Emerging Technology in Precision Engineering XIV

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Authors: Sung Ho Jang, Yuki Shimizu, Takemi Asai, So Ito, Wei Gao
Abstract: This paper presents an optical probe employed for edge contour measurement of single point diamond cutting tools. The laser beam from a laser diode (LD) is focused by an objective lens to form a small light spot with a radius of approximately 20 μm, and is then received by a photodiode (PD) after passed through the focal point of the objective lens. The cutting edge of the tool, which is placed on a line with the LD and the PD, is inserted into the laser beam section. At an each X-position, the output of the PD is recorded while the light spot is moved along the Z-direction, scanning across the cutting edge of the tool with its rake face aligned in the XZ plane. The Z-position of the cutting edge is evaluated by determining a specific value from the obtained outputs of the PD. The edge contour of the diamond cutting tool can thus be measured by repeating the Z-scanning at different X-positions. Computer simulation was carried out to investigate the influences of error factors on the evaluation of the cutting edge. Experiments were also carried out to measure a round nose of a tool with nominal nose radius of 2 mm.
Authors: Kazuaki Kawashima, Satoshi Kanai, Hiroaki Date
Abstract: In recent years, changes in plant equipment have been becoming more frequent because of the short lifetime of the products, and constructing 3D shape models of existing plants (as-built models) from large-scale laser scanned data is expected to make their rebuilding processes more efficient. However, the laser scanned data of the existing plant has massive points, captures tangled objects and includes a large amount of noises, so that the manual reconstruction of a 3D model is very time-consuming and costs a lot. Piping systems especially, account for the greatest proportion of plant equipment. Therefore, the purpose of this research was to propose an algorithm which can automatically recognize a piping system from terrestrial laser scan data of the plant equipment. Point clouds of a piping system can be extracted based eigenvalue analysis and using region-growing from the laser scanned points. Eigenvalue analysis of the point clouds then allows for recognition of straight portion of pipes. Connecting parts can be recognized from connection relationship between pipes and neighboring points.
Authors: Toyohiro Azuma, Eiji Niwa, Yu Xin Peng, Junji Kaneko, Yuki Shimizu, So Ito, Wei Gao
Abstract: A strain-gauge-type precision displacement sensor, which is developed for a usage of micro-XY stage, is described in this paper. A thin-film strain-gauge element, which is made by Cr-N alloy, is directly fabricated on the base of the strain gauge. The direct fabrication and using the Cr-N element are expected to achieve higher sensitivity for displacement detection and better stability against the change of ambient temperature. In this study, several designs of the thin-film strain gauge, including both of two-gauge-type and four-gauge-type, are prepared to compare sensor performances such as sensitivity, stability and so on. The designed patterns of the strain-gauge element are directly fabricated on zirconia plates by using photolithography processes. The fabricated strain gauges are then evaluated as precision displacement sensors. At first, stability of the fabricated Cr-N strain-gauge-type displacement sensor was confirmed by comparing with the one made by a conventional strain gauge. Resolution of the fabricated Cr-N strain-gauge-type displacement sensors was then evaluated by comparing with a commercially-available laser displacement sensor, while giving sub-micrometer-order deformation to the strain-gauge-type displacement sensor. Details of the design, fabrication and evaluation results of the Cr-N strain-gauge-type displacement sensor are described.
Authors: So Ito, Kang Won Lee, Yuki Shimizu, Wei Gao
Abstract: A contact stylus-type displacement sensor is proposed for a surface form measurement of micro-structures. The stylus is supported by an air-bearing, thus it can be moved smoothly without friction between the stylus and the air-bearing. In order to reduce the measurement force, a novel controlling technique of a contact force has been developed. During the measurement one edge of the stylus is maintained contact with the measured surface by its own weight. Another end of the stylus is connected with a counter weight by a string and the stylus is hanging on the string in order to reduce the contact force between the edge of the stylus and the measured surface. Measuring force is estimated to confirm the effectiveness of the counter weight. Surface measurement of a steel ball is carried out using the developed air-bearing displacement sensor.
Authors: Yoshiaki Akematsu, Kazuro Kageyama, Naotake Mohri, Hideaki Murayama
Abstract: This paper describes some experimental results on a fundamental phenomenon of the single pulse discharge. In electrical discharge machining (EDM), processing accuracy was effected by behaviors of fused material. Pressure was important for removing fused material. So, it was needed to clarify that the mechanism of pressure occurrence by electrical discharge. In this study, it was investigated that effect of discharge condition on cavitations behavior by single pulse discharge. Gap region medium viscosity was changed by medium and temperature. Electrical discharge current was changed by applied voltage. The optical fiber vibration sensor is located on an aluminum work-piece (cathode) plate. Pressure was measured by optical fiber sensor during single pulse discharge. As the results, burst acoustic emission (AE) wave was occurred during single pulse discharge. The occurrence of several times burst AE wave was caused by cavitations behavior. The condition on which bubble does not collapse has become apparent. It was found that cavitations behavior was mainly depended on discharge current except for the condition on which bubble does not collapse.
Authors: Haruki Okito, Satoru Takahashi, Kiyoshi Takamasu
Abstract: The novel method of sub-nanometer uncertainty for the line width and line profile measurement using STEM (Scanning Transmission Electron Microscope) images is proposed to calibrate CD-SEM line width measurement. In accordance with the proposed method, the traceability and reference metrology of line width measurements are established using Si lattice structures. The interface of SiO2-Air is defined using image intensity of STEM image after metal coating. The edge positions of the Si line from top to bottom are detected. Then, the pixel size of the images is evaluated using 2D Fourier analysis for Si lattice structures. Using the proposed method, the line profile and line width of 50 nm are measured with expanded uncertainty less than 0.3 nm.
Authors: Hideaki Tanaka, Yukio Maeda
Abstract: Magnetic recording technologies are continuing to advance toward higher areal densities, driven by the availability of tunneling magnetoresistive (TMR) heads. However, high areal density heads require smaller physical dimensions, and this can render TMR heads more vulnerable to mechanical stresses generated during the lapping process. Although is important to verify the durability of TMR heads against lapping, it is very difficult to perform a crystallographic analysis of the affected layer because of the small dimensions involved. In this study, we attempted to establish an advanced TMR head verification method based on a magnetic performance analysis involving micro-Kerr hysteresis loops and the magnetic noise spectrum. We found that the magnetic performance changed when nanoscale scratches were removed from the lapped surface using ion beam etching. This indicates that the lapping process produces an affected layer which deteriorates the magnetic characteristics of the TMR head. A correlation was also found between the change in magnetic performance and the morphology of lapped surface.
Authors: Toshiaki Wakabayashi, Toshifumi Atsuta, Akira Tsukuda, Norio Sembongi, Junichi Shibata, Satoshi Suda
Abstract: In minimal quantity lubrication (MQL) machining of aluminum alloys, since they have highly adhesive characteristics, more effective lubrication is necessary. This study therefore proposes that oxygen-including compounds, such as esters, alcohols and acids, are considered to be a potential MQL lubricant. The experimental investigations have shown the cutting performance of those oxygen-including compounds has greatly been influenced by their chemical structures. Some of them have been able to provide the successful cutting performance as a MQL cutting fluid and, in particular, specific alcohols have demonstrated the superior anti-adhesive characteristics in MQL end milling.
Authors: Naohiro Nishikawa, Yoshinori Sato, Fumika Andou, Takekazu Sawa, Yoshihiro Hagihara, Hiromasa Kato, Nobuhito Yoshihara, Hiroaki Okawai, Takatoshi Murase, Toshiro Iyama, Masahiro Mizuno, Shinya Tsukamoto
Abstract: In production site, machining fluid (cutting oil, grinding fluid) is used. It contains several chemicals that are oil, surface active agent, and extreme pressure agent, anti rust agent and so on. Waste fluid disposal which is incineration etc. is necessary and arise huge cost and environmental load. In addition, workers health hazard is concerned for several chemicals while machining. In this investigation, new water machining method system (electric rust preventive machining method system) that uses only water as machining fluid for solving of conventional machining fluid problems is developed. In particularly, this paper mentions optimization of used machining water recycle on purification rate and refined water flow quantity in developed water recycle system. Therefore, high speed adjustment test liquid equipment is developed for stable experimental condition for evaluation. Test liquid turbidity is random for sludge particle and simple filter decreases this fluctuation. However, water recycle system is aimed for constant refined output despite fluctuation of input dirty water, and it is achieved. The optimized refined water flow quantity is 13.3 L/min at 1.0 MPa from viewpoint of purification on iron, turbidity, colour, conductivity and flow rate and purification load for reverse osmosis membrane.
Authors: Naohiro Nishikawa, Yoshinori Sato, Fumika Andou, Takekazu Sawa, Yoshihiro Hagihara, Hiromasa Kato, Nobuhito Yoshihara, Hiroaki Okawai, Takatoshi Murase, Toshiro Iyama, Masahiro Mizuno, Shinya Tsukamoto
Abstract: The machining (cutting, grinding etc.) is conducted in manufacturing. Machining fluid (cutting oil, grinding fluid) that consists of oil, surface active agent, and extreme pressure agent, anti rust agent etc. is used. It improves machining performance, but it needs waste fluid disposal that is incineration or coagulative precipitation and so on. It causes huge cost and environmental load. Furthermore, it is afraid of workers health hazard for several chemicals while machining. Therefore, the electric rust preventive machining method system (water machining) is proposed and developed. This method uses only harmless water (tap water etc.) as machining fluid. In this paper, improvement of electric rust preventive chip sedimentation system that is part of water recycle system which is used for machining water purification and re-use. On long time (3 days) preservation of iron chip in water, decreasing of rust and turbidity is examined. Improved electric rust preventive chip sedimentation system is equipped simple circulation filter unit newly and its effectiveness is clarified. When many quantity of iron powder (3kg) likened to actual sludge is sunken in sedimentation water tank, if electric rust prevention and simple circulation filter activated, turbidity and colour would be decreased greatly. Therefore, it is expected that purification load of next part of filters is decreased and life-time of filter and system will be prolonged.

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