Pub Date : 2026-03-05Epub Date: 2026-02-10DOI: 10.1016/j.addma.2026.105119
Yueqiang Zhu , Lijing Zhong , Ce Zhang , Baiqiang Yang , Jianrong Qiu , Chen Zhang , Kaige Wang , Jintao Bai , Wei Zhao
The advancement of micro/nanofabrication techniques with high throughput, efficiency, and flexibility is critical for fields like integrated photonics, biosensing, and medical diagnostics. This study presents Partition Laser Assembling (PLA), a novel laser technique for fabricating complex micro/nanostructures akin to puzzle pieces. By dividing the target patterns described by scalable vector graphics into partitions, any structures in each partition can be fabricated via structured lights as variable “light stamp” through spatial light modulation. Unlike traditional direct laser writing, PLA eliminates reliance on mechanical components, avoiding step-like artifacts and ensuring smoother fabrication of complex trans-scale structures. By seamlessly assembling basic shapes, PLA achieves intricate structures like micro artworks and meta-lens with unmatched precision and resolution. Leveraging two-photon fabrication, PLA guarantees high resolution and structural integrity, positioning it as a potential transformative tool for nanoscale 3D printing. With applications spanning research and industry, PLA paves the way for advanced optical devices, micro/nano-fabrications, and next-generation manufacturing technologies.
{"title":"Partition laser assembling technique","authors":"Yueqiang Zhu , Lijing Zhong , Ce Zhang , Baiqiang Yang , Jianrong Qiu , Chen Zhang , Kaige Wang , Jintao Bai , Wei Zhao","doi":"10.1016/j.addma.2026.105119","DOIUrl":"10.1016/j.addma.2026.105119","url":null,"abstract":"<div><div>The advancement of micro/nanofabrication techniques with high throughput, efficiency, and flexibility is critical for fields like integrated photonics, biosensing, and medical diagnostics. This study presents Partition Laser Assembling (PLA), a novel laser technique for fabricating complex micro/nanostructures akin to puzzle pieces. By dividing the target patterns described by scalable vector graphics into partitions, any structures in each partition can be fabricated via structured lights as variable “light stamp” through spatial light modulation. Unlike traditional direct laser writing, PLA eliminates reliance on mechanical components, avoiding step-like artifacts and ensuring smoother fabrication of complex trans-scale structures. By seamlessly assembling basic shapes, PLA achieves intricate structures like micro artworks and meta-lens with unmatched precision and resolution. Leveraging two-photon fabrication, PLA guarantees high resolution and structural integrity, positioning it as a potential transformative tool for nanoscale 3D printing. With applications spanning research and industry, PLA paves the way for advanced optical devices, micro/nano-fabrications, and next-generation manufacturing technologies.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105119"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-01-31DOI: 10.1016/j.addma.2026.105099
Sina Zinatlou Ajabshir , Colin Hare , Diego Barletta , Massimo Poletto
In this study, a Discrete Element Method (DEM)-based model was developed to simulate the powder spreading process in Powder Bed Fusion (PBF) using non-spherical Polyamide 6 (PA6) powder. Various spreading tools—including sharp blades, curved round blades, flat blades, a roller, and a rigid rake-style brush—were tested at three spreading speeds (3, 30 and 90 mm/s) to evaluate their impact on powder bed characteristics. Key metrics such as packing fraction (), compressive force distribution, spreading density ratio, and surface roughness were analysed within a defined area of interest. Particle velocity distribution and the vertical-to-horizontal velocity ratio were investigated to understand particle dynamics and settling behaviour during spreading. Results revealed that curved round tools, especially the horizontal round blade and roller, delivered denser, smoother, and more uniform powder layers. In contrast, sharp and flat blades caused poor compaction and elevated roughness, especially at higher speeds. The brush and 135° blade showed moderate but consistent performance. These findings emphasize the importance of tool geometry–speed interaction and provide insight for optimizing spreading strategies in PBF processes.
{"title":"Assessment of the powder spreading parameters for non-spherical polymeric powder used in powder bed fusion process: A DEM simulation study","authors":"Sina Zinatlou Ajabshir , Colin Hare , Diego Barletta , Massimo Poletto","doi":"10.1016/j.addma.2026.105099","DOIUrl":"10.1016/j.addma.2026.105099","url":null,"abstract":"<div><div>In this study, a Discrete Element Method (DEM)-based model was developed to simulate the powder spreading process in Powder Bed Fusion (PBF) using non-spherical Polyamide 6 (PA6) powder. Various spreading tools—including sharp blades, curved round blades, flat blades, a roller, and a rigid rake-style brush—were tested at three spreading speeds (3, 30 and 90 mm/s) to evaluate their impact on powder bed characteristics. Key metrics such as packing fraction (<span><math><mi>η</mi></math></span>), compressive force distribution, spreading density ratio, and surface roughness were analysed within a defined area of interest. Particle velocity distribution and the vertical-to-horizontal velocity ratio were investigated to understand particle dynamics and settling behaviour during spreading. Results revealed that curved round tools, especially the horizontal round blade and roller, delivered denser, smoother, and more uniform powder layers. In contrast, sharp and flat blades caused poor compaction and elevated roughness, especially at higher speeds. The brush and 135° blade showed moderate but consistent performance. These findings emphasize the importance of tool geometry–speed interaction and provide insight for optimizing spreading strategies in PBF processes.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105099"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-12DOI: 10.1016/j.addma.2026.105120
Omer Safa Cavus, Sina Khalilvandi Behrouzyar, Hamidreza Javidrad, Bahattin Koc
Stitch regions pose a fundamental challenge in both single and multi-laser systems due to overlapping scan areas where defects can form. This study introduces a continuous parametric scanning strategy designed to reduce porosity formation in stitch regions, which are frequently observed in these processes. The strategy was developed using a parametric modeling framework, which enables flexible and spatially adaptive scan-path generation while also producing the thermal-analysis inputs and build-machine files required for fabrication. By bridging the gap between design, simulation, and manufacturing, the framework supports a streamlined, end-to-end workflow tailored for metal additive manufacturing. The investigation was carried out in two phases, utilizing both transient thermal analysis and X-ray computed tomography (CT) to capture porosity across multiple scales. First, to assess the effectiveness of the proposed strategy, thermal simulations were conducted and the resulting cooling-rate distributions were analyzed. Second, these findings were validated through X-ray CT. Higher cooling-rate uniformity effectively reduced porosity formation in stitch regions. Each scanning strategy resulted in distinct mechanisms of pore formation that varied in pore size, shape, spatial distribution, and location. Compared with traditional strategies, the proposed continuous approach increased the thermal uniformity, reduced the average pore size by 25%, increased pore sphericity, and decreased the standard deviation of pore sizes.
{"title":"Continuous parametric scanning with thermal modeling to minimize stitch zone defects in laser beam powder bed fusion validated by multi-scale X-ray CT","authors":"Omer Safa Cavus, Sina Khalilvandi Behrouzyar, Hamidreza Javidrad, Bahattin Koc","doi":"10.1016/j.addma.2026.105120","DOIUrl":"10.1016/j.addma.2026.105120","url":null,"abstract":"<div><div>Stitch regions pose a fundamental challenge in both single and multi-laser systems due to overlapping scan areas where defects can form. This study introduces a continuous parametric scanning strategy designed to reduce porosity formation in stitch regions, which are frequently observed in these processes. The strategy was developed using a parametric modeling framework, which enables flexible and spatially adaptive scan-path generation while also producing the thermal-analysis inputs and build-machine files required for fabrication. By bridging the gap between design, simulation, and manufacturing, the framework supports a streamlined, end-to-end workflow tailored for metal additive manufacturing. The investigation was carried out in two phases, utilizing both transient thermal analysis and X-ray computed tomography (CT) to capture porosity across multiple scales. First, to assess the effectiveness of the proposed strategy, thermal simulations were conducted and the resulting cooling-rate distributions were analyzed. Second, these findings were validated through X-ray CT. Higher cooling-rate uniformity effectively reduced porosity formation in stitch regions. Each scanning strategy resulted in distinct mechanisms of pore formation that varied in pore size, shape, spatial distribution, and location. Compared with traditional strategies, the proposed continuous approach increased the thermal uniformity, reduced the average pore size by 25%, increased pore sphericity, and decreased the standard deviation of pore sizes.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105120"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-18DOI: 10.1016/j.addma.2026.105128
Yun Liu , Mingyue Fan , Jiawei Cao , Peng Luo , Jianpeng Liu , Yu Shi , Wei Li , Liping Ren , Yadong Wu , Zaixing Jiang
Digital light processing (DLP) 3D printing technology has contributed significantly to high-resolution crosslinked polymer fabrication. However, its widespread application is limited by an inherent trade-off between printing resolution and workpiece size. To construct the large and intricate architectures, printing followed by modular assembly under external stimuli can make it possible via the imparted dynamic characteristics of designed dynamic crosslinked networks. This study presents a class of DLP-printable imine-based covalent adaptable networks with robust weldability, enabling scalable assembly at ambient temperature using only trace amounts of an aqueous amine solution. The fabricated imine resins were compatible with DLP printing to manufacture high-resolution polymeric modules. Subsequent interfacial interactions between modules at room temperature, activated by drops of primary amine aqueous solution, yield high welding efficiencies ranging from 87.66 % to 99.62 %. Moreover, the imine networks demonstrate sustainability, retaining weldability even after undergoing three recycling cycles. By enabling the scalable assembly of multi-material and multifunctional devices, the proposed strategy overcomes the current size limitations of DLP printing and provides a promising framework for green fabrication of advanced components.
{"title":"Weldable, recyclable, and 3D-printable imine-based covalent adaptable networks for large-scale assembly at ambient temperature","authors":"Yun Liu , Mingyue Fan , Jiawei Cao , Peng Luo , Jianpeng Liu , Yu Shi , Wei Li , Liping Ren , Yadong Wu , Zaixing Jiang","doi":"10.1016/j.addma.2026.105128","DOIUrl":"10.1016/j.addma.2026.105128","url":null,"abstract":"<div><div>Digital light processing (DLP) 3D printing technology has contributed significantly to high-resolution crosslinked polymer fabrication. However, its widespread application is limited by an inherent trade-off between printing resolution and workpiece size. To construct the large and intricate architectures, printing followed by modular assembly under external stimuli can make it possible via the imparted dynamic characteristics of designed dynamic crosslinked networks. This study presents a class of DLP-printable imine-based covalent adaptable networks with robust weldability, enabling scalable assembly at ambient temperature using only trace amounts of an aqueous amine solution. The fabricated imine resins were compatible with DLP printing to manufacture high-resolution polymeric modules. Subsequent interfacial interactions between modules at room temperature, activated by drops of primary amine aqueous solution, yield high welding efficiencies ranging from 87.66 % to 99.62 %. Moreover, the imine networks demonstrate sustainability, retaining weldability even after undergoing three recycling cycles. By enabling the scalable assembly of multi-material and multifunctional devices, the proposed strategy overcomes the current size limitations of DLP printing and provides a promising framework for green fabrication of advanced components.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105128"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-10DOI: 10.1016/j.addma.2026.105117
Joseph Berthel, Jack Beuth, Rahul Panat
The fabrication of lattice structures through laser powder bed fusion (LPBF) has the potential to create architected materials with exceptional mechanical properties at low densities, with plate-lattice structures demonstrating the highest stiffness and strength to weight ratios. However, geometric deviations and defects introduced by the LPBF process result in plate-lattice geometries deviating from their intended ideal design, potentially compromising mechanical properties and increasing density without a proportional increase in strength. The intersecting and inclined thin-plate features that enable the high performance of plate-lattices are especially prone to compromising deviations, since plate-lattice features are fabricated at scales approaching the resolution limits of LPBF. This study presents a comprehensive analysis of geometric deviations and defects in AlSi10Mg LPBF plate-lattice structures, focusing on understanding the influence of both processing conditions and geometric features on deviation formation, and determining their detrimental effect on compression mechanics. Micro-CT scanning is used to examine the as-fabricated morphology of plate-lattice unit cells and identify trends in defect severity among different lattice topologies and volume fractions. Finite element analysis (FEA) of the ideal and as-fabricated unit cell geometry under compressive strain is performed to evaluate differences in strain energy density distribution and resultant lattice stiffness. FEA results show that deviations contribute to a 4.4–28.0 % increase in minimally load-bearing lattice mass, reducing the specific stiffness of the lattice by 11.8–31.7 % compared to ideal geometries. Minimally load-bearing mass arises from protruding surface variations and dross formations around powder drainage holes and overhanging features, while underprinting at critical plate intersections introduces stress concentrations. This work provides insight into how plate-lattice design and LPBF fabrication strategy impact as-fabricated lattice geometry and resulting mechanical performance.
{"title":"Geometric deviations and their effects in thin-plate lattice structures fabricated via LPBF","authors":"Joseph Berthel, Jack Beuth, Rahul Panat","doi":"10.1016/j.addma.2026.105117","DOIUrl":"10.1016/j.addma.2026.105117","url":null,"abstract":"<div><div>The fabrication of lattice structures through laser powder bed fusion (LPBF) has the potential to create architected materials with exceptional mechanical properties at low densities, with plate-lattice structures demonstrating the highest stiffness and strength to weight ratios. However, geometric deviations and defects introduced by the LPBF process result in plate-lattice geometries deviating from their intended ideal design, potentially compromising mechanical properties and increasing density without a proportional increase in strength. The intersecting and inclined thin-plate features that enable the high performance of plate-lattices are especially prone to compromising deviations, since plate-lattice features are fabricated at scales approaching the resolution limits of LPBF. This study presents a comprehensive analysis of geometric deviations and defects in AlSi10Mg LPBF plate-lattice structures, focusing on understanding the influence of both processing conditions and geometric features on deviation formation, and determining their detrimental effect on compression mechanics. Micro-CT scanning is used to examine the as-fabricated morphology of plate-lattice unit cells and identify trends in defect severity among different lattice topologies and volume fractions. Finite element analysis (FEA) of the ideal and as-fabricated unit cell geometry under compressive strain is performed to evaluate differences in strain energy density distribution and resultant lattice stiffness. FEA results show that deviations contribute to a 4.4–28.0 % increase in minimally load-bearing lattice mass, reducing the specific stiffness of the lattice by 11.8–31.7 % compared to ideal geometries. Minimally load-bearing mass arises from protruding surface variations and dross formations around powder drainage holes and overhanging features, while underprinting at critical plate intersections introduces stress concentrations. This work provides insight into how plate-lattice design and LPBF fabrication strategy impact as-fabricated lattice geometry and resulting mechanical performance.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105117"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-06DOI: 10.1016/j.addma.2026.105112
Philipp Gabriel , Florian Eibl , Stephan Barcikowski , Anna Rosa Ziefuss
Laser powder bed fusion of metals (PBF-LB/M) is an established additive manufacturing (AM) technique enabling material-efficient production of complex metal components. However, current PBF-LB/M systems cannot monitor or control local chemical composition during fabrication, relying instead on ex-situ analyses after printing to assess material quality, which is incompatible with real-time quality assurance in industrial production. This study applies optical emission spectroscopy (OES) to monitor the chemical composition of parts during fabrication, with a focus on identifying and quantifying key influence factors such as laser energy input, alloy composition, integration time, and analysis position exemplified for magnet (Nd-Fe-B) and Scalmalloy (Al-Mg-Sc) printing. By comparing spectra from powder and bulk samples and evaluating characteristic peak intensity ratios, global spectral effects are effectively minimized. The machine-integrated, optically off-axis OES enabled reproducible measurements with composition sensitivity in the sub-at% range. Thereby, a novel concept for the 2D/3D reconstruction of chemical composition during PBF-LB/M is demonstrated. This approach aligns spatial and temporal OES data with the laser scan path through synchronizing the spectrometer acquisition interval with the machine clock, generating spatially resolved composition maps. Proof of concept is presented through layer-wise 2D mapping, with OES-derived data validated by ex-situ EDX analysis, with layers digitally stacked into a 3D reconstruction. This method lays the groundwork for robust in-situ chemical mapping during PBF-LB/M and supports the advancement of digital twins by a material vector. By enabling real-time monitoring and process control, it will open new pathways for quality assurance and adaptive manufacturing strategies in industrial settings.
{"title":"Toward real-time chemical mapping during laser powder bed fusion: Robust in-situ spectroscopy and 3D reconstruction","authors":"Philipp Gabriel , Florian Eibl , Stephan Barcikowski , Anna Rosa Ziefuss","doi":"10.1016/j.addma.2026.105112","DOIUrl":"10.1016/j.addma.2026.105112","url":null,"abstract":"<div><div>Laser powder bed fusion of metals (PBF-LB/M) is an established additive manufacturing (AM) technique enabling material-efficient production of complex metal components. However, current PBF-LB/M systems cannot monitor or control local chemical composition during fabrication, relying instead on <em>ex-situ</em> analyses after printing to assess material quality, which is incompatible with real-time quality assurance in industrial production. This study applies optical emission spectroscopy (OES) to monitor the chemical composition of parts during fabrication, with a focus on identifying and quantifying key influence factors such as laser energy input, alloy composition, integration time, and analysis position exemplified for magnet (Nd-Fe-B) and Scalmalloy (Al-Mg-Sc) printing. By comparing spectra from powder and bulk samples and evaluating characteristic peak intensity ratios, global spectral effects are effectively minimized. The machine-integrated, optically off-axis OES enabled reproducible measurements with composition sensitivity in the sub-at% range. Thereby, a novel concept for the 2D/3D reconstruction of chemical composition during PBF-LB/M is demonstrated. This approach aligns spatial and temporal OES data with the laser scan path through synchronizing the spectrometer acquisition interval with the machine clock, generating spatially resolved composition maps. Proof of concept is presented through layer-wise 2D mapping, with OES-derived data validated by <em>ex-situ</em> EDX analysis, with layers digitally stacked into a 3D reconstruction. This method lays the groundwork for robust <em>in-situ</em> chemical mapping during PBF-LB/M and supports the advancement of digital twins by a material vector. By enabling real-time monitoring and process control, it will open new pathways for quality assurance and adaptive manufacturing strategies in industrial settings.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105112"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-14DOI: 10.1016/j.addma.2026.105124
Barış Kavas , Efe C. Balta , Lars Witte , Michael R. Tucker , John Lygeros , Markus Bambach
This study investigates the stabilization of interlayer temperature in the laser powder bed fusion process through a novel switched layer-to-layer closed-loop feedback controller. The controller architecture aims to measure the interlayer temperature by a laterally positioned thermal camera and maintain a preset reference temperature by switching between the heating mode through dynamic laser power adjustment and the cooling mode by assigning interlayer dwell time to allow cooling between layers. The switching controller employs a feedback optimization control algorithm for the heating mode to adjust the laser power, and a triggering algorithm that increases the interlayer dwell time until the interlayer temperature reaches the reference value. Additionally, the study compares the performance of the proposed controller in both supported and unsupported overhanging parts to evaluate the effect of support structures on the controller performance as well as the thermal behavior of overhanging parts. Key results demonstrate the controller’s effectiveness in stabilizing interlayer temperature across varying cross-sectional areas while remaining within the material’s stable processing zone. In the heating mode, the controller efficiently tracks the reference temperature, even in geometries with significant cross-section variation. During cooling, the controller adjusts dwell times to enhance thermal control in overhanging sections. The controller’s robustness is further validated by its performance with unsupported parts, where the overheating effect is more pronounced, and in supported parts, where thermal conduction to the build plate is enhanced. The study also identifies trade-offs among process efficiency, energy consumption, and build time. Supported parts exhibit reduced overheating but consume more energy and material, while unsupported parts stabilize interlayer temperature faster but with longer build times due to increased dwell time assignments. This tradeoff is more than compensated by a reduction in post-processing effort. The research highlights notable improvements in interlayer temperature control for geometries prone to excessive thermal stresses. Moreover, the introduction of interlayer dwell time offers a practical solution to maintaining thermal stability in complex geometries.
{"title":"Layer-to-layer closed-loop switched heating and cooling control of the laser powder bed fusion process","authors":"Barış Kavas , Efe C. Balta , Lars Witte , Michael R. Tucker , John Lygeros , Markus Bambach","doi":"10.1016/j.addma.2026.105124","DOIUrl":"10.1016/j.addma.2026.105124","url":null,"abstract":"<div><div>This study investigates the stabilization of interlayer temperature in the laser powder bed fusion process through a novel switched layer-to-layer closed-loop feedback controller. The controller architecture aims to measure the interlayer temperature by a laterally positioned thermal camera and maintain a preset reference temperature by switching between the heating mode through dynamic laser power adjustment and the cooling mode by assigning interlayer dwell time to allow cooling between layers. The switching controller employs a feedback optimization control algorithm for the heating mode to adjust the laser power, and a triggering algorithm that increases the interlayer dwell time until the interlayer temperature reaches the reference value. Additionally, the study compares the performance of the proposed controller in both supported and unsupported overhanging parts to evaluate the effect of support structures on the controller performance as well as the thermal behavior of overhanging parts. Key results demonstrate the controller’s effectiveness in stabilizing interlayer temperature across varying cross-sectional areas while remaining within the material’s stable processing zone. In the heating mode, the controller efficiently tracks the reference temperature, even in geometries with significant cross-section variation. During cooling, the controller adjusts dwell times to enhance thermal control in overhanging sections. The controller’s robustness is further validated by its performance with unsupported parts, where the overheating effect is more pronounced, and in supported parts, where thermal conduction to the build plate is enhanced. The study also identifies trade-offs among process efficiency, energy consumption, and build time. Supported parts exhibit reduced overheating but consume more energy and material, while unsupported parts stabilize interlayer temperature faster but with longer build times due to increased dwell time assignments. This tradeoff is more than compensated by a reduction in post-processing effort. The research highlights notable improvements in interlayer temperature control for geometries prone to excessive thermal stresses. Moreover, the introduction of interlayer dwell time offers a practical solution to maintaining thermal stability in complex geometries.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105124"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-14DOI: 10.1016/j.addma.2026.105123
Siqi Ma , Feng Zhang , Shuai Fu , Benzhi Min , Xiaodi Feng , Shengwen Wang , Guoliang Chen , Peigang He , Dechang Jia , Honghao Yue , Yifan Lu , Yu Zhou
To address the combined demands of impact resistance, thermal protection, and structural support in lunar surface shielding, we developed a multifunctional biomimetic multilayer barrier using a lunar-regolith-simulant-based geopolymer via Direct Ink Writing (DIW). The barrier comprises three bio-inspired tiers: a Bouligand helicoidal layer providing superior impact resistance, a dendritic fractal network integrating thermal insulation with load-bearing capacity, and a honeycomb-like sandwich panel mitigating vibration. Mortise-and-tenon interlocks integrate these tiers into a mechanically robust whole. Mechanical and thermal performance were evaluated through static loading, impact, and insulation experiments, supported by finite element simulations. The Bouligand layer, optimized at a 90° stacking angle, dissipated impact energy through sequential failure, enhancing toughness and resistance to dynamic loading. The dendritic layer, tuned to a 60° branching angle, achieved optimal stability and deformation adaptability, yielding the highest energy absorption and over 60 % thermal insulation effectiveness. The honeycomb base layer outperformed auxetic and chiral counterparts in compressive strength and robustness, while maintaining efficient vibration isolation. Collectively, the integrated architecture demonstrated complementary mechanical and thermal performance, providing multifunctional protection beyond that achievable by conventional single-function layered materials. Under external thermal loads of up to 127°C, the internal temperature remained stabilized near 30°C, confirming excellent thermal shielding. This study clarifies how geometric parameters of biomimetic substructures govern composite barrier responses and establishes an engineering-feasible design paradigm for multifunctional shielding systems, providing theoretical and experimental foundations for lunar infrastructure optimization.
{"title":"Bioinspired multilayer barriers of 3D-printed lunar regolith simulant-based geopolymers for mechanical and thermal protection","authors":"Siqi Ma , Feng Zhang , Shuai Fu , Benzhi Min , Xiaodi Feng , Shengwen Wang , Guoliang Chen , Peigang He , Dechang Jia , Honghao Yue , Yifan Lu , Yu Zhou","doi":"10.1016/j.addma.2026.105123","DOIUrl":"10.1016/j.addma.2026.105123","url":null,"abstract":"<div><div>To address the combined demands of impact resistance, thermal protection, and structural support in lunar surface shielding, we developed a multifunctional biomimetic multilayer barrier using a lunar-regolith-simulant-based geopolymer via Direct Ink Writing (DIW). The barrier comprises three bio-inspired tiers: a Bouligand helicoidal layer providing superior impact resistance, a dendritic fractal network integrating thermal insulation with load-bearing capacity, and a honeycomb-like sandwich panel mitigating vibration. Mortise-and-tenon interlocks integrate these tiers into a mechanically robust whole. Mechanical and thermal performance were evaluated through static loading, impact, and insulation experiments, supported by finite element simulations. The Bouligand layer, optimized at a 90° stacking angle, dissipated impact energy through sequential failure, enhancing toughness and resistance to dynamic loading. The dendritic layer, tuned to a 60° branching angle, achieved optimal stability and deformation adaptability, yielding the highest energy absorption and over 60 % thermal insulation effectiveness. The honeycomb base layer outperformed auxetic and chiral counterparts in compressive strength and robustness, while maintaining efficient vibration isolation. Collectively, the integrated architecture demonstrated complementary mechanical and thermal performance, providing multifunctional protection beyond that achievable by conventional single-function layered materials. Under external thermal loads of up to 127°C, the internal temperature remained stabilized near 30°C, confirming excellent thermal shielding. This study clarifies how geometric parameters of biomimetic substructures govern composite barrier responses and establishes an engineering-feasible design paradigm for multifunctional shielding systems, providing theoretical and experimental foundations for lunar infrastructure optimization.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105123"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-18DOI: 10.1016/j.addma.2026.105129
Roberto Bernasconi , Pierre Rogiers , Luca Magagnin
A self-activating photocurable resin system is proposed as a cost-effective route for the direct electroless metallization of 3D printed components. The strategy relies on the incorporation of inexpensive metallic precursors, namely NiCl2 and CuSO4, into a commercial digital light processing (DLP) resin, enabling the in situ formation of catalytic sites after a single chemical reduction step. This approach removes the need for conventional multi-step surface activation and the use of noble metals such as palladium. The rheological and photopolymerization behavior of the composite resins demonstrates that all formulations remain compatible with DLP printing, with the embedded salts significantly affecting viscosity, curing depth and mechanical properties of the resulting photopolymerized materials. The printed parts are reduced in aqueous environment, resulting in partial dissolution and conversion of the precursors into metallic nuclei that can initiate electroless deposition of NiP and Cu. The obtained metallic coatings exhibit uniform morphology, compact structure and strong adhesion to the polymer substrate, as confirmed by SEM/EDS and XRD. Moreover, the metallized substrates enable the sequential electroplating of multiple metallic layers using electrolytic deposition, producing continuous and adherent multilayer architectures. The versatility of the proposed method is further expanded through multimaterial DLP printing, which allows selective metallization by combining clear and self-activating regions within a single object. Metallization occurrs exclusively in the catalytically active areas following reduction. Overall, this study introduces a simple and scalable metallization route for polymer-based additive manufacturing, reducing cost and process complexity while maintaining high coating quality. The proposed self-activating resins provide a sustainable pathway toward functional metallic architectures, electronic interconnects and decorative finishes produced directly via DLP 3D printing.
{"title":"Self-activating resins for the straightforward electroless metallization of 3D printed parts","authors":"Roberto Bernasconi , Pierre Rogiers , Luca Magagnin","doi":"10.1016/j.addma.2026.105129","DOIUrl":"10.1016/j.addma.2026.105129","url":null,"abstract":"<div><div>A self-activating photocurable resin system is proposed as a cost-effective route for the direct electroless metallization of 3D printed components. The strategy relies on the incorporation of inexpensive metallic precursors, namely NiCl<sub>2</sub> and CuSO<sub>4</sub>, into a commercial digital light processing (DLP) resin, enabling the in situ formation of catalytic sites after a single chemical reduction step. This approach removes the need for conventional multi-step surface activation and the use of noble metals such as palladium. The rheological and photopolymerization behavior of the composite resins demonstrates that all formulations remain compatible with DLP printing, with the embedded salts significantly affecting viscosity, curing depth and mechanical properties of the resulting photopolymerized materials. The printed parts are reduced in aqueous environment, resulting in partial dissolution and conversion of the precursors into metallic nuclei that can initiate electroless deposition of NiP and Cu. The obtained metallic coatings exhibit uniform morphology, compact structure and strong adhesion to the polymer substrate, as confirmed by SEM/EDS and XRD. Moreover, the metallized substrates enable the sequential electroplating of multiple metallic layers using electrolytic deposition, producing continuous and adherent multilayer architectures. The versatility of the proposed method is further expanded through multimaterial DLP printing, which allows selective metallization by combining clear and self-activating regions within a single object. Metallization occurrs exclusively in the catalytically active areas following reduction. Overall, this study introduces a simple and scalable metallization route for polymer-based additive manufacturing, reducing cost and process complexity while maintaining high coating quality. The proposed self-activating resins provide a sustainable pathway toward functional metallic architectures, electronic interconnects and decorative finishes produced directly via DLP 3D printing.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105129"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147424818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05Epub Date: 2026-02-18DOI: 10.1016/j.addma.2026.105127
Sarra Oueslati , Mathieu Ritou , Elodie Paquet , Farouk Belkadi , Philippe Le Bot
Wire Arc Additive Manufacturing (WAAM) is a promising technology to produce large metallic components. However, drifts of the Contact Tube to Workpiece Distance (CTWD) are difficult to manage, which can induce process instability and defects like porosity. To safeguard material integrity, instability must be detected before it occurs, which is very challenging. This paper proposes an original predictive model for process instability caused by CTWD drift. In-process monitoring data were collected on a robotic cell and sixteen key features were extracted as potential monitoring criteria for CTWD drift estimation. Feature selection was then performed by several filtering methods, to identify the best indicator for CTWD drift estimation through regression model. ANOVA was used to identify which Key Process Parameters (KPP) should be considered for finetuning the linear regression model. Then, Support Vector Regression (SVR) model was developed to predict the boundary of instability T*, based on dedicated KPP identified by ANOVA. By combining the estimated CTWD drift and drift speed with the predicted boundary T*, the model predicts the Number of Remaining Layers (nRL) before process instability onset. The proposed method was evaluated on a use-case of thin wall manufacturing. Instability predictions aligned with observations, demonstrating the model capability to anticipate defects. The instability consequences on material integrity were confirmed by metallographic examination. The combination of real-time monitoring, data-driven models and eXplainable AI, provides a robust and interpretable framework to improve WAAM control, while providing manufacturing experts with new insight on the KPP for instability prediction and proactive intervention.
{"title":"Prediction of process instability by WAAM in-process monitoring and CTWD drift estimation","authors":"Sarra Oueslati , Mathieu Ritou , Elodie Paquet , Farouk Belkadi , Philippe Le Bot","doi":"10.1016/j.addma.2026.105127","DOIUrl":"10.1016/j.addma.2026.105127","url":null,"abstract":"<div><div>Wire Arc Additive Manufacturing (WAAM) is a promising technology to produce large metallic components. However, drifts of the Contact Tube to Workpiece Distance (CTWD) are difficult to manage, which can induce process instability and defects like porosity. To safeguard material integrity, instability must be detected before it occurs, which is very challenging. This paper proposes an original predictive model for process instability caused by CTWD drift. In-process monitoring data were collected on a robotic cell and sixteen key features were extracted as potential monitoring criteria for CTWD drift estimation. Feature selection was then performed by several filtering methods, to identify the best indicator for CTWD drift estimation through regression model. ANOVA was used to identify which Key Process Parameters (KPP) should be considered for finetuning the linear regression model. Then, Support Vector Regression (SVR) model was developed to predict the boundary of instability T*, based on dedicated KPP identified by ANOVA. By combining the estimated CTWD drift and drift speed with the predicted boundary T*, the model predicts the Number of Remaining Layers (n<sub>RL</sub>) before process instability onset. The proposed method was evaluated on a use-case of thin wall manufacturing. Instability predictions aligned with observations, demonstrating the model capability to anticipate defects. The instability consequences on material integrity were confirmed by metallographic examination. The combination of real-time monitoring, data-driven models and eXplainable AI, provides a robust and interpretable framework to improve WAAM control, while providing manufacturing experts with new insight on the KPP for instability prediction and proactive intervention.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"119 ","pages":"Article 105127"},"PeriodicalIF":11.1,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147424819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号