Pub Date : 2024-01-05DOI: 10.20965/ijat.2024.p0104
Jun Ito, Shin Usuki
This research paper introduces a novel methodology for optimizing pressure dispersion in interactive bed systems, aiming to enhance sleep comfort while considering variegated body shapes and sleeping positions. By controlling the spring constant with precision, which is further optimized by a secondary differential filter, the proposed methodology assures ideal pressure distribution across the bed surface. At the heart of the proposed methodology lies the design of an interactive bed system that effectively responds to the unconscious postural shifts of the user during sleep. The implementation of a secondary differential filter in modulating the spring constant is an integral part of this approach, facilitating the crafting of a responsive bedding surface that promptly adapts to pressure alterations. The effectiveness of this novel method is verified through finite element method (FEM) analysis, which confirms successful pressure dispersion across the bed surface, an essential factor in enhancing sleep comfort. The research also proposes potential enhancements to this methodology, such as incorporating air-pressure control mechanisms, thereby introducing additional pressure control axes akin to those present in existing technologies. This study represents a significant stride forward in the advancement of interactive bed systems by presenting a new method for optimizing pressure dispersion, and hence, enhancing sleep comfort. The employment of FEM analysis not only validates the effectiveness of the proposed methodology but also highlights the potential for the future development of personalized and adaptive bedding solutions.
{"title":"Measurement and Control of Body Pressure Towards Smart Bed System","authors":"Jun Ito, Shin Usuki","doi":"10.20965/ijat.2024.p0104","DOIUrl":"https://doi.org/10.20965/ijat.2024.p0104","url":null,"abstract":"This research paper introduces a novel methodology for optimizing pressure dispersion in interactive bed systems, aiming to enhance sleep comfort while considering variegated body shapes and sleeping positions. By controlling the spring constant with precision, which is further optimized by a secondary differential filter, the proposed methodology assures ideal pressure distribution across the bed surface. At the heart of the proposed methodology lies the design of an interactive bed system that effectively responds to the unconscious postural shifts of the user during sleep. The implementation of a secondary differential filter in modulating the spring constant is an integral part of this approach, facilitating the crafting of a responsive bedding surface that promptly adapts to pressure alterations. The effectiveness of this novel method is verified through finite element method (FEM) analysis, which confirms successful pressure dispersion across the bed surface, an essential factor in enhancing sleep comfort. The research also proposes potential enhancements to this methodology, such as incorporating air-pressure control mechanisms, thereby introducing additional pressure control axes akin to those present in existing technologies. This study represents a significant stride forward in the advancement of interactive bed systems by presenting a new method for optimizing pressure dispersion, and hence, enhancing sleep comfort. The employment of FEM analysis not only validates the effectiveness of the proposed methodology but also highlights the potential for the future development of personalized and adaptive bedding solutions.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"60 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.20965/ijat.2024.p0084
H. Matsukuma, M. Nagaoka, Hisashi Hirose, R. Sato, Y. Shimizu, Wei Gao
In this study, a method for controlling the repetition frequency of a mid-infrared ultrashort pulse laser with a central wavelength of 2.8 µm is developed. A ring cavity that is insensitive to the polarization state of the laser light emitted from the fiber end was constructed to stabilize the oscillation of the mid-infrared ultrashort pulse laser. More oscillation conditions for the ultrashort pulse laser based on nonlinear polarization rotation are found than the conventional method. To confirm that the pulse oscillation is mode-locked, ultrashort pulse oscillation was confirmed by an autocorrelator. The pulse repetition frequency of this robust ultrashort pulse laser was controlled. The control method was based on the phase-locked loop (PLL) control. A wedge window was inserted into the cavity and mounted on a linear stage driven by a piezoelectric transducer. By driving the piezoelectric transducer, the position of the wedge window changed, and the resulting optical path length also changed. The repetition frequency was controlled based on this principle. Optical path length control by the wedge window and temperature control provides an Allan deviation of approximately 1 mHz.
{"title":"Repetition Frequency Control of a Mid-Infrared Ultrashort Pulse Laser","authors":"H. Matsukuma, M. Nagaoka, Hisashi Hirose, R. Sato, Y. Shimizu, Wei Gao","doi":"10.20965/ijat.2024.p0084","DOIUrl":"https://doi.org/10.20965/ijat.2024.p0084","url":null,"abstract":"In this study, a method for controlling the repetition frequency of a mid-infrared ultrashort pulse laser with a central wavelength of 2.8 µm is developed. A ring cavity that is insensitive to the polarization state of the laser light emitted from the fiber end was constructed to stabilize the oscillation of the mid-infrared ultrashort pulse laser. More oscillation conditions for the ultrashort pulse laser based on nonlinear polarization rotation are found than the conventional method. To confirm that the pulse oscillation is mode-locked, ultrashort pulse oscillation was confirmed by an autocorrelator. The pulse repetition frequency of this robust ultrashort pulse laser was controlled. The control method was based on the phase-locked loop (PLL) control. A wedge window was inserted into the cavity and mounted on a linear stage driven by a piezoelectric transducer. By driving the piezoelectric transducer, the position of the wedge window changed, and the resulting optical path length also changed. The repetition frequency was controlled based on this principle. Optical path length control by the wedge window and temperature control provides an Allan deviation of approximately 1 mHz.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"83 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.20965/ijat.2024.p0113
Tsuyoshi Yamada, Ryo Inada, Kazuhisa Ito
Variable displacement hydraulic pumps are widely used for energy efficiency, and they often have a mechanical feedback mechanism to ensure target tracking control performance and stability of tilt angle control. Furthermore, there are many examples which add electronic control to realize higher tracking control performance. However, in such cases, the control performance is significantly affected by the dynamic characteristics of the mechanical feedback mechanism, and this problem prevent its widespread use. Additionally, tilt angle control is susceptible to changes in dynamic characteristics and load pressure depending on the operating point, and there are constraints on the tilt angle. Hence, high control performance cannot be obtained without considering these nonlinearities. In this study, the variable displacement pump without mechanical feedback mechanism is focused on, and the objective of this study is to design a displacement control system for a hydraulic pump based on a model predictive control (MPC) that can consider various constraints on the design step. An adaptive system, which handles changes in dynamic characteristics and the effects of load pressure, is introduced. Additionally, the control performance of adaptive MPC is compared to adaptive model matching-based MPC with inverse optimization that can optimally design the weight matrices of the evaluation function without trial and error. Furthermore, in order to improve the transient response, a variable control input constraints are added in these two control systems. Experimental results of control performance have shown that the proposed method achieved a high tracking performance and short settling time, which confirmed the effectiveness of the variable control input constraints.
{"title":"Designing a Model Predictive Controller for Displacement Control of Axial Piston Pump","authors":"Tsuyoshi Yamada, Ryo Inada, Kazuhisa Ito","doi":"10.20965/ijat.2024.p0113","DOIUrl":"https://doi.org/10.20965/ijat.2024.p0113","url":null,"abstract":"Variable displacement hydraulic pumps are widely used for energy efficiency, and they often have a mechanical feedback mechanism to ensure target tracking control performance and stability of tilt angle control. Furthermore, there are many examples which add electronic control to realize higher tracking control performance. However, in such cases, the control performance is significantly affected by the dynamic characteristics of the mechanical feedback mechanism, and this problem prevent its widespread use. Additionally, tilt angle control is susceptible to changes in dynamic characteristics and load pressure depending on the operating point, and there are constraints on the tilt angle. Hence, high control performance cannot be obtained without considering these nonlinearities. In this study, the variable displacement pump without mechanical feedback mechanism is focused on, and the objective of this study is to design a displacement control system for a hydraulic pump based on a model predictive control (MPC) that can consider various constraints on the design step. An adaptive system, which handles changes in dynamic characteristics and the effects of load pressure, is introduced. Additionally, the control performance of adaptive MPC is compared to adaptive model matching-based MPC with inverse optimization that can optimally design the weight matrices of the evaluation function without trial and error. Furthermore, in order to improve the transient response, a variable control input constraints are added in these two control systems. Experimental results of control performance have shown that the proposed method achieved a high tracking performance and short settling time, which confirmed the effectiveness of the variable control input constraints.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"75 7","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.20965/ijat.2024.p0135
Yigedeb Abay, T. Kaihara, D. Kokuryo
Sales and operation planning is one of the major categories of supply chain planning that enables the balancing of demand with supply through the integration of internal functions as well as external supply chain members. The major issues are its large scale, dynamic, multi-objective nature and presence of uncertain parameters. Handling uncertainty, extending the level of integration, enhancing collaboration, and contextualization of the models already developed in different industrial situations are the gaps identified in the literature. This research aims to develop a discrete-event simulation model from the literature in the context of the Ethiopian automotive industry and extend the level of collaboration to suppliers and customers. The industry’s sales and operation planning process is surveyed to develop the model as a decision support system that can be utilized for understanding the system behavior, evaluation of manufacturing flexibility, and inventory control policies. The research findings demonstrate that the customer service level and total profit can be significantly improved through the proposed joint primary and negotiated backup supply policy with price revision. Managerial implications that are expected to improve the technical capability of Ethiopian automotive industries are also highlighted.
{"title":"A Discrete-Event Simulation Study of Multi-Objective Sales and Operation Planning Under Demand Uncertainty: A Case of the Ethiopian Automotive Industry","authors":"Yigedeb Abay, T. Kaihara, D. Kokuryo","doi":"10.20965/ijat.2024.p0135","DOIUrl":"https://doi.org/10.20965/ijat.2024.p0135","url":null,"abstract":"Sales and operation planning is one of the major categories of supply chain planning that enables the balancing of demand with supply through the integration of internal functions as well as external supply chain members. The major issues are its large scale, dynamic, multi-objective nature and presence of uncertain parameters. Handling uncertainty, extending the level of integration, enhancing collaboration, and contextualization of the models already developed in different industrial situations are the gaps identified in the literature. This research aims to develop a discrete-event simulation model from the literature in the context of the Ethiopian automotive industry and extend the level of collaboration to suppliers and customers. The industry’s sales and operation planning process is surveyed to develop the model as a decision support system that can be utilized for understanding the system behavior, evaluation of manufacturing flexibility, and inventory control policies. The research findings demonstrate that the customer service level and total profit can be significantly improved through the proposed joint primary and negotiated backup supply policy with price revision. Managerial implications that are expected to improve the technical capability of Ethiopian automotive industries are also highlighted.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"11 3","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon fiber reinforced plastic (CFRP) is a composite material with high specific strength and is applied to transportation and aviation equipment. However, conventional processing methods require large-scale production apparatus or a high level of dexterity that only comes with extensive experience which makes it difficult to achieve high processing efficiency. The objective of this study is to develop a novel method for forming thermos-plastic CFRP (CFRTP) preforms implementing a 3D printer for press molding. Applying this method offers the advantage that continuous carbon fibers can be formed on a free-form surface. It also reduces the manufacturing time and operator skill required. The goal of this research is to establish a method for molding a free-form surface composed of continuous fibers by employing a 3D-printed preform designed to match the unfolded polygonised diagram of the free-form surface. Previous research introduced an unfolding approach for converting a three-dimensional shape to a plane surface based on a computer-aided design and manufacturing (CAD/CAM) system, enabling the generation of an unfolding diagram that maintains the continuity of fiber tow. Furthermore, the validity of unfolded diagram was confirmed by reproducing the objective three-dimensional shape from the unfolded diagram using thermos-setting CPRP (CFRTS) tow prepreg. In this study, the viability of the proposed molding process using CFRTP preform fabricated by a 3D printer was verified and an assessment of the formability of the molded parts was conducted.
碳纤维增强塑料（CFRP）是一种复合材料，具有很高的比强度，被广泛应用于交通和航空设备。然而，传统的加工方法需要大规模的生产设备，或者需要凭借丰富的经验才能掌握的高超技艺，因此很难实现高效加工。本研究的目的是开发一种新型热塑 CFRP（CFRTP）预型件成型方法，使用三维打印机进行压制成型。采用这种方法的优点是可以在自由形态表面上形成连续的碳纤维。它还能缩短制造时间，降低对操作员技能的要求。本研究的目标是建立一种由连续纤维组成的自由形态表面的成型方法，方法是采用三维打印预型件，其设计与自由形态表面的展开多边形图相匹配。之前的研究基于计算机辅助设计和制造（CAD/CAM）系统，引入了一种将三维形状转换为平面的展开方法，从而能够生成保持纤维束连续性的展开图。此外，通过使用热固性 CPRP（CFRTS）丝束预浸料再现展开图中的客观三维形状，证实了展开图的有效性。在这项研究中，使用 3D 打印机制造的 CFRTP 预成型件验证了所建议的成型工艺的可行性，并对成型件的可成形性进行了评估。
{"title":"Fundamental Study of Press Molding Method for CFRP Preform Using a 3D Printer","authors":"Hidetake Tanaka, Yuuki Nishimura, Tatsuki Ikari, Emir Yilmaz","doi":"10.20965/ijat.2024.p0128","DOIUrl":"https://doi.org/10.20965/ijat.2024.p0128","url":null,"abstract":"Carbon fiber reinforced plastic (CFRP) is a composite material with high specific strength and is applied to transportation and aviation equipment. However, conventional processing methods require large-scale production apparatus or a high level of dexterity that only comes with extensive experience which makes it difficult to achieve high processing efficiency. The objective of this study is to develop a novel method for forming thermos-plastic CFRP (CFRTP) preforms implementing a 3D printer for press molding. Applying this method offers the advantage that continuous carbon fibers can be formed on a free-form surface. It also reduces the manufacturing time and operator skill required. The goal of this research is to establish a method for molding a free-form surface composed of continuous fibers by employing a 3D-printed preform designed to match the unfolded polygonised diagram of the free-form surface. Previous research introduced an unfolding approach for converting a three-dimensional shape to a plane surface based on a computer-aided design and manufacturing (CAD/CAM) system, enabling the generation of an unfolding diagram that maintains the continuity of fiber tow. Furthermore, the validity of unfolded diagram was confirmed by reproducing the objective three-dimensional shape from the unfolded diagram using thermos-setting CPRP (CFRTS) tow prepreg. In this study, the viability of the proposed molding process using CFRTP preform fabricated by a 3D printer was verified and an assessment of the formability of the molded parts was conducted.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"56 12","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.20965/ijat.2024.p0077
Eiki Okuyama, Takato Fukuda
A three-point method has been used to separate the roundness profile of a workpiece and radial motions of a turntable. First, weighted addition is used to extract the roundness profile, and then, inverse filtering is used to recover the original roundness profile. The three-point method works well in the low spatial frequency domain. However, in the high spatial frequency domain, the setting angle error of the sensor causes a large deflection of the transfer function. Therefore, a combination method of the three-point method for roundness profile measurement and an integration method for the straightness profile measurement is proposed. The three-point method for roundness profile measurement is used to estimate low spatial frequency domain and the integration method for straightness profile measurement is used to estimate the high spatial frequency domain. Experimental results showed that the standard deviation of the combination method was smaller than that of the three-point method for most positions.
{"title":"Roundness Profile Measurement Using a Combination Method of Three-Point Method for Roundness Profile Measurement and Integration Method for Straightness Profile Measurement","authors":"Eiki Okuyama, Takato Fukuda","doi":"10.20965/ijat.2024.p0077","DOIUrl":"https://doi.org/10.20965/ijat.2024.p0077","url":null,"abstract":"A three-point method has been used to separate the roundness profile of a workpiece and radial motions of a turntable. First, weighted addition is used to extract the roundness profile, and then, inverse filtering is used to recover the original roundness profile. The three-point method works well in the low spatial frequency domain. However, in the high spatial frequency domain, the setting angle error of the sensor causes a large deflection of the transfer function. Therefore, a combination method of the three-point method for roundness profile measurement and an integration method for the straightness profile measurement is proposed. The three-point method for roundness profile measurement is used to estimate low spatial frequency domain and the integration method for straightness profile measurement is used to estimate the high spatial frequency domain. Experimental results showed that the standard deviation of the combination method was smaller than that of the three-point method for most positions.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"15 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139383046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-05DOI: 10.20965/ijat.2023.p0551
Toshiyuki Enomoto, Tatsuya Sugihara
In recent years, the field of manufacturing has become increasingly diversified and complex to meet various requirements, such as improved manufacturing accuracy, productivity, environmental friendliness, and automation/intelligence in manufacturing sites. Consequently, the fusion of different fields as well as interdisciplinary research has become indispensable for the creation of innovative manufacturing technologies that can realize advanced production systems. This special issue comprises seven outstanding research papers that focus on advanced precision engineering in manufacturing systems, covering the following topics: - Advanced cutting technologies - Advanced machine tools and elements - Surface finishing technologies - Non-traditional machining and additive manufacturing - Nano-scale surface finishing - Advanced surface processing All research papers were originally presented at the 19th International Conference on Precision Engineering (ICPE2022), held in Nara, Japan, in 2022. The editors hope that the research papers included in this special issue will offer valuable insights to readers for their future research in the field of manufacturing technology. Each paper underwent a rigorous peer-review process, and the editors would like to express their deep appreciation for the efforts and excellent work of all the authors and anonymous reviewers who contributed to the realization of this special issue. Finally, it is our sincere hope that the papers in this special issue will further contribute to the advancement of our future society.
{"title":"Special Issue on Recent Progress in Precision Engineering","authors":"Toshiyuki Enomoto, Tatsuya Sugihara","doi":"10.20965/ijat.2023.p0551","DOIUrl":"https://doi.org/10.20965/ijat.2023.p0551","url":null,"abstract":"In recent years, the field of manufacturing has become increasingly diversified and complex to meet various requirements, such as improved manufacturing accuracy, productivity, environmental friendliness, and automation/intelligence in manufacturing sites. Consequently, the fusion of different fields as well as interdisciplinary research has become indispensable for the creation of innovative manufacturing technologies that can realize advanced production systems. This special issue comprises seven outstanding research papers that focus on advanced precision engineering in manufacturing systems, covering the following topics: - Advanced cutting technologies - Advanced machine tools and elements - Surface finishing technologies - Non-traditional machining and additive manufacturing - Nano-scale surface finishing - Advanced surface processing All research papers were originally presented at the 19th International Conference on Precision Engineering (ICPE2022), held in Nara, Japan, in 2022. The editors hope that the research papers included in this special issue will offer valuable insights to readers for their future research in the field of manufacturing technology. Each paper underwent a rigorous peer-review process, and the editors would like to express their deep appreciation for the efforts and excellent work of all the authors and anonymous reviewers who contributed to the realization of this special issue. Finally, it is our sincere hope that the papers in this special issue will further contribute to the advancement of our future society.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135725762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-05DOI: 10.20965/ijat.2023.p0627
Minoru Yamashita, Nozomi Minowa, Makoto Nikawa
A simple material contact sensor on the forming tool was devised for sheet hydroforming. The applicability was investigated for the shallow forming of aluminum alloy sheet. A flat bottom axisymmetric die or a conical one was used. An antistatic electric tape was used as contact sensor. It is flexible and attached to the die cavity in the radial direction. Electrical resistance of the tape between the center and the contact position of the material changes as the forming progresses. The change in voltage of the resistance part corresponding to the contact length was captured continuously. The strain at the center of the circular test piece was also continuously measured using a strain gage for large deformation. A short contact length was captured for the flat bottom die, since the test piece deforms into a dome shape, and the tip of the dome contacts to the center of the die cavity. On the other hand, the captured length was longer in the forming with the conical die. The repetitive separation and contact motion of the test piece to the die in impact forming due to the impulsive water pressure was successfully captured by the contact sensor. The accuracy was relatively coarse due to that the diameter of the die cavity was small. However, it was found that the simple contact sensor can be applied to evaluate the deformation behavior of the material. The measured maximum strain of the test piece was larger in impact forming, and the strain concentration occurred. This may be due to the negative strain rate sensitivity of the material.
{"title":"Simple Contact Sensor for Material on Die in Sheet Hydroforming","authors":"Minoru Yamashita, Nozomi Minowa, Makoto Nikawa","doi":"10.20965/ijat.2023.p0627","DOIUrl":"https://doi.org/10.20965/ijat.2023.p0627","url":null,"abstract":"A simple material contact sensor on the forming tool was devised for sheet hydroforming. The applicability was investigated for the shallow forming of aluminum alloy sheet. A flat bottom axisymmetric die or a conical one was used. An antistatic electric tape was used as contact sensor. It is flexible and attached to the die cavity in the radial direction. Electrical resistance of the tape between the center and the contact position of the material changes as the forming progresses. The change in voltage of the resistance part corresponding to the contact length was captured continuously. The strain at the center of the circular test piece was also continuously measured using a strain gage for large deformation. A short contact length was captured for the flat bottom die, since the test piece deforms into a dome shape, and the tip of the dome contacts to the center of the die cavity. On the other hand, the captured length was longer in the forming with the conical die. The repetitive separation and contact motion of the test piece to the die in impact forming due to the impulsive water pressure was successfully captured by the contact sensor. The accuracy was relatively coarse due to that the diameter of the die cavity was small. However, it was found that the simple contact sensor can be applied to evaluate the deformation behavior of the material. The measured maximum strain of the test piece was larger in impact forming, and the strain concentration occurred. This may be due to the negative strain rate sensitivity of the material.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"29 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135725581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-05DOI: 10.20965/ijat.2023.p0583
Tomohiro Koyano, Taisei Hokin, Tatsuaki Furumoto
Electrochemical machining was performed on two cemented carbides with different compositions using unipolar and bipolar short-pulse voltages to investigate the effects of the composition and pulse conditions on the machining characteristics. In the case of cemented carbides with high cobalt and low tungsten carbide (WC) contents, machining progressed even when a unipolar voltage was used. This is believed to be due to the dissolution of the binder, that is, Co, which causes the WC and WO 3 particles to drop out. Machining progressed more easily when a bipolar voltage was used than when a unipolar voltage was used. This is attributed to the effective removal of WO 3 . The unevenness of the machined surface was also reduced with bipolar voltage. The negative pulse duration had to be sufficiently but appropriately long, because too long a duration increased the wear of the tool electrode. Even when bipolar pulse voltages were used, similar to the machining of general materials, a shorter positive pulse duration resulted in more precise machining. However, in the case of cemented carbide with low Co and high WC contents, the removal did not progress when a unipolar pulse voltage was applied. On the other hand, the machining progressed when a bipolar voltage was applied. However, if the positive pulse duration was excessively long, the amount of removal decreased. This is believed to be because the longer positive pulse duration increased the amount of WO 3 generated, thereby inhibiting the current flow. Therefore, it is necessary to set an appropriate positive pulse duration to avoid the excessive production of WO 3 .
{"title":"Effect of Pulse Conditions on Machining Characteristics in Bipolar-Pulse Electrochemical Machining of Cemented Carbide","authors":"Tomohiro Koyano, Taisei Hokin, Tatsuaki Furumoto","doi":"10.20965/ijat.2023.p0583","DOIUrl":"https://doi.org/10.20965/ijat.2023.p0583","url":null,"abstract":"Electrochemical machining was performed on two cemented carbides with different compositions using unipolar and bipolar short-pulse voltages to investigate the effects of the composition and pulse conditions on the machining characteristics. In the case of cemented carbides with high cobalt and low tungsten carbide (WC) contents, machining progressed even when a unipolar voltage was used. This is believed to be due to the dissolution of the binder, that is, Co, which causes the WC and WO 3 particles to drop out. Machining progressed more easily when a bipolar voltage was used than when a unipolar voltage was used. This is attributed to the effective removal of WO 3 . The unevenness of the machined surface was also reduced with bipolar voltage. The negative pulse duration had to be sufficiently but appropriately long, because too long a duration increased the wear of the tool electrode. Even when bipolar pulse voltages were used, similar to the machining of general materials, a shorter positive pulse duration resulted in more precise machining. However, in the case of cemented carbide with low Co and high WC contents, the removal did not progress when a unipolar pulse voltage was applied. On the other hand, the machining progressed when a bipolar voltage was applied. However, if the positive pulse duration was excessively long, the amount of removal decreased. This is believed to be because the longer positive pulse duration increased the amount of WO 3 generated, thereby inhibiting the current flow. Therefore, it is necessary to set an appropriate positive pulse duration to avoid the excessive production of WO 3 .","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"29 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135725580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a novel methodology was proposed to investigate the influence of the built-up layer (BUL) formation on the stress state distribution in the primary shear zone (PSZ) using analytical model and particle image velocimetry (PIV) analysis. Orthogonal cutting tests were performed under a range of uncut chip thicknesses and cutting speeds using two uncoated cemented carbide tools with different rake angles. A series of shear strain, shear strain rate, and velocity distributions in PSZ were obtained by PIV analysis. Al7075-T6511 was used as the workpiece. Subsequently, the influences of cutting conditions on the BUL/built-up edge (BUE) formation and the plastic deformation in PSZ were investigated. Using these results, the parameters of the proposed analytical model were identified, and the influences of the BUL/BUE formation on the stress state distribution were investigated. From the experimental results, it was found that in the cutting speed range below 2 m/min, only BUE is formed, and the uncut chip thickness and tool rake angle have a significant influence on its formation. The agreement between the measured and calculated results demonstrated the effectiveness of the proposed methodology. The results confirmed that the BUE formation has little effect on the bell-shaped distribution of shear strain rate, but has a significant influence on the thickness of PSZ, chip sliding velocity near the outlet boundary of PSZ, maximum shear strain rate, stress state, and temperature in PSZ. It was also confirmed that the stress triaxiality plays an important role in the BUE formation. These results provide a deeper understanding of the BUL/BUE formation.
{"title":"Investigation of the Influence of Built-Up Layer on the Stress State in the Primary Shear Zone Using Particle Image Velocimetry Analysis","authors":"Xiaoqi Song, Kenji Suzuki, Weiming He, Tohru Ihara","doi":"10.20965/ijat.2023.p0552","DOIUrl":"https://doi.org/10.20965/ijat.2023.p0552","url":null,"abstract":"In this study, a novel methodology was proposed to investigate the influence of the built-up layer (BUL) formation on the stress state distribution in the primary shear zone (PSZ) using analytical model and particle image velocimetry (PIV) analysis. Orthogonal cutting tests were performed under a range of uncut chip thicknesses and cutting speeds using two uncoated cemented carbide tools with different rake angles. A series of shear strain, shear strain rate, and velocity distributions in PSZ were obtained by PIV analysis. Al7075-T6511 was used as the workpiece. Subsequently, the influences of cutting conditions on the BUL/built-up edge (BUE) formation and the plastic deformation in PSZ were investigated. Using these results, the parameters of the proposed analytical model were identified, and the influences of the BUL/BUE formation on the stress state distribution were investigated. From the experimental results, it was found that in the cutting speed range below 2 m/min, only BUE is formed, and the uncut chip thickness and tool rake angle have a significant influence on its formation. The agreement between the measured and calculated results demonstrated the effectiveness of the proposed methodology. The results confirmed that the BUE formation has little effect on the bell-shaped distribution of shear strain rate, but has a significant influence on the thickness of PSZ, chip sliding velocity near the outlet boundary of PSZ, maximum shear strain rate, stress state, and temperature in PSZ. It was also confirmed that the stress triaxiality plays an important role in the BUE formation. These results provide a deeper understanding of the BUL/BUE formation.","PeriodicalId":43716,"journal":{"name":"International Journal of Automation Technology","volume":"29 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135725582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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