verification of Machining Process of Ultrasonic Drilling
Authors: Isobe Hiromi , Uehara Yusuke , Hara Keisuke , Onuma Takashi , Mihara Arata
Published: June 2012

Drill processing of difficult-to-cut materials such as ceramics, hardened steel, glass and heat-resistant steel is widely required in the industrial world. Furthermore the drilling process becomes more and more difficult in the case of hole diameters less than one millimetre. In order to achieve the requirements for the drilling process, ultrasonically assisted machining is applicable. Ultrasonic vibration assisted machining techniques are suitable for machining difficult-to-cut materials precisely. However, the cutting process of ultrasonic drilling has not been clarified. It is difficult to observe directly the effect of vibration. The aim of this study is to observe the dynamic, instantaneous and micro cutting process. In this report, a high-speed camera with a polarized device, which is appropriately arranged, realized the visualization of the process of ultrasonic drilling based on photoelastic analysis. For conventional drilling, the stress distribution diagram showed that the intensive stress occurred in limited areas under the chisel because the chisel edge of the drill produces large plastic deformation. On the other hand, the ultrasonic drilling produced spread stress distribution and a stress boundary far away from the chisel. The photoelastic analysis showed the explicit difference of drilling processes.
Nano-Motion X-Y Stage by Pneumatic Servo Spherical Bearing Actuators
Authors: Sugimoto Atsushi , Hirayama Tomoko , Matsuoka Takashi , Sasaki Katsumi
Published: June 2012

With the development of IC technology, ultraprecise positioning actuators with nanometre-order resolution are in demand, especially for semiconductor stepper equipment. A prototype X-Y stage for ultraprecise positioning composed of six pneumatic servo spherical bearing actuators (PSSBAs) was developed and its specifications were evaluated especially focusing on the step response and its minimum resolution. The minimum positioning resolution of the prototype was 3 nm under the best conditions, and the positioning resolution as a practical specification was approximately 10 nm for all conditions, even without feedback controls. With a simple feedback control, the minimum resolution was improved to 1 nm, which is enough to meet the demands of current ultraprecise positioning technology.
Study on Effect of Ultrasonic Vibration in Machining of Alumina Ceramic
Authors: Park Kyung Hee , Kim Kyeong Tae , Hong Yun Hyuck , Choi Hon Jong , Choi Young Jae
Published: June 2012

Ultrasonic machining can be applied for the machining of difficult-to-cut materials using ultrasonical oscillation in an axial direction on top of tool rotation, which can cause reduction of cutting temperature and tool wear. In this study, the experiments were performed on a DMG ULTRASONIC 20 linear machine tool using diamond tools in both conventional and ultrasonic vibration assisted machining. The machining performance was evaluated and compared for both cases in terms of cutting forces, machined surface roughness and tool wear. And the combination technique of 3D surface topography measurement and image processing was applied for the tool wear progress. Overall, the experimental results showed that ultrasonic machining had less tool wear and lower cutting forces at low cutting speed compared to conventional machining. Also surface roughness was slightly lower in ultrasonic machining than that without ultrasonic vibration.
Development of Composite Abrasives for Various Materials
Authors: Ichinoho Naoaki , Murata Junji , Tani Yasuhiro , Yanagihara Takeshi , Yamada Miyuki
Published: June 2012

The development of composite abrasives considering the cleanability of the polished work piece was previously reported. In glass polishing, composite abrasives exhibit improved polishing characteristics and result in superior cleanability in comparison with conventional polishing compounds. In this study, the application of these composite abrasives to the polishing of stainless alloy, cast iron and sapphire are investigated. New manufacturing methods and polymer particles are proposed for the various material applications. The experimental results show that composite abrasives improve the polishing removal rate for metal and sapphire substrates.
Design of Digital Filters for Si Wafer Surface Profile Measurement - Denoising by Total Variation
Authors: Ojima Hirotaka , Nonomura Kazutaka , Zhou Li Bo , Shimizu Jun , Onuki Teppei
Published: June 2012

In the semiconductor industry, high resolution and high accuracy measurement is needed for the geometric evaluation of Si wafers. The flatness parameters are important to evaluate the wafer profile and are required to be the same level as the design rule of IC, and the tolerance for flatness is very tight. According to SEMI (Semiconductor Equipment and Materials International) standards, the required wafer flatness will be 22 nanometres by the year 2016. However, to obtain a higher resolution for sensors, the uncertainty becomes very large compared to the resolution and influences the measured data when the noise is increased. High resolution instruments always incorporate a certain degree of noise. In the presence of noise, form parameters are normally biased. Correction and compensation need a large population of measurements to analytically estimate both bias and uncertainty. The estimation is still far from perfect because of the nature of noise. Another approach is to extract a true profile by filtering noise from the measured data. For the purpose of noise reduction, low-pass filters by Gaussian smoothing and Fourier transform are often used. The noise is normally considered to be a component of small deviation (amplitude) with high frequency which also takes a normal distribution around zero. However these conventional filters can remove the noise in the spatial frequency domain only. So, it is essential to design a filter capable of removing the noise both in the spatial frequency domain and the amplitude component. Thus, we have designed and developed new type of digital filter for denoising. We introduce two new digital filters. One is wavelet transform capable of denoising in the spatial frequency domain and amplitude component, and the other is total variation that can be applied to discontinuous signals without introducing artificial Gibbs Effects.
Development of Operation Interface for Machine Tool Using 6-DOF Haptic Device - Guidance of Tool Movement Using Force Sense
Authors: Kobori Syuhei , Morishige Koichi
Published: June 2012

In the previous report, the operation interface for multi-axis controlled machine tools was developed by using the haptic device that is used in the field of virtual reality and it was changed from a haptic device with 3-DOF to that with 6-DOF. In order to improve the system, more useful functions should be added. In this report, the function to guide the tool in consideration of the tools characteristics is developed. The square end mill cannot cut at its bottom part. So, when the bottom part contacts the removal shape, the square end mill should be guided into a posture contacting at the side part by the force sense. The experiment supposed that the machining of the curved surface had been done. In the case of using the developed function, the number of contacts at the bottom part of the tool was decreased. As a result, the usefulness of the developed function was confirmed.
Noncontact Figuring of Millimeter-Thick Elliptical Mirror Substrate by Numerically Controlled Local Wet Etching
Authors: Nagano Mikinori , Yamaga Fumiya , Yamazaki Dai , Maruyama Ryuji , Soyama Kazuhiko , Yamamura Kazuya
Published: June 2012

Aspherical supermirrors are some of the most useful neutron-focusing optics. We aim to develop multiple aspherical supermirror devices using high-precision figured aspherical focusing supermirrors to focus neutron beams with high intensities, because multiple mirrors collect a very large beam divergence. Thin mirrors with millimetre thickness are required to minimize the absorption loss of incident neutron beams since the thickness of a mirror shadows the reflective area of other mirrors. However, it is difficult to fabricate thin mirror substrates with a form accuracy at the sub-micrometre level by conventional machining. Conventional machining deforms a substrate by machining force and spring back after machining causes figure error. Furthermore the deposition of supermirrors deforms the mirror substrate by film stress. Thus, we developed a new process of fabricating a precise millimetre-thick elliptical supermirror. This process consists of non-contact figuring by the numerically controlled local wet etching technique, the minimization of surface roughness without degrading form accuracy by low-pressure polishing with a polishing pressure less than about 7 kPa (1psi), and the ion beam sputter deposition of NiC/Ti multilayers on both sides of the mirror substrate to compensate for film stress. In this paper, we report on the fabrication results of aplano-elliptical mirror substrate with a thickness of 1 mm.
Correcting Distortion of Elliptical Trajectory for Maximizing Cutting Performance in Elliptical Vibration Cutting
Authors: Loh Byoung Gook , Kim Gi Dae
Published: June 2012

To maximize cutting performance of elliptical vibration cutting (EVC) (also known as two-dimensional vibration assisted cutting), the elliptical trajectory of a cutting tool needs to be corrected. In this study, the effect of the shape of the elliptical trajectory on the machining characteristics of EVC is investigated. Various elliptical trajectories were created by modulating the relative phase and magnitude of the sinusoidal input voltages to the piezoelectric actuators and the effect of tilt angle of the elliptical trajectory on the machining quality such as the cutting resistance and machining quality is experimentally observed in successive micro-V grooving as the tilt angle is changed between 0o, 30o, -30o, and 90o. It is found that the tilt angle significantly affects both the cutting resistance and machining quality.
Modeling and Analysis of Material Removal Characteristics in Silicon Wafer Double Side Polishing
Authors: Lee Sang Jik , Kim Hyoung Jae , Jeong Hae Do
Published: June 2012

As advancing technologies increase the demand for yield and planarity in integrated circuits, wafers have become larger and their specifications more stringent. Flatness, thickness variation and nanotopography have emerged as important concerns in the wafering process. Double side polishing has been adopted as a solution to these problems. This paper focuses on the material removal characteristics and wafer profile variation during Si double side polishing. A polishing experiment to investigate Si removal characteristics according to process parameters was carried out in a single head rotary polisher equipped with a monitoring system for friction force. It was found that the material removal rate is related to friction energy rate, and the polishing state was transited and divided into three conditions according to pressure. On the basis of the experimental results, the wafer profile variation in double side polishing was modelled and simulated according to pressure. The friction energy was calculated to find the material removal amount across the wafer. With the conversion of calculated friction energy to the material removal amount, wafer profile variation was simulated. As a result, the wafer profile variation and its range were increased with a pressure increase, and originated from the position near the wafer edge.
Analysis of Tangential Position Error or Removal Function Error in Ultrasonic-Magnetorheological Combined Finishing
Authors: Zhang Fei Hu , Yu Xing Bin , Zhang Yong
Published: June 2012

Ultrasonic-magnetorheological combined finishing (UMCF) is a new technique for the ultra precision machining of aspheric surfaces, especially for high quality work pieces with small curvature radius concave surfaces. The goal with UMCF is to minimize surface figure errors by optimizing the dwell time and tool path, and the current approach typically results in low amplitude form errors. However, discrepancies exist between the predicted and observed form errors. The major sources of such errors are machine axes positioning errors and unpredicted variations of the removal function. Errors that can produce discrepancies between actual and predicted removal profiles were modelled. A diagnostic method was developed to determine the residual error induced by two types of error. Their effects were examined with numerical simulations and the simulation result was presented. Finally, UMCF experiments are performed on a variety of optical surfaces. The final residual error after polishing is less than 2.6 nm PV values. The successful figuring results prove the validity and advantages of UMCF.
Nanomanipulator Based on a High-Speed Atomic Force Microscopy
Authors: Ishisaki Itsuhachi , Ohashi Yuya , Ushiki Tatsuo , Iwata Futoshi
Published: June 2012

We developed a real-time nanomanipulation system based on high-speed atomic force microscopy (HS-AFM). During manipulation, the operation of the manipulation is momentarily interrupted for a very short time for high-speed imaging; thus, the topographical image of the fabricated surface is periodically updated during the manipulation. By using a high-speed imaging technique, the interrupting time could be much reduced during the manipulation; as a result, the operator almost does not notice the blink time of the interruption for imaging during the manipulation. As for the high-speed imaging technique, we employed a contact-mode HS-AFM to obtain topographic information through the instantaneous deflection of the cantilever during high-speed scanning. By using a share motion PZT scanner, the surface could be imaged with a frame rate of several fps. Furthermore, the high-speed AFM was coupled with a haptic device for human interfacing. By using the system, the operator can move the AFM probe into any position on the surface and feel the response from the surface during manipulation. As a demonstration of the system, nanofabrication under real-time monitoring was performed. This system would be very useful for real-time nanomanipulation and fabrication of sample surfaces.
Kinematics and Dexterity Analysis for a Novel Hybrid Kinematic Machine
Authors: Yu Hong Jian , Li Bing , Wang Yang , Hu Ying
Published: June 2012

In this paper a novel 4 Degree-of-Freedom (DOF) parallel mechanism with the configuration of 4PUS-1RPU is applied for a 5-axis Hybrid Kinematic Machine (HKM), combined with an additional linear motion. The Parallel Kinematic Mechanism (PKM) is composed of four symmetrical driving chains and one central passive sub-chain. Firstly, the mechanism is described, and the mobility is analyzed. Then the inverse kinematics of the 4-DOF PKM and the direct kinematics for the serial central sub-chain are then presented. The dexterity and the workspace analysis for the mechanism are also carried out. Finally, machining experiment research is presented to verify the effect of the prototype. The research provides the basis for the further parametric design with consideration of kinematic and dexterity performance.
Lubricated Friction Reduction by Spiral-Groove-Shape Nano-Texturing
Authors: Tanaka Yusuke , Okada Kazuma , Hirayama Tomoko , Matsuoka Takashi , Sawada Hiroshi , Kawahara Kosuke , Noguchi Shunji
Published: June 2012

To effectively reduce the friction in machines operating under lubrication, the sliding surfaces should be fully fluid-film lubricated. Under the full fluid-film lubricated conditions, the upper surface is completely supported by the lubrication film formed in the gap between the surfaces, resulting in low friction and no wear. Surface texuturing is a promising way to modify the tribological properties of sliding surfaces, and a technique for fabricating surface textures with a nanometre-order depth using a femtosecond laser can be used to easily and quickly produce periodic grooves in metal surfaces. It can thus be applied to industrial sliding surfaces to improve their tribological properties. The purpose of the study is to verify the effect of surface nanotextures fabricated using a femtosecond laser to reduce friction under lubrication. As a result, the two disks continued to operate under full fluid-film lubricated conditions even when the bearing clearance became quite small, less than 200 nm. Our testing showed that grooves with a nanometre-order depth can support a higher load than ones with a micrometre-order depth, and we proved that nanotexture can expand the full-lubricated condition.
Research of a Novel Combined Metal-Fused Silica Resonator for Cylinder Shell Vibrating Gyroscopes
Authors: Wu Yu Lie , Luan Qing Lei , Cui Hong Juan , Wu Xiao Mei , Xi Xiang
Published: June 2012

A novel combined metal-fused silica resonator for the cylinder vibrating gyroscope is proposed in this paper. The cylinder wall of the resonator is made of fused silica, while the bottom is made of metal, and then the two parts are connected by strong glue. With this method, the manufacturing difficulty of the fused silica resonator can be reduced significantly and the performance can be retained without remarkable degeneration. In this paper, the novel metal-fused silica resonator is analyzed, including the structural optimization design and fabrication, testing of the stability of the resonance frequency and the Q factor. The preliminary experimental results show that the low-cost combined metal-fused silica resonator has potential good performance to achieve high accuracy in a cylinder shell vibrating gyroscope.
Novel Diaphragm-Control Restrictor for Precision Hydrostatic-Bearing Spindle
Authors: Mizumoto Hiroshi , Sunahara Taiki , Yabuta Yoshito , Arii Shiro , Fujii S. , Matsumoto K. , Murakami K.
Published: June 2012

A novel diaphragm-control restrictor (DCR) is proposed for improving the performance of the hydrostatic-bearing spindle used in machine tools. The unique function of the proposed DCR is the wide adjustability of its restrictor characteristic. A two-step restriction system is adopted for the DCR; a spool restrictor is used as the first step restrictor. By changing the restrictor resistance of the spool restrictor, the effect of the active control in the DCR, the second step restrictor, can be altered. The proposed DCR is incorporated into a hydrostatic bearing supporting a precision spindle, and the performance of the bearing is analyzed. Numerical and experimental analyses show that the stiffness of the hydrostatic bearing with the proposed DCR can be five times as large as a conventional hydrostatic bearing of the same dimensions. Analysis of the dynamic compliance shows that the effect of the active control can be observed up to 20Hz. These results show that the proposed DCR is useful for improving the performance of the hydrostatic-bearing spindle in precision applications.
Shape Reproduction of Object with Many-Colored Surface by Photometric Stereo Method
Authors: Nakatani Ryo , Hirogaki Toshiki , Aoyama Eiichi , Nakamura Seishi
Published: June 2012

Three-dimensional shapes created from photographic imagery using a photometric stereo method is restored in the present study. We used one object and one digital camera. The source of light was moved and the camera took a picture of two or more object shape data. The radiance value of the obtained photographic imagery was requested respectively. It was restored to three-dimensional geometry by calculating the normal vector from the radiance value, and combining the data of the photographic imagery. As for this method, it is well-known that application is difficult for objects that have lustre. Therefore, an improvement was attempted using spline interpolation. It has been understood that the method which reproduces it by using spline interpolation as a result is effective. Furthermore, because an error margin is caused when an object with colour variation is reproduced, an improvement was tried. First of all, the colour component of the image was extracted. Then, the image with a small change in brightness was chosen and reproduced. Consequently, a shape near the theoretical value was able to be reproduced for the reproduction of a two-colour object including white.
A Study on Pulse Generator for Micro WEDM of Polycrystalline Diamond
Authors: Yan Mu Tian , Liu Yi Ting , Fang Guan Ren
Published: June 2012

This paper presents a new pulse generator for cutting of polycrystalline diamond (PCD) by micro wire-EDM. Three pulse control methods (AC power supply pulse control method, fixed pulse width modulation pulse control method and improved AC power supply pulse control method) have been proposed to achieve high frequency and low energy discharge pulses. The improved AC power supply pulse control method enables the pulse generator to provide a period of 20 μs off duty cycle followed by a period of duty cycle for reionization of the dielectric in the spark. Compared to the other two methods, the improved AC method can provide smaller peak current and discharge duration and thereby achieve a smaller slit width and better surface finish. Tests revealed that the developed power supply using anti-electrolysis circuitry and a digital signal processor-based pulse control circuit can provide very low discharge energy pulses with a frequency of 200 KHz, discharge duration of 0.75 μs and a peak current of 3 A. Experimental results demonstrate that the proposed pulse generator can achieve a feed rate of 0.4 mm/min, a surface finish of 0.53 μm Ra and a damaged layer of 5 μm on PCD surface through proper machining settings.
A Geometry-Based Method for Prediction of Shot-Peening Coverage
Authors: Kim Hong Seok , Lee Yong Sung , Shin Ki Hoon
Published: June 2012

Shot-peening is the process of repeatedly hitting the work piece surface with small balls, making overlapping indentations on the surface. This process is extensively used on shafts, gears, springs, and jet engine parts because it imparts compressive residual stresses on the surface, thus improving the fatigue life of components. Under-peening does not give a sufficient fatigue life while over-peening induces cracking and reduces fatigue performance. Hence, determining optimal peening conditions such as peening time is very important. In general, optimal peening conditions are experimentally determined by measuring arc-height using Almen-strip or calculating coverage using microscope images. Shot-peening coverage is defined as the proportion of the exposed surface that has been impacted in a given time of shot-peening. To save the time and effort spent in repeating experimental measurement needed whenever the geometry of a work piece and peening conditions change, this paper presents a computer simulation algorithm for the prediction of shot-peening coverage, which is based on the geometry of a work piece. An example is presented to validate the proposed method.
Fabrication of Fine Mesh Filter Screen with Pulsed Laser
Authors: Ogawa Keiji , Nakagawa Heisaburo , Murase Fumiya , Nishida Susumu
Published: June 2012

This paper proposes a novel manufacturing process of a fine mesh filter screen with a pulsed laser. The fine mesh filter screen, made of stainless steel, has many small diameter holes with high aspect ratio and fine pitch. In the conventional process, an electron beam drills in a vacuum. However, this is very costly because of the expensive equipment required and batch process. Therefore, a laser drilling process for small diameter hole drilling in air with higher flexibility was proposed. The post-processes after the laser drilling completed the fine mesh filter screen.
Study on the Effect of Rake Angle on Cutting Forces in Ultra-Precision Machining
Authors: Duong Thanh Hung , Chul Kim Huyn , Yoon Lee Dong
Published: June 2012

In recent years, there have been many studies concerning the effect of cutting parameters and tool parameters on the ultra precision machining of electroless nickel. However, there is no known reported study on the relationship between the cutting force and tool rake angle in ultra precision machining of electroless nickel. The objective of this study is to compare and investigate the cutting force with various rake angles for micro machining electroless nickel work pieces by theoretical analysis and experiment. Diamond tools with rake angles of-10o, 0o and 10o were used in the experiment. According to theoretical analysis, the tool with a 10o rake angle induces the smallest cutting force. However, the experiment showed that the tool with zero rake angle always gave us the smallest cutting force for all cutting speeds, cutting depths and pattern pitches.
Theoretical Study of Optical Vibration and Circulation of a Microsphere
Authors: Watanabe Nobuyuki , Taguchi Kozo
Published: June 2012

In this paper, we proposed an optical vibration and circulation technique of a microsphere using plural optical flat-top fibres, mounted horizontally on the bottom of a sample chamber, and verify that an optically trapped object can be circulated by controlling laser power emerging from optical fibres without moving the optical fibres. We theoretically analyzed the optical forces exerted on a microsphere, a 10μm diameter polystyrene particle (refractive index 1.59), by laser beams. From these theoretical results, we verify that our proposed optical manipulation technique is useful for the manipulation of biological cells.
Relationship between Thermal Influence and Magnetic Characteristics in Electrical Discharge Machining of Magnetic Materials
Authors: Takezawa Hideki , Ichimura Yoshihiro , Suzuki Tatsuya , Muramatsu Tamao , Mohri Naotake
Published: June 2012

t is difficult to perform traditional machining, including turning, milling and grinding, of a permanent magnet, which is a functional material, because of magnetic forces. However, electrical discharge machining (EDM), which is a non-contact machining method, has been used for shape machining of magnetic materials. In the EDM process, non-magnetic materials such as copper or graphite are typically used as electrodes.
Magnetic materials have a Curie point; therefore, their magnetic flux density reduces when they are heated to a high temperature. Because EDM is a thermal process, it has the potential to control the magnetic flux density of a machined surface.
In this study, to clarify the influence of magnetic flux density on a machined surface, the following machining conditions were investigated: (1) the Duty Factor (D.F.) and (2) the input energy of one pulse. A sintered neodymium material was used as the work piece. The magnetic flux density of a cross-section of a machined neodymium magnet was measured. The results showed that the influence of the magnetic flux density was low under low-energy machining conditions. In contrast, for high-energy machining conditions or a high D.F., the magnetic flux density significantly reduced compared to the initial value. These results confirm the importance of machining conditions for EDM of magnetic materials.
Chemically Etched Single Mode Fiber Tip for High Lateral Resolution Imaging in Optical Coherence Tomography
Authors: Taguchi Kozo , Totsuka Masafumi
Published: June 2012

In this paper, we propose a high lateral resolution common-path Fourier domain optical coherence tomography (OCT) system with the use of a chemically etched single mode fibre. In our experiments, a single mode optical fibre of 840 nm was used for preparing the tapered tips. Our system used a conical microlens that was chemically etched by a selective chemical etching technique using an etching solution of buffered hydrofluoric acid (BHF). From the experimental results, we verified that our proposed optical coherence tomography system could operate as a common-path Fourier domain OCT system and the apex angle of the chemically etched single mode fibre tip was a very important parameter for generating high-resolution OCT images.
Optical Fiber Oxygen Sensor Based on Ru (II) Complex and Porous Silica Nanoparticles Embedded in Sol-Gel Matrix
Authors: Chu Cheng Shane
Published: June 2012

This paper presents a high-sensitivity oxygen sensor that comprises an optical fibre coated at one end with tris (4, 7-diphenyl-1, 10-phenanthroline) ruthenium (II) ([Ru (dpp)3]2+) and porous silica nanoparticles embedded in an n-octyltriethoxysilane (Octyl-triEOS)/tetraethylorthosilane (TEOS) composite xerogel. The sensitivity of the optical oxygen sensor is quantified in terms of the ratio IN2/IO2, where IN2 and IO2 represent the detected fluorescence intensities in pure nitrogen and pure oxygen environments, respectively. The experimental results show that the oxygen sensor has a sensitivity of 26. The experimental results show that compared to oxygen sensor based on Ru (II) complex immobilized in the sol-gel matrix, the proposed optical fibre oxygen sensor has higher sensitivity. In addition to the increased surface area per unit mass of the sensing surface, the porous silica nanoparticles increase the sensitivity because a substantial number of aerial oxygen molecules penetrate the porous silica shell. The proposed optical sensor has the advantages of easy fabrication, low cost, fast response and high sensitivity for oxygen monitoring using a cheap LED as a light source.
Optimal Design of Microneedles Inserts into Skin by Numerical Simulation
Authors: Chiu Chui Yu , Kuo Hsin Chuan , Lin Yi , Lee Jeou Long , Shen Yung Kang , Kang Sheng Jie
Published: June 2012

The purpose of this research is to find the optimal design for biodegradable polymer microneedle patches. Based on the mechanical properties of different skin layers and the failure criterion of the material, this research designs a microneedle of four types and three sizes, then discusses the insertion force and the variation of stress during the process of PLA microneedle insertion into skin by numerical simulation. This research uses the dynamic finite element software ANSYS / LS-DYNA to simulate the processing for PLA microneedle inserts into skin. The master microneedle array was fabricated by the MEMS process. This research uses PDMS to fabricate the mould for microneedles. Finally, a biodegradable polymer polylactic acid (PLA) microneedle patch was fabricated using a PDMS mould micro hot embossing method.
3D FE-Based Modelling and Simulation of the Micro Milling Process
Authors: Wu Tao , Cheng Kai
Published: June 2012

Modelling and simulation of the micro milling process has the potential to improve tool design and optimize cutting conditions. This paper presents a novel and effective 3D finite element (FE) based method for simulating the micro milling process under large deformations. A tooling model incorporating a helix angle is developed for cutting forces, tooling temperature and chip formation prediction. The proposed approach is experimentally validated and the simulated micro milling performance such as micro chip formation and cutting forces are in reasonable agreement with the measured results in cutting trials.
Nonlinear Dynamics of Tool Vibration in Micro-Cutting
Authors: Zhang Shao Jian , To Suet , Cheung Chi Fai
Published: June 2012

This study focuses on the nonlinear dynamic characteristics of tool vibration in ultra precision diamond turning. Considering the first mode vibration of a tool, the tool is modelled as a one degree of freedom spring-mass-damper system with a developed cutting force model. Numerical simulations were carried out to anlyze the nonlinear dynamics of the system, using bifurcation diagrams, Poincaré maps, phase protraits, time histories and power spectral densities. The results indicated that the dynamic response of the tool is dominantly periodic and harmonic at its natural frequency with a little negligible chaos and its natural frequency, more than its fundamental frequency, is slightly shifted by depth of cut and cutting force.
Cutting Characteristics of Lanthanum Base Metallic Glass in Single Point Diamond Turning
Authors: Chong F.F. , To Suet , Chan K.C.
Published: June 2012

To investigate the maintainability of bulk metallic glasses (BMGs), two Lanthanum base metallic glass were first characterized by using X-ray diffraction and then machined by single point diamond turning (SPDT). With increasing depths of cut (DOC) from 1 um to 5 um, surface finish was improved. However, surface finish is not improved significantly when the DOC is further increased.
Bio-Inspired Synthesis of Al2O3/Polymer Composite
Authors: Nam Kyung Mok , Lee Yoon Joo , Kim Soo Ryong , Kwon Woo Teck , Kim Hyung Sun , Kim Y.
Published: June 2012

The formation of organic-inorganic hybrid composite with ceramic platelets and polymeric compound can have the higher strength and higher elasticity than metal, which is a nanocomposite with high strength and light weight. Ceramic platelet such as Al2O3has been used to form organic-inorganic composite material using PMMA as an organic polymer. Bending strength and density of the composites prepared by infiltration and post-warm pressing were measured. FE-SEM and TG analysis were carried out to determine the microstructure of the organic-inorganic composite materials. Bending strengths and densities of the composites prepared by Al2O3ceramic plate and PMMA after post-warm pressing were ~70MPa and ranged from 2.4 to 2.6, respectively.
MLCA (Material Life Cycle Assessment) for ITO Recycling
Authors: Lee Soo Sun , Lee Na Ri , Kim Kyeong Il , Hong Sung Jei , Hong Tae Whan
Published: June 2012

Recently, touch screen is one of the most popular pieces of electrical and electronic equipment in our society, such as laptops, cellular phones, and digital cameras. Indium tin oxide (ITO) is mainly used to make transparent conductive coatings for touch and flat screen. Therefore, there is an increasing demand accordingly. Although accounted for 1% of the touch screen, indium is rare metals. Consequently, it is important to Recycling ITO for National Strategies about Resource Conservation, and reduce Environmental burden. The case which disuses ITO like landfill or incineration, it cloud be harmful to the human health in the long-term. This study intended to identify the environmental aspects with the ITO recycling. The potential environmental impacts were evaluated by using Material Life Cycle assessment method (MLCA). As the result of this study, MLCA would provide more information for environmental issues of ITO. So that it is possible to improve the environmental issues by the monitoring that could be useful and effective for ITO. The study includes two scenarios, the basic scenario is recycling of ITO (10, 20 and 30%) and the other scenario is landfill of ITO.
Cu2O Doping Effects on Microstructure and Piezoelectric Properties in (Na0.52K0.44)(Nb0.9Sb0.06)O3-0.04LiTaO3 Pb-Free Ceramics
Authors: Kweon Soon Young , Lee Youn Ki , Ryu Sung Lim
Published: June 2012

The (Na0.52K0.44)(Nb0.9Sb0.06)O3-0.04LiTaO3 (NKNS-LT) ceramics doped with various Cu2O contents were prepared by the conventional solid state reaction method. The Cu2O content was varied in the range of 0.1~0.4 wt%. The effects of Cu on microstructure, crystallographic phase transition, and piezoelectric properties were investigated. The material with perovskite structure had a tetragonal phase (T1) when Cu2O concentration was less than 0.3 wt% and it was transformed to another tetragonal phase (T2) when the Cu2O amount was greater than 0.3 wt%. The phase boundary between T1 and T2 phases was appeared at around 0.3 wt% of Cu2O concentration. The piezoelectric properties were shown the maximum values at the composition of the phase boundary. The electro-mechanical coupling factor (kp) was 0.42 and the piezoelectric charge constant (d33) was 245 pC/N at the 0.3 wt% of Cu2O concentration.