The integration of mobile robots in material handling in flexible manufacturing systems is made possible by the recent advancements in Industry 4.0 and industrial artificial intelligence. However, effectively scheduling these robots in real-time remains a challenge due to the constantly changing, complex and uncertain nature of the shop floor environment. Therefore, this paper studies the robot scheduling problem for a multiproduct flexible production line using a mobile robot for loading/unloading parts among machines and buffers. The problem is formulated as a Markov Decision Process and the Q-learning algorithm is used to find an optimal policy for the robot's movements in handling different product types. The performance of the system is evaluated using a reward function based on permanent production loss and the cost of demand dissatisfaction. The proposed approach is validated through a numerical case study that compares the resulting policy to a first-come-first-served policy, showing a significant improvement in production throughput of approximately 23%.
{"title":"Adaptive Mobile Robot Scheduling in Multiproduct Flexible Manufacturing Systems Using Reinforcement Learning","authors":"Muhammad Waseem, Qing Chang","doi":"10.1115/1.4062941","DOIUrl":"https://doi.org/10.1115/1.4062941","url":null,"abstract":"\u0000 The integration of mobile robots in material handling in flexible manufacturing systems is made possible by the recent advancements in Industry 4.0 and industrial artificial intelligence. However, effectively scheduling these robots in real-time remains a challenge due to the constantly changing, complex and uncertain nature of the shop floor environment. Therefore, this paper studies the robot scheduling problem for a multiproduct flexible production line using a mobile robot for loading/unloading parts among machines and buffers. The problem is formulated as a Markov Decision Process and the Q-learning algorithm is used to find an optimal policy for the robot's movements in handling different product types. The performance of the system is evaluated using a reward function based on permanent production loss and the cost of demand dissatisfaction. The proposed approach is validated through a numerical case study that compares the resulting policy to a first-come-first-served policy, showing a significant improvement in production throughput of approximately 23%.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41726734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone cutting with high performance material removal is critical for enhancing orthopedic surgery. Ultrasonically assisted cutting (UAC) is an advanced process with the potential to improve the material removal. However, strain and other intermediate variables in bone cutting are difficult to obtain because of the lack of suitable measurement methods, especially for high-frequency vibration-assisted cutting. In this study, digital image correlation (DIC) analysis was applied for the first time to investigate the mechanism of crack development during conventional cutting (CC) and ultrasonically assisted cutting of cortical bone. A novel method for calculating cutting and thrust forces under the mixed fracture mode of bone was also proposed. Extensive experimental results showed that the average strain and strain rate of cortical bone decreased after the application of UAC, but the maximum transient strain rate in UAC was greater than that in CC, and the crack-affected area and shear band width in UAC were smaller than those in CC. In addition, the strain parameters obtained by the DIC analysis were used to calculate the cutting and thrust forces in the hybrid fracture mode. The calculated values of forces matched well with the measured results, indicating the strong feasibility of DIC applications in orthogonal bone cutting research. This study has significant theoretical and practical value since it reveals the fracture mechanism of cortical bone in UAC, demonstrates a non-contact full-field measurement method for tissue strain calculation, and provides inspiration for optimizing the design of innovative orthopedic instruments.
{"title":"Characterization of ultrasonically assisted orthogonal cutting of bone using digital image correlation analysis","authors":"W. Bai, Yuhao Zhai, Jiaqi Zhao, Xuzhe Jia, Guangchao Han, Liming Shu, Dong Wang, Jianfeng Xu","doi":"10.1115/1.4062942","DOIUrl":"https://doi.org/10.1115/1.4062942","url":null,"abstract":"\u0000 Bone cutting with high performance material removal is critical for enhancing orthopedic surgery. Ultrasonically assisted cutting (UAC) is an advanced process with the potential to improve the material removal. However, strain and other intermediate variables in bone cutting are difficult to obtain because of the lack of suitable measurement methods, especially for high-frequency vibration-assisted cutting. In this study, digital image correlation (DIC) analysis was applied for the first time to investigate the mechanism of crack development during conventional cutting (CC) and ultrasonically assisted cutting of cortical bone. A novel method for calculating cutting and thrust forces under the mixed fracture mode of bone was also proposed. Extensive experimental results showed that the average strain and strain rate of cortical bone decreased after the application of UAC, but the maximum transient strain rate in UAC was greater than that in CC, and the crack-affected area and shear band width in UAC were smaller than those in CC. In addition, the strain parameters obtained by the DIC analysis were used to calculate the cutting and thrust forces in the hybrid fracture mode. The calculated values of forces matched well with the measured results, indicating the strong feasibility of DIC applications in orthogonal bone cutting research. This study has significant theoretical and practical value since it reveals the fracture mechanism of cortical bone in UAC, demonstrates a non-contact full-field measurement method for tissue strain calculation, and provides inspiration for optimizing the design of innovative orthopedic instruments.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41893502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Walczyk, Jiachen Yang, Jennifer Gilbert-Jenkins
This paper discusses a new method for decorticating bast fiber stalks through a mastication process without damaging the fiber for use in biocomposites. Conventional automated decortication methods provide high stalk processing throughput, but they significantly damage the bast fibers and adversely affect their performance in biocomposite applications. Initial experiments with industrial hemp using a matched set of tools indicate that indexing the stalk by, at most, half a tooling period for each mastication cycle maximizes both the crushed stalk flexing action and dehurding efficiency. Further process insight was gained through simple stalk crushing experiments (force vs. deflection) between matching teeth with no indexing, where force spikes correspond to initial collapse of the stalk cross section and initial hurd bending fracture along the stalk length. A more extensive experimental design with stiffer tooling reveals that adding spaces in the bottom die for hurd to fall through, and using the smallest practical indexing distance less than half a tooling period and also more teeth maximizes hurding efficiency. However, shorter indexing and more teeth also decreases throughput rate and complicates stalk handling. Future work for optimizing and commercializing the process are suggested.
{"title":"Bast Fiber Decortication for Biocomposites by a Mastication Process","authors":"D. Walczyk, Jiachen Yang, Jennifer Gilbert-Jenkins","doi":"10.1115/1.4062913","DOIUrl":"https://doi.org/10.1115/1.4062913","url":null,"abstract":"\u0000 This paper discusses a new method for decorticating bast fiber stalks through a mastication process without damaging the fiber for use in biocomposites. Conventional automated decortication methods provide high stalk processing throughput, but they significantly damage the bast fibers and adversely affect their performance in biocomposite applications. Initial experiments with industrial hemp using a matched set of tools indicate that indexing the stalk by, at most, half a tooling period for each mastication cycle maximizes both the crushed stalk flexing action and dehurding efficiency. Further process insight was gained through simple stalk crushing experiments (force vs. deflection) between matching teeth with no indexing, where force spikes correspond to initial collapse of the stalk cross section and initial hurd bending fracture along the stalk length. A more extensive experimental design with stiffer tooling reveals that adding spaces in the bottom die for hurd to fall through, and using the smallest practical indexing distance less than half a tooling period and also more teeth maximizes hurding efficiency. However, shorter indexing and more teeth also decreases throughput rate and complicates stalk handling. Future work for optimizing and commercializing the process are suggested.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48109170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Robert O. Jung, F. Bleicher, S. Krall, Christian Juricek, Rainer Lottes, Karoline Steinschuetz, T. Reininger
Deep Drawing is an essential manufacturing technology for car body parts. High process stability is a key for reducing scrap and therefore the ecological footprint during the production. To deal with an unknown fluctuation of the incoming material properties and uncertainties considering the friction, an adaptive process needs to be implemented. Various approaches have been pursued in the past, but not all of them are suited for an industrial series production with high demands for equipment durability, cost efficiency and flexibility. For this reason, a new concept for cyber physical production systems (CPPS) in deep drawing is presented, linking the data from the simulation, tool, press, material and finished part quality. Two common application scenarios are distinguished. These are firstly large outer parts with a complex geometry and high value, typically produced with tandem presses. Secondly smaller structural parts from high strength steel for the body in white (BIW), usually produced through a transfer or progressive die. Non destructive material testing, supplier material certificates and data measured directly in the forming tool are considered regarding the input. A variation of the servo curve and blank holder force (BHF) operate as control instances. Within the two application scenarios, a reactive and a preventive solution are characterized. As a first step towards the implementation of the CPPS, material inflow and force sensors are installed in an industrially relevant deep drawing tool.
{"title":"Cyber Physical Production Systems for Deep Drawing","authors":"Robert O. Jung, F. Bleicher, S. Krall, Christian Juricek, Rainer Lottes, Karoline Steinschuetz, T. Reininger","doi":"10.1115/1.4062903","DOIUrl":"https://doi.org/10.1115/1.4062903","url":null,"abstract":"\u0000 Deep Drawing is an essential manufacturing technology for car body parts. High process stability is a key for reducing scrap and therefore the ecological footprint during the production. To deal with an unknown fluctuation of the incoming material properties and uncertainties considering the friction, an adaptive process needs to be implemented. Various approaches have been pursued in the past, but not all of them are suited for an industrial series production with high demands for equipment durability, cost efficiency and flexibility. For this reason, a new concept for cyber physical production systems (CPPS) in deep drawing is presented, linking the data from the simulation, tool, press, material and finished part quality. Two common application scenarios are distinguished. These are firstly large outer parts with a complex geometry and high value, typically produced with tandem presses. Secondly smaller structural parts from high strength steel for the body in white (BIW), usually produced through a transfer or progressive die. Non destructive material testing, supplier material certificates and data measured directly in the forming tool are considered regarding the input. A variation of the servo curve and blank holder force (BHF) operate as control instances. Within the two application scenarios, a reactive and a preventive solution are characterized. As a first step towards the implementation of the CPPS, material inflow and force sensors are installed in an industrially relevant deep drawing tool.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63504257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pee-Yew Lee, H. Huang, T. Ko, Ying-Lun Hung, Li-Yan Wu, Jianhua Fan, Yung-Sheng Lin
Abstract The fluoride-assisted galvanic replacement reaction is a conventional method for fabricating metallic dendrites on silicon wafers. However, whether bubbles affect manufacturing metallic dendrites is unclear. This study investigated the effects of bubbles on manufacturing Au dendrites and silicon nanowires through metal-assisted chemical etching. The results of manufacture under three conditions (standard, shaking, and vacuum conditions) were compared. Synchronous growth of Au dendrites and silicon nanowires were observed on the silicon wafers. The Au dendrite deposition rate was higher than the silicon etching rate. Compared with the standard condition, the vacuum condition increased the synthesis rates of Au dendrites and silicon nanowires by 1.1 and 0.2 μm/min, respectively. Therefore, the elimination of bubbles by vacuum can considerably accelerate manufacturing Au dendrites and silicon nanowires.
{"title":"Effects of bubbles on manufacturing gold dendrites and silicon nanowires through the fluoride-assisted galvanic replacement reaction","authors":"Pee-Yew Lee, H. Huang, T. Ko, Ying-Lun Hung, Li-Yan Wu, Jianhua Fan, Yung-Sheng Lin","doi":"10.1115/1.4062878","DOIUrl":"https://doi.org/10.1115/1.4062878","url":null,"abstract":"\u0000 Abstract The fluoride-assisted galvanic replacement reaction is a conventional method for fabricating metallic dendrites on silicon wafers. However, whether bubbles affect manufacturing metallic dendrites is unclear. This study investigated the effects of bubbles on manufacturing Au dendrites and silicon nanowires through metal-assisted chemical etching. The results of manufacture under three conditions (standard, shaking, and vacuum conditions) were compared. Synchronous growth of Au dendrites and silicon nanowires were observed on the silicon wafers. The Au dendrite deposition rate was higher than the silicon etching rate. Compared with the standard condition, the vacuum condition increased the synthesis rates of Au dendrites and silicon nanowires by 1.1 and 0.2 μm/min, respectively. Therefore, the elimination of bubbles by vacuum can considerably accelerate manufacturing Au dendrites and silicon nanowires.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47974110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper summarizes the perspectives from a manufacturing engineer on how the government policy, global partnership, and diversity of the United States (US), Japanese, European, and traditional Chinese cultures in Taiwan have created a workforce of semiconductor manufacturing talent in the past five decades. The complex interwoven events of Covid-19 pandemic, supply chain resilience, national security, and geopolitical conflicts have made semiconductor manufacturing a key focus of government policy. As a world leader in integrated circuit (IC) design, design software, equipment, and research, the US has struggled in the past few years on the high yield volume manufacturing of the most advanced logic IC and failed to translate research innovations to quality production. Manufacturing, not innovation or equipment, is a key barrier of the US semiconductor industry. Two models for excellence in advanced manufacturing are described. Three pillars of government policy, global collaboration, and multicultural diversity empower semiconductor manufacturing excellence in Taiwan is described. An approach to evaluate, select, educate, and train manufacturing talents is proposed. Directions for semiconductor manufacturing research are discussed. There is no genius in semiconductor manufacturing, which requires extensive experience and continuous improvement without shortcuts to be competitive. The steadfast good government policy, multicultural diversity workforce, and global technology collaboration to achieve semiconductor manufacturing excellence are the focus of the conclusion.
{"title":"Multicultural Diversity Workforce and Global Technology Collaboration Empowered Semiconductor Manufacturing Excellence in Taiwan: A Manufacturing Engineer’s Perspective","authors":"A. Shih","doi":"10.1115/1.4062729","DOIUrl":"https://doi.org/10.1115/1.4062729","url":null,"abstract":"\u0000 This paper summarizes the perspectives from a manufacturing engineer on how the government policy, global partnership, and diversity of the United States (US), Japanese, European, and traditional Chinese cultures in Taiwan have created a workforce of semiconductor manufacturing talent in the past five decades. The complex interwoven events of Covid-19 pandemic, supply chain resilience, national security, and geopolitical conflicts have made semiconductor manufacturing a key focus of government policy. As a world leader in integrated circuit (IC) design, design software, equipment, and research, the US has struggled in the past few years on the high yield volume manufacturing of the most advanced logic IC and failed to translate research innovations to quality production. Manufacturing, not innovation or equipment, is a key barrier of the US semiconductor industry. Two models for excellence in advanced manufacturing are described. Three pillars of government policy, global collaboration, and multicultural diversity empower semiconductor manufacturing excellence in Taiwan is described. An approach to evaluate, select, educate, and train manufacturing talents is proposed. Directions for semiconductor manufacturing research are discussed. There is no genius in semiconductor manufacturing, which requires extensive experience and continuous improvement without shortcuts to be competitive. The steadfast good government policy, multicultural diversity workforce, and global technology collaboration to achieve semiconductor manufacturing excellence are the focus of the conclusion.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47829756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an experimental and numerical study on the mechanical quasi-static behavior of self-piercing rivet (SPR) connections with three stacked sheets made from an AA6016-T4 aluminum alloy. The goal was to study the effects of sheet thickness and stack up of the SPR connection under large deformation and failure. Several different types of tests were performed to investigate the initial load-bearing capacity as well as the remaining capacity after partial joint failure. Additionally, the performance of state-of-the-art constraint modeling techniques was evaluated. The parameters for large-scale connector models were found through inverse modeling of the experiments. The models were validated against an additional test configuration where the middle sheet was load-free.
{"title":"Behavior and large-scale modeling of multi-sheet aluminum connections with self-piercing rivets","authors":"V. André, M. Costas, M. Langseth, D. Morin","doi":"10.1115/1.4062859","DOIUrl":"https://doi.org/10.1115/1.4062859","url":null,"abstract":"\u0000 This paper presents an experimental and numerical study on the mechanical quasi-static behavior of self-piercing rivet (SPR) connections with three stacked sheets made from an AA6016-T4 aluminum alloy. The goal was to study the effects of sheet thickness and stack up of the SPR connection under large deformation and failure. Several different types of tests were performed to investigate the initial load-bearing capacity as well as the remaining capacity after partial joint failure. Additionally, the performance of state-of-the-art constraint modeling techniques was evaluated. The parameters for large-scale connector models were found through inverse modeling of the experiments. The models were validated against an additional test configuration where the middle sheet was load-free.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42798781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Human-robot collaboration has become a hotspot in smart manufacturing, and it also has shown the potential for surface defect inspection. The robot can release workload, while human collaboration can help to recheck the uncertain defects. However, the human-robot collaboration-based defect inspection can be hardly realized unless some bottlenecks have been solved, and one of them is that the current methods cannot decide which samples to be rechecked, and the workers can only recheck all of the samples to improve inspection results. To overcome this problem and realize the human-robot collaboration-based surface defect inspection, a two-stage Transformer model with focal loss is proposed. The proposed method divides the traditional inspection process into detection and recognition, designs a collaboration rule to allow workers to collaborate and recheck the defects, and introduces the focal loss into the model to improve the recognition results. With these improvements, the proposed method can collaborate with workers by rechecking the defects, and improve surface quality. The experimental results on the public dataset have shown the effectiveness of the proposed method, the accuracies are significantly improved by the human collaboration, which are 1.70%~4.18%. Moreover, the proposed method has been implemented into a human-robot collaboration-based prototype to inspect the carton surface defects, and the results also verify the effectiveness. Meanwhile, the proposed method has a good ability for visualization to find the defect area, and it is also conducive to defect analysis and rechecking.
{"title":"A Two-stage Focal Transformer for Human-Robot Collaboration-based Surface Defect Inspection","authors":"Yiping Gao, Liang Gao, Xinyu Li","doi":"10.1115/1.4062860","DOIUrl":"https://doi.org/10.1115/1.4062860","url":null,"abstract":"\u0000 Human-robot collaboration has become a hotspot in smart manufacturing, and it also has shown the potential for surface defect inspection. The robot can release workload, while human collaboration can help to recheck the uncertain defects. However, the human-robot collaboration-based defect inspection can be hardly realized unless some bottlenecks have been solved, and one of them is that the current methods cannot decide which samples to be rechecked, and the workers can only recheck all of the samples to improve inspection results. To overcome this problem and realize the human-robot collaboration-based surface defect inspection, a two-stage Transformer model with focal loss is proposed. The proposed method divides the traditional inspection process into detection and recognition, designs a collaboration rule to allow workers to collaborate and recheck the defects, and introduces the focal loss into the model to improve the recognition results. With these improvements, the proposed method can collaborate with workers by rechecking the defects, and improve surface quality. The experimental results on the public dataset have shown the effectiveness of the proposed method, the accuracies are significantly improved by the human collaboration, which are 1.70%~4.18%. Moreover, the proposed method has been implemented into a human-robot collaboration-based prototype to inspect the carton surface defects, and the results also verify the effectiveness. Meanwhile, the proposed method has a good ability for visualization to find the defect area, and it is also conducive to defect analysis and rechecking.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44282921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Salvador Gómez-Jiménez, T. Saucedo-Anaya, V. H. Baltazar Hernandez, Ada Rebeca Contreras-Rodriguez
The automotive industry is evolving by incorporating innovative tools to improve production processes. A proper manufacturing process influences the behavior of the door grommet during its lifetime. In this paper, molecular dynamics simulations are conducted to evaluate the chemical and physical crosslinking of the EPDM rubber over a range of temperatures using a COMPASS force field. Then, once the EPDM model was equilibrated and all possible crosslinks were formed, additional simulations were performed on the model to explore its mechanical behavior. Subsequently, using the superposition principle, viscosity and curing kinetics were evaluated using phenomenological models. To, validate the results of the simulations, three injection tests of the door grommet, were performed at different temperature conditions. The results indicate that the viscosity and elastic properties increase with increasing levels of crosslink density and that the critical gel point decreases with temperature. Molecular dynamics superposition results in phenomenological models are in reasonable agreement with the kinetic and viscoelastic behavior of EPDM during and after the injection process. The results presented in this paper provide novel molecular-level findings on the crosslinking mechanisms of amorphous polymers and their influence on viscoelastic behavior, which could facilitate the design of the injection process for door grommet applications
{"title":"Characterization of viscoelastic properties of EPDM molding compound for door grommet component using molecular dynamics and phenomenological modeling.","authors":"Salvador Gómez-Jiménez, T. Saucedo-Anaya, V. H. Baltazar Hernandez, Ada Rebeca Contreras-Rodriguez","doi":"10.1115/1.4062858","DOIUrl":"https://doi.org/10.1115/1.4062858","url":null,"abstract":"\u0000 The automotive industry is evolving by incorporating innovative tools to improve production processes. A proper manufacturing process influences the behavior of the door grommet during its lifetime. In this paper, molecular dynamics simulations are conducted to evaluate the chemical and physical crosslinking of the EPDM rubber over a range of temperatures using a COMPASS force field. Then, once the EPDM model was equilibrated and all possible crosslinks were formed, additional simulations were performed on the model to explore its mechanical behavior. Subsequently, using the superposition principle, viscosity and curing kinetics were evaluated using phenomenological models. To, validate the results of the simulations, three injection tests of the door grommet, were performed at different temperature conditions. The results indicate that the viscosity and elastic properties increase with increasing levels of crosslink density and that the critical gel point decreases with temperature. Molecular dynamics superposition results in phenomenological models are in reasonable agreement with the kinetic and viscoelastic behavior of EPDM during and after the injection process. The results presented in this paper provide novel molecular-level findings on the crosslinking mechanisms of amorphous polymers and their influence on viscoelastic behavior, which could facilitate the design of the injection process for door grommet applications","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41275738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Freeform bending offers a wide range of possibilities in terms of component geometries, material grades and profile cross-sections. In the field of circular solid and hollow profiles, the design of the tool is determined by the circular shape of the profile used. When using rectangular profiles, the cross-section of the tool cannot be easily obtained by an offset of the profile cross-section. The large tolerance ranges of the profile standards require compromises with regard to the shape and tolerances of the tool. Tests have shown that the design of the tool has a great influence on the quality of the component. Furthermore, the trade-off in the tool design can lead to unsuitable tool shapes leading to defects and damages on the profile. These are mainly wrinkling, cross-sectional deformations and strongly deformed profile corners, which in some cases form cracks in the material. In this paper, the influences of the tool design on the bending result and the defects of the profiles are investigated. For this purpose, several tool designs with different variants and combinations of the movable die and the fixed die are compared with each other.
{"title":"Freeform bending tool design for rectangular profiles and its influence on the process","authors":"M. Werner, Lorenzo Scandola, D. Maier, W. Volk","doi":"10.1115/1.4062811","DOIUrl":"https://doi.org/10.1115/1.4062811","url":null,"abstract":"\u0000 Freeform bending offers a wide range of possibilities in terms of component geometries, material grades and profile cross-sections. In the field of circular solid and hollow profiles, the design of the tool is determined by the circular shape of the profile used. When using rectangular profiles, the cross-section of the tool cannot be easily obtained by an offset of the profile cross-section. The large tolerance ranges of the profile standards require compromises with regard to the shape and tolerances of the tool. Tests have shown that the design of the tool has a great influence on the quality of the component. Furthermore, the trade-off in the tool design can lead to unsuitable tool shapes leading to defects and damages on the profile. These are mainly wrinkling, cross-sectional deformations and strongly deformed profile corners, which in some cases form cracks in the material. In this paper, the influences of the tool design on the bending result and the defects of the profiles are investigated. For this purpose, several tool designs with different variants and combinations of the movable die and the fixed die are compared with each other.","PeriodicalId":16299,"journal":{"name":"Journal of Manufacturing Science and Engineering-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45941054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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