Hanyu Zhu, Nanzhu Zhao, S. Patil, A. Bhasin, Wei Li
Additive manufacturing (AM) of metallic parts is rapidly evolving and the fatigue behavior of AM parts has become a significant concern in both industry and academia. In this paper, a method to predict the fatigue life of additively manufactured metallic parts is presented based on the electrical resistance measurement. The damage of the AM parts is characterized by the resistance change during the fatigue process. By combining the electrical resistance measurement with a continuum damage mechanics theory, a mathematical model is developed to predict the fatigue life of the AM samples. Fatigue tests were conducted under different loading conditions with AM 316L stainless steel samples. The result showed that the electrical resistance held steady at the beginning and increased gradually with the number of fatigue loading cycles. The resistance increased dramatically as the sample approached the fracture point, and this sudden increase can be used to indicate the beginning of fracture. By converting the electrical resistance to fatigue damage, experimental data was used to estimate parameters of the fatigue life model. By comparing the model prediction with experimental data, it is shown that the change of electrical resistance can be used to predict the fatigue life of additively manufactured metallic parts.
{"title":"A Method to Predict Fatigue Life of Additively Manufactured Metallic Parts","authors":"Hanyu Zhu, Nanzhu Zhao, S. Patil, A. Bhasin, Wei Li","doi":"10.1115/msec2021-63632","DOIUrl":"https://doi.org/10.1115/msec2021-63632","url":null,"abstract":"\u0000 Additive manufacturing (AM) of metallic parts is rapidly evolving and the fatigue behavior of AM parts has become a significant concern in both industry and academia. In this paper, a method to predict the fatigue life of additively manufactured metallic parts is presented based on the electrical resistance measurement. The damage of the AM parts is characterized by the resistance change during the fatigue process. By combining the electrical resistance measurement with a continuum damage mechanics theory, a mathematical model is developed to predict the fatigue life of the AM samples. Fatigue tests were conducted under different loading conditions with AM 316L stainless steel samples. The result showed that the electrical resistance held steady at the beginning and increased gradually with the number of fatigue loading cycles. The resistance increased dramatically as the sample approached the fracture point, and this sudden increase can be used to indicate the beginning of fracture. By converting the electrical resistance to fatigue damage, experimental data was used to estimate parameters of the fatigue life model. By comparing the model prediction with experimental data, it is shown that the change of electrical resistance can be used to predict the fatigue life of additively manufactured metallic parts.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88588778","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}
Mohan Yu, Logan Lawrence, P. Claudio, James B. Day, Roozbeh Salary
Pneumatic micro-extrusion (PME), a direct-write additive manufacturing process, has emerged as a high-resolution method for the fabrication of a broad range of biological tissues and organs. However, the PME process is intrinsically complex, governed by complex physical phenomena. Hence, investigation of the effects of consequential parameters would be an inevitable need. The goal of this research work is to fabricate biocompatible, porous bone tissue scaffolds for the treatment of osseous fractures, defects, and eventually diseases. In pursuit of this goal, the objective of this study is to investigate the influence of material deposition factors — i.e., (i) deposition head temperature, (ii) flow pressure, and (iii) infill pattern — on the mechanical performance of PME-fabricated bone scaffolds. It was observed that the deposition head temperature as well as the flow pressure significantly affected scaffold diameter (unlike scaffold height). In addition, material deposition rate increased significantly as a result of an increase in the deposition temperature; this phenomenon stems from a reduction in Polycaprolactone (PCL) viscosity. Furthermore, there was a direct correlation between the amount of deposited mass and scaffold stiffness. Overall, the results of this study pave the way for future investigation of PME-deposited PCL scaffolds with optimal functional properties for incorporation of stem cells toward the treatment of osseous fractures and defects.
{"title":"Pneumatic Microextrusion-Based Additive Biofabrication of Polycaprolactone Bone Scaffolds: Part II – Investigation of the Influence of Polymer Flow Parameters","authors":"Mohan Yu, Logan Lawrence, P. Claudio, James B. Day, Roozbeh Salary","doi":"10.1115/msec2021-63412","DOIUrl":"https://doi.org/10.1115/msec2021-63412","url":null,"abstract":"\u0000 Pneumatic micro-extrusion (PME), a direct-write additive manufacturing process, has emerged as a high-resolution method for the fabrication of a broad range of biological tissues and organs. However, the PME process is intrinsically complex, governed by complex physical phenomena. Hence, investigation of the effects of consequential parameters would be an inevitable need. The goal of this research work is to fabricate biocompatible, porous bone tissue scaffolds for the treatment of osseous fractures, defects, and eventually diseases. In pursuit of this goal, the objective of this study is to investigate the influence of material deposition factors — i.e., (i) deposition head temperature, (ii) flow pressure, and (iii) infill pattern — on the mechanical performance of PME-fabricated bone scaffolds.\u0000 It was observed that the deposition head temperature as well as the flow pressure significantly affected scaffold diameter (unlike scaffold height). In addition, material deposition rate increased significantly as a result of an increase in the deposition temperature; this phenomenon stems from a reduction in Polycaprolactone (PCL) viscosity. Furthermore, there was a direct correlation between the amount of deposited mass and scaffold stiffness. Overall, the results of this study pave the way for future investigation of PME-deposited PCL scaffolds with optimal functional properties for incorporation of stem cells toward the treatment of osseous fractures and defects.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82287308","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}
Laser powder bed fusion (LPBF) is an increasingly popular approach for additive manufacturing (AM) of metals. However, parts produced by LPBF are prone to residual stresses, deformations, and other defects linked to nonuniform temperature distribution during the process. Several works have highlighted the important role (laser) scanning strategies, including laser power, scan speed, scan pattern and scan sequence, play in achieving uniform temperature distribution in LPBF. However, scan sequence continues to be determined offline based on trial-and-error or heuristics, which are neither optimal nor generalizable. To address these weaknesses, we present a framework for intelligent online scan sequence optimization to achieve uniform temperature distribution in LPBF. The framework involves the use of physics-based models for online optimization of scan sequence, while data acquired from in-situ thermal sensors provide correction or calibration of the models. The proposed framework depends on having: (1) LPBF machines capable of adjusting scan sequence in real-time; and (2) accurate and computationally efficient models and optimization approaches that can be efficiently executed online. The first challenge is addressed via a commercially available open-architecture LPBF machine. As a preliminary step towards tackling the second challenge, an analytical model is explored for determining the optimal sequence for scanning patterns in LPBF. The model is found to be deficient but provides useful insights into future work in this direction.
{"title":"Toward Intelligent Online Scan Sequence Optimization for Uniform Temperature Distribution in LPBF Additive Manufacturing","authors":"Keval S. Ramani, Ehsan Malekipour, C. Okwudire","doi":"10.1115/msec2021-63870","DOIUrl":"https://doi.org/10.1115/msec2021-63870","url":null,"abstract":"\u0000 Laser powder bed fusion (LPBF) is an increasingly popular approach for additive manufacturing (AM) of metals. However, parts produced by LPBF are prone to residual stresses, deformations, and other defects linked to nonuniform temperature distribution during the process. Several works have highlighted the important role (laser) scanning strategies, including laser power, scan speed, scan pattern and scan sequence, play in achieving uniform temperature distribution in LPBF. However, scan sequence continues to be determined offline based on trial-and-error or heuristics, which are neither optimal nor generalizable. To address these weaknesses, we present a framework for intelligent online scan sequence optimization to achieve uniform temperature distribution in LPBF. The framework involves the use of physics-based models for online optimization of scan sequence, while data acquired from in-situ thermal sensors provide correction or calibration of the models. The proposed framework depends on having: (1) LPBF machines capable of adjusting scan sequence in real-time; and (2) accurate and computationally efficient models and optimization approaches that can be efficiently executed online. The first challenge is addressed via a commercially available open-architecture LPBF machine. As a preliminary step towards tackling the second challenge, an analytical model is explored for determining the optimal sequence for scanning patterns in LPBF. The model is found to be deficient but provides useful insights into future work in this direction.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86568111","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 the past few years, Hybrid Additive Manufacturing has emerged to take advantage of both Additive Manufacturing and Subtractive Manufacturing processes and also to overcome the limitation of one process with the other. In aerospace applications, material wastage has become an issue in conventional machining process which reflects in total production cost and time. Especially, when dealing with expensive materials, conventional processes lack material efficiency with high buy-to-fly ratio which results in increased material cost. This paper deals with Hybrid Additive Manufacturing involving two different volume partitioning strategies — (i) Feature-based volume partitioning method (ii) Stock-based near net-shaping volume partitioning method to discuss the economics and material efficiency of Hybrid Additive Manufacturing process via simple cost estimator (formulated from the existing literature) by comparing these two volume partitioning strategies through suitable case studies — (i) Turbine blade and (ii) Impeller. From the results, it was found that the feature-based volume partitioning method was found to be material efficient and cost effective than the stock based near net shaping volume partitioning method in both the case studies.
{"title":"Material Efficiency and Economics of Hybrid Additive Manufacturing","authors":"Peter Francis Reginald Elvis, S. Kumaraguru","doi":"10.1115/msec2021-63739","DOIUrl":"https://doi.org/10.1115/msec2021-63739","url":null,"abstract":"\u0000 In the past few years, Hybrid Additive Manufacturing has emerged to take advantage of both Additive Manufacturing and Subtractive Manufacturing processes and also to overcome the limitation of one process with the other. In aerospace applications, material wastage has become an issue in conventional machining process which reflects in total production cost and time. Especially, when dealing with expensive materials, conventional processes lack material efficiency with high buy-to-fly ratio which results in increased material cost. This paper deals with Hybrid Additive Manufacturing involving two different volume partitioning strategies — (i) Feature-based volume partitioning method (ii) Stock-based near net-shaping volume partitioning method to discuss the economics and material efficiency of Hybrid Additive Manufacturing process via simple cost estimator (formulated from the existing literature) by comparing these two volume partitioning strategies through suitable case studies — (i) Turbine blade and (ii) Impeller. From the results, it was found that the feature-based volume partitioning method was found to be material efficient and cost effective than the stock based near net shaping volume partitioning method in both the case studies.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85958409","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 chief objective of manufacturing process improvement efforts is to significantly minimize process resources such as time, cost, waste, and consumed energy while improving product quality and process productivity. This paper presents a novel physics-informed optimization approach based on artificial intelligence (AI) to generate digital process twins (DPTs). The utility of the DPT approach is demonstrated for the case of finish machining of aerospace components made from gamma titanium aluminide alloy (γ-TiAl). This particular component has been plagued with persistent quality defects, including surface and sub-surface cracks, which adversely affect resource efficiency. Previous process improvement efforts have been restricted to anecdotal post-mortem investigation and empirical modeling, which fail to address the fundamental issue of how and when cracks occur during cutting. In this work, the integration of in-situ process characterization with modular physics-based models is presented, and machine learning algorithms are used to create a DPT capable of reducing environmental and energy impacts while significantly increasing yield and profitability. Based on the preliminary results presented here, an improvement in the overall embodied energy efficiency of over 84%, 93% in process queuing time, 2% in scrap cost, and 93% in queuing cost has been realized for γ-TiAl machining using our novel approach.
{"title":"In-Situ Calibrated Digital Process Twin Models for Resource Efficient Manufacturing","authors":"D. Adeniji, J. Schoop","doi":"10.1115/msec2021-63460","DOIUrl":"https://doi.org/10.1115/msec2021-63460","url":null,"abstract":"\u0000 The chief objective of manufacturing process improvement efforts is to significantly minimize process resources such as time, cost, waste, and consumed energy while improving product quality and process productivity. This paper presents a novel physics-informed optimization approach based on artificial intelligence (AI) to generate digital process twins (DPTs). The utility of the DPT approach is demonstrated for the case of finish machining of aerospace components made from gamma titanium aluminide alloy (γ-TiAl). This particular component has been plagued with persistent quality defects, including surface and sub-surface cracks, which adversely affect resource efficiency. Previous process improvement efforts have been restricted to anecdotal post-mortem investigation and empirical modeling, which fail to address the fundamental issue of how and when cracks occur during cutting. In this work, the integration of in-situ process characterization with modular physics-based models is presented, and machine learning algorithms are used to create a DPT capable of reducing environmental and energy impacts while significantly increasing yield and profitability. Based on the preliminary results presented here, an improvement in the overall embodied energy efficiency of over 84%, 93% in process queuing time, 2% in scrap cost, and 93% in queuing cost has been realized for γ-TiAl machining using our novel approach.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"147 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82939306","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}
Fiber Laser Welding (FLW) is a versatile joining technique of metals and alloys because it allows welding of dissimilar materials without filler material. FLW utilizes intensified heat energy to liquify the workpiece interface and joins when they are solidified. In this study, dissimilar joining between Ti6Al4V-Nitinol was performed using FLW process and the thermomechanical model was developed to understand the metallurgical mechanisms and investigate weldability of dissimilar alloys. The FLW of Ti6Al4V and Nitinol plates was performed with variable power density, welding speed, and focal distance. In this three-dimensional numerical model, heat flows in two different workpieces were computed during active laser welding and cooling process using a combined effect of radiation and convection. Both of the top and bottom surfaces of the welded zone were studied considering the combined effect from focused heat source and Argon shielding gas. Significant thermal cracks were produced through the welded interface. However, this numerical study illustrated thermomechanical foundation and discuss future challenges to improve the integrity and desirable FLW parameters in the dissimilar metal joining.
{"title":"Thermo-Mechanical Simulation of Ti6Al4V-NiTi Dissimilar Laser Welding Process","authors":"Aspen Glaspell, J. Ryu, K. Choo","doi":"10.1115/msec2021-58537","DOIUrl":"https://doi.org/10.1115/msec2021-58537","url":null,"abstract":"\u0000 Fiber Laser Welding (FLW) is a versatile joining technique of metals and alloys because it allows welding of dissimilar materials without filler material. FLW utilizes intensified heat energy to liquify the workpiece interface and joins when they are solidified. In this study, dissimilar joining between Ti6Al4V-Nitinol was performed using FLW process and the thermomechanical model was developed to understand the metallurgical mechanisms and investigate weldability of dissimilar alloys.\u0000 The FLW of Ti6Al4V and Nitinol plates was performed with variable power density, welding speed, and focal distance. In this three-dimensional numerical model, heat flows in two different workpieces were computed during active laser welding and cooling process using a combined effect of radiation and convection. Both of the top and bottom surfaces of the welded zone were studied considering the combined effect from focused heat source and Argon shielding gas. Significant thermal cracks were produced through the welded interface. However, this numerical study illustrated thermomechanical foundation and discuss future challenges to improve the integrity and desirable FLW parameters in the dissimilar metal joining.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77830038","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}
Ultrasonic welding is one of the most practical joining method for polymer composite materials and has been adapted in the aerospace and automotive industries. To effectively join polymer composite assemblies, it is critical to understand the dynamic response of the welding system so that sound heating generation and welding sequences in the ultrasonic welding of the assemblies can be properly obtained. This study presents a dynamic response model of a multi-spot configuration assembly using ultrasonic welding. Here, a dynamic model of joining a U-shaped carbon fiber reinforced thermoplastic composite part with a flat part is developed and analyzed through the ratio between the frequencies generated at different locations of the spot with respect to the edges of the assembly and the natural frequency. Finally, this ratio is correlated with the weld quality of the multiple spot configuration. Guidelines for designing multisport sequence are extracted. This study provides a method to design the welding sequence in ultrasonic welding of carbon fiber reinforced composites.
{"title":"Investigation of the Dynamic Response of a Multispot System at Joining Using Ultrasonic Welding","authors":"T. Lee, Pei-chung Wang, S. Hu, M. Banu","doi":"10.1115/msec2021-64916","DOIUrl":"https://doi.org/10.1115/msec2021-64916","url":null,"abstract":"\u0000 Ultrasonic welding is one of the most practical joining method for polymer composite materials and has been adapted in the aerospace and automotive industries. To effectively join polymer composite assemblies, it is critical to understand the dynamic response of the welding system so that sound heating generation and welding sequences in the ultrasonic welding of the assemblies can be properly obtained. This study presents a dynamic response model of a multi-spot configuration assembly using ultrasonic welding. Here, a dynamic model of joining a U-shaped carbon fiber reinforced thermoplastic composite part with a flat part is developed and analyzed through the ratio between the frequencies generated at different locations of the spot with respect to the edges of the assembly and the natural frequency. Finally, this ratio is correlated with the weld quality of the multiple spot configuration. Guidelines for designing multisport sequence are extracted. This study provides a method to design the welding sequence in ultrasonic welding of carbon fiber reinforced composites.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72493350","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}
Zane Decker, Mason Makulinski, Suprita Vispute, M. Sundaram
Fused Deposition Modeling (FDM) with Poly(lactic Acid) plus (PLA+) is frequently used in rapid prototyping and 3D printing of complex shapes. Owing to their light weight, manufacturability and cost effectiveness, thermoplastic parts made by FDM are increasingly used in several applications ranging from tissue engineering to consumer goods industry. Understanding the size effects on the strength of these parts is essential to extend their use in the microsystem applications. This paper studies the effect of scale on the mechanical properties and failure mechanisms of a 3D printed parts made by FDM. Process parameter such as extrusion temperature, infill density, infill pattern, print speed, layer thickness and nozzle diameter were kept consistent for this experiment. Five samples each with a square cross-sectional area of side lengths of 2mm, 4mm, 6mm, and 10mm were subjected to a tensile test. It was observed that parts with a smaller cross-sectional area experienced ductile failure as opposed to brittle fracture in larger cross-sectional area. Failure is shown to occur at sections where the geometry changes for brittle fractures while it occurs at the center of the parts displaying ductile failure. Results of the tensile test show a non-uniform ultimate yield strength across the four sizes. Crystallization of the material due to nozzle temperature at extrusion could be a contributing factor to failure discrepancies. Increase in the cycle time is theorized to improve the layer to layer adhesion of the part thereby affecting its mode of failure.
{"title":"Effects of Size Reduction on the Failure Mechanism of 3D Printed PLA+ Parts","authors":"Zane Decker, Mason Makulinski, Suprita Vispute, M. Sundaram","doi":"10.1115/msec2021-64133","DOIUrl":"https://doi.org/10.1115/msec2021-64133","url":null,"abstract":"\u0000 Fused Deposition Modeling (FDM) with Poly(lactic Acid) plus (PLA+) is frequently used in rapid prototyping and 3D printing of complex shapes. Owing to their light weight, manufacturability and cost effectiveness, thermoplastic parts made by FDM are increasingly used in several applications ranging from tissue engineering to consumer goods industry. Understanding the size effects on the strength of these parts is essential to extend their use in the microsystem applications. This paper studies the effect of scale on the mechanical properties and failure mechanisms of a 3D printed parts made by FDM. Process parameter such as extrusion temperature, infill density, infill pattern, print speed, layer thickness and nozzle diameter were kept consistent for this experiment. Five samples each with a square cross-sectional area of side lengths of 2mm, 4mm, 6mm, and 10mm were subjected to a tensile test. It was observed that parts with a smaller cross-sectional area experienced ductile failure as opposed to brittle fracture in larger cross-sectional area. Failure is shown to occur at sections where the geometry changes for brittle fractures while it occurs at the center of the parts displaying ductile failure. Results of the tensile test show a non-uniform ultimate yield strength across the four sizes. Crystallization of the material due to nozzle temperature at extrusion could be a contributing factor to failure discrepancies. Increase in the cycle time is theorized to improve the layer to layer adhesion of the part thereby affecting its mode of failure.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89152394","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 three-dimensional cell culture, key parameters such as cell concentration and material concentration may affect cell survival rate, proliferation and differentiation ability and other functional expression, which has very important practical significance, It has great research value in analytical chemistry, microarray, drug screening, tissue culture and so on. In this paper, the principle of active mixing is introduced for dynamic mixers. The moving parts are biocompatible mixers. Different components of alginate gel are mixed quickly in the mixing chamber, and finally the homogenized material is extruded through the replacement needle installed at the outlet of the mixing chamber. The feeding system is a push rod injection pump, and the linear motion of the injection pump is transformed into the liquid flow rate of the gel solution through a single chip microcomputer, and the flow feed is precisely controlled. In addition, by changing the flow rate ratio of the two components solution and the rapid mixing of the micro mixer, the real-time concentration change of the mixed material at the outlet can be realized, that is, gradient printing. In this paper, the printing method of gel microspheres is characterized by the distribution of the components in the Gel Microspheres according to any proportion, and because of the micro mixing process of micromixers, the demand for biological reagents and materials such as cells, proteins, cytokines and other materials is greatly reduced, which reduces the experimental cost and improves the feasibility of practical use.
{"title":"Three-Dimensional Cell Culture With Alginate Hetero Gel Microspheres","authors":"Gong Youping, Qi Jinlai, Rougang Zhou, Honghao Chen, Junling He, Zizhou Qiao, Bi Zhikai, Chen Huipeng, Haiqiang Liu, Guojin Chen, Xiang Zhang, Shao Huifeng","doi":"10.1115/msec2021-63242","DOIUrl":"https://doi.org/10.1115/msec2021-63242","url":null,"abstract":"\u0000 In three-dimensional cell culture, key parameters such as cell concentration and material concentration may affect cell survival rate, proliferation and differentiation ability and other functional expression, which has very important practical significance, It has great research value in analytical chemistry, microarray, drug screening, tissue culture and so on. In this paper, the principle of active mixing is introduced for dynamic mixers. The moving parts are biocompatible mixers. Different components of alginate gel are mixed quickly in the mixing chamber, and finally the homogenized material is extruded through the replacement needle installed at the outlet of the mixing chamber. The feeding system is a push rod injection pump, and the linear motion of the injection pump is transformed into the liquid flow rate of the gel solution through a single chip microcomputer, and the flow feed is precisely controlled. In addition, by changing the flow rate ratio of the two components solution and the rapid mixing of the micro mixer, the real-time concentration change of the mixed material at the outlet can be realized, that is, gradient printing. In this paper, the printing method of gel microspheres is characterized by the distribution of the components in the Gel Microspheres according to any proportion, and because of the micro mixing process of micromixers, the demand for biological reagents and materials such as cells, proteins, cytokines and other materials is greatly reduced, which reduces the experimental cost and improves the feasibility of practical use.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"108 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75862031","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}
Laurent Heinrich, T. Feldhausen, K. Saleeby, C. Saldana, T. Kurfess
This paper presents the integration of wire-arc additive manufacturing (WAAM) using Gas Metal Arc Welding (GMAW) into a machine tool to create a retrofit hybrid computer numeric control (CNC) machine tool. GMAW, along with other direct energy deposition systems, has the capacity to deposit material faster than the excess thermal energy can dissipate. This results in the need to allow the part to cool between consecutive layers, which is the most time-consuming part of the additive process. Finite element analysis (FEA) was used in conjunction with monitored build plate surface temperatures during deposition samples to improve adequate dwell time prediction and to develop a cooling system. A deposition was completed where no dwell time was used and the build plate along with the machine table temperatures were monitored. A second deposition was completed where only one bead was deposited and the traverse speed was increased. The GMAW welder was mounted on a 3-axis CNC machine where two square deposition samples were completed. A FEA model was designed and verified using the monitored samples. The model will be used to determine improved depositions speeds and whether forced cooling would allow for an increased deposition rate without structural failure. It was determined the FEA software can be used to accurately model and predict the thermal response of WAAM AM components.
{"title":"Prediction of Thermal Conditions of DED With FEA Metal Additive Simulation","authors":"Laurent Heinrich, T. Feldhausen, K. Saleeby, C. Saldana, T. Kurfess","doi":"10.1115/msec2021-63841","DOIUrl":"https://doi.org/10.1115/msec2021-63841","url":null,"abstract":"\u0000 This paper presents the integration of wire-arc additive manufacturing (WAAM) using Gas Metal Arc Welding (GMAW) into a machine tool to create a retrofit hybrid computer numeric control (CNC) machine tool. GMAW, along with other direct energy deposition systems, has the capacity to deposit material faster than the excess thermal energy can dissipate. This results in the need to allow the part to cool between consecutive layers, which is the most time-consuming part of the additive process. Finite element analysis (FEA) was used in conjunction with monitored build plate surface temperatures during deposition samples to improve adequate dwell time prediction and to develop a cooling system. A deposition was completed where no dwell time was used and the build plate along with the machine table temperatures were monitored. A second deposition was completed where only one bead was deposited and the traverse speed was increased. The GMAW welder was mounted on a 3-axis CNC machine where two square deposition samples were completed. A FEA model was designed and verified using the monitored samples. The model will be used to determine improved depositions speeds and whether forced cooling would allow for an increased deposition rate without structural failure. It was determined the FEA software can be used to accurately model and predict the thermal response of WAAM AM components.","PeriodicalId":56519,"journal":{"name":"光:先进制造(英文)","volume":"94 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75250106","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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