Keita Marumoto, A. Fujinaga, Takeshi Takahashi, Hikaru Yamamoto, Motomichi Yamamoto
This study presents a new gas metal arc welding (GMAW) technique that achieves both high efficiency and low heat input using a hybridization of the hot-wire method. The optimal combination of welding speed and welding current conditions was investigated using a fixed hot-wire feeding speed of 10 m/min on a butt joint with a V-shaped groove using 19 mm thick steel plates. Molten pool stability and defect formation were observed using high-speed imaging and cross-sectional observations. The power consumption and heat input were predicted prior to welding and measured in the experiments. The results indicate that a combination of a welding current of 350–500 A and welding speed of 0.3–0.7 m/min is optimal to avoid defect formation and molten metal precedence using three or four passes. The higher efficiency and lower heat input achieved by hot-wire GMAW results in a weld metal of adequate hardness, narrower heat-affected zone, smaller grain size at the fusion boundary, and lower power consumption than those obtained using tandem GMAW and high-current GMAW. Based on the experimental results, a single bevel groove, which is widely used in construction machinery welding joints, was welded using hot-wire GMAW, and we confirmed that the welding part could be welded in six passes, whereas eight passes were required with GMAW only.
{"title":"Selection of Welding Conditions for Achieving Both a High Efficiency and Low Heat Input for Hot-Wire Gas Metal Arc Welding","authors":"Keita Marumoto, A. Fujinaga, Takeshi Takahashi, Hikaru Yamamoto, Motomichi Yamamoto","doi":"10.3390/jmmp8020082","DOIUrl":"https://doi.org/10.3390/jmmp8020082","url":null,"abstract":"This study presents a new gas metal arc welding (GMAW) technique that achieves both high efficiency and low heat input using a hybridization of the hot-wire method. The optimal combination of welding speed and welding current conditions was investigated using a fixed hot-wire feeding speed of 10 m/min on a butt joint with a V-shaped groove using 19 mm thick steel plates. Molten pool stability and defect formation were observed using high-speed imaging and cross-sectional observations. The power consumption and heat input were predicted prior to welding and measured in the experiments. The results indicate that a combination of a welding current of 350–500 A and welding speed of 0.3–0.7 m/min is optimal to avoid defect formation and molten metal precedence using three or four passes. The higher efficiency and lower heat input achieved by hot-wire GMAW results in a weld metal of adequate hardness, narrower heat-affected zone, smaller grain size at the fusion boundary, and lower power consumption than those obtained using tandem GMAW and high-current GMAW. Based on the experimental results, a single bevel groove, which is widely used in construction machinery welding joints, was welded using hot-wire GMAW, and we confirmed that the welding part could be welded in six passes, whereas eight passes were required with GMAW only.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140689312","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}
Induction heating is a fast, reproducible, and efficient heating method used in various manufacturing processes. However, there is no established additive manufacturing (AM) process based on induction heating using wire as feedstock. This study investigates a novel approach to AM based on inductive heating, where a steel wire is melted and droplets are detached periodically using a two-winding induction coil. The process parameters and energy input into the droplets are characterized. The induction generator exhibits a sluggish response to the excitation voltage, resulting in a lag in the coil current. The process is captured using a high-speed camera, revealing a regular droplet formation of 14 Hz and uniform shapes and sizes between 2.11 and 2.65 mm in diameter when operated within an appropriate process window. Larger drops and increased spatter formation occur outside this window. The proposed method allows for the production of droplets with almost spherical shapes. Further analysis and characterization of droplet formation and energy input provide insights into process optimization and indicate an overall efficiency of approximately 10%.
感应加热是一种快速、可重复、高效的加热方法，可用于各种制造工艺。然而，目前还没有基于感应加热、以钢丝为原料的增材制造（AM）工艺。本研究探讨了一种基于感应加热的新型 AM 方法，即使用双绕组感应线圈定期熔化钢丝并分离液滴。研究对工艺参数和输入液滴的能量进行了表征。感应发生器对激励电压的反应迟缓，导致线圈电流滞后。使用高速照相机拍摄的过程显示，在适当的过程窗口内操作时，液滴形成的频率为 14 赫兹，形状和大小均匀，直径在 2.11 至 2.65 毫米之间。在此窗口之外，液滴会变大，飞溅物也会增多。所提出的方法可以生产出几乎呈球形的液滴。对液滴形成和能量输入的进一步分析和表征为工艺优化提供了启示，并表明总体效率约为 10%。
{"title":"Droplet Formation and Energy Input during Induction Wire Melting with Pulsed and Constant Generator Power","authors":"J. Kimme, Jonas Gruner, A. Hälsig, Jonas Hensel","doi":"10.3390/jmmp8020080","DOIUrl":"https://doi.org/10.3390/jmmp8020080","url":null,"abstract":"Induction heating is a fast, reproducible, and efficient heating method used in various manufacturing processes. However, there is no established additive manufacturing (AM) process based on induction heating using wire as feedstock. This study investigates a novel approach to AM based on inductive heating, where a steel wire is melted and droplets are detached periodically using a two-winding induction coil. The process parameters and energy input into the droplets are characterized. The induction generator exhibits a sluggish response to the excitation voltage, resulting in a lag in the coil current. The process is captured using a high-speed camera, revealing a regular droplet formation of 14 Hz and uniform shapes and sizes between 2.11 and 2.65 mm in diameter when operated within an appropriate process window. Larger drops and increased spatter formation occur outside this window. The proposed method allows for the production of droplets with almost spherical shapes. Further analysis and characterization of droplet formation and energy input provide insights into process optimization and indicate an overall efficiency of approximately 10%.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140686596","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}
Getachew A. Ambaye, Enkhsaikhan Boldsaikhan, Krishna Krishnan
Advancements in smart manufacturing have embraced the adoption of soft robots for improved productivity, flexibility, and automation as well as safety in smart factories. Hence, soft robotics is seeing a significant surge in popularity by garnering considerable attention from researchers and practitioners. Bionic soft robots, which are composed of compliant materials like silicones, offer compelling solutions to manipulating delicate objects, operating in unstructured environments, and facilitating safe human–robot interactions. However, despite their numerous advantages, there are some fundamental challenges to overcome, which particularly concern motion precision and stiffness compliance in performing physical tasks that involve external forces. In this regard, enhancing the operation performance of soft robots necessitates intricate, complex structural designs, compliant multifunctional materials, and proper manufacturing methods. The objective of this literature review is to chronicle a comprehensive overview of soft robot design, manufacturing, and operation challenges in conjunction with recent advancements and future research directions for addressing these technical challenges.
{"title":"Soft Robot Design, Manufacturing, and Operation Challenges: A Review","authors":"Getachew A. Ambaye, Enkhsaikhan Boldsaikhan, Krishna Krishnan","doi":"10.3390/jmmp8020079","DOIUrl":"https://doi.org/10.3390/jmmp8020079","url":null,"abstract":"Advancements in smart manufacturing have embraced the adoption of soft robots for improved productivity, flexibility, and automation as well as safety in smart factories. Hence, soft robotics is seeing a significant surge in popularity by garnering considerable attention from researchers and practitioners. Bionic soft robots, which are composed of compliant materials like silicones, offer compelling solutions to manipulating delicate objects, operating in unstructured environments, and facilitating safe human–robot interactions. However, despite their numerous advantages, there are some fundamental challenges to overcome, which particularly concern motion precision and stiffness compliance in performing physical tasks that involve external forces. In this regard, enhancing the operation performance of soft robots necessitates intricate, complex structural designs, compliant multifunctional materials, and proper manufacturing methods. The objective of this literature review is to chronicle a comprehensive overview of soft robot design, manufacturing, and operation challenges in conjunction with recent advancements and future research directions for addressing these technical challenges.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140697194","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}
I. Dey, Raphael Floeder, Rick Solcà, T. Schudeleit, Konrad Wegener
Additive manufacturing (AM) by using direct metal deposition (DMD) often causes erratic distortion patterns, especially on large parts. This study presents a systematic distortion analysis by employing numerical approaches using transient–thermal and structural simulations, experimental approaches using tomography, X-ray diffraction (XRD), and an analytical approach calculating the buckling distortion of a piston. The most essential geometrical features are thin walls situated between massive rings. An eigenvalue buckling analysis, a DMD process, and heat treatment simulation are presented. The eigenvalue buckling simulation shows that it is highly dependent on the mesh size. The computational effort of the DMD and heat treatment simulation was reduced through simplifications. Moreover, artificial imperfections were imposed in the heat treatment simulation, which moved the part into the buckling state inspired by the experiment. Although the numerical results of both simulations are successful, the eigenvalue and DMD simulation cannot be validated through tomography and XRD. This is because tomography is unable to measure small elastic strain fields, the simulated residual stresses were overestimated, and the part removal disturbed the residual stress equilibrium. Nevertheless, the heat treatment simulation can predict the distortion pattern caused by an inhomogeneous temperature field during ambient cooling in an oven. The massive piston skirt cools down and shrinks faster than the massive core. The reduced yield strength at elevated temperatures and critical buckling load leads to plastic deformation of the thin walls.
{"title":"Comprehensive Distortion Analysis of a Laser Direct Metal Deposition (DMD)-Manufactured Large Prototype Made of Soft Martensitic Steel 1.4313","authors":"I. Dey, Raphael Floeder, Rick Solcà, T. Schudeleit, Konrad Wegener","doi":"10.3390/jmmp8020078","DOIUrl":"https://doi.org/10.3390/jmmp8020078","url":null,"abstract":"Additive manufacturing (AM) by using direct metal deposition (DMD) often causes erratic distortion patterns, especially on large parts. This study presents a systematic distortion analysis by employing numerical approaches using transient–thermal and structural simulations, experimental approaches using tomography, X-ray diffraction (XRD), and an analytical approach calculating the buckling distortion of a piston. The most essential geometrical features are thin walls situated between massive rings. An eigenvalue buckling analysis, a DMD process, and heat treatment simulation are presented. The eigenvalue buckling simulation shows that it is highly dependent on the mesh size. The computational effort of the DMD and heat treatment simulation was reduced through simplifications. Moreover, artificial imperfections were imposed in the heat treatment simulation, which moved the part into the buckling state inspired by the experiment. Although the numerical results of both simulations are successful, the eigenvalue and DMD simulation cannot be validated through tomography and XRD. This is because tomography is unable to measure small elastic strain fields, the simulated residual stresses were overestimated, and the part removal disturbed the residual stress equilibrium. Nevertheless, the heat treatment simulation can predict the distortion pattern caused by an inhomogeneous temperature field during ambient cooling in an oven. The massive piston skirt cools down and shrinks faster than the massive core. The reduced yield strength at elevated temperatures and critical buckling load leads to plastic deformation of the thin walls.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140696970","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}
Tanja Emilie Henriksen, T. Brustad, Rune Dalmo, Aleksander Pedersen
Additive manufacturing (AM) is a field with both industrial and academic significance. Computer-aided optimisation has brought advances to this field over the years, but challenges and areas of improvement still remain. Design to execution inaccuracies, void formation, material anisotropy, and surface quality are examples of remaining challenges. These challenges can be improved via some of the trending optimisation topics, such as artificial intelligence (AI) and machine learning (ML); STL correction, replacement, or removal; slicing algorithms; and simulations. This paper reviews AM and its history with a special focus on the printing process and how it can be optimised using computer software. The most important new contribution is a survey of the present challenges connected with the prevailing optimisation topics. This can be seen as a foundation for future research. In addition, we suggest how certain challenges can be improved and show how such changes affect the printing process.
快速成型制造（AM）是一个同时具有工业和学术意义的领域。多年来，计算机辅助优化技术为这一领域带来了进步，但挑战和需要改进的地方依然存在。设计到执行的误差、空洞的形成、材料的各向异性和表面质量都是仍然存在的挑战。这些挑战可以通过一些趋势性的优化主题得到改善，如人工智能（AI）和机器学习（ML）；STL 修正、替换或移除；切片算法和模拟。本文回顾了 AM 及其历史，特别关注印刷过程以及如何使用计算机软件对其进行优化。最重要的新贡献是调查了当前与现行优化主题相关的挑战。这可以视为未来研究的基础。此外，我们还提出了如何改进某些难题的建议，并展示了这些变化对印刷工艺的影响。
{"title":"Computer-Aided Optimisation in Additive Manufacturing Processes: A State of the Art Survey","authors":"Tanja Emilie Henriksen, T. Brustad, Rune Dalmo, Aleksander Pedersen","doi":"10.3390/jmmp8020076","DOIUrl":"https://doi.org/10.3390/jmmp8020076","url":null,"abstract":"Additive manufacturing (AM) is a field with both industrial and academic significance. Computer-aided optimisation has brought advances to this field over the years, but challenges and areas of improvement still remain. Design to execution inaccuracies, void formation, material anisotropy, and surface quality are examples of remaining challenges. These challenges can be improved via some of the trending optimisation topics, such as artificial intelligence (AI) and machine learning (ML); STL correction, replacement, or removal; slicing algorithms; and simulations. This paper reviews AM and its history with a special focus on the printing process and how it can be optimised using computer software. The most important new contribution is a survey of the present challenges connected with the prevailing optimisation topics. This can be seen as a foundation for future research. In addition, we suggest how certain challenges can be improved and show how such changes affect the printing process.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140700627","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}
Four dimensional printing enables the advanced manufacturing of smart objects that can morph and adapt shape over time in response to stimuli such as heat. This study presents a single-material 4D printing workflow which explores the residual stress and anisotropy arising from the fused deposition modelling (FDM) printing process to create heat-triggered self-morphing objects. In particular, the study first investigates the effect of printing patterns on the residual stress of FDM-printed acrylonitrile butadiene styrene (ABS) products. Through finite element analysis, the raster angle of printing patterns was identified as the key parameter influencing the distribution of residual stresses. Experimental investigations further reveal that the non-uniform distribution of residual stress results in the anisotropic thermal deformation of printed materials. Thus, through the design of printing patterns, FDM-printed materials can be programmed with desired built-in residual stresses and anisotropic behaviours for initiating and controlling the transformation of 4D-printed objects. Using the proposed approach, any desktop FDM printers can be turned into 4D printers to create smart objects that can self-morph into target geometries. A series of 4D printing prototypes manufactured from conventional ABS 3D printing feedstock are tested to illustrate the use and reliability of this new workflow. Additionally, the custom-made wood–plastic composite (WPC) feedstocks are explored in this study to demonstrate the transposability of the 4D printing approach.
{"title":"Interrelations between Printing Patterns and Residual Stress in Fused Deposition Modelling for the 4D Printing of Acrylonitrile Butadiene Styrene and Wood–Plastic Composites","authors":"Yerong Huang, S. Löschke, Yixiang Gan, G. Proust","doi":"10.3390/jmmp8020077","DOIUrl":"https://doi.org/10.3390/jmmp8020077","url":null,"abstract":"Four dimensional printing enables the advanced manufacturing of smart objects that can morph and adapt shape over time in response to stimuli such as heat. This study presents a single-material 4D printing workflow which explores the residual stress and anisotropy arising from the fused deposition modelling (FDM) printing process to create heat-triggered self-morphing objects. In particular, the study first investigates the effect of printing patterns on the residual stress of FDM-printed acrylonitrile butadiene styrene (ABS) products. Through finite element analysis, the raster angle of printing patterns was identified as the key parameter influencing the distribution of residual stresses. Experimental investigations further reveal that the non-uniform distribution of residual stress results in the anisotropic thermal deformation of printed materials. Thus, through the design of printing patterns, FDM-printed materials can be programmed with desired built-in residual stresses and anisotropic behaviours for initiating and controlling the transformation of 4D-printed objects. Using the proposed approach, any desktop FDM printers can be turned into 4D printers to create smart objects that can self-morph into target geometries. A series of 4D printing prototypes manufactured from conventional ABS 3D printing feedstock are tested to illustrate the use and reliability of this new workflow. Additionally, the custom-made wood–plastic composite (WPC) feedstocks are explored in this study to demonstrate the transposability of the 4D printing approach.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140702754","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}
Various industries, including mechanical engineering, utilize steel rings featuring variable cross-sectional profiles, such as eccentric rings. Presently employed methods for producing eccentric rings possess drawbacks like restricted geometries, significant material wastage or uneven microstructures. The radial–axial ring rolling process serves to create seamless rolled steel rings with near-net-shaped cross-sections. A novel technique involves achieving eccentricity by dynamically adjusting the mandrel’s position during the ring rolling process. This method’s fundamental feasibility has previously been showcased using a blend of oil clay and a labor test bench. Transferring the possibility of manufacturing eccentric rings on industrial radial–axial ring rolling mills would expand the product range of ring manufacturers without encountering drawbacks associated with existing manufacturing processes. The objective of this paper is to demonstrate the basic feasibility of the concept of an industrial radial–axial ring rolling mill. In the first step, FEA simulation studies were carried out to develop the rolling strategy and estimate the achievable eccentricity on the institute’s radial–axial ring mill. Subsequently, the rolling strategy was implemented on an industrial ring rolling mill with the help of a unique technology module programmed in C++. Finally, an eccentric ring was ring rolled and compared with the FEA simulation, and the reproducibility was demonstrated to be successful.
包括机械工程在内的各行各业都在使用具有可变截面轮廓的钢环，如偏心环。目前采用的偏心环生产方法存在几何形状受限、材料浪费严重或微观结构不均匀等缺点。径向-轴向环形轧制工艺可生产出横截面接近网状的无缝轧制钢环。一种新颖的技术是在轧环过程中通过动态调整芯轴的位置来实现偏心。这种方法的基本可行性此前已通过使用混合油粘土和劳动试验台进行了展示。在工业径向轴向轧环机上制造偏心环的可能性将扩大环制造商的产品范围，而不会遇到与现有制造工艺相关的弊端。本文旨在论证工业径向轴向轧环机概念的基本可行性。首先，进行了有限元分析模拟研究，以制定轧制策略并估算研究所径向轴向环轧机可达到的偏心率。随后，在用 C++ 编程的独特技术模块的帮助下，在工业环轧机上实施了轧制策略。最后，对偏心环进行了环轧制，并与有限元分析模拟结果进行了比较，证明其再现性是成功的。
{"title":"Rolling Eccentric Steel Rings on an Industrial Radial–Axial Ring Rolling Mill","authors":"M. Gröper, Marten Quadfasel, D. Bailly, G. Hirt","doi":"10.3390/jmmp8020075","DOIUrl":"https://doi.org/10.3390/jmmp8020075","url":null,"abstract":"Various industries, including mechanical engineering, utilize steel rings featuring variable cross-sectional profiles, such as eccentric rings. Presently employed methods for producing eccentric rings possess drawbacks like restricted geometries, significant material wastage or uneven microstructures. The radial–axial ring rolling process serves to create seamless rolled steel rings with near-net-shaped cross-sections. A novel technique involves achieving eccentricity by dynamically adjusting the mandrel’s position during the ring rolling process. This method’s fundamental feasibility has previously been showcased using a blend of oil clay and a labor test bench. Transferring the possibility of manufacturing eccentric rings on industrial radial–axial ring rolling mills would expand the product range of ring manufacturers without encountering drawbacks associated with existing manufacturing processes. The objective of this paper is to demonstrate the basic feasibility of the concept of an industrial radial–axial ring rolling mill. In the first step, FEA simulation studies were carried out to develop the rolling strategy and estimate the achievable eccentricity on the institute’s radial–axial ring mill. Subsequently, the rolling strategy was implemented on an industrial ring rolling mill with the help of a unique technology module programmed in C++. Finally, an eccentric ring was ring rolled and compared with the FEA simulation, and the reproducibility was demonstrated to be successful.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140711187","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}
Neda Ghodrati, Henri Champliaud, J. Morin, Mohammad Jahazi
The influence of hot-top designs with different heat capacities on the distribution of positive and negative macrosegregation was investigated on a 12 metric tonne (MT) cast ingot made using Cr-Mo low-alloy steel. The three-dimensional finite element modeling code THERCAST® was used to simulate the thermo-mechanical phenomena associated with the solidification process, running from filling the mold until complete solidification. The model was validated on an industrial-scale ingot and then utilized to evaluate the influence of the thermal history of the hot-top, a crucial component in the cast ingot setup. This assessment aimed to comprehend changes in solidification time, temperature, and heat flux—all of which contribute to the determination of macrosegregation severity. The results showed that preheating the hot-top had a minor effect on solidification time, while modifications of thermal conductivity in the hot-top region increased the solidification time by 31%, thereby significantly affecting the macrosegregation patterns. The results are discussed and interpreted in terms of the fundamental mechanisms governing the kinetics of solidification and macrosegregation phenomena.
{"title":"Influence of the Hot-Top Thermal Regime on the Severity and Extent of Macrosegregation in Large-Size Steel Ingots","authors":"Neda Ghodrati, Henri Champliaud, J. Morin, Mohammad Jahazi","doi":"10.3390/jmmp8020074","DOIUrl":"https://doi.org/10.3390/jmmp8020074","url":null,"abstract":"The influence of hot-top designs with different heat capacities on the distribution of positive and negative macrosegregation was investigated on a 12 metric tonne (MT) cast ingot made using Cr-Mo low-alloy steel. The three-dimensional finite element modeling code THERCAST® was used to simulate the thermo-mechanical phenomena associated with the solidification process, running from filling the mold until complete solidification. The model was validated on an industrial-scale ingot and then utilized to evaluate the influence of the thermal history of the hot-top, a crucial component in the cast ingot setup. This assessment aimed to comprehend changes in solidification time, temperature, and heat flux—all of which contribute to the determination of macrosegregation severity. The results showed that preheating the hot-top had a minor effect on solidification time, while modifications of thermal conductivity in the hot-top region increased the solidification time by 31%, thereby significantly affecting the macrosegregation patterns. The results are discussed and interpreted in terms of the fundamental mechanisms governing the kinetics of solidification and macrosegregation phenomena.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140714171","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 monitoring of additive manufacturing processes such as powder bed fusion enables the detection of several process quantities important to the quality of the built part. In this context, radiation-based monitoring techniques have been used to obtain information about the melt pool and the general temperature distribution on the surface of the powder bed. High temporal and spatial resolution have been achieved at the cost of large storage requirements. This contribution aims to offer an alternative strategy of gaining information about the powder bed’s temperature field with sufficient resolution but with an economical amount of data. The investigated measurement setup uses a spectrometer to detect the spectral radiation intensities emitted by an area enclosing the melt pool and part of its surroundings. An analytical description of this process is presented, which shows that the measured spectral entities can be reconstructed by the Ritz method. It is also shown that the corresponding weighting factors can be physically interpreted as subdomains of constant temperature within the measurement area. Two different test cases are numerically analyzed, showing that the methodology allows for an approximation of the melt pool size while further assumptions remain necessary to reconstruct the actual temperature distribution.
{"title":"Theoretical-Numerical Investigation of a New Approach to Reconstruct the Temperature Field in PBF-LB/M Using Multispectral Process Monitoring","authors":"Lisa May, M. Werz","doi":"10.3390/jmmp8020073","DOIUrl":"https://doi.org/10.3390/jmmp8020073","url":null,"abstract":"The monitoring of additive manufacturing processes such as powder bed fusion enables the detection of several process quantities important to the quality of the built part. In this context, radiation-based monitoring techniques have been used to obtain information about the melt pool and the general temperature distribution on the surface of the powder bed. High temporal and spatial resolution have been achieved at the cost of large storage requirements. This contribution aims to offer an alternative strategy of gaining information about the powder bed’s temperature field with sufficient resolution but with an economical amount of data. The investigated measurement setup uses a spectrometer to detect the spectral radiation intensities emitted by an area enclosing the melt pool and part of its surroundings. An analytical description of this process is presented, which shows that the measured spectral entities can be reconstructed by the Ritz method. It is also shown that the corresponding weighting factors can be physically interpreted as subdomains of constant temperature within the measurement area. Two different test cases are numerically analyzed, showing that the methodology allows for an approximation of the melt pool size while further assumptions remain necessary to reconstruct the actual temperature distribution.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140716665","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}
Addison J. Rayner, Greg A. W. Sweet, Owen Craig, Mahdi Habibnejad-Korayem, Paul Bishop
The directed energy deposition (DED) parameters were determined for near-β alloy Ti-55511 by employing statistical design of experiments (DOEs) methods. Parameters resulting in fully dense freeform deposits were identified using two sequential DOEs. Single laser tracks were printed with several laser power, traverse rate, and powder feed rate settings in an initial DOE to identify promising build parameters. The capture efficiency and effective deposition rate were used to characterize and rank the single track deposits. The best parameters were then used to print a solid cube with various X–Y and Z overlaps (different hatch spacing, HS, and layer thickness, ZS) in a second DOE. Suitable deposition parameters were selected based on the cube density and microstructure and were used to fabricate larger tensile samples for mechanical testing. Multiple parameter sets were found to provide dense Ti-55511 deposits with acceptable mechanical properties and the parametric models showed statistical significance.
采用统计实验设计（DOEs）方法确定了近β合金Ti-55511的定向能沉积（DED）参数。通过两个连续的 DOE，确定了导致完全致密自由形态沉积的参数。在初始 DOE 中，使用多种激光功率、横移速率和粉末进给速率设置打印单个激光轨迹，以确定有前景的构建参数。利用捕获效率和有效沉积率对单轨沉积物进行表征和排序。然后，在第二次 DOE 中使用最佳参数打印具有各种 X-Y 和 Z 重叠（不同的舱口间距 HS 和层厚度 ZS）的实心立方体。根据立方体的密度和微观结构选择合适的沉积参数，并用于制造较大的拉伸样品进行机械测试。发现多个参数集可提供具有可接受机械性能的致密 Ti-55511 沉积物，并且参数模型显示出统计学意义。
{"title":"Investigation of Deposition Parameters for Near-Beta Alloy Ti-55511 Fabricated by Directed Energy Deposition","authors":"Addison J. Rayner, Greg A. W. Sweet, Owen Craig, Mahdi Habibnejad-Korayem, Paul Bishop","doi":"10.3390/jmmp8020072","DOIUrl":"https://doi.org/10.3390/jmmp8020072","url":null,"abstract":"The directed energy deposition (DED) parameters were determined for near-β alloy Ti-55511 by employing statistical design of experiments (DOEs) methods. Parameters resulting in fully dense freeform deposits were identified using two sequential DOEs. Single laser tracks were printed with several laser power, traverse rate, and powder feed rate settings in an initial DOE to identify promising build parameters. The capture efficiency and effective deposition rate were used to characterize and rank the single track deposits. The best parameters were then used to print a solid cube with various X–Y and Z overlaps (different hatch spacing, HS, and layer thickness, ZS) in a second DOE. Suitable deposition parameters were selected based on the cube density and microstructure and were used to fabricate larger tensile samples for mechanical testing. Multiple parameter sets were found to provide dense Ti-55511 deposits with acceptable mechanical properties and the parametric models showed statistical significance.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140718171","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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