Abhijit Cholkar, R. McCann, D. Kinahan, D. Brabazon
Metallic surfaces are increasingly used in medical applications due to their favorable material properties such as high strength and biocompatibility. In medical applications anti-fouling properties are an important requirement especially for implants and medical devices which come into contact with different types of fluid streams. These should be anti-fouling in order to prevent contamination and corrosion. Laser processing methods such as ultrafast laser processing is a one-step and scalable process for surface texturing. This process can be used to produce well-defined surface nano- and microscale superficial textures such as Laser-induced Periodic Surface Structures (LIPSS) which can enhance the anti-fouling capability of the surface. In this study, micro and nano scaled LIPSS structures are manufactured on a biocompatible grade stainless steel 316L substrate using an ultrafast (< 370 fs) and low power (< 4 W) laser system. With an aim to optimize the anti-fouling properties, laser process parameters such as pulse energy, pulse repetition rate and beam scanning speed were varied to produce microstructures on the stainless-steel surface of varying dimensions. Surface roughness was analyzed using a laser surface profilometer and changes in the hydrophobicity were examined using water contact angle goniometry.
{"title":"Ultrafast Laser-Induced Surface Structuring of Anti-Fouling Steel Surfaces for Biomedical Applications","authors":"Abhijit Cholkar, R. McCann, D. Kinahan, D. Brabazon","doi":"10.1115/msec2022-85249","DOIUrl":"https://doi.org/10.1115/msec2022-85249","url":null,"abstract":"\u0000 Metallic surfaces are increasingly used in medical applications due to their favorable material properties such as high strength and biocompatibility. In medical applications anti-fouling properties are an important requirement especially for implants and medical devices which come into contact with different types of fluid streams. These should be anti-fouling in order to prevent contamination and corrosion. Laser processing methods such as ultrafast laser processing is a one-step and scalable process for surface texturing. This process can be used to produce well-defined surface nano- and microscale superficial textures such as Laser-induced Periodic Surface Structures (LIPSS) which can enhance the anti-fouling capability of the surface.\u0000 In this study, micro and nano scaled LIPSS structures are manufactured on a biocompatible grade stainless steel 316L substrate using an ultrafast (< 370 fs) and low power (< 4 W) laser system. With an aim to optimize the anti-fouling properties, laser process parameters such as pulse energy, pulse repetition rate and beam scanning speed were varied to produce microstructures on the stainless-steel surface of varying dimensions. Surface roughness was analyzed using a laser surface profilometer and changes in the hydrophobicity were examined using water contact angle goniometry.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"289 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76306922","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}
Semih Akin, Puyuan Wu, Chandra Nath, Jun Chen, M. Jun
Supersonic cold spraying of droplets containing functional nanomaterials is of particular interest in advanced thin-film coating, that enabling high-adhesion strength particle deposition. In this method, coating occurs when the particles are accelerated to supersonic velocities in a converging-diverging nozzle, and then impact onto a target surface. Here, the optimum design of the nozzle is essential to deal with low-inertia particles like droplets. In particular, nozzle geometrical parameters (i.e., throat diameter, exit diameter, divergent length) determine droplets’ acceleration and deposition characteristics under supersonic flow conditions. To this end, we thoroughly investigate the influence of nozzle geometrical parameters on droplets acceleration by numerical modeling followed by experimental validation, and a case study on surface coating application. Two-phase flow modeling was used to predict droplets’ behavior in continuous gas flow for different nozzle configurations. The results show that the nozzle expansion ratio — a function of throat and exit diameters — has a significant influence on droplet velocity, followed by divergent length. In particular, to correctly accelerate low-inertia liquid droplets, optimum nozzle expansion ratio for an axisymmetric convergent-divergent nozzle is found to be in a range of 1.5–2.5 for various sets of parameters, which is different than the recommended expansion ratio (i.e., 5–9) for cold spraying of micro-scale metal particles. The findings can help determine the ideal design of a supersonic nozzle to minimize turbulent velocity fluctuation and shock wave formation that in turn assist to effectively spray low-inertia particles like micro-scale droplets. Based on the simulation results, an optimal design of supersonic nozzle is selected and prototyped for the experimental studies. Numerical modeling results are validated by particle image velocimetry (PIV) measurements. Moreover, coating experiments confirm the adaptability of the optimized nozzle for supersonic cold spraying of droplets containing nanoparticles, which thereby has the potential for rapid production of advanced thin films.
{"title":"A Study on the Effect of Nozzle Geometrical Parameters on Supersonic Cold Spraying of Droplets","authors":"Semih Akin, Puyuan Wu, Chandra Nath, Jun Chen, M. Jun","doi":"10.1115/msec2022-85703","DOIUrl":"https://doi.org/10.1115/msec2022-85703","url":null,"abstract":"\u0000 Supersonic cold spraying of droplets containing functional nanomaterials is of particular interest in advanced thin-film coating, that enabling high-adhesion strength particle deposition. In this method, coating occurs when the particles are accelerated to supersonic velocities in a converging-diverging nozzle, and then impact onto a target surface. Here, the optimum design of the nozzle is essential to deal with low-inertia particles like droplets. In particular, nozzle geometrical parameters (i.e., throat diameter, exit diameter, divergent length) determine droplets’ acceleration and deposition characteristics under supersonic flow conditions. To this end, we thoroughly investigate the influence of nozzle geometrical parameters on droplets acceleration by numerical modeling followed by experimental validation, and a case study on surface coating application. Two-phase flow modeling was used to predict droplets’ behavior in continuous gas flow for different nozzle configurations. The results show that the nozzle expansion ratio — a function of throat and exit diameters — has a significant influence on droplet velocity, followed by divergent length. In particular, to correctly accelerate low-inertia liquid droplets, optimum nozzle expansion ratio for an axisymmetric convergent-divergent nozzle is found to be in a range of 1.5–2.5 for various sets of parameters, which is different than the recommended expansion ratio (i.e., 5–9) for cold spraying of micro-scale metal particles. The findings can help determine the ideal design of a supersonic nozzle to minimize turbulent velocity fluctuation and shock wave formation that in turn assist to effectively spray low-inertia particles like micro-scale droplets. Based on the simulation results, an optimal design of supersonic nozzle is selected and prototyped for the experimental studies. Numerical modeling results are validated by particle image velocimetry (PIV) measurements. Moreover, coating experiments confirm the adaptability of the optimized nozzle for supersonic cold spraying of droplets containing nanoparticles, which thereby has the potential for rapid production of advanced thin films.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"44 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77380463","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}
Manufacturers have great power to change the sustainability of products over the whole life cycle, but they need holistic life cycle models to guide those decisions. Challenges exist in connecting the product’s life cycle data to model-based sustainability metrics and in quantifying uncertainty in the product data. This study develops a life-cycle energy framework around two application cases to showcase informed and transparent decision-making. The case studies investigate additively manufactured parts in two friction scenarios, one where low friction is desired and one where high friction is preferred. The layer height is chosen as process parameter of additive manufacturing that changes the surface roughness of the sample parts, but also the manufacturing time and energy. The use phase energy in the first friction scenario is influenced by the user behavior, and by a random input function in the second scenario. The life-cycle energy framework is used to discuss total life cycle energy for each scenario. In general, this framework should be used to better connect product use phase and manufacturing phase, in particular by examining the interconnections of part design, manufacturing phase impacts, and use performance. Product quality is the central aspect of optimization. The framework can be used for engineering education and be expanded to study data uncertainty, user behavior, system complexity, process chains, machine learning, sustainability metrics, and more.
{"title":"Product Life-Cycle Energy Framework in Friction Scenarios","authors":"B. Linke, Shivam Gupta","doi":"10.1115/msec2022-85263","DOIUrl":"https://doi.org/10.1115/msec2022-85263","url":null,"abstract":"\u0000 Manufacturers have great power to change the sustainability of products over the whole life cycle, but they need holistic life cycle models to guide those decisions. Challenges exist in connecting the product’s life cycle data to model-based sustainability metrics and in quantifying uncertainty in the product data. This study develops a life-cycle energy framework around two application cases to showcase informed and transparent decision-making. The case studies investigate additively manufactured parts in two friction scenarios, one where low friction is desired and one where high friction is preferred. The layer height is chosen as process parameter of additive manufacturing that changes the surface roughness of the sample parts, but also the manufacturing time and energy. The use phase energy in the first friction scenario is influenced by the user behavior, and by a random input function in the second scenario. The life-cycle energy framework is used to discuss total life cycle energy for each scenario. In general, this framework should be used to better connect product use phase and manufacturing phase, in particular by examining the interconnections of part design, manufacturing phase impacts, and use performance. Product quality is the central aspect of optimization. The framework can be used for engineering education and be expanded to study data uncertainty, user behavior, system complexity, process chains, machine learning, sustainability metrics, and more.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"53 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76382402","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":"32 1","pages":""},"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}
Additive manufacturing (AM) sits poised to make a large impact on the manufacturing sector. Fused deposition modeling (FDM), a type of AM, while versatile, and increasingly appearing in full production systems, has performance limitations in certain geometries, such as arcs and holes. This is especially true for the desktop setups common in College Maker Spaces and other prototyping environments. For these use cases, it is critical to obtain accurate parts quickly, yet often difficult, diminishing the value of using FDM, whether it be to prototype new designs, make final parts, or anything in between. Iterative Learning Control (ILC) has been applied to robot control, plastic extrusion, and other similar processes where disturbances to a system are present and relatively constant, but difficult to model and correct. Since desktop printers perform repetitive tasks subject to nearly constant disturbances that induce inaccuracies, a natural research question arises: can ILC be used to allow desktop printers to learn these inaccuracies and account for them, allowing such printers to create more accurate and useful parts for the average prototyping user? Details on the printer, a LulzBot Taz 6, and the scanner, an Einscan 3D Scanner, being used to answer this question are first presented with some baseline data to establish the scanner’s nominal accuracy. Subsequently, a simple bounding box approach was developed and tested where only the part’s length, width, and height were monitored and adjusted. This approach determined an error metric for a scalene triangular prism by determining the length, width, and height of a box that bounds the shape. The ILC algorithm used this error metric to generate a new file to print for the next iteration, thus creating parts that became more and more accurate. While this approach exhibited some success, it cannot account for larger, more common issues such as warping (where shrinking occurs as the plastic cools over time causing bending or bowing in the part), or a hole being geometrically inaccurate compared to the desired diameter. To address these concerns, a grid approach was developed where the cardinal dimensions had a grid overlaid so that points along each dimension could be checked and adjusted in subsequent prints to account for such issues. This approach was applied to rectangular bars with relative success. The overall dimensional accuracy (e.g. length, width, height) was not significantly improved, however, warping along the length of the bar was significantly reduced. A similar approach for more complex geometries, (i.e. holes and arcs) is currently under development. Initial thoughts and plans are presented as concluding remarks. Using ILC to account for common issues with desktop FDM printers could enable higher quality parts to be made, without a substantial investment in higher-grade equipment.
{"title":"Using Iterative Learning Control to Improve the Accuracy of Desktop Fused Deposition Modeling Printers: An Experimental Case Study","authors":"Lawrence W. Funke, Matthew N. Opara","doi":"10.1115/msec2022-78324","DOIUrl":"https://doi.org/10.1115/msec2022-78324","url":null,"abstract":"\u0000 Additive manufacturing (AM) sits poised to make a large impact on the manufacturing sector. Fused deposition modeling (FDM), a type of AM, while versatile, and increasingly appearing in full production systems, has performance limitations in certain geometries, such as arcs and holes. This is especially true for the desktop setups common in College Maker Spaces and other prototyping environments. For these use cases, it is critical to obtain accurate parts quickly, yet often difficult, diminishing the value of using FDM, whether it be to prototype new designs, make final parts, or anything in between. Iterative Learning Control (ILC) has been applied to robot control, plastic extrusion, and other similar processes where disturbances to a system are present and relatively constant, but difficult to model and correct. Since desktop printers perform repetitive tasks subject to nearly constant disturbances that induce inaccuracies, a natural research question arises: can ILC be used to allow desktop printers to learn these inaccuracies and account for them, allowing such printers to create more accurate and useful parts for the average prototyping user?\u0000 Details on the printer, a LulzBot Taz 6, and the scanner, an Einscan 3D Scanner, being used to answer this question are first presented with some baseline data to establish the scanner’s nominal accuracy. Subsequently, a simple bounding box approach was developed and tested where only the part’s length, width, and height were monitored and adjusted. This approach determined an error metric for a scalene triangular prism by determining the length, width, and height of a box that bounds the shape. The ILC algorithm used this error metric to generate a new file to print for the next iteration, thus creating parts that became more and more accurate. While this approach exhibited some success, it cannot account for larger, more common issues such as warping (where shrinking occurs as the plastic cools over time causing bending or bowing in the part), or a hole being geometrically inaccurate compared to the desired diameter. To address these concerns, a grid approach was developed where the cardinal dimensions had a grid overlaid so that points along each dimension could be checked and adjusted in subsequent prints to account for such issues. This approach was applied to rectangular bars with relative success. The overall dimensional accuracy (e.g. length, width, height) was not significantly improved, however, warping along the length of the bar was significantly reduced. A similar approach for more complex geometries, (i.e. holes and arcs) is currently under development. Initial thoughts and plans are presented as concluding remarks. Using ILC to account for common issues with desktop FDM printers could enable higher quality parts to be made, without a substantial investment in higher-grade equipment.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"55 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85582496","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":"67 1","pages":""},"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}
This paper introduces using GLancing Angle Deposition (GLAD) with corral seeds for synthesizing nanodots and nanolines. GLAD is an advanced physical vapor deposition technique for creating three dimensional nanostructures. GLAD is commonly combined with pre-determined seeds on the substrate to create periodic nanofeature arrays; the seeds are usually artificial nucleation sites to rearrange the deposition patterns. However, the concept of corral seeds is different: the incident vapor will be depositing both on and inside the sacrificial layer of the corrals that consist various shapes; the desired nanostructures are grown from the overlapped deposition areas inside the corrals while the substrate rotates, depending on the shape of the corrals, and eventually will be remaining on the substrate when the sacrificial layer of the corral seeds is removed. The thickness of the sacrificial corrals along with the incident angle of the vapor define the shadow areas and deposition areas inside the corrals on the substrate. In this paper, three types of corrals are introduced: circular corrals, dumbbell corrals, and line corrals. The different nanofeatures of nanodots, limited-length nanolines and wafer-length nanolines created by different shaped corrals are presented. The fabricated nanodots and nanolines are potentially used in various optical and sensing applications. The two-step fabrication process of preparing corrals and GLAD provides numerous benefits for the synthesis of the nanofeatures.
{"title":"Synthesis of Nano-Dots and Lines by Glancing Angle Deposition With Corrals","authors":"C. Qu, S. Mcnamara, K. Walsh","doi":"10.1115/msec2022-83720","DOIUrl":"https://doi.org/10.1115/msec2022-83720","url":null,"abstract":"\u0000 This paper introduces using GLancing Angle Deposition (GLAD) with corral seeds for synthesizing nanodots and nanolines. GLAD is an advanced physical vapor deposition technique for creating three dimensional nanostructures. GLAD is commonly combined with pre-determined seeds on the substrate to create periodic nanofeature arrays; the seeds are usually artificial nucleation sites to rearrange the deposition patterns. However, the concept of corral seeds is different: the incident vapor will be depositing both on and inside the sacrificial layer of the corrals that consist various shapes; the desired nanostructures are grown from the overlapped deposition areas inside the corrals while the substrate rotates, depending on the shape of the corrals, and eventually will be remaining on the substrate when the sacrificial layer of the corral seeds is removed. The thickness of the sacrificial corrals along with the incident angle of the vapor define the shadow areas and deposition areas inside the corrals on the substrate. In this paper, three types of corrals are introduced: circular corrals, dumbbell corrals, and line corrals. The different nanofeatures of nanodots, limited-length nanolines and wafer-length nanolines created by different shaped corrals are presented. The fabricated nanodots and nanolines are potentially used in various optical and sensing applications. The two-step fabrication process of preparing corrals and GLAD provides numerous benefits for the synthesis of the nanofeatures.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85661182","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 constrained surface vat photopolymerization, the separation process between a newly printed layer and the vat film has long been a limiting factor for printing speed and feature size. This paper aims to compare the performance of a hydrogel film and a conventionally used polytetrafluoroethylene (PTFE) in terms of separation forces, vertical separation distances, and dimensional accuracies of the printed parts. PTFE is commonly adopted because of its low surface energy and thus low separation force, while the hydrogel film is hypothetically effective because of its repelling nature to the non-polar characteristic in most photopolymers. A custom-designed building platform with an integrated sensor is used to continuously sample the force at 1,000Hz with 0.1N resolution. The separation distance is calculated based on the ascending and descending force profiles. The results show a 26% reduction in separation forces and a 60% reduction in vertical separation distances, with 95% statistical significance when comparing the hydrogel film to the PTFE film. The dimensional accuracies of produced parts in both films are similar.
{"title":"Separation Process Comparison of Hydrogel Film and PTFE Film in Vat Photopolymerization","authors":"F. Yang, Aamer A. Kazi, Caleb Liu, Bruce Tai","doi":"10.1115/msec2022-85380","DOIUrl":"https://doi.org/10.1115/msec2022-85380","url":null,"abstract":"\u0000 In constrained surface vat photopolymerization, the separation process between a newly printed layer and the vat film has long been a limiting factor for printing speed and feature size. This paper aims to compare the performance of a hydrogel film and a conventionally used polytetrafluoroethylene (PTFE) in terms of separation forces, vertical separation distances, and dimensional accuracies of the printed parts. PTFE is commonly adopted because of its low surface energy and thus low separation force, while the hydrogel film is hypothetically effective because of its repelling nature to the non-polar characteristic in most photopolymers. A custom-designed building platform with an integrated sensor is used to continuously sample the force at 1,000Hz with 0.1N resolution. The separation distance is calculated based on the ascending and descending force profiles. The results show a 26% reduction in separation forces and a 60% reduction in vertical separation distances, with 95% statistical significance when comparing the hydrogel film to the PTFE film. The dimensional accuracies of produced parts in both films are similar.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"35 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75558854","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}
The front matter for this proceedings is available by clicking on the PDF icon.
通过点击PDF图标可获得本次会议的主题。
{"title":"MSEC2022 Front Matter","authors":"","doi":"10.1115/msec2022-fm1","DOIUrl":"https://doi.org/10.1115/msec2022-fm1","url":null,"abstract":"\u0000 The front matter for this proceedings is available by clicking on the PDF icon.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75727763","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}
Fused Filament Fabrication (FFF) is one of the common methods among the Additive Manufacturing (AM) processes. In this study, hemp fiber, a sustainable, and fast degraded material introduced and mixed with fresh Polylactic Acid (PLA) filament with 3 wt%, 7.5 wt%, and 10 wt% to improve the drawbacks of pure PLA filament and sustain its required properties. The results from the fatigue testing of pure PLA, and various hemp-fiber infused PLA indicated that increasing the wt% content of a hemp fiber infused PLA specimen at a certain point does increase the ultimate bending stress as well as the overall fatigue life of a pure PLA specimen. The 10 wt% hemp fiber specimens provided a 7.32% increase in the mean ultimate flexural strength over pure PLA. The mean of Young’s modulus also increased by 10.65% for the 10 wt% hemp fiber specimen and by 23.05% for the 7.5 wt% hemp fiber specimen over PLA. The 10 wt% hemp fiber specimens also provided a 4.05% increase in fatigue life over PLA. The 3 wt% did not provide a significant improvement in the study. These findings provide insight into the AM processes and lead to the development of environment-friendly composites in the industries.
{"title":"Characterization of Polylactic Acid Filament With Biodegradable Hemp Fiber Infused During Additive Manufacturing Process","authors":"M. Hanson, Che-Hao Yang","doi":"10.1115/msec2022-85176","DOIUrl":"https://doi.org/10.1115/msec2022-85176","url":null,"abstract":"\u0000 Fused Filament Fabrication (FFF) is one of the common methods among the Additive Manufacturing (AM) processes. In this study, hemp fiber, a sustainable, and fast degraded material introduced and mixed with fresh Polylactic Acid (PLA) filament with 3 wt%, 7.5 wt%, and 10 wt% to improve the drawbacks of pure PLA filament and sustain its required properties. The results from the fatigue testing of pure PLA, and various hemp-fiber infused PLA indicated that increasing the wt% content of a hemp fiber infused PLA specimen at a certain point does increase the ultimate bending stress as well as the overall fatigue life of a pure PLA specimen. The 10 wt% hemp fiber specimens provided a 7.32% increase in the mean ultimate flexural strength over pure PLA. The mean of Young’s modulus also increased by 10.65% for the 10 wt% hemp fiber specimen and by 23.05% for the 7.5 wt% hemp fiber specimen over PLA. The 10 wt% hemp fiber specimens also provided a 4.05% increase in fatigue life over PLA. The 3 wt% did not provide a significant improvement in the study. These findings provide insight into the AM processes and lead to the development of environment-friendly composites in the industries.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"9 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74315907","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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