論文 - 閻　紀旺

Algorithm of Micro-Grooving and Imaging Processing for the Generation of High-Resolution Structural Color Images

Zhou T., He Y., Wang T., Dong X., Liu P., Zhao W., Hu Y., Yan J.

Nanomanufacturing and Metrology （Nanomanufacturing and Metrology）  3 （ 3 ） 187 - 198 2020年09月

ISSN  2520811X

　概要を見る

© 2020, International Society for Nanomanufacturing and Tianjin University and Springer Nature Singapore Pte Ltd. The use of submicron structures for structural coloration of surfaces has broad applications for color filters, projection displays, virtual reality, and anti-counterfeiting. Currently, structural color images lack high resolution due to low manufacturing accuracy. In this study, the axial-feed fly cutting (AFC) method is proposed to fabricate submicron grooves for the diffraction of visible light to create structural color images. We establish the relationship between the color information in the pixels of the original image and the parameters of the array units corresponding to the pixels. An algorithm to determine groove spacing and the tool path is established, and array units with the desired groove spacing are machined to reproduce the structural color images. The submicron grooves fabricated by AFC have high quality and good consistency. Due to the excellent diffraction performance of the machined grooves, images with high saturation and resolution can be reproduced. It is verified that images with various colors can be efficiently fabricated using the proposed method and algorithm.

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Generation of high-saturation two-level iridescent structures by vibration-assisted fly cutting

He Y., Zhou T., Dong X., Liu P., Zhao W., Wang X., Hu Y., Yan J.

Materials and Design （Materials and Design）  193 2020年08月

ISSN  02641275

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© 2020 The Authors The submicron-level structured surface induces viewing-angle-dependent iridescence, and has wide applications in multi-color printing, micro-display projection, invisibility cloak technology. In this study, several types of two-level structures, which consist of the first-order micro geometric features corresponding to the pattern shape and the second-order submicron grooves corresponding to the diffraction grating, are designed to directly induce a variety of iridescent patterns based on their shape regulations. To fabricate these two-level iridescent structures with high accuracy in a single step, vibration-assisted fly cutting (VAFC) is proposed. VAFC involves the low-frequency vibration of the workpiece in the vertical direction during the feed in the horizontal direction and the high-speed rotation of the diamond cutting tool. A 3D theoretical model is established for the numerical simulation of the generating process of the iridescent structures and the regulation of the first-order geometric feature by vibration parameters. As the key parameter to the iridescent color, the spacing of the second-order submicron grooves is flexibly controlled by the feed rate. A VAFC platform is developed to fabricate the two-level structures and an optical detection system is setup to test the surface iridescence. Various vivid colors are regulated by the two-level structures with high saturation and uniformity.

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Silicon nanoparticle generation and deposition on glass from waste silicon powder by nanosecond pulsed laser irradiation

Momoki K., Manabe T., Li L., Yan J.

Materials Science in Semiconductor Processing （Materials Science in Semiconductor Processing）  111 2020年06月

ISSN  13698001

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© 2020 Elsevier Ltd Silicon nanoparticles can be used for fabricating electrodes in high-performance lithium ion batteries and other high value-added products. Currently, silicon nanoparticles are fabricated by pulsed laser irradiation of single-crystal silicon wafers in water. In this study, we proposed silicon nanoparticle generation by using a nanosecond pulsed laser to irradiate waste silicon powder which is disposed from wire-saw slicing processes of silicon ingots. The laser-induced nanoparticles were backward-transferred and deposited on a glass substrate. It was found that the morphology and amount of the deposited nanoparticles was strongly dependent on the distance between the glass substrate and the waste silicon powder target. Raman spectroscopy showed that the silicon nanoparticles were crystalline, and the average size was ~10 nm. The obtained silicon nanoparticles had high purity, as the diamond abrasives included in the waste silicon powder were removed through oxidation and vaporization during laser irradiation.

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Generating Nanodot Structures on Stainless-Steel Surfaces by Cross Scanning of a Picosecond Pulsed Laser

Kobayashi T., Yan J.

Nanomanufacturing and Metrology （Nanomanufacturing and Metrology）  3 （ 2 ） 105 - 111 2020年06月

ISSN  2520811X

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© 2020, The Author(s). Ultrashort pulsed laser-induced periodic surface structures (LIPSS) can be generated on different kinds of materials, which are widely utilized for modifying surface properties such as wettability, adhesion, and tribological, as well as optical performances. Previous studies have focused mainly on one-dimensional LIPSS (i.e., line structure) generation. In this study, a picosecond pulsed laser was used to irradiate stainless-steel surfaces for generating two-dimensional LIPSS, namely nanodot structures, by cross-scanning the laser beam for a different number of times. The obtained nanodot structures were found to be super hydrophilic just after laser irradiation, but turned to be hydrophobic after exposure in air for a few days. By cross-scanning the laser beam for the same number of times, local LIPSS rewriting was realized. This study showed the possibility of improving the homogeneity of the surface properties of steel materials through laser-induced nanodot structuring.

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Surface formation mechanism in ultraprecision diamond turning of coarse-grained polycrystalline ZnSe

Huang W., Yan J.

International Journal of Machine Tools and Manufacture （International Journal of Machine Tools and Manufacture）  153 2020年06月

ISSN  08906955

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© 2020 Elsevier Ltd Zinc selenide is an excellent infrared optical material. In this study, ultraprecision diamond turning experiments were carried out on coarse-grained polycrystalline ZnSe (p-ZnSe) under various conditions and the corresponding surface formation mechanisms were investigated by examining the surface topography, chip morphology, material microstructural change, and cutting forces. Two kinds of surface defects were observed (i.e. plowing-induced micron-scale cleavage craters and tearing-induced submicron-scale tearing pits). It was determined that plowing induced micron-scale cleavage craters could be suppressed by reducing undeformed chip thickness. Furthermore, it was ascertained that tearing-induced submicron-scale tearing pits could be restrained by using a cutting tool with a zero rake angle. The minimal surface roughness was dominated by grain boundary steps formed when the cutting tool crossed twin boundaries at a large angle. A model was proposed for correlating surface defects and boundary steps with crystal orientations and cutting directions. By using a large-nose diamond tool for cutting, a smooth surface of 1.5 nm Sa was obtained. In addition, a zinc blende to cinnabar phase transformation was observed in the cutting chips, and metallization of cutting chips occurred at an extremely small undeformed chip thickness (~20 nm). Moreover, it was discovered that phase transformation inside the workpiece depends on the radius of the tool nose. The findings of this study provide an important reference for ultraprecision machining of brittle polycrystalline materials.

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フレキシブルステージを用いた超音波振動援用研削による超硬合金の穴あけ加工

寺町亮則，ターヴァイネンさゆり，閻 紀旺

砥粒加工学会誌 64 （ 6 ） 320 - 325 2020年06月

研究論文（学術雑誌）, 共著, 査読有り

Additive manufacturing of three-dimensional metal-glass functionally gradient material components by laser powder bed fusion with in situ powder mixing

Zhang X., Chueh Y.h., Wei C., Sun Z., Yan J., Li L.

Additive Manufacturing （Additive Manufacturing）  33 2020年05月

　概要を見る

© 2020 Elsevier B.V. Existing commercial three-dimensional (3D) printing systems based on powder bed fusion approach can normally only print a single material in each component. In this paper, functionally gradient materials (FGM) with composition variation from a copper alloy to a soda-lime glass were manufactured using a proprietary nozzle-based multi-material selective laser melting (MMSLM) system. An in situ powder mixing system was designed to mix both metal and glass powders at selective ratios and the mixed powders were dispensed with an ultrasonic vibration powder feeding system with multiple nozzles. From the cross section analysis of the gradient structures, glass proportion increased gradually from the metallic matrix composite (MMC), transition phase to ceramic matrix composite (CMC). The pure copper alloy joined the MMC part and the pure glass phase penetrated into the CMC part during laser processing, which anchored the glass phase, as the main mechanism of combining pure metal and pure glass by FGM in 3D printed parts. From results of indentation, tensile and shear tests on the gradient material samples, it showed that mechanical properties of the FGM gradually changed from ductility (metal side) to brittle (glass side). The weakest part of the FGM structure occurred at the interface between transition phase and the CMC, which was also the interface between the ductile and brittle phases.

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Generating silicon nanofiber clusters from grinding sludge by millisecond pulsed laser irradiation

Momoki K., Takahashi K., Kobinata K., Kobayashi Y., Kawai A., Yan J.

Nanomaterials （Nanomaterials）  10 （ 4 ）  2020年04月

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© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Silicon nanofiber clusters were successfully generated by the irradiation of millisecond pulsed laser light on silicon sludge disposed from wafer back-grinding processes. It was found that the size, intensity, and growing speed of the laser-induced plume varied with the gas pressure, while the size and morphology of the nanofibers were dependent on the laser pulse duration. The generated nanofibers were mainly amorphous with crystalline nanoparticles on their tips. The crystallinity and oxidation degree of the nanofibers depended on the preheating conditions of the silicon sludge. This study demonstrated the possibility of changing silicon waste into functional nanomaterials, which are possibly useful for fabricating high-performance lithium-ion battery electrodes.

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Effect of relative tool sharpness on subsurface damage and material recovery in nanometric cutting of mono-crystalline silicon: A molecular dynamics approach

Ameli Kalkhoran S., Vahdati M., Yan J.

Materials Science in Semiconductor Processing （Materials Science in Semiconductor Processing）  108 2020年03月

ISSN  13698001

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© 2019 Elsevier Ltd Depth of cut (h0) and tool edge radius (re) are two key parameters in nanometric cutting, investigating both of the two parameters simultaneously can provide comprehensive understanding of the cutting mechanism. In this paper, relative tool sharpness (RTS), which is quantified as h0/re, is employed as a factor to examine the subsurface damage and material recovery in nanometric cutting of mono-crystalline silicon using molecular dynamics (MD) simulation. Various RTS values were generated by changes of cutting depth at different tool edge radius of 1, 3 and 5 nm respectively. Results indicate that there is always a layer of particles which sticks on the tool surface and influences the machined surface, even at RTS = 0. Besides that, the increase of RTS results in subsurface damage layer serration, which is caused by stick-slip phenomenon between the tool and workpiece. A bigger RTS causes a bigger depth of serrations, although the number of serrations remains constant. Increase in RTS also causes the formation of the hexagonal diamond structure. The material recovery drops dramatically by RTS increase. Using a sharper tool edge (RTS<0.25) at a cutting depths below 1 nm does not necessarily decrease subsurface damage due to the drastic stress concentration. It is also demonstrated that silicon amorphisation can occur in the unmachined region in front of the tool due to the hydrostatic pressure wave caused by tool advancement.

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Electrical Discharge/Electrochemical Hybrid Machining Based on the Same Machine and Tool Electrode

Kishi R., Yan J.

Journal of Micro and Nano-Manufacturing （Journal of Micro and Nano-Manufacturing）  8 （ 1 ）  2020年03月

ISSN  21660468

　概要を見る

Electrical discharge machining (EDM) causes surface defects such as resolidified layer and microcracks, and a finishing process is usually needed to remove these defects. In this paper, a hybrid process was proposed where electrochemical machining (ECM) was performed as a finishing process after EDM using the same tool electrode on the same machine. By using two kinds of disk-type rotary electrodes, rectangular grooves and grooves with convex inner structures were fabricated. Surface topography were investigated by using scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDX), and laser-probe surface profilometer. The material removal mechanism of resolidified layers was clarified. The surface roughness of the rectangular groove was improved from 3.82 μm Ra to 0.86 μm Ra after ECM. Electrode rotation was effective for flushing electrolytic products when fabricating inner structures. As there is no need for exchanging tools and machines, tool alignment error can be prevented and productivity can be improved. Therefore, the proposed EDM/ECM hybrid process contributes to rapid fabrication of microscale products with high surface integrity.

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Effects of deep subsurface damages on surface nanostructure formation in laser recovery of grinded single-crystal silicon wafers

Niitsu K., Yan J.

Precision Engineering （Precision Engineering）  62   213 - 222 2020年03月

ISSN  01416359

　概要を見る

© 2019 Elsevier Inc. A nanosecond pulsed Nd:YVO4 laser was irradiated on a boron-doped single-crystal silicon wafer after rough and fine grinding processes to recover the grinding-induced subsurface damages. The surface topography of samples was investigated by using a white-light interferometer, a scanning electron microscope, and an atomic force microscope; while the crystallinity was analyzed by a laser micro-Raman spectrometer. It was found that surface nanostructures were generated by the Mullins-Sekerka instability, which remained on the surface under recoil pressure and surface tension. The rough grinding-induced deep subsurface damages influenced the interface instability between liquid and solid silicon during recrystallization process. By increasing pulse width and decreasing laser peak irradiance, the subsurface damage was recovered and a flat surface with surface roughness of ~1 nm Sa was obtained. This study reveals important correlations among grinding-induced latent subsurface defects, laser peak irradiance and nanoscale surface topography formation in laser recovery, which contributes to high quality silicon wafer manufacturing.

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Surface modification and functionalization by electrical discharge coating: A comprehensive review

Liew P.J., Yap C.Y., Wang J., Zhou T., Yan J.

International Journal of Extreme Manufacturing （International Journal of Extreme Manufacturing）  2 （ 1 ）  2020年03月

ISSN  26318644

　概要を見る

© 2020 The Author(s). Published by IOP Publishing Ltd on behalf of the IMMT Hard coatings are extensively required in industry for protecting mechanical/structural parts that withstand extremely high temperature, stress, chemical corrosion, and other hostile environments. Electrical discharge coating (EDC) is an emerging surface modification technology to produce such hard coatings by using electrical discharges to coat a layer of material on workpiece surface to modify and enhance the surface characteristics or create new surface functions. This paper presents a comprehensive overview of EDC technologies for various materials, and summarises the types and key parameters of EDC processes as well as the characteristics of resulting coatings. It provides a systematic summary of the fundamentals and key features of the EDC processes, as well as its applications and future trends.

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Nanoparticle generation from various types of silicon materials by nanosecond-pulsed laser irradiation

Momoki K., Yan J.

Applied Physics Express （Applied Physics Express）  13 （ 2 ）  2020年02月

ISSN  18820778

　概要を見る

© 2020 The Japan Society of Applied Physics. A huge amount of silicon sludge is disposed of from silicon wafer manufacture, and its reuse is a critical issue. In this study, silicon nanoparticle generation from sludge was explored by nanosecond-pulsed laser irradiation. The nanoparticle production efficiency from silicon sludge was compared with that from silicon wafers. The result showed that using silicon sludge as a laser irradiation target leads to a distinctly higher production efficiency of nanoparticles; the smaller the powder size of the silicon sludge, the higher the efficiency. The generated silicon nanoparticles were crystalline with sizes at the 10 nm level.

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Direct observation of discharging phenomena in vibration-assisted micro-electrical discharge machining

Shitara T., Fujita K., Yan J.

International Journal of Advanced Manufacturing Technology （International Journal of Advanced Manufacturing Technology）  108 （ 4 ） 1125 - 1138 2020年

ISSN  02683768

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© 2020, Springer-Verlag London Ltd., part of Springer Nature. It has been previously reported that electrical discharge machining (EDM) performance can be improved by tool electrode vibration. However, the mechanism of vibration-assisted EDM has not been clarified and the optimal vibration condition remains unknown due to the difficulty in direct process observation. In this study, direct observation of the EDM gap by using a high-speed video camera through a transparent workpiece electrode made of single-crystal 4H-SiC was attempted. It was found that tool vibration caused discharge dispersion and discharge frequency increase, and this tendency was more significant at higher amplitudes and higher frequencies. In addition, tool vibration-induced periodic discharge was observed, which prevented concentrated discharge and short-circuiting. Accordingly, the machining speed was improved and surface roughness was reduced. This study succeeded for the first time in observing the discharge behaviors in vibration-assisted EDM, thus revealed the effects of key parameters for process optimization.

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Surface formation behaviors in wavy microgroove cutting on various workpiece materials

Terabayashi T., Yan J.

International Journal of Automation Technology （International Journal of Automation Technology）  14 （ 2 ） 245 - 252 2020年

ISSN  18817629

　概要を見る

© 2020, Fuji Technology Press. All rights reserved. Functional films with multi-directional wavy microgrooves can be applied to reduce fluid drag in turbulent flow applications. For high-efficiency mass production of functional films through polymer imprinting, it is necessary to machine wavy microgrooves on the surfaces of metal roll molds. When wavy grooves are cut, to reduce the follow-up errors of machine tools, a very low cutting speed is normally used, but the mechanism of this cutting is still unclear. In this study, microgrooving experiments were conducted on three different workpiece materials: brass, oxygen free copper, and aluminum alloy, and their cutting mechanisms were investigated. Distinct differences in chip formation behavior and machined surface integrity were identified among these materials. Aluminum alloy was chosen as the most suitable material for roll mold fabrication. Two-directional wavy microgrooves with form accuracy on 1 µm level and surface roughness of less than 10 nm Ra were obtained.

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Influence of Wax Lubrication on Cutting Performance of Single-Crystal Silicon in Ultraprecision Microgrooving

Ameli Kalkhoran S.N., Vahdati M., Zhang Z., Yan J.

International Journal of Precision Engineering and Manufacturing - Green Technology （International Journal of Precision Engineering and Manufacturing - Green Technology）  8 （ 2 ） 611 - 624 2020年

ISSN  22886206

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© 2020, Korean Society for Precision Engineering. Lubrication can improve the tool-workpiece interface condition in ultraprecision machining, especially in microgrooving processes. The aim of this study was to compare the effects of dry, liquid (cutting oil), solid (wax) and hybrid (cutting oil and wax) lubrication conditions, on the creation of arc-sectioned microgrooves on single-crystal silicon wafers using a single-crystal diamond tool. Micro cutting forces, chip morphology, and surface quality at different locations of the grooves were investigated. Rose-shaped continuous chips were observed in dry cutting, indicating stable ductile mode material removal. The entrance side of the groove was always smoother than the exit side with a higher degree of phase transformation. Chip adhesions on the tool edge were found in dry and oil lubricated cutting, whereas wax coating could prevent the adhesion. Wax coating played the dual roles of a chip breaker as well as a high-performance lubricant, thus improved the surface integrity. This study demonstrated the capability of using wax coating as an environmentally friendly solid lubricant for microgrooving of single-crystal silicon and possibly for other hard brittle materials.

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Measurement and compensation of tool contour error using white light interferometry for ultra-precision diamond turning of freeform surfaces

Nagayama K., Yan J.

International Journal of Automation Technology （International Journal of Automation Technology）  14 （ 4 ） 654 - 664 2020年

ISSN  18817629

　概要を見る

© 2020, Fuji Technology Press. All rights reserved. In ultra-precision diamond turning of freeform optics, it is necessary to obtain submicron-level form accuracy with high efficiency. In this study, we proposed a new method for the quick measurement and compensation of tool contour errors to improve the form accuracy of the workpiece. In this method, the nanometer-scale contour error of a diamond tool is quickly and precisely measured using a white light interferometer and then compensated for, before machining. Results showed that the contour of a diamond tool was measured with an error less than 0.05 μm peak-to-valley (P-V) and the feasibility of error compensation was verified through cutting experiments to create a paraboloid mirror and a microlens array. The form error decreased to 0.2 μm P-V regardless of the contour error of the diamond tools when cutting the paraboloid mirror, and that of the microlens array was reduced to 0.15 μm P-V during a single machining step.

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Manufacturing of multiscale structured surfaces

Brinksmeier E., Karpuschewski B., Yan J., Schönemann L.

CIRP Annals （CIRP Annals）  69 （ 2 ） 717 - 739 2020年

ISSN  00078506

　概要を見る

© 2020 Multiscale structured surfaces are a way to provide advanced, otherwise not attainable functionality on a technical part. Applications of such parts can be manifold, and numerous works have already covered the transfer of natural examples into bio-inspired surfaces or the geometrical and functional metrology of such surfaces. After briefly presenting typical functionalities of multiscale structured surfaces, this keynote paper will focus on the available manufacturing processes and review their capabilities to generate multiscale structured surfaces. To compare such processes, the so-called “multiscality” is defined that characterizes the structured surfaces according to the lateral and vertical extent of the individual stacked elements and is used as a first indicator to assess the difficulty of their manufacture. As the boundaries of what is considered a multiscale structure are diffuse, ranges of low, medium and high multiscality are defined instead. After presenting the state of the art of manufacturing processes currently utilized for the manufacture of (not only multiscale) structured surfaces, this keynote paper summarizes the capabilities of single-step and multi-step/multi-physics approaches for their applicability across different scales and gives an outlook on which processes could potentially become relevant in the future.

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New evidences for understanding the serrated flow and shear band behavior in nanoindentation of metallic glasses

Huang H., Jiang M., Yan J.

Journal of Alloys and Compounds （Journal of Alloys and Compounds）  857 2020年

ISSN  09258388

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© 2020 Elsevier B.V. Nanoindentation of a Zr-based metallic glass was performed under various loading rates by using a cube-corner indenter. Experimental results showed that increasing the loading rate from 2 to 20 mN/s, the size of serrated flow was greatly weakened, but the number of serrated flow kept very stable, together with very similar shear band features around the residual indents. These results challenge the current understanding derived from the results obtained by using the Berkovich indenter, and can be well explained by the shear-band propagation dynamics model, i.e., loading rate impeded the propagation of shear band rather than its nucleation.

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Effects of cyclic loading on subsurface microstructural changes of zirconia polycrystals in nanoscale mechanical processing

Kosai K., Yan J.

International Journal of Machine Tools and Manufacture （International Journal of Machine Tools and Manufacture）  159 2020年

ISSN  08906955

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© 2020 Elsevier Ltd Yttria stabilized zirconia (YSZ) is an attractive biomaterial with excellent properties, but its deformation mechanism under repetitive loads is still unclear. In this study, the subsurface microstructural changes of YSZ polycrystals under repetitive loading/unloading were investigated by multi-cyclic nanoindentation. Raman spectroscopy analysis revealed that a tetragonal-to-monoclinic (t-m) phase transformation occurred, and multi-cyclic indentation promoted this transformation significantly. Cross-sectional scanning transmission electron microscopy showed that monoclinic variants were extensively generated beneath the free surfaces outside the indent planes, whereas grain refinement was dominant beneath the indenter tip. In addition, load-displacement curve analysis demonstrated that the t-m phase transformation occurred during unloading rather than loading, and that the phase transformation-induced volume expansion caused an incremental change of residual indent depth. The extension of monoclinic variants was promoted by repetitive shear deformation, resulting in significant pileups, as detected by atomic force microscopy. The effect of sample surface preprocessing on indentation behaviors was also investigated. Microcracking and surface spalling were confirmed around the multi-cyclic indents made on a diamond-turned YSZ sample. Based on the experimental results, a model of subsurface microstructure distribution and evolution was established. The findings from this study help clarify the historical effects in subsurface damaging mechanism of brittle polycrystalline materials caused by cyclic tool-workpiece interactions in nanoscale mechanical processing.

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