Details of a Researcher - Kakinuma, Yasuhiro

Papers - Kakinuma, Yasuhiro

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Acquired Angle Error Correction Based on Variation of an Angle Detection Signal Intensity in Rotary Encoders

Sato A., Kakinuma Y.

Journal of Manufacturing Science and Engineering 147 ( 1 ) 2025.01

ISSN 10871357

Rotary encoders are used in various machines to measure the angular position of a rotating axis. Therefore, rotary encoders are required not only to be highly accurate, but also usable in various environments. When using a rotary encoder on a machine, acquired angle errors occur due to the eccentricity between the encoder and the machine, the deformation of the scale, and the shaft runout of the rotation axis. Various methods have been adopted to reduce such angle errors. However, these methods have problems such as the large size and high cost of the encoder, the necessity of additional devices for measuring, and increasing installation labor, so the environment in which they can be implemented is limited. In this study, we have proposed a method to correct the acquired angle errors based on variation of an angle detection signal intensity in the sensor head. This method can correct the errors on the machine without using multiple sensor heads or additional devices. The angle error estimated by this method is compared with that measured by the external equipment of a reference encoder. While the maximum angle error was 28.36″ without correction, the residual error with correction of the acquired error can be reduced to 1.75″ or less. From this result, the proposed method can improve the measurement accuracy of the rotary encoder already installed on the machine. Therefore, this method is an effective means for achieving both high rotational accuracy on machines and ease of correcting an error in rotary encoder machines.

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Thermal modeling techniques designed for high-speed directed energy deposition coatings

TAKEMURA Shiho, MIYATA Yuichiro, HIRONO Yoko, KAKINUMA Yasuhiro

Journal of Advanced Mechanical Design, Systems, and Manufacturing (The Japan Society of Mechanical Engineers) 19 ( 1 ) JAMDSM0012 - JAMDSM0012 2025

ISSN 1881-3054

High-speed directed energy deposition (DED) offers advantages such as efficiency, thin coating layers, and reduced heat-affected zones, making it ideal for repairs and coating on existing parts across various industries. In the DED process, various deposition parameters are included and affect the thermal history. Moreover, a thermal history significantly affects the deposit's mechanical properties by varying metallographic structure. Therefore, thermal simulations of DED are highly demanded due to the time and cost challenges associated with experimenting across different process parameters. However, thermal simulations of DED have difficulties because of the process by which material and heat source are supplied from time to time to the melt pool. Many studies have been conducted on thermal simulations of DED, however, few studies focus on high-speed DED coating. Therefore, this research develops the thermal simulation techniques for high-speed DED coating by exploring five simple methods for element addition and heat input. The geometry of the workpiece model was simplified to reduce the simulation cost. Using the Ansys Parametric Design Language (APDL) software and the simplified workpiece model, we conducted thermal simulations and validated them against experimental data acquired from high-speed imaging and two-color temperature measurements. Through these methods, the study proposed the temperature comparison method of experiment and simulation results and identified the suitable method for element addition and heat input in high-speed DED coating that closely replicates the actual temperature within the coating layer. This method reduces the need for finer mesh, effectively lowering computational costs while maintaining accuracy. The findings provide insights into practical simulation practices for DED and contribute to enhancing parameter validation in additive manufacturing simulations, supporting further development in high-speed DED coating technology.

Entangled chip removal utilizing mass-spring model with mobile manipulator

Takahashi R., Kimura H., Kakinuma Y.

CIRP Annals 2025

ISSN 00078506

This study aims to automate the removal of entangled chips in manufacturing environments using a mobile manipulator. Despite advancements in factory automation technology, this task often necessitates manual intervention. Accordingly, this study proposes a deformable chip model (based on a reconfigurable mass-spring system per frame), incorporating visual chip tracking data and force reactions. Consequently, to evaluate the removal state, an efficient removal strategy is derived by defining the instantaneous stiffness and energy absorption rate. Validation of system performance through two removal tests demonstrates the feasibility of automating entangled chip removal, contributing to enhanced operational efficiency in fully automated production lines.

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AI-based sensor layout for predicting thermal deformations of CFRP machine tools

Finkeldey F., Kato M., Wiederkehr P., Kakinuma Y.

CIRP Annals 2025

ISSN 00078506

Using data-based approaches, accurate predictions of thermal deformations, which can significantly affect the quality of manufactured components, can be enabled. However, a sufficient amount of data with maximised information content is necessary for efficient training. In this paper, an approach for optimising sensor configurations for predicting thermal deformations is presented. From initially 300 temperature sensors, the number of required sensors was significantly reduced while maintaining predictive accuracy. Furthermore, a pattern for sensor placement was identified, providing the potential for an efficient sensor layout that enables cost-effective data acquisition and improved monitoring of machining and wear progression of machine tool components.

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Process-state visualization map in grinding ceramic

Ichikawa Mari, Nakayama Seiji, Hosokawa Hirofumi, Kakinuma Yasuhiro

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2024A ( 0 ) 674 - 675 2024.08

セラミックスの研削加工において，センサを用いて加工面に生じる異常を実時間検知できれば，不良品の早期発見やプロセス改善につなげることができる．本研究では，センサデータの解析手法として，加工状態可視化マップを提案した．センサデータを加工位置に対してマッピングすることで，工作物表面への影響を視覚的に捉える手法である．可視化マップと工作物の表面プロファイルの関係を調べ，その有効性を確認した．

Digital Twin in Process Planning of the Additive and Subtractive Process Chain for Laser Metal Deposition and Micro Milling of Stainless Steel

Denkena B., Wichmann M., Malek T., Nguyen H.N., Kato M., Isshiki K., Koike R., Kakinuma Y.

Journal of Manufacturing Science and Engineering 146 ( 7 ) 2024.07

ISSN 10871357

Additive and subtractive (Add/Sub) manufacturing processes are increasingly being combined to produce complex parts with unique geometries and properties. However, the design of such combined processes is often challenging as it requires a deep understanding of the interaction between the different processes. On the other hand, digital twin (DT) technology has become a powerful tool in recent years for optimizing manufacturing processes. This article explores the use of the digital twin technology for a holistic process planning of combined additive and subtractive processes. The article describes the integration of laser metal deposition (LMD) and micro-milling prediction models of resulting geometry (width and height), hardness, and surface roughness into the digital twin. This is then used for combined process planning to achieve different target values regarding resulting geometry and surface roughness. For the planning of this combined process chain, further criteria such as tool life, energy, and process time are considered in the optimization, showing the potential for sustainable and efficient production. Sensorless cutting force estimation is also used to detect small cutting forces, with the potential to use this as a soft sensor for roughness estimation. The measured width, height, and roughness as a result of the process parameters suggested by the optimization algorithms showed a mean absolute percentage error (MAPE) of 4, 17, and 16%, respectively.

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指向性エネルギー堆積法を用いた高速コーティングの加工条件と熱履歴の伝熱解析による評価

Takemura Shiho, Kakinuma Yasuhiro, Hirono Yoko, Oda Yohei

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2024S ( 0 ) 535 - 536 2024.02

金属積層造形の一方式である指向性エネルギー堆積法（DED）を用いた高速コーティングは，高効率な金属皮膜技術として期待されている．しかし，DEDではレーザによる入熱や自己冷却が繰り返され，それらの熱履歴が機械的性質に複雑に影響するため，所望の機械的性質を得るためには熱履歴に対する加工条件の影響を調べる必要がある．本研究では，伝熱解析により高速コーティングによる被膜層や母材の熱履歴を評価する．

Experimental analysis of chemical removal effect in RISA grinding of optical glass

Shimodo K., Takamaru H., Chiba Y., Kato H., Nagano M., Fukuta M., Tanaka K., Watanabe K., Hamazono K., Kakinuma Y.

Procedia CIRP 123 304 - 309 2024

ISSN 22128271

In the large-aperture lens manufacturing, not only high surface quality but also high productivity is required. From this perspective, Reaction-Induced-Slurry-Assisted grinding (RISA grinding), in which cerium oxide slurry is supplied instead of using general grinding fluid, has been developed to achieve high surface quality at high removal rate. However, the surface profile error becomes large due to chemical removal effect of the cerium oxide slurry. Therefore, the purpose of this study is to experimentally investigate the influence of the chemical removal effect on the surface profile error using AE signals and servo current signals in RISA grinding. First, relation between dwell time and removal depth is analyzed by conducting a basic grinding test without the workpiece rotation. The result shows that the actual removal depth increases with increase of dwell time despite applying the constant depth of cut. Then, zero-cut RISA grinding test is conducted. It is found that the removal process proceeds even though zero-cut grinding, and its removal rate varies according to the wheel feed rate. Furthermore, the amount of cerium oxide abrasives adhered to the grinding wheel can be estimated from the AE signals and servo current signals.

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Task Planning Optimization in Assisting Multiple NC Machine Tools Using AMR

Kusashio K., Yakoh T., Kakinuma Y.

Proceedings of the IEEE International Conference on Industrial Technology 2024

ISSN 26410184

Although advanced manufacturing strategies such as Industry 4.0 are becoming popular, many small and medium-sized enterprises (SMEs) are still facing challenges in factory automation. One of the reasons is that factory automation may require significant system updates. A retrofittable system that handle versatile tasks is needed to facilitate easier integration in the manufacturing industry. This paper proposes a system that can assist multiple numerical control (NC) machine tools using an autonomous mobile robots (AMR). The tasks integrated are chip removal inside the NC machine tool's chuck, vibration analysis while the NC machine tool is processing and charging AMR. AMR has to perform these tasks within the production line's strict time constraints and AMR's battery constraint. The proposed system produced a feasible schedule of the tasks. Numerical simulation evaluated the feasibility of the produced schedule. The produced schedule was verified by performing in the real world.

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The influence of friction compensation and input data on cutting force estimation using gray-box model

SAITO Reo, KAKINUMA Yasuhiro

The Proceedings of The Manufacturing & Machine Tool Conference (The Japan Society of Mechanical Engineers) 2024.15 ( 0 ) A09 2024

Various cutting-force estimation methods based on different disturbance observers have been proposed. However, each method has a modeling error, decreasing the estimation accuracy in a certain frequency band. In order to compensate for the modeling error and improve the performance, we have proposed that three different cutting estimation methods are integrated by using a neural network. In this study, the influence of friction compensation and input data on the cutting force estimation is analyzed. The results showed that estimation accuracy remarkably decreased when friction compensation was not implemented, and the accuracy decreased including the experimental conditions of interpolation and extrapolation experiment conditions when directly inputting servo informations to a neural network.

Relationship between dwell time and removal height in RISA grinding

NISHIGUCHI Taiki, SHIMODO Kodai, CHIBA Yusuke, KAKU Tsuyoshi, FUKUTA Masahiko, TANAKA Katsutoshi, KAKINUMA Yasuhiro

The Proceedings of The Manufacturing & Machine Tool Conference (The Japan Society of Mechanical Engineers) 2024.15 ( 0 ) A32 2024

RISA grinding method using cerium oxide slurry has been proposed for grinding optical glass lenses. While the surface quality can be maintained at high feed rate and depth of cut, there is a problem that the profile error increases toward the center of the workpiece. The workpiece is SSG and the grinding wheel is a resin diamond wheel. In this study, the relationship between dwell time and depth of cut is experimentally investigated, and dwell time control method is proposed to achieve a uniform depth of cut. This method changes the rotation speed of workpiece to keep the slurry dwell time constant regardless of the distance from the center of workpiece. The effectiveness of this method was evaluated through orbicular machining tests. With conventional RISA grinding, the grinding trace becomes deeper as it gets closer to the center of the workpiece. By using dwell time control, the depth of the grinding trace is almost the same regardless of the distance from the center.

Influence of metal structure on mechanical characteristics in high-speed coating layer fabricated via Directed Energy Deposition

Hashimoto M., Koike R., Kakinuma Y., Hirono Y., Mori T., Oda Y.

Procedia CIRP 124 227 - 230 2024

ISSN 22128271

Directed energy deposition (DED) is an additive manufacturing process wherein a metal powder is fed through a nozzle onto a baseplate, melted, and solidified using a laser. Potential applications of DED have been actively discussed. In this study, laser-based DED (DED-LB) was applied as a high-speed metal-coating technique to a cylindrical pipe. The mechanical properties of DED-fabricated objects were strongly affected by processing parameters such as laser power, powder feed rate, and rotational speed of the cylindrical pipe when using 20MnCr5 and M2 as the coating materials. Hardness measurements showed that the hardness of 20MnCr5 increased with a high heat input, whereas that of M2 increased with a low heat input. The two metals exhibited opposite trends in terms of hardness variation because of the differences in their transformation points. This study analyzed a layer coated with DED-LB from the viewpoint of metal morphology.

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High-speed laser metal deposition(HS-LMD)による高硬度鋼コーティングの現象解析

柿沼康弘

Report of Grant-Supported Researches The Amada Foundation (The Amada Foundation) 37 ( 0 ) 334 2024

ISSN 24340723

Dispersion Engineering of Crystalline Microresonators for Optical Frequency Comb Generation beyond C-Band

Takabayashi R., Kodama H., Tanikawa K., Kakinuma Y., Tanabe T., Fujii S.

16th Pacific Rim Conference on Lasers and Electro-Optics, CLEO-PR 2024 2024

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Dispersion engineering of crystalline microresonators for optical frequency comb generation beyond C-band

Takabayashi R., Kodama H., Tanikawa K., Kakinuma Y., Tanabe T., Fujii S.

Conference on Lasers and Electro-Optics/Pacific Rim, CLEO-PR 2024 in Proceedings 2024 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR) 2024

回転エンコーダにおける角度検出信号の強度変化を利用した角度誤差計測方法の提案

Sato Akihiko, Kakinuma Yasuhiro

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2023A ( 0 ) 517 - 518 2023.08

回転エンコーダは、回転スケールの偏心や変形によって角度誤差が生じる。このとき、回転スケールの円筒面に角度信号の検出面を有する場合、偏心や変形によって検出面とセンサヘッドとのギャップ量が変化するため、センサヘッドが検出する角度信号の強度が変化する。本研究では、回転エンコーダを構成するセンサヘッドでこの強度変化を検出し、回転スケールの偏心や変形の量を逆算することで角度誤差を計測する方法を提案する。

超高速レーザークラッディングにおけるレーザー再溶融処理の応用

Hashimoto Masayuki, Koike Ryo, Kakinuma Yasuhiro, Mori Takanori, Hirono Yoko, Oda Yohei

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2023A ( 0 ) 623 - 624 2023.08

Relation between vibration condition and critical depth of cut in elliptical-vibration-assisted cutting of single crystal magnesium fluoride

Kodama Hikaru, Matsuda Kanon, Fujii Shun, Tanabe Takasumi, Kakinuma Yasuhiro

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2023S ( 0 ) 246 - 247 2023.03

より優れた光コムや光センサの開発に向けて，高性能な微小光共振器が求められている．光学特性に優れた単結晶MgF2を超精密切削することで実現できる可能性があるが，硬脆材かつ異方性を有するため微小き裂のない表面品位を維持することが難しい．そこで，本研究では楕円振動切削を適用することで，臨界切り込み深さの向上を目指した．加工面や切りくず観察を通して，振動条件が臨界切り込み深さに与える影響を調べた．

Machine Learning-Based Shape Error Estimation Using the Servomotor Current Generated During Micro-Milling of a Micro-Lens Mold

Mizuhara Kenta, Nakamichi Daisuke, Yanagihara Wataru, Kakinuma Yasuhiro

International Journal of Automation Technology (Fuji Technology Press Ltd.) 17 ( 2 ) 92 - 102 2023.03

ISSN 18817629

The demand for the mass production of micro-lens arrays (MLAs) is increasing. An MLA is fabricated through an injection molding process, and its mold is manufactured by a five-axis high-precision machine tool using a small diameter endmill. A visual examination is not available to judge the quality of the mold while machining. Therefore, an effective process monitoring technology must be developed. A promising approach is to apply a servomotor current to in-process monitoring because as long as the servomotor works well, no external sensors, capital investment, or maintenance processes are required. From this perspective, a machine learning-based shape error estimation method using only the servomotor current is proposed. To explore the relationship between the motor current generated during micro-milling and the shape error of the mold, the servomotor current in X-, Y-, and Z-axes was recorded, and the corresponding shape error of the MLA mold was measured after machining. Input data were prepared by converting time-domain servomotor current data to frequency-domain data using short-time Fourier transform and reducing the dimensions of the data via principal component analysis. In terms of a meaningful label for the output data, the average shape error in the machined area corresponding to each window was provided. The input/output relationships were used to train five different machine learning models, and the accuracy of shape error estimation using each model was evaluated. In addition, the estimation accuracies using the X-, Y-, and Z-axes were compared to find the axis that senses the shape error with the highest accuracy. The results show that the non-linear method using the X-axis servomotor current information closest to the machining point achieved the highest shape error estimation accuracy.

Model-based analysis of temperature-dependent dynamics in CFRP spindle unit

Kato M., Kakinuma Y.

CIRP Annals 72 ( 1 ) 337 - 340 2023.01

ISSN 00078506

The application of CFRP to machine tool structures can potentially improve their dynamic characteristics and energy efficiency owing to its highly specific material properties. The different thermal characteristics of CFRP and steel in spindle units likely induce unique thermal deformation, which affects the bearing dynamics. This research proposes a modeling method of CFRP spindle unit dynamics via generalized multipoint receptance coupling with contact characteristics at the spindle-holder interface. The temperature-dependent mechanical properties are analyzed by parameter identification from the model. The translational stiffness and damping of bearings in the CFRP spindle increase with temperature increase at high rotational speed.

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Study on Cutting Force and Tool Wear in Machining of Die Materials with Textured PCD Tools Under Ultrasonic Elliptical Vibration

Maeng S., Ito H., Kakinuma Y., Min S.

International Journal of Precision Engineering and Manufacturing - Green Technology 10 ( 1 ) 35 - 44 2023.01

ISSN 22886206

Machining of steel-based alloy (STAVAX) and tungsten carbide (WC) is very challenging due to their superior hardness. Severe wear in the machining of the die materials is the dominant problem. Texturing on the rake face of the tool and ultrasonic elliptical vibration cutting (UEVC) may resolve this issue and could prolong tool life. The patterns on the rake face of the tool entrap the chip and debris created in machining and prevent abrasion. During UEVC the flank face of the tool does not contact the workpiece and the rake face of the tool helps the chip evacuate from the machining area when the tool disengages with the workpiece. Thus, UEVC reduces cutting force and tool wear compared to conventional cutting. This paper investigates the cutting performance and tool wear in machining of the die materials with textured polycrystalline diamond (PCD) tools under UEVC. The linear patterns parallel or perpendicular to the chip flow are engraved on the rake face of the PCD tools with the focus ion beam (FIB) process. Orthogonal cutting experiments are carried out on ultra-precision machine tools with and without UEVC. Machining under UEVC remarkably reduces the cutting and thrust force and improves tool life. For machining of STAVAX with the textured PCD tool, the linear patterns alone do not improve the cutting, but they improve the cutting when they are combined with UEVC. In machining of WC, the linear pattern becomes effective by slightly decreasing the thrust force and friction coefficient when UEVC is not applied.

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Slurry Conditions for Reaction-Induced Slurry-Assisted Grinding of Optical Glass Lens

Kawasato Tappei, Takamaru Hinata, Hamazono Kazuhisa, Fukuta Masahiko, Tanaka Katsutoshi, Chiba Yusuke, Nagano Mikinori, Kato Hidebumi, Kakinuma Yasuhiro

International Journal of Automation Technology (Fuji Technology Press Ltd.) 17 ( 1 ) 40 - 46 2023.01

ISSN 18817629

The demand for optical glass lenses is rising owing to the increase in image resolution. Optical glass is a hard and brittle material. Thus, an efficient and precise grinding method is required for optical glass to improve lens quality and productivity. There are a few methods of producing crack-free machined surfaces; however, they provide only limited grinding efficiency. To resolve this issue, the authors’ group has proposed the reaction-induced slurry-assisted (RISA) grinding method, which expands the range of ductile-regime grinding by utilizing the chemical–mechanical action of a cerium oxide slurry. In this study, the grinding performance of RISA grinding is experimentally evaluated for different pH levels. The results are compared using Tukey’s test, where surface roughness is considered as the characteristic value and the pH value as the analyzed factor. The result shows that RISA grinding efficiently produces a high-quality surface when the slurry is alkaline. The adhesion of cerium oxide abrasives to the wheel in RISA grinding follows the same mechanism as slurry aggregation. In addition, adhesion is more likely to occur when the alkalization of the slurry promotes aggregation. The tank in the slurry supply unit is replaced with a rotating tank to ensure stable RISA grinding with a highly aggregable slurry while preventing aggregation. The performance evaluation shows that a high-quality surface with a surface roughness of less than 10 nm in most parts is obtained. Moreover, the critical depth of cut stably increases by a factor of 5.8.

Evaluation of fabrication parameters for foam stainless steel in directed energy deposition

IKEDA Yushi, TAKEUCHI Toshihiro, KOIKE Ryo, KAKINUMA Yasuhiro, KONDO Masaki, ODA Yohei, MORI Takanori

Journal of Advanced Mechanical Design, Systems, and Manufacturing (The Japan Society of Mechanical Engineers) 17 ( 1 ) JAMDSM0011 - JAMDSM0011 2023

ISSN 1881-3054

Directed energy deposition (DED), a metal additive manufacturing process, has attracted considerable attention in various industries. In the past few decades, several studies have been conducted to enhance the quality of DED-produced parts. Various studies on powder- and laser-based DED have focused on eliminating the residual pores in the fabricated parts, which decrease the mechanical strength. In contrast, this study aims at intentionally increasing the residual pores to produce a porous structure in metals called as foam metal, which realizes lightweight and excellent energy absorption properties. Despite being well-known for their attractive properties, Foam metals are rarely used due to the technical difficulties in their production, which requires special devices and entails considerable cost. The simplicity of the DED process makes it a promising approach to fabricate foam metals because it is easy to foam at the fabrication point by mixing a foaming agent, such as titanium hydride (TiH2), into the material powder. This study evaluates the DED foaming process in stainless steel alloys by changing the particle size of the TiH2 powder and the scanning path to obtain the optimal conditions for enhancing the pore dispersion. The experimental results show that, when the particle size of the foaming agent is small, the number of pores and their distribution increases. Additionally, the mechanical properties are also evaluated through compression experiments, and the energy absorption ratio is found to be higher when a smaller foaming agent is used.

Mechanical property evaluation of the SLM support structure and lattice structure of SUS316L

Ikeda Y., Okochi W., Koike R., Maki T., Takaki K., Mori T., Hirono Y., Kakinuma Y.

Journal of Advanced Mechanical Design, Systems and Manufacturing 17 ( 1 ) 2023

Selective laser melting (SLM) is one of the additive manufacturing (AM) methods which is applicable to metal. This technique makes it possible to form complex internal shapes such as lattice structures. The lattice structure is expected to have weight reduction and vibration suppression effects on the product. In addition, a support structure is essential for the SLM fabrication process, which has the role of supporting the product and dissipating heat from the product. However, steep temperature gradients due to local laser irradiation and non-uniform heat conduction during the process can cause bending and cracking of the product. In particular, the support structure and lattice structure consisting of thin metal struts are greatly affected by process conditions, so it is necessary to select conditions suitable for stable and high-precision modeling. In this study, the influence of laser power and scanning speed on the mechanical characteristics of the support structure and lattice structure formed by SLM is investigated. In the tensile test of the support structure, a positive correlation with the volumetric energy density was confirmed, and suitable laser conditions were examined. In the compression test of the lattice structure, it was clear that the amount of energy absorption changed depending on the laser power, and the condition of 240 W achieved the maximum energy absorption.

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Process Monitoring for Machine Tools

KAKINUMA Yasuhiro

Journal of the Japan Society for Precision Engineering (The Japan Society for Precision Engineering) 89 ( 12 ) 866 - 870 2023

ISSN 09120289

A machine learning approach for simulation of multi-stage laser forming process

Ikeda, Y; Okochi, W; Koike, R; Maki, T; Takaki, K; Mori, T; Hirono, Y; Kakinuma, Y

JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 17 ( 1 ) 2023

ISSN 1881-3054

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Enhancing the multi-encoder-based cutting force estimation along the stationary axis of a machine tool with multiple inertia dynamics

Yamamoto K., Kamba A., Takeuchi K., Fujita J., Fujimagari Y., Kakinuma Y.

International Journal of Advanced Manufacturing Technology 123 ( 3-4 ) 1215 - 1229 2022.11

ISSN 02683768

Wideband cutting force sensing is a key technology for process monitoring. Sensorless cutting force estimation using the internal servo information of a machine tool with ball-screw-driven stages has been studied owing to its high maintainability and ease of introduction. In the motor current-based method, the cutting force estimation along the stationary axis is challenging, and the estimation bandwidth is significantly limited owing to the low sensitivity of the motor current in the high-frequency range. The dual-inertia model-based load-side disturbance observer (LDOB) can estimate the cutting force along the stationary axis using the relative position obtained from the rotary and linear encoder. The linear encoder is installed relatively near the cutting point and has a high sensitivity in the high-frequency range. However, this approach is not applicable to machine tools with complicated structural dynamics. To address this challenge, we propose a cutting force estimation method along the stationary axis using the Kalman filter (KF) based on a multiple inertia model derived solely from the relative position signal. The dynamics, depending on the stage position of the feed drive, were modeled using linear interpolation. Through end milling tests, we confirmed that the cutting force estimation accuracy along the stationary axis of a machine tool with multiple inertia dynamics was significantly improved by the proposed method compared to the current and LDOB-based methods. Additionally, the wideband cutting force could be estimated using the proposed method for bandwidths up to 1000 Hz.

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BASIC STUDY ON GEAR COATING TECHNOLOGY USING DIRECTED ENERGY DEPOSITION

Ikeda Yuriko, Okochi Wataru, Maki Teppei, Takaki Kazuhiro, Shiwaku Noriyuki, Mori Takanori, Hirono Yoko, Koike Ryo, Kakinuma Yasuhiro

Proceedings of the International Symposium on Flexible Automation (The Institute of Systems, Control and Information Engineers) 2022 ( 0 ) 141 - 143 2022.07

In recent years, with the spread of electric vehicles, development of high-performance mechanical parts has been required. With respect to the manufacturing process, metal Additive Manufacturing (AM) such as Directed Energy Deposition (DED) is attracting attention in automobile industry. Since the DED process can deposit molten material onto the specific surface, where it solidified, it is regarded as a promising coating process to enhance the hardness and surface functionality of mechanical parts. From this perspective, a gear coating process using DED is proposed in this research to strengthen gear surface and its basic study is conducted. Concretely, the coated material quality and mechanical properties like hardness are evaluated.

ENHANCEMENT OF MAGNETIC PROPERTIES AND CRYSTAL STRUCTURE OF SOFT MAGNETIC MATERIALS FABRICATED BY DIRECTED ENERGY DEPOSITION

Kanemaru Soma, Koike Ryo, Kakinuma Yasuhiro, Hirono Yoko, Mori Takanori

Proceedings of the International Symposium on Flexible Automation (The Institute of Systems, Control and Information Engineers) 2022 ( 0 ) 131 - 134 2022.07

Additive manufacturing (AM) allows objects to be designed and formed directly from three-dimensional data. Directed energy deposition (DED), an AM method, can produce near net shape parts, which can reduce lead time and material waste, resulting in lower costs. From the growing interest in vehicle electrification, usage of AM technology for functional materials such as soft magnetic materials has been attracting attention. Performance indicators of soft magnetic materials are high saturation polarization, high susceptibility, and low coercivity. These properties depend on microstructure and crystal texture. In this research, experiments were carried out to find ideal process parameters of DED using two soft magnetic materials, FeSi and FeCoV. Crystal orientation of both materials showed anisotropic properties with columnar grains in the build direction. Six process parameters, laser power, feed rate of nozzle head, dwell time, rotational speed of disc in powder pod, powder supply rate, and carrier gas speed were adjusted to perform a screening test. It was found that dwell time and powder supply rate have a large influence on the shape of deposit. Also, higher deposit density is achieved by higher laser power and lower feed rate. Consequently, optimal process parameters of both FeSi and FeCoV deposits were obtained.

Dynamical characteristic validation of motorized CFRP spindle unit based on receptance coupling

Kato M, Kono D, Kakinuma Y

Mechanical Systems and Signal Processing 173 2022.07

ISSN 08883270

Carbon fiber reinforced plastic (CFRP) is used in machine tool components to provide high specific stiffness with high damping properties and low thermal expansion; further, it is combined with metals in specific ratios to enable the use of existing equipment and machine design. The development of CFRP spindle shafts has design flexibility in the stacking sequence. The improvement and analysis of spindle unit dynamics are essential for achieving high productivity in machining, and prediction methods for dynamic stiffness with lower computational costs are required to estimate and optimize the machine performance of the design proposals. Therefore, parameter identification for the equivalent physical properties of composite materials with CFRP and steel was proposed in this paper to use general solutions for a one-dimensional Timoshenko beam model. Four different analytical models of the CFRP spindle shaft following the actual development phase were designed via generalized receptance coupling to multi points in order to observe the model shapes. The frequency response functions and mode shapes of the spindle shaft models were compared with those of finite element methods and impact tests. The spindle shaft model reflecting the applicable location of CFRP in the rotational axis demonstrates a sufficient estimation accuracy for natural frequencies and mode shapes. The spindle shaft model reflecting the stacking sequence demonstrates robustness against the parameterization errors of the CFRP. A motorized CFRP spindle unit was modeled by combining a spindle shaft model and bearing models; the bearing dynamics were experimentally studied under heat radiation after stopping the spindle rotation. Moreover, a steel spindle shaft model and several types of CFRP layout with the same dimensions were compared on the spindle unit model; the CFRP spindle unit yielded a greater dynamic stiffness. The layout of the CFRP application and requirements on manufacturing are discussed for the further improvement of the dynamic stiffness.

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Experimental Confirmation of a Controllable Transmission/Braking Element Consisting of a Functional Elastomer Pasted on a Winding Surface

Koyanagi K., Kakinuma Y., Anzai H., Sakurai K., Oshima T.

Actuators 11 ( 4 ) 2022.04

Electoadhesive (EA) gel can be applied to various mechatronics devices because it provides more degrees of freedom in mechanical design than other functional materials. While case studies have revealed much about these devices, the knowledge attained is still not integrated. We assembled new structured and controllable transmission and braking elements by fixing EA gel on plain and/or winding surfaces. This paper summarizes the characteristics of these devices from experimental findings on the initial pressure on the EA gel surface. The results showed that it is important for the initial pressure to be stable at approximately 0.5–1 kPa.

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超硬合金の楕円振動切削における逃げ面テクスチャ工具の開発

Ito Hiroaki, Kobayashi Yutaka, Shimada Hiroyuki, Yamada Hiroki, Kakinuma Yasuhiro

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2022S ( 0 ) 383 - 384 2022.03

超硬合金の金型を製造するための切削加工技術が求められている．超硬合金の切削では，粉末状の微細な切りくずが工具と工作物の界面に入り込み工具摩耗を促進する．そこで，本研究では，切りくず排出性を向上させるために，工具逃げ面に微細溝テクスチャを施した切削工具を提案し，これを用いて超硬合金の楕円振動切削試験を行った．テクスチャ形状と切りくず排出性の関係を実験的に調べ，提案工具の耐摩耗性を評価した．

Robot polishing control with an active end effector based on macro-micro mechanism and the extended Preston's law

Kakinuma Y., Ogawa S., Koto K.

CIRP Annals 71 ( 1 ) 341 - 344 2022.01

ISSN 00078506

There is a strong demand for automating the rough polishing process in plastic-mold manufacturing. In this study, with the active end effector being capable of fast force control and dynamic spindle control, a robot polishing control system based on a macro-micro-mechanism was built, which controls all parameters related to Preston's law and can be linked with computer-aided manufacturing. Based on the extended Preston equation, a polishing control algorithm that achieves uniform surface quality and uniform removal depth was proposed. The spherical rough polishing test on carbon steel demonstrated the efficacy of the proposed robot polishing control.

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Theoretical approach on the critical depth of cut of single crystal MgF<inf>2</inf> and application to a microcavity

Hayama Y., Fujii S., Tanabe T., Kakinuma Y.

Precision Engineering (ELSEVIER SCIENCE INC) 73 234 - 243 2022.01

ISSN 01416359

Optical microcavity, which can localize light at a certain spot for a short period of time, has a wide range of applications, such as optical signal processing and optical frequency combs. Single crystal CaF2 has excellent optical properties and many research on the manufacturing process to create a microcavity has been done. However, due to its unstable thermal conditions, stable oscillation of Kerr comb could not be done. Single crystal MgF2, which also has excellent optical properties, has stable thermal conditions suitable to create a microcavity. Like CaF2, MgF2 microcavity can only be manufactured by ultra-precision cylindrical turning, yet its appropriate processing conditions is not known. In this study, a method to derive the critical depth of cut theoretically in ductile mode machining was proposed in consideration of specific cutting energy, mechanical properties and slip system of workpiece, and tool geometry. The critical depth of cut calculated by the proposed method roughly agreed with the experimental value on the MgF2 plane. Unlike CaF2, MgF2 has an optical anisotropy; therefore, in order to create a microcavity where the refractive angle is constant, the resonance part needs to be made on a cylinder with (001) plane as end face. Therefore, a microcavity was fabricated according to the critical depth of cut on a cylinder with (001) as end face derived from the proposed method, and the surface integrity was evaluated from the viewpoint of microcavity performance.

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Application of RISA grinding method to multiple optical glasses

Takamaru H., Kawasato T., Watanabe K., Fukuta M., Tanaka K., Chiba Y., Kato H., Nagano M., Kakinuma Y.

Procedia CIRP 108 ( C ) 454 - 458 2022

ISSN 22128271

A more efficient and precise grinding method for optical glasses is demanded to improve lens quality and productivity. The Reaction Induced Slurry Assisted (RISA) grinding method enhances the ability of ductile regime grinding by utilizing the chemical mechanical action of cerium oxide slurry. In this study, the grinding performance of RISA grinding to multiple optical glasses is experimentally evaluated. The result shows that RISA grinding efficiently produces a fine quality surface of crown glass with high Si-O bond content.

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Development of temperature analysis environment for Cyber-Physical Systems on IoT platform: a study of dynamical properties under temperature change in machine tool spindle unit using carbon fiber reinforced plastics

Kato M., Kizaki T., Uwano T., Iijima K., Kakinuma Y.

Procedia CIRP 107 1485 - 1490 2022

ISSN 22128271

Industrial networks with a database for collecting and analyzing machine information and process data are key components in production systems in Industry 4.0. In proposed IoT system, more than 300 temperature sensors were externally mounted on a carbon fiber reinforced plastics structured machine tool, and their information was collected through an OPC UA server. Based on impact tests, the spindle nose temperature was found to be correlated to the variation in compliance and resonant frequency. The carbon fiber reinforced plastics structured spindle shaft conducted heat quickly and induced a temperature increase after stopping spindle rotation. The IoT system of a temperature-analysis environment can contribute to experimental analysis and model construction for intelligent technologies.

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Electrical Resistance Characteristics of Electro-adhesive Gel Sheet While Fixing Conductor Object

NISHIMURA Ryo, HIOKI Yuka, ANZAI Hidenobu, SAKURAI Kouzi, NAGATSUMA Akemi, AOYAMA Tojiro, KAKINUMA Yasuhiro

Journal of the Japan Society for Precision Engineering (The Japan Society for Precision Engineering) 88 ( 1 ) 117 - 123 2022

ISSN 09120289

In this study, Electro-Adhesive Gel Sheet (EAGS) was fabricated. It is suggested that the electrical resistance characteristics of EAGS could be applied as slip detection sensors or contact detection sensors. EAG is a functional elastomer which can change surface adhesiveness depending on an electric field, and EAGS is a sheet of EAG fabricated on a flexible electrode sheet. It was found that slipping on the surface when grasping an object or contact with a grounded conductor changes the resistance inside the EAGS, and the mechanism was analyzed from an engineering point of view.

Large force actuator using an electro-adhesive gel super multi-disk

Koyanagi K., Takata Y., Kakinuma Y., Anzai H., Sakurai K., Oshima T.

Advanced Robotics 36 ( 19 ) 983 - 994 2022

ISSN 01691864

Actuators with clutch mechanisms have advantages in safety, backdriveability, and controllability for human-coexistence robots. This paper presents a large force actuator using electro-adhesive gels, which are functional materials controlled by the magnitude of an electric field. The developed actuator can generate and continuously control a force over 560 N and resist with a small force when de-energized. The number of electro-adhesive gel disks is drastically increased to increase the generative force. This paper reports the structural plan for the new actuator and experiments to investigate its basic characteristics. Based on the experimental results, an actuator model is identified for the future design of its control system. This paper contributes to the development of a clutch-type linear actuator with a large generative force, maintaining safety and a high force-to-weight ratio. It also addresses the problem of high-voltage power supply costs for electro-rheological and electro-adhesive materials.

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Shape error analysis in ultra-precision grinding of optical glass by using motor-current-based grinding force monitoring

Iinuma N., Chen B., Kawasato T., Kakinuma Y.

Proceedings of ASME 2022 17th International Manufacturing Science and Engineering Conference, MSEC 2022 2 2022

4K and 8K technologies are attracting attention in optical industries. The most important mechanical element to enhance the imaging performance is the aspherical lens requiring higher surface quality and higher form accuracy. Currently, the production process of optical lenses consists of brittle-mode grinding and pro-longed polishing process, which play a role of shaping the form and producing the fine surface, respectively. However, this process is not considered to be suitable for manufacturing such higher-quality lenses for 4K and 8K imaging devices because a required form accuracy could not be ensured, and the polishing time gets longer. To enhance the form accuracy and production efficiency, application of ductile-mode grinding is expected to reduce polishing amount. However, the shape error generated by the ductile mode grinding is not clear. Therefore, the purpose of this research is to analyze the relation between the shape error and the grinding force estimated from motor-current in the grinding machine. The motor-current acquisition system in all translational axes and the work spindle is constructed and implemented into a 4-Axis ultraprecision aspherical machine. The grinding force in each axis is derived by subtracting the motor current during non-grinding previously obtained in air-grinding test from the current during grinding. Firstly, the behavior of the motor current in each axis is investigated from the viewpoint of repeatability and position dependency. While the periodic fluctuation of the motor current affected by the influence of permanent magnet in the linear motor is confirmed, it shows high repeatability at each position. This result indicated that grinding force is easily calculated from the motor current with less uncertainty. Then, influence of grinding condition in the range of ductile mode grinding on the shape error is analyzed by monitoring the motor current. Toward the outside of the workpiece, the shape error gradually increases with the increase of motor current, which means larger grinding force at the outer side causes the deformation of the resin grinding wheel.

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Optimization of process parameters for hardness in high speed coating by Directed Energy Deposition

Satoh T., Koike R., Kakinuma Y., Hirono Y., Mori T., Oda Y.

Procedia CIRP 111 214 - 217 2022

ISSN 22128271

In recent years, metal 3D printers have been attracting attention not only for building solid parts but also for repairing and coating processes. The goal of this study is to apply the directed energy deposition (DED), which is one of the additive manufacturing, to realize high-quality metal coating by depositing the coating material on a cylindrical object. To evaluate the effect of process parameters, experimental points were set up based on the central composite design and deposition was performed using Inconel 625 as the material powder. The hardness of the coating was measured and statistically analyzed by the response surface methodology. From the analysis results, it was found that laser power has the largest influence on the coating hardness, which was improved by 28% compared to the low rotation speed by depositing under the optimum processing parameters.

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指向性エネルギー堆積法における軟磁性造形物の磁気特性と結晶粒構造評価

Kanemaru Soma, Koike Ryo, Kakinuma Yasuhiro, Hirono Yoko, Mori Takanori

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2021A ( 0 ) 326 - 327 2021.09

複雑形状部品を一体造形ができる付加製造技術は，自動車産業においても注目を集めている．本研究は指向性エネルギー堆積法を用いた電気自動車のモータ製造法の確立を目指し，磁芯に利用される軟磁性材料FeSi，FeCoVを用いた造形物の磁性と結晶粒組織を評価した．安定造形が可能な造形パラメータを同定し，FeCoV造形物についてレーザ出力を増加させることで鉄損の原因となる保磁力を低めることができた．

Machining condition monitoring in ultra-precision grinding of optical glass by using servo information and AE signals

Kuriyama Mitsuru, Sadaka Shiori, Kakinuma Yasuhiro

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2021S ( 0 ) 283 - 284 2021.03

大口径の光学ガラスレンズの形状創成において，ガラスを割らずに加工する延性モード研削の適用とその効率向上が求められている．安定した延性モード研削を行うためには，研削加工中に延性／脆性モードを判別する技術が必要不可欠である．そこで，本研究では，工作物主軸に組み込んだAEセンサと各軸のサーボ情報を用いた加工状態監視手法を提案した．信号波形を解析し，加工状態に応じて各信号に生じる特徴を明らかにした．

Development of Automatic Chatter Suppression System in Parallel Milling by Real-Time Spindle Speed Control with Observer-Based Chatter Monitoring

Yamato S, Nakanishi K, Suzuki N, Kakinuma Y

International Journal of Precision Engineering and Manufacturing 22 ( 2 ) 227 - 240 2021.02

ISSN 22347593

To maximize the potential for high material removal rates in simultaneous processes such as parallel milling, developing strategies for successful chatter suppression/avoidance is an important concern for manufacturers. In this study, the effectiveness of the spindle speed difference method (SDM) for chatter suppression is discussed in a parallel end-milling process where a flexible workpiece is machined by two tools rotating in opposite direction. The process model is developed, considering that the dynamic variation due to the regenerative effect occurs on a plane perpendicular to the tool axis direction. Through the process simulations and the experiments, this study provides informative discussion for comprehending the process behavior. Additionally, a real-time active chatter suppression system with adaptive SDM, where the spindle speed difference is sequentially optimized during the process according to the tracked chatter frequency, is developed by integrating a chatter monitoring system based on sensorless cutting force estimation with sliding discrete Fourier transform. The results show that the developed real-time adaptive system of spindle speed suppresses chatter vibrations more effectively than non-adaptive SDM system; hence, the integrated system can contribute self-optimizing machining systems oriented to Industry 4.0.

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Vibration analysis and cutting simulation of structural nonlinearity for machine tool

Irino N., Imabeppu Y., Higuchi Y., Shinba Y., Kawai K., Suzuki N., Kaneko J., Kakinuma Y., Mori M.

CIRP Annals 70 ( 1 ) 317 - 320 2021.01

ISSN 00078506

The dynamic behavior of a machine tool is affected by the forces applied to the structure. However, cutting processes have been analyzed considering the linear systems in most of the studies so far. In this study, a machine tool structure was excited by using an electromagnetic shaker and the force-dependant frequency response characteristics were measured. Based on the measured result, the nonlinear characteristics of the machine tool structure was identified, and a machine tool with the nonlinear characteristics was mathematically reproduced, which enabled to analyse the nonlinear frequency response characteristics and simulate cutting processes.

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Enhancement of force control performance of macro-micro system based polishing robot with gravity compensation

Ogawa S., Koto K., Tsukada T., Kakinuma Y.

Proceedings of the ASME 2021 16th International Manufacturing Science and Engineering Conference, MSEC 2021 1 2021

In a fine mold manufacturing process, the polishing process plays an important role in enhancing the surface quality and is performed manually by skilled workers. However, there are many problems such as decrease in skilled workers, health hazards due to scattering of abrasives, and difference in surface quality due to difference in the proficiency. Hence, there is a strong demand for automation of the polishing process at present. In this research, a robot polishing system that applies macro-micro mechanism is proposed. The functional polishing module of the end effector is developed and attached to the hand of the serial link robot. Tool path and posture are controlled in a serial link robot as a macro mechanism, and polishing force and tool rotation speed are controlled in the developed polishing module as micro mechanism. This mechanism ideally controls position, force, and rotation speed at the same time. An interlocking control system for position and force has already been constructed. In this paper, we constructed gravity compensation and evaluated the force control performance of the constructed system. Through the evaluation, the followability of the estimated reaction force to the command force and the validity of the actual force behavior measured by the force sensor were evaluated.

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Development of an electro-adhesive hand with the function of contact and slip detection

HIOKI Yuka, NISHIMURA Ryo, ANZAI Hidenobu, SAKURAI Kouji, NAGATSUMA Akemi, AOYAMA Tojiro, KAKINUMA Yasuhiro

Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21 (The Japan Society of Mechanical Engineers) 2021.10 ( 0 ) 637 - 639 2021

In this study, Electro-Adhesive Gel Sheet (EAGS) was attached to a robot hand and used as a gripper. Electro-Adhesive Gel (EAG) is a functional elastomer which can change surface adhesiveness depending on an electric field. EAGS is a sheet of EAG fabricated on a flexible electrode substrate. It is confirmed that the electrical current flow inside EAGS is changed when the robot hand with EAGS (EA hand) touches a grounded metal object or slips on it. By applying these current characteristics, the applicability of contact detection and slip detection is investigated to monitor gripping status in robot hand. From the results, EA hand can detect not only the contact but also lifting the object from the base plate. Furthermore, slipping can be suppressed by adjusting an applied potential difference of the electrodes according to the slip detection.

Basic study of fabrication conditions for foam stainless in directed energy deposition

TAKEUCHI Toshihiro, KOIKE Ryo, KAKINUMA Yasuhiro, KONDO Masaki, ODA Yohei, MORI Takanori

Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21 (The Japan Society of Mechanical Engineers) 2021.10 ( 0 ) 677 - 682 2021

Directed energy deposition (DED) is one of additive manufacturing processes attracting attention from various industries. Foam metal is a material having beneficial characteristics, but is difficult to produce with conventional manufacturing system. This study proposes a simple foam metal fabrication method by applying DED. The proposed method produces foam stainless alloy in DED by adding a foaming agent, titanium hydride (TiH2), into the powder material. This study evaluates the foaming behavior of porous stainless in DED by changing the particle size of TiH2 and the number of layers per line, and obtains the optimal number of layers to improve the porosity dispersion.

Experimental Evaluation of Reaction Induced Slurry Assisted Grinding for BK7 Optical Glass

Kawasato T., Hamazono K., Fukuta M., Tanaka K., Nagano M., Kato H., Kakinuma Y.

10th International Conference on Leading Edge Manufacturing Technologies in 21st Century, LEM 2021 287 - 290 2021

A more accurate and more efficient grinding method for optical glasses is demanded as high-resolution imaging devices become more popular. We propose a reaction-induced-slurry-assisted (RISA) grinding method as a chemical mechanical grinding method using cerium oxide slurry instead of ordinary coolant. In this study, the grinding performance of RISA grinding for BK7 optical glass is experimentally evaluated from the viewpoints of sub-surface damage and repeatability of ductile regime grinding at various wheel feed rates. From the grinding tests, RISA grinding causes less sub-surface damages and successfully generates ductile regime surface repeatedly under 3.0 mm/min wheel feed rate.

Study on cutting mechanism of mold steel in ultrasonic elliptical vibration cutting with textured tool

Ito Hiroaki, Maeng Sangjin, Min Sangkee, Kakinuma Yasuhiro

Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21 (The Japan Society of Mechanical Engineers) 2021.10 ( 0 ) 234 - 237 2021

Machining of mold steel like STAVAX is still challenging due to significant tool wear. The ultrasonic elliptical vibration cutting (UEVC) that enables dramatic reduction of cutting force is considered as a potential solution. Tool-texturing on the rake face to reduce the friction coefficient between chips and the tool can be another solution as well. Hence, combining these two approaches may provide synergetic effect to further reduce the cutting force. In order to understand this effect, chip formation using these approaches is experimentally investigated. Chip morphology is totally different whether to use UEVC and textured tools. It was shown that the perpendicular pattern to the chip flow direction may enhance the chip-lifting effect during UEVC. Thus, upward force is applied to the workpiece, which causes reduction of thrust force.

Powder velocity-based nozzle design for directed energy deposition

TAKEMURA Keisuke, KOIKE Ryo, KAKINUMA Yasuhiro, YAMAZAKI Keiichi, MORI Takanori, HIRONO Yoko

Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21 (The Japan Society of Mechanical Engineers) 2021.10 ( 0 ) 458 - 461 2021

Directed energy deposition (DED), which is one of the metal-powder additive manufacturing processes, is a promising method suitable for repairing. Because the carrier gas that transports the metal powder and the shield gas that protects the optical system are supplied in DED, it is difficult to estimate the transport of metal powder due to the complex turbulence around the processing point, resulting the powder supply efficiency gets lowered. This study computationally analyzed the fluid dynamics of two types of DED nozzles for improving the powder supply efficiency by changing the number of powder channels, working distance and channel diameter.

Performance evaluation of robot polishing in macro-micro system based polishing robot

Koto K., Tukada T., Ogawa S., Kakinuma Y.

Proceedings of the ASME 2021 16th International Manufacturing Science and Engineering Conference, MSEC 2021 1 2021

Polishing is an important process performed in the finishing and repair processes of mechanical parts and is still a manual work of skilled workers. However, in addition to the time and cost required for manual polishing, there are also problems such as a decrease in the number of workers and health hazards due to dust generated during polishing. From these problems, the demand for automatic polishing is increasing at manufacturing sites. To automate polishing process, a macro-micro system based polishing robot which consists of a functional end-effector and industrial robot has been proposed. Regarding end effectors, mechanical design aiming for high rigidity and motion control methods for keeping the contact force constant is being researched. Meanwhile, the tool rotation speed of the spindle is independently controlled typically. Therefore, in this research, a functional polishing module capable of polishing force control and tool rotation control according to the tool feed rate is developed as the end effector. For the polishing automation, the macro-micro system based polishing robot is constructed attaching the polishing module to the industrial robot. From the viewpoint of Preston’s law, the effectiveness of the robot polishing is investigated through polishing experiments and measuring the shape of the polished surface.

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Mechanical property evaluation of the SLM support structure and lattice structure of SUS316L

Okochi W., Ikeda Y., Koike R., Mori T., Hirono Y., Maki T., Takaki K., Kakinuma Y.

10th International Conference on Leading Edge Manufacturing Technologies in 21st Century, LEM 2021 452 - 455 2021

Selective laser melting (SLM) is one of the additive manufacturing (AM) methods which is applicable to metal. Although this technology enables to form complex inner shapes such as lattice structure, steep temperature gradients due to local laser irradiation and uneven heat conduction during the process may cause bending and cracking of the product. In this study, the influence of laser power and scanning speed on the mechanical characteristics of the support structure and lattice structure formed by SLM is investigated. In the tensile test of the support structure, a positive correlation with volumetric energy density was confirmed. In the compression test of the lattice structure, it was clear that larger amount of heat energy from the laser makes struts of lattice structure thicker and its Young's modulus higher.

Machine learning-based shape error estimation in micromilling by using motor current

MIZUHARA Kenta, NAKAMICHI Daisuke, YANAGIHARA Wataru, KAKINUMA Yasuhiro

Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21 (The Japan Society of Mechanical Engineers) 2021.10 ( 0 ) 594 - 596 2021

The requirement for Mass production of Microlens array (MLA) mold is increasing. MLA molds are manufactured by 5-axis ultra-precision machining center using an ultra-small diameter end mill. Since visual examination is not good at judging quality of product while machining, the development of effective process monitoring technology is required. The ultra-precision machining center used in this study employs a linear motor and has low sliding resistance while machining. Therefore, machining information is directly reflected in servo information. Focusing on this point, we developed a machine learning-based shape error estimation model using servomotor current alone and discussed its usefulness.

Fabrication of dispersion engineered ultrahigh-Q crystalline optical microresonator for broad-bandwidth optical parametric oscillation

Fujii S., Wada K., Kakinuma Y., Tanabe T.

Proceedings of SPIE - The International Society for Optical Engineering (SPIE-INT SOC OPTICAL ENGINEERING) 11672 2021

ISSN 0277786X

We demonstrate the all-precision-machining fabrication of ultrahigh-quality-factor (Q) crystalline optical microresonators. The obtained Q exceeds 100 million for both magnesium fluoride (MgF2) and calcium fluoride (CaF2) materials. This constitutes the highest Q factor obtained for whispering gallery mode crystalline microresonators fabricated solely by ultra-precision machining. We also achieve octave-wide optical parametric oscillation using an MgF2 resonator fabricated with a computer-controlled machining process. This method readily enables advanced dispersion engineering for optical parametric oscillation and makes it possible to explore microcavity nonlinear optics and quantum optics without the need for skilled manual polishing techniques.

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Basic study on electro-adhesive surface applying 3-dimensional micro structures

Yamada Soichiro, Koike Ryo, Arano Shintaro, Kakinuma Yasuhiro, Aoyama Tojiro

International Journal of Automation Technology (Fuji Technology Press) 10 ( 1 ) 48 - 54 2016

Research paper (scientific journal), ISSN 1881-7629

Electro Adhesive Gel (EAG) has the unique characteristic of changing its surface adhesive property with the intensity of the electrical field applied. This propertymakes EAG useful in applications to fixing devices and mechanical brakes. Although its adhesion performance depends on the distribution of the electrorheological particles in the EAG, it is difficult to arrange the particle distribution uniformly in a wide area from the perspective of production process. In this study, a novel functional elastomer that has the same function as EAG is developed, Electro Adhesive Surface (EAS). In EAS, micro photolithography is used to fabricate strut pyramids distributed uniformly on a substrate, and then silicone gel is poured into the structure. When an electrical field is applied, the silicone gel rises to the tops of the pyramids formed by the struts, and adhesion occurs to an object on EAS. To determine a micro structure design for EAS, the fixing force was measured with various struts diameter and gaps. Experimental result shows that the larger struts diameter and the narrower gaps enhance the fixing force of EAS.

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Replication of skilled polishing technique with serial-parallel mechanism polishing machine

Oba Yuta, Yamada Yuki, Igarashi Keisuke, Katsura Seiichiro, Kakinuma Yasuhiro

Precision Engineering (ELSEVIER SCIENCE INC) 45 292 - 300 2015.10

Research paper (scientific journal), ISSN 0141-6359

Currently, viscoelastic polymers are used to coat automotive body to prevent scratches. On the other hand, the application of a polymer with high viscoelasticity makes the repair polishing process of the coated body more difficult. Hence, performing the polishing process requires the operator to be technically skilled. However, the number of workers with necessary technical skill has been decreasing because of an aging population. In addition, the surface quality and process time are dependent on the proficiency level of the worker. To automate the repair polishing process, in our past research, a serial-parallel mechanism polishing machine was developed to simultaneously control the tool trajectory, tool posture, and polishing force. The present study aims to construct a replication system of a skilled polishing technique on the basis of the above three physical parameters by applying the developed polishing machine. First, the tool trajectory, tool posture, and polishing force of a skilled worker, which reflect the polishing technique, were acquired using a high-speed camera and a dynamometer. By inputting the acquired data to the developed machine, the machine can copy the polishing technique because the tool trajectory, tool posture, and polishing force can be independently controlled. From the results of the polishing test, the surface quality after polishing was comparable to that of the skilled worker output, which satisfies the criteria of surface quality.

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Experimental study of crystal anisotropy based on ultra-precision cylindrical turning of single-crystal calcium fluoride

Azami, Shunya, Kudo, Hiroshi, Mizumoto, Yuta, Tanabe, Takasumi, Yan, Jiwang, Kakinuma, Yasuhiro

PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND NANOTECHNOLOGY (ELSEVIER SCIENCE INC) 40 172 - 181 2015.04

Research paper (scientific journal), Accepted, ISSN 0141-6359

To realize ultimately efficient signal processing, it is necessary to replace electrical signal processing circuits with optical ones. The optical micro-resonator, which localizes light at a certain spot, is an essential component in optical signal processing. Single-crystal calcium fluoride (CaF2) is the most suitable material for a highly efficient optical micro-resonator. The CaF2 resonator can only be manufactured by ultra-precision machining processes, because its crystal anisotropy does not allow the application of chemical etching. However, the optical micro-resonator's performance depends definitely on the surface integrity.
This study investigated the relationship between surface quality after ultra-precision machining and crystal anisotropy. Firstly, crack initiation was investigated on the (1 0 0), (1 1 0), and (1 1 1) planes using the micro-Vickers hardness test. Secondly, brittle-ductile transition was investigated by orthogonal cutting tests. Finally, cutting performance of cylindrical turning was evaluated, which could be a suitable method for manufacturing the CaF2 resonator. The most difficult point in cylindrical turning of CaF2 is that the crystalline plane and cutting direction vary continuously. In order to manufacture the CaF2 optical micro-resonator more efficiently, analysis was conducted on crack initiation and surface quality of all crystallographic orientations from the perspective of slip system and cleavage. (C) 2014 Elsevier Inc. All rights reserved.

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サーボ情報を応用したびびり振動に対する安定主軸回転数同定

小池綾, 柿沼康弘, 青山藤詞郎, 大西公平

日本機械学会誌 81 ( 830 ) 15-00387 2015

Research paper (scientific journal)

Evaluation of subsurface damage caused by ultra-precision turning in fabrication of CaF2 optical micro resonator

Kakinuma, Yasuhiro, Azami, Shunya, Tanabe, Takasumi

CIRP ANNALS-MANUFACTURING TECHNOLOGY (ELSEVIER SCIENCE BV) 64 ( 1 ) 117 - 120 2015

Research paper (scientific journal), Accepted, ISSN 0007-8506

The optical micro-resonator, which stores light at a certain spot, is essential in next-generation optical signal processing. Single-crystal calcium fluoride (CaF2) is the most suitable material for this element. Ultra-precision turning is a feasible fabrication process for CaF2 optical micro-resonators. In this study. the influence of subsurface damage on the resonator's Q factor is investigated. TEM observation shows that the subsurface layer of up to several tens of nanometers thickness changed from single-crystal to polycrystalline morphology due to ultra-precision turning. A diamond tool with 0 degrees rake angle results in lower damage than one with negative rake angle, which enhances the resonator's performance. (C) 2015 CIRP.

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Ultrasonic vibration-assisted machining of chemically strengthened glass with workpiece bending

Noma, Kazuki, Kakinuma, Yasuhiro, Aoyama, Tojiro, Hamada, Seiji

JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING (JAPAN SOC MECHANICAL ENGINEERS) 9 ( 2 ) 2015

Research paper (scientific journal), ISSN 1881-3054

This paper deals with axial ultrasonic vibration-assisted machining with workpiece bending. It was proposed as a novel machining method for the reduction of the chippings at the machined holes during micro through-hole drilling of chemically strengthened glass. In micro through-hole drilling of chemically strengthened glass, machining accuracy and efficiency tend to be low because the material's high hardness and brittleness cause rapid tool wear and large chippings at the inlet and outlet of the machined holes. In order to machine small holes with high accuracy, the reduction of the tensile stress that causes large chippings at the outlet of the machined holes is an issue of primary importance that deserves investigation. In the proposed machining method, the glass plate is bent slightly to be convex upward through the application of a compressive stress at the posterior surface of chemically strengthened glass, with a specially designed jig. Using this proposed method that can reduce the tensile stress, the chipping size at the outlet of the machined holes was successfully reduced with applied compressive stress values of 38.9 MPa. In conclusion, it has been clear that the axial ultrasonic vibration-assisted machining with workpiece bending has the potential for achieving high-precision and high-efficiency machining for chemically strengthened glass.

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三次元微細構造を用いた電気粘着表面の開発

山田宗一郎, 青山藤詞郎, 柿沼康弘

精密工学会誌 (The Japan Society for Precision Engineering) 81 ( 3 ) 264 - 269 2015

Research paper (scientific journal), Accepted, ISSN 0912-0289

Electro adhesive gel (EAG) shows a unique characteristic changing its surface adhesive property according to the applied electric field, which is named as electro-adhesive effect (EA effect). Our recent research results indicated that the EAG is feasible to be applied to fixture, clutch, damping, and brake mechanisms. While the performance of EAG has been dramatically enhanced over the past decade, the individual difference caused by the production process has been still problem. In other word, adhesive area of EAGs under the same electric filed is non-uniform and uncontrollable. In this research, to ensure stable EA effect, an electro-adhesive surface (EAS) applying 3-dimensional micro structure alternative to the EAG is proposed. The proposed EAS is composed of the 3-D micro-mesh structure fabricated by the photolithography and silicone gel. The prototype of the EAS was developed and its characteristic was experimentally investigated by microscopic observation and shear test. The result obviously shows that the EAS generates larger adhesive force in higher intensity of electric filed. Furthermore, a uniform and regular pattern of adhesion area is clearly observed. From these results, EAS has a strong possibility to improve the stability of EA effect and enhance the performance of its application devices.

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エンドミル加工における外乱オブザーバを用いたセンサレスびびり振動検知技術の開発（第2報）－移動分散値と移動離散フーリエ変換を併用したびびり振動の種類別検知－

小池綾, 柿沼康弘, 青山藤詞郎, 大西公平

精密工学会誌 (The Japan Society for Precision Engineering) 81 ( 7 ) 692 - 698 2015

Research paper (scientific journal), Accepted, ISSN 0912-0289

Chatter vibration deteriorates the machining accuracy and shortens the tool life. Thus, In-process monitoring methods have been proposed by using additional sensors such as dynamometers and acceleration sensors. However, introducing additional sensors leads to high cost and reduction of machine-tool stiffness. To solve these problems, a sensor-less monitoring method applying the disturbance observer theory was proposed in our previous research which has experimentally shown that chatter vibration can be detected only from the servo information in milling. For further demand, because chatter vibration can be classified into self-excited vibration and forced vibration, an assorted detection method is required. In this study, we propose a novel frequency analysis method combining moving variance and moving Fourier transform algorithms, which can obtain the power spectrum density of each chatter vibration type separately with small computational load. The validity of the proposed method is evaluated through milling tests with different rotational speeds.

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Sensorless tool stiffness monitoring in buffing

Koike Ryo, Kumakura Ryo, Arai Takashi, Uchishiba Eishiro, Murakami Makoto, Sagara Takahisa, Kakinuma Yasuhiro

International Journal of Automation Technology 8 ( 6 ) 827 - 836 2014.11

Research paper (scientific journal), ISSN 1881-7629

In current practice, the buffing process required to finish the surface of mechanical parts is performed manually by a technical expert as it requires a delicate adjustment of the buffing force. The automation of this process is desirable in an effort to shorten the process time and reduce labor cost. To automate the buffing process, a beneficial process monitoring technique that supervises the buffing tool conditions in real time must be developed. From a practical perspective, an observer technique that does not require additional sensors would be most suitable for monitoring the tool operating condition. The authors propose a technique that estimates the buffing tool stiffness based on a disturbance observer. The validity of the proposed method as a buffing tool condition monitoring technique is verified through numerical simulations and experiments.

Sensorless tool stiffness monitoring in buffing

Ryo Koike; Ryo Kumakura; Takashi Arai; Eishiro Uchishiba; Makoto Murakami; Takahisa Sagara; Yasuhiro Kakinuma

International Journal of Automation Technology 8 ( 6 ) 827 - 836 2014

Research paper (scientific journal)

Active chatter suppression in turning by band-limited force control

Kakinuma, Yasuhiro, Enomoto, Kazuto, Hirano, Takayuki, Ohnishi, Kouhei

CIRP ANNALS-MANUFACTURING TECHNOLOGY (ELSEVIER SCIENCE BV) 63 ( 1 ) 365 - 368 2014

Research paper (scientific journal), ISSN 0007-8506

The suppression of chatter vibration is required to enhance the machined surface quality and to increase tool life. In this study, a new, conceptually active approach for chatter suppression in machining is proposed. The hybrid control method developed by applying sensorless force control with a disturbance observer enables the simultaneous and independent control of the position trajectory and band-limited forces. The proposed method is introduced to the carriage of a prototype desktop-sized turning machine, and the ability to suppress chatter is evaluated by end-face cutting tests. The results demonstrate that actively controlling a band-limited force leads to the avoidance of chatter. (C) 2014 CIRP.

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Basic study on high efficiency ultra-precision grinding of the optical glass lens

Rei Sekiguchi; Shun Yoshikawa; Yasuhiro Kakinuma; Katsutoshi Tanaka; Masahiko Fukuta

Advanced Materials Research (Trans Tech Publications Ltd) 1017 21 - 26 2014

Research paper (scientific journal), ISSN 1662-8985

The demand for large aperture lenses with high surface quality and form accuracy used for single-lens reflex cameras has been increasing. Generally, large aperture glass lenses are produced by ultra-precision grinding. Considering the increasing global competition, the grinding process has to be improved. However, highly efficient grinding causes worse surface quality, which leads to much polishing and ultimately results in lower form accuracy. Thus in this study, aiming at the realization of highly efficient and precise grinding of glass lenses, cross grinding of optical glass BK7 is carried out. As a first step of the study, the influence of grinding conditions on the surface quality is investigated experimentally.

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Drill fracture detection by integrating disturbance observer and rotational digital filter

R. Koike; Y. Kakinuma; T. Aoyama

CIRP Journal of Manufacturing Science and Technology (Elsevier BV) 7 ( 3 ) 177 - 184 2014

Research paper (scientific journal), ISSN 1755-5817

Tool fracture detection is important to avoid tool breakage and ensure cutting accuracy. However, conventional tool condition monitoring methods use additional sensors that are expensive, increase the failure rate, and reduce the machine-tool stiffness. This study proposes a novel in-process method to detect tool fracture based on disturbance observer theory. It uses only servo information in a ballscrew-driven stage control system. Furthermore, a rotational digital filter is developed and applied to drilling tests to enhance the detection accuracy. Tool fracture is successfully detected without any external sensors by the proposed method. © 2014 CIRP.

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Monitoring of tool collision in drilling by disturbance observer

S. Tönissen; R. Koike; Y. Kakinuma; T. Aoyama; F. Klocke

CIRP Journal of Manufacturing Science and Technology (Elsevier Ltd) 7 ( 3 ) 274 - 282 2014

Research paper (scientific journal), ISSN 1755-5817

Disturbance observation is a sensorless process monitoring technique that has not yet been applied to the monitoring of tool collision in the use of machine tools. This paper presents a monitoring algorithm that detects collisions that involve the breakage of drills through observation of the disturbance force change rate. A comprehensive experimental study of diverse operator-induced collisions was conducted to analyze the collision detection potential of the disturbance observer. It was found that collision monitoring by the disturbance observer is more sensitive and responsive than that using a sensorless jerk observer. © 2014 CIRP.

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Sensorless cutting force estimation in ball-screw-driven system using triple-inertia model

Yuki Yamada; Yasuhiro Kakinuma; Takamichi Ito; Jun Fujita; Makoto Sawazaki; Makoto Sagara

Advanced Materials Research (Trans Tech Publications Ltd) 1017 619 - 623 2014

Research paper (scientific journal), ISSN 1662-8985

In this paper, we propose cutting-force-estimation method for a ball-screw-driven system using triple inertia model. In many cases, dual-inertia model is applied to describe the dynamic behavior of the ball-screw-driven system. In this paper, triple-inertia model is applied and cutting force was estimated without additional sensors, such as dynamometer. The cutting force observer is designed, regarding the ball-screw-driven system as two input and three output system. Simulation results indicate that the proposed method enables accurate estimation around the resonance frequencies. Experimental results showed that the proposed method could monitor external force without being interrupted by the inertia forces.

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Temperature and shear rate characteristics of electrorheological gel applied to a clutch

K. Koyanagi; Y. Takata; Y. Kakinuma; H. Anzai; K. Sakurai; T. Motoyoshi; T. Oshima

Journal of Physics: Conference Series (IOP PUBLISHING LTD) 412 ( 1 ) 827 - 836 2013

Research paper (scientific journal), ISSN 1742-6588

This investigation reports the physical characteristics of electrorheological (ER) gels, which are a type of functional material having controlled surface friction. We previously developed slip clutches using ER gels sandwiched between electrodes, and verified their responses and controllability. We newly report the temperature and shear rate characteristics of ER gel in this study because the input and output electrodes of the clutch continuously slip past each other. While the temperature of ER gels increased when energized, the shear stress hardly changed. Instead, wearing and adaptation to the electrode affect the property. The shear rate hardly affected the shear stress in the high-shear-rate region. Conversely, the shear stress depended on the shear rate in the lower region.

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Development of 5-axis polishing machine capable of simultaneous trajectory, posture, and force control

Kakinuma, Yasuhiro, Igarashi, Keisuke, Katsura, Seiichiro, Aoyama, Tojiro

CIRP ANNALS-MANUFACTURING TECHNOLOGY (ELSEVIER SCIENCE BV) 62 ( 1 ) 379 - 382 2013

Research paper (scientific journal), ISSN 0007-8506

The buffing process for finishing an automobile's body is still done manually, and the final surface quality of the body depends on the skill and technique of the worker. To automate buffing, not only tool path control but also precise and fast force control is required. In this study, a novel methodology based on the sensor-less force control technique and the quarry matrix capable of the mode decoupling is proposed for a parallel mechanism polishing machine to control x-y trajectory, tool posture, and polishing force in z-direction, and its validity for automated buffing is verified. (C) 2013 CIRP.

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Ultra-precision cryogenic machining of viscoelastic polymers

Y. Kakinuma, S. Kidani, T. Aoyama

CIRP Annals-Manufacturing Technology (ELSEVIER SCIENCE BV) 61 ( 1 ) 79-82 - 82 2012.08

Research paper (scientific journal), Joint Work, Accepted, ISSN 0007-8506

Microfluidic chips with micro- or nanoscale channels are currently in great demand. PDMS (polydimethylsiloxane), a viscoelastic polymer, has high transparency and good chemical stability, making it a suitable substrate material for such chips. However, it is difficult to machine PDMS by conventional cutting processes because of its high elasticity and adhesion. We proposed the cryogenic micromachining of PDMS completely immersed in liquid nitrogen as a direct process to fabricate customized 3D nano/microfluidic chips precisely. In this study, the feasibility of ultra-precision cryogenic machining is studied as an extended nanofabrication process. (C) 2012 CIRP.

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センサレス研磨圧制御法を用いた低弾性樹脂材のバフ研磨特性解析

五十嵐恵介, 柿沼康弘

砥粒加工学会誌 56 ( 12 ) 835-840 2012

Research paper (scientific journal), Joint Work, Accepted

Three-dimensional measurement of gas dissolution process in gas–liquid microchannel ﬂow

M. Ichiyanagi, I. Tsutsui, Y. Kakinuma, Y. Sato, K. Hishida

International Journal of Heat and Mass Transfer (PERGAMON-ELSEVIER SCIENCE LTD) 55 ( 11-12 ) 2872-2878 - 2878 2012

Research paper (scientific journal), Joint Work, Accepted, ISSN 0017-9310

The three-dimensional CO2 dissolution process through a gas-liquid interface in microfluidic devices was investigated experimentally, for the precise control of CO2 dissolution. The gas dissolution was evaluated by using confocal micron-resolution particle image velocimetry (micro-Ply) combined with laser induced fluorescence (LIF), which has the ability to measure the velocity and dissolved CO2 concentration distribution in a liquid flow field. The measurement system is based on the confocal microscope, which has excellent depth resolution and enables visualization of the three-dimensional distributions of velocity and dissolved CO2 concentration by rendering two-dimensional data. The device is comprised of a polydimethylsiloxane chip, whose microchannels were fabricated by using a cryogenic micromachining system. The width and depth of the liquid flow channel are larger than those of the gas flow channel. This is due to the need for decreasing the width of the gas-liquid interface and increasing the hydraulic diameter of the liquid channel, whose conditions generate a static gas-liquid interface. The experiments were performed for three different liquid flow conditions corresponding to Reynolds numbers of 1.0 x 10(-2), 1.2 x 10(-2) and 1.7 x 10(-2), and the gas flow rate was set to be constant at 150 mu L/min. The LIF measurements indicate that an increase in the Reynolds number yields a decrease in dissolved gas in the spanwise directions. Furthermore, molar fluxes by convection and diffusion were evaluated from the experimental data. The molar fluxes in the streamwise direction were at least 20 times as large as those in the spanwise and depthwise directions. This reveals that an increase in momentum transport in the spanwise and depthwise directions is an important factor for enhancing mass transfer in the gas-liquid microchannel flow. (C) 2012 Elsevier Ltd. All rights reserved.

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Evaluation methodology of gas permeable characterization in a polymer-based microfluidic device by confocal fluorescence imaging

M. Ichiyanagi, K. Sakai, S. Kidani, Y. Kakinuma, Y. Sato, K. Hishida

Journal of Micromechanics and Microengineering (IOP PUBLISHING LTD) 22 ( 6 ) 065023 2012

Research paper (scientific journal), Joint Work, Accepted, ISSN 0960-1317

The evaluation technique of gas permeable characterization has been developed for an increased efficiency of gas-liquid chemical reactions and high accuracy of environmental diagnosis. This technique enables us to measure spatial distributions of velocity and dissolved gas concentration by utilizing confocal micron-resolution particle image velocimetry combined with a laser-induced fluorescence technique. Microfluidic devices with gas permeability through polymer membranes are composed of a cover glass and a polydimethylsiloxane (PDMS) chip with the ability to permeate various gases, since PDMS is an elastomeric material. In the chip, microchannels are manufactured using a cryogenic micromachining system. The gas permeation is dominated by several factors, such as the gas and liquid flow rates, the membrane thickness between the gas and liquid flow, and the surface area of the membranes. The advantage of the present device is to realize the control of gas permeability by changing the surface roughness of PDMS, because the cryogenic micromachining enables us to control the surface roughness of microchannels and an increase in roughness yields an increase in the surface area of membranes. The experiments were performed under several conditions with a change in the gas flow rate, the PDMS membrane thickness and the surface roughness, which affect the gas permeation phenomena. The spatial distributions of velocity and dissolved gas concentration were measured in the liquid flow fields. The results indicate that the velocity-vector distributions have similar patterns under all experimental conditions, while the dissolved gas concentration distributions have different patterns. It was observed that the gas permeability through PDMS membranes increased with an increase in gas flow rates and surface roughness and with a decrease in membrane thicknesses, which is in qualitative agreement with membrane theory. The important conclusion is that the proposed technique is suggested to have the possibility of evaluating the characterization of gas permeable microfluidic device through membranes.

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Basic Performance Evaluation of Electro-adhesive Film with Micro Mesh Sheet

T. Kubo, Y. Kakinuma

Key Engineering Materials (TRANS TECH PUBLICATIONS LTD) 516 222-227 - 227 2012

Research paper (scientific journal), Joint Work, Accepted, ISSN 1013-9826

Smart materials have been developed in many leading technologies. Smart material is a material that gives a specific reaction to the change and stimulus of the external environment such as light, heat and electromagnetic fields. Electro-rheological Gel (ERG) is one smart material. ERG changes its surface adhesive properties rapidly according to the intensity of the applied electrical field. This unique property is named Electro-adhesive effect (EA effect). In this research, as a novel electro-adhesive film which is replaced with ERG, Electro-adhesive film with micro mesh sheets is developed and named EAMS. Furthermore, it is proved that the developed film using the mesh sheet produces the EA effect and that the performance of EAMS is enhanced according to the increase of the open space and the number of layers.

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Real-Time Cutting Force/Torque Prediction During Turning

K. Enomoto, M. Takei, Y. Kakinuma

International Journal of Automation Technology (Fuji Technology Press) 6 ( 5 ) 669-674 - 674 2012

Research paper (scientific journal), Joint Work, Accepted, ISSN 1883-8022

The automation of machining processes requireshighly accurate process monitoring. However, the use of additional sensors leads to a significant increase in the cost and reduces the stiffness and reliability of mechanical systems. Hence, we propose a system called the cutting force observer, which uses a sensor-less and real-time cutting force estimation methodology based on the disturbance observer theory. Monitoring methods using the cutting force observer may enhance the productivity during turning. One of the parameters that significantly affect the cutting process is the shear angle. The determination of the shear angle is very important as it can be used for identifying the machining conditions. In this study, an external sensor-less monitoring system of the shear angle during turning is developed, and its performance is evaluated.

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Development of an intelligent stage with sensor-less cutting force and torque monitoring function

T. Kamigochi, Y. Kakinuma

International Journal of Automation Technology (Fuji Technology Press) 6 ( 6 ) 736-741 - 741 2012

Research paper (scientific journal), Joint Work, Accepted, ISSN 1883-8022

Intelligent machine tool is required to implement highprecision process monitoring for judging the abnormal tool conditions. Various techniques have been widely researched and studied to maintain machine tool in good condition and to detect tool wear. The occurrence of tool wear can be detected by monitoring the cutting torque, which is basic information for machining. The purpose of this study was to propose a sensor-less cutting force and torque monitoring method and to develop an intelligent stage using this method.

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Sensor-less Tool Fracture Detection Applying Disturbance Observer Theory

R. Koike, Y. Kakinuma, T.Aoyama

Key Engineering Materials (TRANSACTION PUBLISHERS) 523 439-444 - 444 2012

Research paper (scientific journal), Joint Work, Accepted, ISSN 1013-9826

Detection of a tool fracture is necessary to ensure cutting accuracy and to avoid a tool breakage because tool fracture is one of the significant prediction signals of the tool breakage. For monitoring the tool condition, generally additional sensors are used. However using these sensors causes high cost and increase of failure rate. In this paper, a novel sensor-less detection method of tool fracture in drilling process is proposed on the basis of a disturbance observer theory. It is applied to the x-y stage of the machine tool. The proposed method requires no external sensor because it uses only the servo information of the spindle control system. Since structures of normal drills with two floats are symmetrical with respect to a point, theoretically the cutting force in the x and y directions does not work. When the drill is fractured, its structure becomes asymmetry so that unbalanced forces would exert in the x and y directions at intervals of the spindle speed. Therefore, it is possible to detect a tool fracture by the frequency analysis of estimated disturbance force with a wavelet transform. The experimental results show that the proposed method is available for detection of the small tool fracture effectively.

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低弾性樹脂材料の研磨表面評価

久保貴生，柿沼康弘

砥粒加工学会誌 55 ( 9 ) 546-551 2011

Research paper (scientific journal), Joint Work, Accepted

Basic Study on Nanofabrication of Biodegradable Plastics applying Biochemical Machining

S. Ikeda, Y. Kakinuma

Precision Engineering (ELSEVIER SCIENCE INC) 35 ( 3 ) 440-446 - 446 2011

Research paper (scientific journal), Joint Work, Accepted, ISSN 0141-6359

Plastics are regarded as proper materials for microfluidic chips, and, in particular, biodegradable plastics will be more appropriate from the viewpoint of environmental friendliness. In addition, when they are utilized as chip substrate, biochemical machining can be applied. Biochemical machining is a process, which utilizes enzymatic biodegradation. This paper describes studies on application of biochemical machining to nanofabrication of poly(L-lactic acid) (PLLA), which is one of the most widely used biodegradable plastics industrially. The degradation performance of enzyme (proteinase K) was experimentally evaluated to extrapolate a suitable condition for nanofabrication. Additionally, in order to make arbitrary channels with nano-order depth on PLLA, mask fabrication was proposed. It is a fabrication method to control degraded regions and obtain desired shapes with a mask, which has penetrating grooves. Using this method, we achieved fabrication of straight grooves with nano-scale depth. In conclusion, it is clear that biochemical machining can realize an effective process of arbitrarily shaped nanogrooves on PLLA. (C) 2011 Elsevier Inc. All rights reserved.

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Hybrid Control for Machine Tool Table Applying Sensor-less Cutting Force Monitoring

M. Takei, D. Kurihara, S. Katsura, Y. Kakinuma

International Journal of Automation Technology (Fuji Technology Press) 5 ( 4 ) 587-593 - 593 2011

Research paper (scientific journal), Joint Work, Accepted, ISSN 1883-8022

Accurate monitoring and adaptive control to maintain optimum machining conditions are required for intelligent machine tools. Methods using additional sensors have been studied to add these functions to machine tools
however, incorporating additional sensors leads to higher production costs and reductions in mechanical stiffness. In the present study, a sensorless method of monitoring cutting force that utilizes the current signal and the second-order derivative of position is developed. Moreover, applying sensorless cutting force monitoring, a hybrid control method is proposed in which the sensorless monitoring is used to simultaneously control both the position trajectory and cutting force in the feed direction.

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Detection of Chatter Vibration in End Milling applying Disturbance Observer

Y. Kakinuma, Y. Sudo, T. Aoyama

CIRP Annals-Manufacturing Technology (ELSEVIER SCIENCE BV) 60 ( 1 ) 109-112 - 112 2011

Research paper (scientific journal), Joint Work, Accepted, ISSN 0007-8506

Suppression of chatter vibration is required to improve the machined surface quality and enhance tool life. For monitoring the chatter vibrations, additional sensors such as acceleration sensors are generally used, which results in high costs and low reliability of the machine tools. In this study, a novel in-process method to detect chatter vibrations in end milling is developed on the basis of a disturbance observer theory. The developed system does not require any external sensors because it uses only the servo information of the spindle control system. Self-excited and forced chatter vibrations are successfully detected. (C) 2011 CIRP.

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Buffing Performance Analysis of Viscoelastic Polymer with Sensor-less Polishing Pressure Control

K. Igarashi, M. Sato, Y. Kakinuma

Advanced Materials Research (TRANS TECH PUBLICATIONS LTD) 325 482-488 - 488 2011

Research paper (scientific journal), Joint Work, Accepted, ISSN 1022-6680

Viscoelastic polymer with high scratch resistance has been developed for coating material of product. Due to some particular characteristics such as viscoelasticity, it is difficult to finish the polymer coated surface. In the present circumstances, its polishing process is carried out by the trained technician and depends on the skill like adjustment of the polishing pressure according to the situation. To realize automation of the polishing, high-precision and highly-responsive force control is required firstly. Typically force control is done with force sensor. However when external sensor is used, there are some problems such as high-cost, reduction of machine stiffness and thermal drift. The thermal drift which is caused by polishing heat prohibits accurate measuring of force. The purpose of this research is to develop the polishing pressure control method without any additional sensor. In addition, applying the control method to buffing machine, buffing performance of viscoelastic polymer is experimentally analyzed.

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Stabilizing Output of an Electrorheological Gel Linear Actuator

K. Koyanagi, Y. Kakinuma, H.Anzai, K. Sakurai, T. Oshima

Journal of Intelligent Material Systems and Structures (SAGE PUBLICATIONS LTD) 22 ( 15 ) 1685-1692 - 1692 2011

Research paper (scientific journal), Joint Work, Accepted, ISSN 1045-389X

ER gel is a relatively new type of functional material. The surface of ER gel has a shear stress characteristic, which increases according to the applied electric field. Introducing the gel into interface elements of a force transmission system realizes functional clutches and brakes. This study aims to develop a linear actuator that is safe, can operate in reverse, and can generate a large force using such a functional clutch. Applying an ER gel clutch in a force transmission system decreases inertia and the mechanical limits of the maximum speed while not limiting controllability. Such properties contribute to a high level of safety. This article reports, in particular, on stabilizing the output of the linear actuator.

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Basic Performance Evaluation of ER gel in vacuum Condition

Y. Shida, Y.Kakinuma, T. Aoyama, H. Minami, H. Anzai

Journal of Intelligent Material Systems and Structures (SAGE PUBLICATIONS LTD) 22 ( 15 ) 1699-1706 - 1705 2011

Research paper (scientific journal), Joint Work, Accepted, ISSN 1045-389X

ER gel exhibits various adhesive characteristics according to the applied electric field. This characteristic is called the EA effect. The results of a recent study reveal that the EA effect also occurs in a vacuum. Therefore, it is expected that ER gel can be applied to a chucking or damping device in a vacuum process. However, the characteristics of ER gel in a vacuum have not been sufficiently clarified. The purpose of this study is to experimentally evaluate the characteristic of ER gel in a vacuum. The performance of an ERG fixture element used for a silicon wafer in a vacuum is evaluated through shearing tests. The experimental results indicate that the ER gel demonstrates satisfactory performance in a vacuum. Moreover, the outgas released from the ER gel in a vacuum is evaluated, and the influence of the degassing time on the outgas is investigated.

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Development of Tactile Display Device using ERG Multiple-Disk Clutch

Y. Urakami, T. Aoyama, H. Anzai, Y. Kakinuma

Journal of Intelligent Material Systems and Structures (SAGE PUBLICATIONS LTD) 22 ( 15 ) 1693-1698 - 1698 2011

Research paper (scientific journal), Joint Work, Accepted, ISSN 1045-389X

Nowadays, due to the widespread use of rehabilitation and virtual reality technology, tactile display systems have attracted the attention of researchers from the medical and amusement fields. A clutch mechanism that employs ER and MR fluids is appropriate for force transmission in a tactile display device, because the ER and MR effects are passive and safe for the operator compared with an active actuator using motor. The developed ERG produces approximately 20 times higher shear forces than ER fluid and exhibits stable performance. In this research, an ERG multiple-disk clutch is fabricated and applied to a tactile display system. The experimental results of the control test indicate that the tactile display system with the proposed control method can exhibit the 'sense of touch' of various viscous fluids.

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エンドミル加工における外乱オブザーバを用いたセンサレスびびり振動検出技術の開発（第１報）

周藤唯, 柿沼康弘, 大西公平, 青山藤詞郎

精密工学会誌 77 ( 7 ) 707-712 2011

Research paper (scientific journal), Joint Work, Accepted

材料パラメータの異なるERゲルの性能評価

内藤洋介, 柿沼康弘, 青山藤詞郎, 安齊秀伸

日本機械学科誌C2編 77 ( 782 ) 308-318 2011

Research paper (scientific journal), Joint Work, Accepted

Electrorheological Gel Linear Actuator for Human-Coexistence Robots

K. Koyanagi, Y. Kakinuma, H. Anzai, T. Yamaguchi,

Advanced Robotics,The International Journal of the Robotics Society of Japan (TAYLOR & FRANCIS LTD) 24 ( 14 ) 1963-1981 - 1981 2010

Research paper (scientific journal), Single Work, ISSN 0169-1864

Robots manipulated by humans are being aggressively researched and developed. Such robots have requirements such as a large generative force, high-speed response, good controllability, high safety, low friction and backdriveability. We focused on backdriveability and created a prototype for a novel linear actuator with a new structure that includes an electrorheological (ER) gel, which is a recently designed functional material. The device is an all-purpose actuator that satisfies the demands for application in a human-coexistence welfare robot, such as power-assist systems. This paper presents the original plan for the linear actuator, shows the actuator as currently manufactured and presents the basic characteristics of the actuator as investigated experimentally. We obtained larger force from the linear actuator than the initial target. Additionally, the linear actuator shows possibilities of further improvement of the force-weight ratio by an increase of the ER gel structures. With regard to stabilizing the response of the linear actuator, spring elements contributed to its improvement. However, further stabilization remains as a future issue for practical use in human-coexistence robots. (C) Koninklijke Brill NV, Leiden and The Robotics Society of Japan, 2010

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Evaluation of Polished Surface for Viscoelastic Polymer

T. Kubo, S. Ota, M. Oda, K. Hashishita, Y. Kakinuma,

Advanced Materials Research (TRANS TECH PUBLICATIONS LTD) 126-128 493-498 - + 2010

Research paper (scientific journal), Single Work, ISSN 1022-6680

Viscoelastic polymers are used as one of coating materials for protecting the products from scratches. Presently, the repair of the coating surface for removing dust or extraneous matters has been performed through several polishing processes. However, it becomes increasingly difficult to polish its surface by only applying good skill and experience of skilled worker because a leading-edge viscoelastic polymer for coating is further scratch-resistant. Thus, based on quantitative evaluation of relation between polishing process and finished surface, it is necessary to make the polishing process appropriate for the leading-edge viscoelastic polymers. In this study, we attempt to establish the evaluation method of the polished surface and clarify the surface condition with invisible scratches.

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Development of Multiple-disk Brake Element Using Electro-rheological Gel

Y. Kakinuma, H. Tanaka, T. Aoyama

International Journal of Applied Electromagnetics and　Mechanics (IOS PRESS) 33 ( 3-4 ) 1677-1683 - 1683 2010

Research paper (scientific journal), Single Work, ISSN 1383-5416

Electro-rheological gel (ERG) is a functional elastomer, which changes its surface adhesive property according to the intensity of electric field. In this study, ERG is applied to multiple-disk brake element to realize both simplification of structure and wide range of controlled brake torque. First, static performance of ERG multiple-disk brake (ERG-MDB) is evaluated experimentally. It is clear that a generated brake torque depends on an electric field and the number of layer of ERG. ERG-MDB with 6 layers shows 5 times brake torque as high as that with 1 layer. Second, considering the dynamical model of the ERG-MDB, dynamic performance is investigated through the forced vibration test. The result shows that dynamic damping and stiffness coefficients are changed widely according to applied electric field.

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Cutting Force Control using Sensor-less Cutting force Monitoring Method

D. Kurihara, Y. Kakinuma, S. Katsura,

Journal of Advanced Mechanical Design, Systems, and Manufacturing 5 ( 4 ) 955-965 2010

Research paper (scientific journal), Single Work

Pre-Deformation-assisted Cryogenic Micromachining for Fabrication of Three-dimensional Unique Micro Channels

K. Mishima, Y. Kakinuma, T. Aoyama

Journal of Advanced Mechanical Design, Systems, and Manufacturing (JAPAN SOC MECHANICAL ENGINEERS) 5 ( 4 ) 936-947 - 947 2010

Research paper (scientific journal), Single Work, ISSN 1881-3054

Polydimethylsiloxane (PDMS) is difficult to machine by conventional cutting process because of its low elasticity and high adhesion. We proposed the cryogenic micromachining method assisted by liquid nitrogen cooling for direct fabrication of 3D micro channels on PDMS substrate in short time. In this paper, the cryogenic cutting mechanism is clarified through some verification experiments. Moreover, Pre-Deformation-assisted Cryogenic Micromachining (PDCM) method is also proposed for fabricating the unique shapes of channels and its validity is evaluated experimentally. The results of cutting tests show that 3D unique micro channels can be processed precisely and rapidly on PDMS.

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Development of High-performance ER Gel based on the Principle of Electro-adhesive Effect

Y. Kakinuma, T. Aoyama, H. Anzai

Journal of Intelligent Material Systems and Structures (SAGE PUBLICATIONS LTD) 21 ( 15 ) 1501-1508 - 1508 2010

Research paper (scientific journal), Single Work, ISSN 1045-389X

Electrorheological gel (ERG) is a novel functional elastomer, which has frictional and adhesive surface properties that vary according to the intensity of an applied electric field. This peculiar phenomenon is referred to as the electro-adhesive (EA) effect. The shear stress of ERG generated under an applied electric field is approximately 30-40 times higher than that of electrorheological fluids (ERF), due to its high adhesive strength. However, the generated EA effect of ERGs varies widely due to surface conditions, especially the density and distribution of ER particles at the surface. In order to stabilize and improve the performance of ERG, the electrical field-assisted molding process is proposed as a production method. In this process, the mixture solution including ERFs and gel agent is gelling under electric field. The principle of the EA effect is theoretically investigated and a high-performance ERG produced by the proposed process, in which ER particles are aligned densely at the surface, is developed and the performance is experimentally evaluated by surface observation and shear test, revealing a highly dense arrangement of ER particle at its surface and a higher shear stress twice that of conventional ERG.

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解説電気粘性(ER)ゲルの開発とその応用

柿沼康弘, 青山藤詞郎

トライボロジスト 54 ( 10 ) 677-682 2009

Research paper (scientific journal), Joint Work, Accepted

Development of High-performance ER Gel Produced by Electric-field assisted Molding

Y. Kakinuma, T. Aoyama, H. Anzai

Journal of Physics: Conference Series (Institute of Physics Publishing) 012013 2009

Research paper (scientific journal), Joint Work, Accepted, ISSN 1742-6596

Electro-rheological gel (ERG) is a novel functional elastomer whose surface frictional and adhesive property varies according to the intensity of applied electric field. This peculiar phenomenon is named as Electro-adhesive effect. A generated shear stress of ERG under applied electric field is approximately 30∼40 times higher than that of ERF because of high adhesive strength. However, the performances of ERG vary widely due to its surface condition, especially density and distribution of ER particles at the surface. In order to stabilize and improve the performance of ERG, the electric- filed assisted molding process is proposed as the producing method of ERG. In this study, first, the principle of electro-adhesive effect is theoretically investigated. Second, a high-performance ERG produced by the proposed process, in which ER particles are aligned densely at the surface, is developed and its performance is evaluated experimentally. As the experimental result, the high-performance ERG shows twice higher shear stress than the conventional ERG. © 2009 IOP Publishing Ltd.

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A Study on Fixing Force Generation Mechanism of ER Gel

H. Tanaka, Y. Kakinuma, T. Aoyama, H. Anzai

Journal of Physics: Conference Series 01029 2009

Research paper (scientific journal), Joint Work, Accepted

Basic Research of Novel Linear Actuator with Electro-Rheological Gel Drum

T. Yamaguchi, K. Koyanagi, Y. Kakinuma, H. Anzai, K. Sakurai, and T.Oshima

Journal of Physics: Conference Series 012020 2009

Research paper (scientific journal), Joint Work, Accepted

Electric Field-Assisted Glass Polishing Using Electro-Rheological Gel Pad

Y. Kakinuma, S. Takezawa, T. Aoyama, K. Tanaka and H. Anzai

Journal of Advanced Material Research (TRANS TECH PUBLICATIONS LTD) 76-78 319-324 - + 2009

Research paper (scientific journal), Joint Work, Accepted, ISSN 1022-6680

A polishing process, which is the final process in manufacturing optical elements, takes a long time and often depends on the experience and special skills. Development of a skill-less polishing technology and automation of its process, therefore, has been required. One of the most promising polishing technologies is Field-assisted Fine Finishing (FFF). In this study, an Electro-rheological Gel (ERG) polishing pad with one-sided patterned electrodes is developed to polish insulator materials and, moreover, a novel electric-field-assisted polishing technology for glass polishing is proposed applying this pad. The ERG polishing pad can change the polishing performance according to applied electric field due to "electro-adhesion effect". Results of several polishing tests show that the performance of polishing a blue glass can be controlled by applying electric field to the ERG pad.

電気粘着クラッチと力覚提示への応用

柿沼康弘, 渡邊拡昭, 青山藤詞郎, 安齊秀伸

日本機械学会論文集C編 75 ( 755 ) 2009

Research paper (scientific journal), Joint Work, Accepted

Sensorless Cutting Force Monitoring using Parallel Disturbance Observer

D. Kurihara, Y. Kakinuma, S. Katsura

International Journal of Automation Technology 3 ( 4 ) 415-421 - 415 2009

Research paper (scientific journal), Joint Work, Accepted

Numerical and Experimental Analysis of Transient State Micro-bounce of Aerostatic Guideways Caused by Small Pores

T. Aoyama, K. Koizumi, Y. Kakinuma, Y. Kobayashi

CIRP Annals-Manufacturing Technology (TECHNISCHE RUNDSCHAU EDITION COLIBRI LTD) 58 ( 1 ) 367-370 - 370 2009

Research paper (scientific journal), Joint Work, Accepted, ISSN 0007-8506

Aerostatic guideways have been applied to precision machine elements. Recently, downsizing and the increased use of high-density technology in IT devices have generated demand for higher accuracy in aerostatic guideways. It has been pointed out that the micro-bounce occurs when the slider passes over the aerostatic guideway with small pores. This transient state micro-vibration decreases the accuracy of aerostatic guideways and, thus, it is now expected to be suppressed. The purpose of this study is to analyze the micro-bounce mechanism of aerostatic guideways caused by pores, and to propose new designs for the suppression of micro-bounce. (C) 2009 CIRP.

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展望　平成19年度の機能性流体分野の研究動向

青山藤詞郎，柿沼康弘

フルードパワーシステム学会誌緑陰特集号 39 ( E1 ) E19-E23 2008

Research paper (scientific journal), Joint Work, Accepted

Virtual Motor Control for the Machine Tools Table with 3 Linear Servo Motors

K.Umezawa, Y. Kakinuma, S. Katsura, K. Ohnishi, T. Aoyama, K. Yokoi

Journal of Advanced Mechanical Design, Systems, and Manufacturing 2 ( 4 ) 482-492 2008

Research paper (scientific journal), Joint Work, Accepted

Micro machining of Soft Polymer Material applying the Cryogenic Cooling

Y. Kakinuma, N. Yasuda, T. Aoyama

Journal of Advanced Mechanical Design, Systems, and Manufacturing (JAPAN SOC MECHANICAL ENGINEERS) 2 ( 4 ) 560-569 - 569 2008

Research paper (scientific journal), Joint Work, Accepted, ISSN 1881-3054

Polydimethylsiloxane (PDMS) is one of the important materials for microfluidic chips. The pattern of micro channels on the PDMS plate is usually fabricated through the photolithography and micro molding process. However, the photolithographic method requires multi chemical and mechanical processes and resultant long process time. The micro milling process is a feasible method for rapid fabrication of various patterns of micro channels. However, micromachining has not yet been applied to soft polymer materials. It is difficult to machine elastic materials such as PDMS because of their low toughness. In order to machine a micro grooves on soft polymer materials, the cutting process applying cryogenic cooling is proposed because the elastic properties of soft polymer materials remarkably change from rubbery state to glassy state below the glass transition temperature. In this study, the freezing milling method using liquid nitrogen is applied to the micro grooving of PDMS. The result of a cutting test shows that micro grooves can be shaped easily and machined accurately in PDMS by the proposed method.

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Development of Fixture element for Vacuum Transportation of Silicon Wafer using Electrorheological Gel

M. Tanaka, Y. Kakinuma, T. Aoayama, H.Anzai

Journal of Advanced Mechanical Design, Systems, and Manufacturing (JAPAN SOC MECHANICAL ENGINEERS) 2 ( 4 ) 762-772 - 772 2008

Research paper (scientific journal), Joint Work, ISSN 1881-3054

Semiconductor process technology increasingly requires high accuracy and efficiency. In the case of processing thin fragile substrate such as silicon wafer, it has to be fixed with low strain. In addition, its fixture device can be used under vacuum condition because some processes are carried out in vacuum. It is required to develop a new fixture device for vacuum transportation of silicon wafer. ERG is the functional material whose friction characteristic varies according to the intensity of applied electric field. The surface friction of ERG can be changed quickly and reversibly applying the electric field. In other words, it becomes easy to fix and release a substrate by control of electric field. In this study, ERG is applied to a fixture element of silicon wafer available for vacuum process. The ERG fixture element was trial-manufactured and its performance under vacuum condition was evaluated experimentally. The result shows that the ERG effect emerges in vacuum and ERG can fix silicon wafer sufficiently. Moreover, numerical analysis of electric filed was carried out to obtain the optimal pattern of the one-sided electrodes used for the ERG fixture element. It is clear that the optimal width of electrodes exists according to the gap of electrodes and the thickness of ERG.

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Development of A New Fluid Supply System for Near Dry Machining Process

M. Yamashita, Y. Kakinuma, T. Aoyama, M. Aoki

Key Engineering Materials (TRANS TECH PUBLICATIONS LTD) 389-390 175-180 - + 2008

Research paper (scientific journal), Joint Work, Accepted, ISSN 1013-9826

Large amount of cutting oil consumption is one of the issues for environment. The Minimum Quantity Lubrication (MQL) technique has been applied to the near-dry cutting process. However, MQL technique generates oil mist which is harmful to the working environment and the health of factory workers. In this study, a new lubrication system called Direct Oil Shot Lubrication System (DOS) was developed and applied to milling processes. The performances of DOS technique was evaluated by measuring the floating oil mist and carrying out the cutting tests. The amount of floating oil mist of DOS system was considerably reduced compared to the MQL. The behavior of small oil drops supplied from DOS nozzle to cutting edge was analyzed by means of a high speed video observation, and the optimum setting for DOS was obtained. The experimental result shows developed DOS system realized the smaller density of oil mist floating than the MQL technique while the DOS attained the almost same lubrication effect in milling process as the MQL technique.

ERゲルを用いた電場援用研磨法の開発

柿沼康弘, 竹澤慎吾, 青山藤詞郎, 田中克敏, 相良誠, 安齊秀伸

砥粒加工学会誌 52 ( 12 ) 712-717 2008

Research paper (scientific journal), Joint Work, Accepted

Development of the Variable Friction Clutch Applying the Functional Medium

Y. Kakinuma, T. Aoyama, H. Anzai

Journal of Mechanical Engineering (ASSOC MECHANICAL ENGINEERS TECHNICIANS SLOVENIA) 53 ( 11/07 ) 755-770 - 770 2007

Research paper (scientific journal), Single Work, Accepted, ISSN 0039-2480

A new functional material known as electro-rheological gel (ERG) that shows variable surface friction according to an applied electric field has been developed. It was expected that ERG could be applied to a machine element to transfer force such as a clutch, because the frictional force of an ERG surface can be controlled electrically. The one-sided patterned electrodes, which arrange anode and cathode alternately on the insulating base, are proposed in a recent study of electro-rheological fluid (ERF) to simplify the structure of the wiring. In this study, one-sided patterned electrodes are applied to an ERG, and the influence of the pattern of the one-sided electrode on the ERG effect is numerically and experimentally investigated. Based on the results of the electrode pattern evaluation, an ERG clutch element, using the one-sided electrodes with an optimum electrode pattern, is developed and the performance of the ERG clutch is experimentally evaluated. The ERG clutch shows excellent performance for static and dynamic characteristics in torque transfer, and an ERG clutch unit shows excellent performance for torque transfer The transferred torque changes widely and smoothly in response to the variation of the applied electric field. (c) 2007 Journal of Mechanical Engineering. All rights reserved.

Application of the Electro-rheological Gel to Fixture Devices for Micro Milling Processes

KAKINUMA YASUHIRO

Journal of Advanced Mechanical Design, Systems, and Manufacturing of JSME (JAPAN SOC MECHANICAL ENGINEERS) 1 ( 3 ) 387-398 - 398 2007

Research paper (scientific journal), Joint Work, Accepted, ISSN 1881-3054

Electro-rheological gel (ERG) is a new functional material whose surface friction and adhesive properties vary according to the intensity of the applied electric field. In a recent study, one-sided patterned electrodes were applied to the ERG and the change in surface frictional and adhesive property under the electric field, which is called the ERG effect, was experimentally confirmed. The ERG with one-sided patterned electrodes is considered to be suitable for application to a fixture device for micro milling. In this study, a prototype of the ERG fixture device was developed and its performance was experimentally investigated. The proposed ERG fixture devices can be useful for fixturing both metallic and nonmetallic workpieces, such as glass. Micro shrinkage of the ERG occurs in proportion to the voltage applied to the ERG material. Using this characteristic, the alignment of the workpiece can be also adjusted. The developed ERG fixture device was applied to the micro grooving process of a thin glass workpiece, and successful results were obtained.

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工作機械用テーブルの仮想モータ制御

KAKINUMA YASUHIRO

精密工学会誌 73 ( 1 ) 150-155 2007

Research paper (scientific journal), Joint Work, Accepted

ERゲルに対する片側構造電極の適用とその性能評価（第二報）

KAKINUMA YASUHIRO

精密工学会誌 73 ( 7 ) 792-797 2007

Research paper (scientific journal), Joint Work, Accepted

ERゲルを適用した力伝達素子における片側電極の最適設計

KAKINUMA YASUHIRO

日本機械学会論文集 73 ( 733 ) 192-199 2007

Research paper (scientific journal), Joint Work, Accepted

The influences of the material and geometrical properties of sliding plate on ER effect of Gel-structured ERF

7. S. Saito, Y. Kakinuma, T. Aoyama, K. Tanaka, H. Anzai

International Journal of Modern Physics B (WORLD SCIENTIFIC PUBL CO PTE LTD) 21 ( 28/29 ) 4751-4757 - 4757 2007

Research paper (scientific journal), Single Work, Accepted, ISSN 0217-9792

Electro-rheological Fluid (ERF) is the functional fluid that can change its viscoelastic property by applying electric field. However, ERF shows the sedimentation of the ER particles in long time use, and it caused the unstable ER effect. The Gel-structured ERF (ERG) has been developed to solve this problem. When a metallic flat plate is placed on the ERG sheet, ERG shows the high shear force due to the occurrence of the contact between the gel and the plate in response to the applying electric field (ERG effect). ERG effect can be obtained not only for metallic materials but also non-metallic materials by applying the one-sided electrode, and the ER effect is supposed to be considerably influenced by the material and geometrical properties of flat plate on the ERG sheet. In this study, the influences of the material and geometrical properties of sliding plate are experimentally analyzed from the viewpoint of the relative permittivity, surface roughness and flatness, and the design instruction for the selection of materials and their geometrical issues are proposed.

Application of ER gel with Variable Friction Surface to the Clamp System of Aerostatic slider

KAKINUMA YASUHIRO

Precision Engineering (ELSEVIER SCIENCE INC) 30 ( 3 ) 280-287 - 287 2006

Research paper (scientific journal), Joint Work, Accepted, ISSN 0141-6359

An electro-rheological fluid (ERF) is a functional fluid whose viscoelastic properties vary according to the intensity of the applied electric field. ERFs are mixtures of nonconductive silicone oil and inorganic/organic composite electro-rheological particles. The properties of ERFs have been exploited to control the performance of machine elements. ERFs have been applied to machine elements such as variable dampers and clutches. However, ERFs have disadvantages, namely the sedimentation of ER particles and the requirement of a seal mechanism. The sedimentation of ER particles reduces the ER effects and results in low stability of ER devices. In order to suppress the sedimentation, and thereby improve the performance of ERF devices, a new functional material called the gel-structured ERF (ERG) is developed, whose basic properties are analyzed in this study. The ER particles are suspended in the gel component, and thus will not precipitate out. This suppresses the decrease in the ER effect caused by precipitation. The ERG developed shows a large shear stress variation in response to the applied electric field. This high performance of ERG originates in a mechanism different from the ER effects of ERF. In order to elucidate the mechanism in ERG, the behavior of ER particles was observed under an electric field. The results show that the contact conditions at the interface between electrode and ERG change rapidly in response to the applied electric field, which result in a variation in shear force. On the basis of the results of a preliminary analysis, ERG was applied to the precision clamp system of an aerostatic slider, and its performance was assessed experimentally. (c) 2005 Elsevier Inc. All rights reserved.

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Basic Properties of Gel-structured Electro-rheological Fluids

KAKINUMA YASUHIRO

International Journal of Modern Physics B (WORLD SCIENTIFIC PUBL CO PTE LTD) 19 ( 7-9 ) 1339-1345 - 1345 2005

Research paper (scientific journal), Joint Work, Accepted, ISSN 0217-9792

Electro-rheological fluids (ERFs) are composed of a functional fluid and colloidal suspension. Their rheological properties vary rapidly and reversibly with the applied electric field intensity. ERFs are mixtures of nonconductive silicone oil and inorganic/organic composite electro-rheological particles. Investigations into the properties of ERFs have led to remarkable advances in their performance in recent years. However, ERFs exhibit an undesirable property that obstructs the long-term use of ERF devices, namely the sedimentation and separation of ER particles from the silicone oil. The sedimentation of ER particles reduces the electro-rheological effect. In order to suppress the sedimentation and thereby improve the performance of ERF devices, a new functional material called Get Structured ERF (ERG) is developed and its basic properties are analyzed in this study. The ER particles are sustained in the gel component, and thus will not precipitate out. This suppresses the decrease in ER effect associated with precipitation. The developed ERG shows large shear stress variation in response to the applied electric field. This high performance of ERGs involves a different mechanism than that observed in ERFs. In order to elucidate the mechanism in ERGs, the behavior of ER particles was observed under an electric field. Conditions at the interface between the electrode and ERG were found to change rapidly in response to the applied electric field, resulting in the variation of shear force.

ERゲルにおけるせん断応力発生のメカニズム

KAKINUMA YASUHIRO

フルードパワーシステム学会誌 36 ( 1 ) 15-21 2005

Research paper (scientific journal), Joint Work, Accepted

ERゲルに対する片側構造電極の適用とその性能評価(第一報)

KAKINUMA YASUHIRO

精密工学会誌 71 ( 12 ) 1607-1612 2005

Research paper (scientific journal), Joint Work, Accepted

ゲル構造電気粘性流体の開発とその基本特性

KAKINUMA YASUHIRO

精密工学会誌 70 ( 12 ) 1538-1543 2004

Research paper (scientific journal), Joint Work, Accepted

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