Microscale Selective Laser Sintering is an Additive Manufacturing process which involves the creation of parts using nanoparticles, precision substrate motion control, and an optical setup aimed at achieving sub-micron resolution on the printed parts. In order to drive the Microscale Selective Laser Sintering process towards this proposed goal, it is important to understand the kinetics of nanoparticle sintering to be able to make predictions of the properties that can be expected from the manufacturing process. To this end, Phase Field Modelling simulations have been built which model how nanoparticles sinter together when heated. In the past these simulations have yielded measurements such as the densification in the powder bed as a function of temperature and time, however it is extremely difficult to measure the density of parts built from the microscale Selective Laser Sintering system. Electrical resistance is a much more easily quantified property. As such, in order to fully validate these nanoparticle sintering simulations, it is necessary to measure the electrical resistance in the simulation bed and compare these resistance curves against experimentally derived electrical resistance measurements. This paper presents the approach used to extract electrical resistance data from the simulations as well as preliminary resistance results collated from this study.
{"title":"Electrical Resistance Metrology in Nanoparticle Sintering Simulations","authors":"O. Dibua, C. S. Foong, M. Cullinan","doi":"10.1115/msec2022-85997","DOIUrl":"https://doi.org/10.1115/msec2022-85997","url":null,"abstract":"\u0000 Microscale Selective Laser Sintering is an Additive Manufacturing process which involves the creation of parts using nanoparticles, precision substrate motion control, and an optical setup aimed at achieving sub-micron resolution on the printed parts. In order to drive the Microscale Selective Laser Sintering process towards this proposed goal, it is important to understand the kinetics of nanoparticle sintering to be able to make predictions of the properties that can be expected from the manufacturing process. To this end, Phase Field Modelling simulations have been built which model how nanoparticles sinter together when heated. In the past these simulations have yielded measurements such as the densification in the powder bed as a function of temperature and time, however it is extremely difficult to measure the density of parts built from the microscale Selective Laser Sintering system. Electrical resistance is a much more easily quantified property. As such, in order to fully validate these nanoparticle sintering simulations, it is necessary to measure the electrical resistance in the simulation bed and compare these resistance curves against experimentally derived electrical resistance measurements. This paper presents the approach used to extract electrical resistance data from the simulations as well as preliminary resistance results collated from this study.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76012686","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}
Metamaterials have emerged as a group of promising materials with potential applications in a wide range of industries such as aerospace and automobile, owing to their unconventional properties. The state-of-the-art suggests that lattice metamaterials offer lightweight structures while ensuring good mechanical properties, and hollow lattices can be leveraged to achieve ultra-lightweight metamaterials to further broaden the application horizons. In this research, hollow cross-sections are designed for lattice-based metamaterials in order to achieve a high stiffness/strength-to-weight ratio. The Mechanics of Structure Genome method is adopted to perform the beam cross-section analysis, leading to three cross-sections studied including solid, elliptical, and rectangular cross-sections. The designed metamaterials with hollow cross-sections have complex structures and therefore they are fabricated using the Selective Laser Sintering process. The compressive tests suggest that metamaterials with hollow cross-sections have a higher stiffness-to-weight ratio of 25% to 30% in comparison with solid cross-sections. In addition, hollow lattice metamaterials demonstrate better energy absorption capability compared to solid lattices of the same density, which is a critical characteristic to avoid catastrophic mechanical failure. It is observed from the compressive tests that the nodes in the unit cells tend to break first, indicating possible future research to further enhance the strength of hollow lattice metamaterials.
{"title":"Additive Manufacturing of Novel Beam Lattice Metamaterials With Hollow Cross-Sections Towards High Stiffness/Strength-to-Weight Ratio","authors":"Md Humaun Kobir, Xin Liu, Yiran Yang, Fang Jiang","doi":"10.1115/msec2022-85627","DOIUrl":"https://doi.org/10.1115/msec2022-85627","url":null,"abstract":"\u0000 Metamaterials have emerged as a group of promising materials with potential applications in a wide range of industries such as aerospace and automobile, owing to their unconventional properties. The state-of-the-art suggests that lattice metamaterials offer lightweight structures while ensuring good mechanical properties, and hollow lattices can be leveraged to achieve ultra-lightweight metamaterials to further broaden the application horizons. In this research, hollow cross-sections are designed for lattice-based metamaterials in order to achieve a high stiffness/strength-to-weight ratio. The Mechanics of Structure Genome method is adopted to perform the beam cross-section analysis, leading to three cross-sections studied including solid, elliptical, and rectangular cross-sections. The designed metamaterials with hollow cross-sections have complex structures and therefore they are fabricated using the Selective Laser Sintering process. The compressive tests suggest that metamaterials with hollow cross-sections have a higher stiffness-to-weight ratio of 25% to 30% in comparison with solid cross-sections. In addition, hollow lattice metamaterials demonstrate better energy absorption capability compared to solid lattices of the same density, which is a critical characteristic to avoid catastrophic mechanical failure. It is observed from the compressive tests that the nodes in the unit cells tend to break first, indicating possible future research to further enhance the strength of hollow lattice metamaterials.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83857088","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}
Theodore Gabor, Semih Akin, J. Tsai, Seunghwan Jo, Feraas Al-Najjar, M. Jun
Cold spray additive manufacturing (CSAM) is an emerging technique for scalable and rapid deposition of thick metallic coatings on various substrates. Despite great promises, CSAM with no upper limit of coating thickness remains challenging due to the stochastic nature of cold spray (CS) deposition. In particular, using axisymmetric nozzles (i.e., circular supersonic nozzles) lead to a quasi-Gaussian shaped particle distribution on the target surface, which limits the CSAM due to the formation of triangular-shaped (i.e., peak/valley-shaped) coating morphology. Recently, rectangular cold spray nozzles have been applied to CS particle deposition, and found to be promising for CSAM owing to its more uniform particle distribution and wider spray beam. In these studies, however, process-structure properties of cold spray deposition with a rectangular nozzle have not been sufficiently elucidated. Practical expansion of rectangular nozzles in CSAM strictly depends on uncovering process-structure properties of CS deposition phenomenon. To this end, we investigate cold spray deposition of microscale particles using a rectangular nozzle through three-dimensional discrete-phase turbulent flow modeling. The numerical modeling results are experimentally justified using a dual disc anemometer setup. The influence of operating gas conditions on critical particle deposition parameters is studied. An experimental case study of cold spray particle deposition on a polymer (ABS) substrate is also conducted to show the potential of rectangular nozzle in cold-spray based polymer metallization. The results suggest that cold spraying using a rectangular nozzle is beneficial for a more uniform, compact, and higher precision particle distribution on the target surface.
{"title":"Numerical Studies on Cold Spray Particle Deposition Using a Rectangular Nozzle","authors":"Theodore Gabor, Semih Akin, J. Tsai, Seunghwan Jo, Feraas Al-Najjar, M. Jun","doi":"10.1115/msec2022-85673","DOIUrl":"https://doi.org/10.1115/msec2022-85673","url":null,"abstract":"\u0000 Cold spray additive manufacturing (CSAM) is an emerging technique for scalable and rapid deposition of thick metallic coatings on various substrates. Despite great promises, CSAM with no upper limit of coating thickness remains challenging due to the stochastic nature of cold spray (CS) deposition. In particular, using axisymmetric nozzles (i.e., circular supersonic nozzles) lead to a quasi-Gaussian shaped particle distribution on the target surface, which limits the CSAM due to the formation of triangular-shaped (i.e., peak/valley-shaped) coating morphology. Recently, rectangular cold spray nozzles have been applied to CS particle deposition, and found to be promising for CSAM owing to its more uniform particle distribution and wider spray beam. In these studies, however, process-structure properties of cold spray deposition with a rectangular nozzle have not been sufficiently elucidated. Practical expansion of rectangular nozzles in CSAM strictly depends on uncovering process-structure properties of CS deposition phenomenon. To this end, we investigate cold spray deposition of microscale particles using a rectangular nozzle through three-dimensional discrete-phase turbulent flow modeling. The numerical modeling results are experimentally justified using a dual disc anemometer setup. The influence of operating gas conditions on critical particle deposition parameters is studied. An experimental case study of cold spray particle deposition on a polymer (ABS) substrate is also conducted to show the potential of rectangular nozzle in cold-spray based polymer metallization. The results suggest that cold spraying using a rectangular nozzle is beneficial for a more uniform, compact, and higher precision particle distribution on the target surface.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80732283","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 manufacturing industries, spherical micro-particles are commonly used as (e.g., brazing powder, metal filler, and 3D printing powder) which are produced with droplet-based particle fabrication techniques. Such processes create spherical morphology but introduce polydispersity and follow a continuous exponential pattern commonly expressed with Rosin-Rammler expression. Sorting those micro-particles in a narrower size range is an important but difficult, costly, and challenging process. Here we demonstrate the successful separation of the particles from a poly-disperse mixture with a particle volume fraction of 10% by dipping process. Nickel-based micro-particles (avg. dia. 5.69 μm) are added in a binder-based liquid carrier system. To encounter the gravitational force, external kinetic energy in the form of agitation is applied to ensure the uniform dispersion of the particles. The cylindrical substrate is prepared and dipped in the ‘pseudo suspension’ to separate the particles by adhering to it. The substrate is dried, and images are taken to characterize the separated particles using image J software. A clear size distribution can be observed which is also plotted. Additionally, a relationship between the process parameter and sorted particles has been established. The proposed method is quick, controllable, and easy to implement, which can be a useful tool for sorting wide-range poly-disperse particles.
{"title":"Size-Based Filtration of Poly-Disperse Micro-Particle by Dipping","authors":"M. Khalil, Bashir Khoda","doi":"10.1115/msec2022-85680","DOIUrl":"https://doi.org/10.1115/msec2022-85680","url":null,"abstract":"\u0000 In manufacturing industries, spherical micro-particles are commonly used as (e.g., brazing powder, metal filler, and 3D printing powder) which are produced with droplet-based particle fabrication techniques. Such processes create spherical morphology but introduce polydispersity and follow a continuous exponential pattern commonly expressed with Rosin-Rammler expression. Sorting those micro-particles in a narrower size range is an important but difficult, costly, and challenging process. Here we demonstrate the successful separation of the particles from a poly-disperse mixture with a particle volume fraction of 10% by dipping process. Nickel-based micro-particles (avg. dia. 5.69 μm) are added in a binder-based liquid carrier system. To encounter the gravitational force, external kinetic energy in the form of agitation is applied to ensure the uniform dispersion of the particles. The cylindrical substrate is prepared and dipped in the ‘pseudo suspension’ to separate the particles by adhering to it. The substrate is dried, and images are taken to characterize the separated particles using image J software. A clear size distribution can be observed which is also plotted. Additionally, a relationship between the process parameter and sorted particles has been established. The proposed method is quick, controllable, and easy to implement, which can be a useful tool for sorting wide-range poly-disperse particles.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73113123","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}
Zoe Alexander, Nathaniel DeVol, Molly Emig, K. Saleeby, T. Feldhausen, Thomas Kurfess, Katherine Fu, Christopher Saldaña
A critical factor in the implementation of direct energy deposition is the ability to maintain the standoff distance between the nozzle and the build surface, as this influences powder capture efficiency and overall part quality. Due to process-related variations, layer height may vary, causing unintended variation in standoff distance and poor build quality. While prior work has utilized contact probing to qualify standoff distance during processing, in situ methods for qualification of standoff distance are of major interest. The present work seeks to understand efficacy of image-based methods for classifying standoff distance variation in real-time using support vector machines (SVMs). It was hypothesized that the size of the melt pool and the amount of spatter will have significant correlations with deviations in the standoff distance; thus, SVMs were used on a dataset that is comprised of morphological features of melt pool size and image entropy. The SVM model was used to classify melt pool images into categories according to standoff distance variation from nominal. K-folds cross validation was used to find the optimal hyperparameters for the SVM model. To understand the impact of the selected features on the classification performance and inference speed, multiple models were trained with differing numbers of included features. Results for classification score, inference time, and image preprocessing/feature extraction from these data are reported. The present results show that the SVM model was able to predict the standoff distance classification with an accuracy of 97 percent and a speed of 0.122 s per image, making it a viable solution for real-time control of standoff distance.
{"title":"Support Vector Machines for Classification of Direct Energy Deposition Standoff Distance for Improved Process Control","authors":"Zoe Alexander, Nathaniel DeVol, Molly Emig, K. Saleeby, T. Feldhausen, Thomas Kurfess, Katherine Fu, Christopher Saldaña","doi":"10.1115/msec2022-85382","DOIUrl":"https://doi.org/10.1115/msec2022-85382","url":null,"abstract":"\u0000 A critical factor in the implementation of direct energy deposition is the ability to maintain the standoff distance between the nozzle and the build surface, as this influences powder capture efficiency and overall part quality. Due to process-related variations, layer height may vary, causing unintended variation in standoff distance and poor build quality. While prior work has utilized contact probing to qualify standoff distance during processing, in situ methods for qualification of standoff distance are of major interest. The present work seeks to understand efficacy of image-based methods for classifying standoff distance variation in real-time using support vector machines (SVMs). It was hypothesized that the size of the melt pool and the amount of spatter will have significant correlations with deviations in the standoff distance; thus, SVMs were used on a dataset that is comprised of morphological features of melt pool size and image entropy. The SVM model was used to classify melt pool images into categories according to standoff distance variation from nominal. K-folds cross validation was used to find the optimal hyperparameters for the SVM model. To understand the impact of the selected features on the classification performance and inference speed, multiple models were trained with differing numbers of included features. Results for classification score, inference time, and image preprocessing/feature extraction from these data are reported. The present results show that the SVM model was able to predict the standoff distance classification with an accuracy of 97 percent and a speed of 0.122 s per image, making it a viable solution for real-time control of standoff distance.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84894661","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}
Shilun Du, Murong Li, Tian Xu, Yingda Hu, Zhen Wang, Yong Lei
3D needle insertion is important both in theoretical research and clinic practice. In literature, most needle insertion experiments use 2D experiment platforms. A few studies use 3D experiment platforms based on ultrasound or traditional stereo camera. The ultrasound has low resolution and traditional stereo camera is difficult to reconstruct objects without textures, which is not suitable for markers reconstruction. Hence, it is needed to design a 3D needle insertion experiment platform with high resolution and 3D reconstruction ability. In this paper, we design a 3D needle insertion platform based on the orthogonal-arranged dual camera. Error analysis and accuracy verification are carried out as well. First, experiment platform framework is designed and essential modules are introduced. Second, the error analyses based on Frechet distance are carried out to quantify the error led by the bevel facing angle and insertion angle. Third, to verify the 3D reconstruction accuracy, the 2D distance sensitivity experiments and 3D reconstruction experiments are carried out for the dual camera system. The accuracy of 3D reconstruction in the region of interest has been verified. To optimize the 3D needle insertion platform, a needle holder to ensure concentricity is applied. Besides, pre-insertion process and orthogonal-arranged double chessboard calibration are introduced into setup procedures. Finally, a 3D needle insertion experiment platform is designed and validated through needle path planning algorithm verification. Results show that the proposed experiment platform can steer the needle accurately and reconstruct the needle path and markers in acceptable accuracy.
{"title":"Design and Analysis of a Novel Experiment Platform for 3D Needle Insertion Based on Orthogonally Arranged Dual Camera","authors":"Shilun Du, Murong Li, Tian Xu, Yingda Hu, Zhen Wang, Yong Lei","doi":"10.1115/msec2022-85764","DOIUrl":"https://doi.org/10.1115/msec2022-85764","url":null,"abstract":"\u0000 3D needle insertion is important both in theoretical research and clinic practice. In literature, most needle insertion experiments use 2D experiment platforms. A few studies use 3D experiment platforms based on ultrasound or traditional stereo camera. The ultrasound has low resolution and traditional stereo camera is difficult to reconstruct objects without textures, which is not suitable for markers reconstruction. Hence, it is needed to design a 3D needle insertion experiment platform with high resolution and 3D reconstruction ability. In this paper, we design a 3D needle insertion platform based on the orthogonal-arranged dual camera. Error analysis and accuracy verification are carried out as well. First, experiment platform framework is designed and essential modules are introduced. Second, the error analyses based on Frechet distance are carried out to quantify the error led by the bevel facing angle and insertion angle. Third, to verify the 3D reconstruction accuracy, the 2D distance sensitivity experiments and 3D reconstruction experiments are carried out for the dual camera system. The accuracy of 3D reconstruction in the region of interest has been verified. To optimize the 3D needle insertion platform, a needle holder to ensure concentricity is applied. Besides, pre-insertion process and orthogonal-arranged double chessboard calibration are introduced into setup procedures. Finally, a 3D needle insertion experiment platform is designed and validated through needle path planning algorithm verification. Results show that the proposed experiment platform can steer the needle accurately and reconstruct the needle path and markers in acceptable accuracy.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79802299","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}
Metal additive manufacturing technology that uses arc welding technology to deposit material is called wire arc additive manufacturing. Robotic manipulators that have a large workspace to size ratio are used to enable wire arc additive manufacturing. Wire arc additive manufacturing is gaining popularity due to the fast build time achieved by the high material deposition rates. It can build large-scale parts at a faster speed compared to other metal additive manufacturing processes. Utilizing a tilting build platform along with a robotic manipulator referred to as a multi-axis setup can enhance the capability of wire arc additive manufacturing. It will allow the setup to build complex supportless geometries that are not possible otherwise. However, maintaining a constant layer height while performing multi-axis wire arc additive manufacturing is challenging due to the forces involved in the process. This paper presents a new sensor-based two-step process along with the tool trajectory generation for maintaining constant layer height while performing multi-axis wire arc additive manufacturing. As the first step, we regulate the tool trajectory velocity to minimize the variation in the layer height. In the second step, we develop a sensor-based intervention scheme to fix the variation in the layer height by introducing additional height compensation layers. Finally, we test our approach by building a few parts, including a tool for the composite layup process.
{"title":"Robot Trajectory Generation for Multi-Axis Wire Arc Additive Manufacturing","authors":"P. Bhatt, Zachary McNulty, S. Gupta","doi":"10.1115/msec2022-85701","DOIUrl":"https://doi.org/10.1115/msec2022-85701","url":null,"abstract":"\u0000 Metal additive manufacturing technology that uses arc welding technology to deposit material is called wire arc additive manufacturing. Robotic manipulators that have a large workspace to size ratio are used to enable wire arc additive manufacturing. Wire arc additive manufacturing is gaining popularity due to the fast build time achieved by the high material deposition rates. It can build large-scale parts at a faster speed compared to other metal additive manufacturing processes. Utilizing a tilting build platform along with a robotic manipulator referred to as a multi-axis setup can enhance the capability of wire arc additive manufacturing. It will allow the setup to build complex supportless geometries that are not possible otherwise. However, maintaining a constant layer height while performing multi-axis wire arc additive manufacturing is challenging due to the forces involved in the process. This paper presents a new sensor-based two-step process along with the tool trajectory generation for maintaining constant layer height while performing multi-axis wire arc additive manufacturing. As the first step, we regulate the tool trajectory velocity to minimize the variation in the layer height. In the second step, we develop a sensor-based intervention scheme to fix the variation in the layer height by introducing additional height compensation layers. Finally, we test our approach by building a few parts, including a tool for the composite layup process.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79858874","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}
Kun Li, J. Zhan, Ruijin Ma, Yingzhi Ren, Jinxin Lin
The near-equiatomic NiTi alloy has a shape memory function, but the simple forming structure limits its application. Selective laser melting is a promising way to manufacture functionally complex structures due to its layer-wise production advantage, which could broaden the applications of NiTi alloy in the engineering fields. This work explored a novel method of controlling the repetition of laser remelting to manufacture NiTi alloys with multiple phase-transformation temperatures via selective laser melting (SLM). The results demonstrates that the remelting strategy not only increases the ultimate tensile strength and elongation of the SLMed NiTi alloy, but also increases the Ms above room temperature. The increase in laser power increases the temperature at which martensite starts (Ms) to transformation in the range higher room temperature (25°C), thus increasing the critical stress of martensitic detwinning in the final sample. Through the optimized repetitive laser remelting strategy with different laser powers on specific areas of the sample, a functionally gradient NiTi build is successfully obtained. This study suggests SLM embedded with laser remelting is a potential method to realize 4D printing for NiTi alloys.
{"title":"A Functionally Gradient NiTi Shape-Memory Alloy Fabricated by Selective Laser Melting","authors":"Kun Li, J. Zhan, Ruijin Ma, Yingzhi Ren, Jinxin Lin","doi":"10.1115/msec2022-83645","DOIUrl":"https://doi.org/10.1115/msec2022-83645","url":null,"abstract":"\u0000 The near-equiatomic NiTi alloy has a shape memory function, but the simple forming structure limits its application. Selective laser melting is a promising way to manufacture functionally complex structures due to its layer-wise production advantage, which could broaden the applications of NiTi alloy in the engineering fields. This work explored a novel method of controlling the repetition of laser remelting to manufacture NiTi alloys with multiple phase-transformation temperatures via selective laser melting (SLM). The results demonstrates that the remelting strategy not only increases the ultimate tensile strength and elongation of the SLMed NiTi alloy, but also increases the Ms above room temperature. The increase in laser power increases the temperature at which martensite starts (Ms) to transformation in the range higher room temperature (25°C), thus increasing the critical stress of martensitic detwinning in the final sample. Through the optimized repetitive laser remelting strategy with different laser powers on specific areas of the sample, a functionally gradient NiTi build is successfully obtained. This study suggests SLM embedded with laser remelting is a potential method to realize 4D printing for NiTi alloys.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84885035","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}
Jiwei Zhou, Jorge D. Camba, N. Hartman, Zhongtian Li
As organizations embrace Industry 4.0 and its corresponding digital transformation, new technologies and practices are enabling more resilient, integrated, and sustainable approaches to product development. Researchers have explored the information flows and data relationships between requirements management (RQM) practices and Computer-Aided Design (CAD) to improve New Product Development (NPD) processes. Similarly, Life Cycle Assessment (LCA) tools can be used to assess the environmental impact of a product at the early stages of development. In this paper, we propose a novel approach to integrate RQM, CAD, and LCA in the NPD process in a manner that extends the “digital thread” of information from the definition of design requirements to the geometry of the digital product model. Specifically, we demonstrate the seeding of mechanical design models directly from design requirements as a starting point for parametrization, the linking of data items to facilitate subsequent design changes involving geometry, and the use of data connections between requirements and 3D models for continuous design verification. Our approach is supported by a Product Lifecycle Management (PLM) system and involves a workflow with several stages and various inputs from stakeholders. We validate our approach through the implementation of a case study involving a mechanical assembly and a commercial PLM system.
{"title":"An Approach to Extend the Digital Thread From Requirements to Model Geometry","authors":"Jiwei Zhou, Jorge D. Camba, N. Hartman, Zhongtian Li","doi":"10.1115/msec2022-80857","DOIUrl":"https://doi.org/10.1115/msec2022-80857","url":null,"abstract":"\u0000 As organizations embrace Industry 4.0 and its corresponding digital transformation, new technologies and practices are enabling more resilient, integrated, and sustainable approaches to product development. Researchers have explored the information flows and data relationships between requirements management (RQM) practices and Computer-Aided Design (CAD) to improve New Product Development (NPD) processes. Similarly, Life Cycle Assessment (LCA) tools can be used to assess the environmental impact of a product at the early stages of development. In this paper, we propose a novel approach to integrate RQM, CAD, and LCA in the NPD process in a manner that extends the “digital thread” of information from the definition of design requirements to the geometry of the digital product model. Specifically, we demonstrate the seeding of mechanical design models directly from design requirements as a starting point for parametrization, the linking of data items to facilitate subsequent design changes involving geometry, and the use of data connections between requirements and 3D models for continuous design verification. Our approach is supported by a Product Lifecycle Management (PLM) system and involves a workflow with several stages and various inputs from stakeholders. We validate our approach through the implementation of a case study involving a mechanical assembly and a commercial PLM system.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80755553","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}
Olalekan O. Olowo, Ruoshi Zhang, A. Sherehiy, B. Goulet, Alexander Curry, Danming Wei, Zhong Yang, Moath H. A. Alqatamin, D. Popa
Enhancing physical human-robot interaction requires the improvement in the tactile perception of physical touch. Robot skin sensors exhibiting piezoresistive behavior can be used in conjunction with collaborative robots. In past work, fabrication of these tactile arrays was done using cleanroom techniques such as spin coating, photolithography, sputtering, wet and dry etching onto flexible polymers. In this paper, we present an addictive, non-cleanroom improved process of depositing PEDOT: PSS, which is the organic polymer responsible for the piezoresistive phenomenon of the robot skin sensor arrays. This publication details the patterning of the robot skin sensor structures and the adaptation of the inkjet printing technology to the fabrication process. This increases the possibility of scaling the production output while reducing the cleanroom fabrication cost and time from an approximately five-hour PEDOT: PSS deposition process to five minutes. Furthermore, the testing of these skin sensor arrays is carried out on a testing station equipped with a force plunger and an integrated circuit designed to provide perception feedback on various force load profiles controlled in an automated process. The results show uniform deposition of the PEDOT: PSS, consistent resistance measurement, and appropriate tactile response across an array of 16 sensors.
{"title":"Inkjet Printing of PEDOT:PSS Inks for Robotic Skin Sensors","authors":"Olalekan O. Olowo, Ruoshi Zhang, A. Sherehiy, B. Goulet, Alexander Curry, Danming Wei, Zhong Yang, Moath H. A. Alqatamin, D. Popa","doi":"10.1115/msec2022-80989","DOIUrl":"https://doi.org/10.1115/msec2022-80989","url":null,"abstract":"\u0000 Enhancing physical human-robot interaction requires the improvement in the tactile perception of physical touch. Robot skin sensors exhibiting piezoresistive behavior can be used in conjunction with collaborative robots. In past work, fabrication of these tactile arrays was done using cleanroom techniques such as spin coating, photolithography, sputtering, wet and dry etching onto flexible polymers. In this paper, we present an addictive, non-cleanroom improved process of depositing PEDOT: PSS, which is the organic polymer responsible for the piezoresistive phenomenon of the robot skin sensor arrays. This publication details the patterning of the robot skin sensor structures and the adaptation of the inkjet printing technology to the fabrication process. This increases the possibility of scaling the production output while reducing the cleanroom fabrication cost and time from an approximately five-hour PEDOT: PSS deposition process to five minutes. Furthermore, the testing of these skin sensor arrays is carried out on a testing station equipped with a force plunger and an integrated circuit designed to provide perception feedback on various force load profiles controlled in an automated process. The results show uniform deposition of the PEDOT: PSS, consistent resistance measurement, and appropriate tactile response across an array of 16 sensors.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90834437","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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