Additive manufacturing最新文献

{"title":"Inducing inter-filament fusion during embedded 3D printing of silicones","authors":"Leanne M. Friedrich,&nbsp;Jeremiah W. Woodcock","doi":"10.1016/j.addma.2025.104741","DOIUrl":"10.1016/j.addma.2025.104741","url":null,"abstract":"<div><div>Embedded 3D printing (EMB3D) is an additive manufacturing technique that enables fabrication of soft materials including silicones and biological tissues. In EMB3D, a nozzle is embedded in a viscoelastic support bath and writes continuous filaments. Because the bath takes care of form holding, inks that are not printable using conventional extrusion methods can be printed using EMB3D. However, EMB3D can experience defects including positioning errors, poor inter-filament fusion, shrinkage, and rupture. Here, we use in-situ imaging experiments to investigate how defects evolve while disturbing pairs of filaments and writing triplets of filaments. By comparing written triplets to disturbed pairs, we isolate whether defects come from writing of subsequent filaments or from nozzle movement alone. Using silicone-based inks printed into water-based supports with varying concentrations of rheological modifier and surfactant, we probe how the balance between interfacial tension and viscous dissipation governs both inter-filament fusion and capillary instabilities. Critically, higher interfacial tensions and lower support viscosities lead to more rupture, more shrinkage, and more inter-filament fusion. Running the nozzle next to unfused pairs of filaments can cause fusion, but it can also cause rupture. The microstructure of the ink can also influence defects, as phase separation can inhibit both inter-filament fusion and rupture. In addition to material properties, the toolpath also controls defect formation. Fusion quality varies depending on whether filaments are horizontal or vertical in the bath, and whether filaments are stacked on top of each other or next to each other. Moreover, considerable overlap is necessary to achieve inter-filament fusion, leading to over-extrusion. Toolpaths should consider the positioning defects that come from this over-extrusion, particularly vertical displacement of horizontal lines. This work provides key guidelines to achieve prints with better shape fidelity, better resolution, and improved mechanical properties.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"102 ","pages":"Article 104741"},"PeriodicalIF":10.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687764","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}

{"title":"Flexible lattice structure using curved struts based on body-centered cubic structure","authors":"Takashi Sasagawa,&nbsp;Naruhiko Nimura,&nbsp;Masato Tanaka","doi":"10.1016/j.addma.2025.104746","DOIUrl":"10.1016/j.addma.2025.104746","url":null,"abstract":"<div><div>Mono-material design is effective for achieving sustainability and a circular economy. Conversely, most industrial products are manufactured using a diverse range of materials to introduce multifunctional properties and characteristics. To resolve this trade-off, a wide range of mechanical properties can be achieved by controlling the porous cellular structures using a single material. For instance, Young’s modulus can be modified by changing the relative density of the cellular structures. However, in the case of 3D printed components, the lower limit of the relative density depends on the dimensional accuracy that can be achieved. Therefore, a novel flexible lattice structure is proposed to increase the range of mechanical property control. The key aspect of our lattice structure is the realization of slender and tilted struts by curving the struts of a conventional lattice structure. Consequently, the resulting structures exhibited approximately 40 times greater flexibility than body-centered cubic and octet truss lattices at the same relative density. Furthermore, Young’s modulus and static energy absorption values were achieved over a range of approximately three orders of magnitude by controlling the relative density from 13.3% to 100% for our lattice.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"103 ","pages":"Article 104746"},"PeriodicalIF":10.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724346","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}

{"title":"Strategic layer reworking using hybrid additive manufacturing for defect-free ceramic parts","authors":"Louis Masters ,&nbsp;Dan Davie ,&nbsp;Pablo J. Cevallos ,&nbsp;Matthew P. Shuttleworth ,&nbsp;Daniel Bara ,&nbsp;James Warren ,&nbsp;Mehmet Dogar ,&nbsp;Robert Kay","doi":"10.1016/j.addma.2025.104752","DOIUrl":"10.1016/j.addma.2025.104752","url":null,"abstract":"<div><div>Hybrid manufacturing combines additive and subtractive processes to create parts of high precision and density. However, extrusion-based processes are susceptible to stochastic defects such as voids, which lower yield and worsen material properties, leading to premature failure of components. This research demonstrates deep learning informed selective layer reworking for a ceramic hybrid additive manufacturing platform. We evaluate each layer in-situ for under and over extrusions using a vision-based monitoring system and a YOLOv8 model trained on a custom dataset. Through closed-loop control, a decision to repair defective layers via subtractive operations, prior to reprinting, was made using conditional gcode programming based on the results of the YOLOv8 model. The YOLOv8 model detected voids with a precision of 91 %, and a mean average precision of 83.5 % across both defect classes. Through CT analysis, it was determined that reworking achieved a 68 % reduction in void content compared to uncorrected parts, showcasing the potential of hybrid manufacturing in the creation of defect-free parts.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"102 ","pages":"Article 104752"},"PeriodicalIF":10.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Warpage of thin additively manufactured continuous fiber thermoset composites","authors":"Mateo Diaz,&nbsp;Jeffery W. Baur","doi":"10.1016/j.addma.2025.104749","DOIUrl":"10.1016/j.addma.2025.104749","url":null,"abstract":"<div><div>Additive manufacturing (AM) of thin continuous fiber thermoset composites can have large and anisotropic residual stresses that result in out of plane shape distortion, or warpage, and limits applicability to thin structures. In this study, the warpage of thin AM laminates was investigated as a function of deposited fiber direction and microstructure heterogeneity. The experimental results were compared with predictions made by Classical Lamination Theory (CLT), which assumed homogeneous deposited layers, and microstructure-informed CLT, which accounted for heterogeneity in the thickness direction. For thin unidirectional laminates, a curvature was observed in the transverse direction upon slow (0.3 °C/min) unconstrained cooling from the maximum curing temperature (140°C). Magnitudes of the observed curvatures (<span><math><mi>κ</mi></math></span>) decreased as the number of deposited layers (n) increased from n = 1 (<span><math><mi>κ</mi></math></span> = 8 m⁻¹) to n = 8 (<span><math><mi>κ</mi></math></span> = 1 m⁻¹) and did not match the CLT prediction of zero curvature. The variation in through-thickness fiber volume fraction was quantified by optical cross-section micrographs and used to make microstructure-informed CLT predictions which ranged from <span><math><mi>κ</mi></math></span> = ∼0.6 m⁻¹ (n = 8) to <span><math><mi>κ</mi></math></span> = 26 m⁻¹ (n = 1). While the curvature of the symmetrically stacked cross-ply laminates (0° and 90°) had near zero curvature and agreed with CLT predictions, the asymmetrically stacked cross-ply laminates predicted a large saddle-like curvature that was not fully observed due to delamination between orthogonally aligned layers. For thin (≤4 layers, ∼0.24 mm/layer) AM thermosetting laminates without delamination, the experimentally observed curvature values were roughly bounded between predictions made by CLT and by microstructure-informed CLT.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"102 ","pages":"Article 104749"},"PeriodicalIF":10.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687773","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}

{"title":"Unveiling ultra-stable cyclic martensitic transformation behavior of an additively manufactured NiTiCu shape memory alloy","authors":"Dan Zheng ,&nbsp;Ruidi Li ,&nbsp;Jingtao Kang ,&nbsp;Changjun Han ,&nbsp;Tiechui Yuan","doi":"10.1016/j.addma.2025.104742","DOIUrl":"10.1016/j.addma.2025.104742","url":null,"abstract":"<div><div>Additively manufactured (AM) nickel-titanium (NiTi) shape memory alloys (SMAs) often suffer from functional fatigue due to intrinsic large hysteresis and process complexities during cyclic operation. This study, by optimizing lattice compatibility between the parent and martensitic phases, presents a laser-directed energy deposited (LDED) Ni40-Ti50-Cu10 (at%) SMA that simultaneously achieves low hysteresis and enhanced cyclic stability in martensitic transformation behavior. Only 0.31°C of martensitic transformation temperature shift was observed after 50 thermal cycles, significantly outperforming conventional SMAs. The non-equilibrium solidification of the LDED process generates cross-scale microstructures and a distinct (100) growth texture, while excellent lattice compatibility restricts martensitic variants to favorable orientations of (010)_B2 || (001)_B19 and (101)_B2 || (010)_B19. Dominant (011) type I twin relationship between martensitic variants is observed with coherent twin interfaces. These characteristics reduce the energy barrier at the phase transition interface, effectively mitigating interface stress and preventing irreversible defects, minimizing hysteresis, and ensuring ultra-stable cyclic martensitic transformation. Additionally, Ti₂Cu precipitates, formed at twin ridges due to cyclic heating during fabrication, pin dislocations and prevent their movement across twin interfaces, ensuring repeatability and reversibility in each cycle. The utilization of pre-alloyed powder guarantees macroscopic uniformity in phase composition and transition behavior, resulting in consistent cycle stability along the build direction. This study provides new insights into the high cyclic stability of LDED-fabricated NiTiCu10 SMAs and advances the development of high-performance SMAs with degradation-free cyclic phase transformation using AM technology.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"102 ","pages":"Article 104742"},"PeriodicalIF":10.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687763","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}

{"title":"Exploring inorganic particle-inclusive RAFT-controlled radical polymerization: Advancing precision in ceramic 3D printing","authors":"Yixuan Gong ,&nbsp;Ruoyu Wang ,&nbsp;Siyu Pan ,&nbsp;Zeyu Ma ,&nbsp;Xiyu Zhu ,&nbsp;Ye Song ,&nbsp;Haitao Song ,&nbsp;Lei Tao ,&nbsp;Dongxue Cao ,&nbsp;Wei Lin","doi":"10.1016/j.addma.2025.104757","DOIUrl":"10.1016/j.addma.2025.104757","url":null,"abstract":"<div><div>Stereolithography is a highly effective method for fabricating intricate ceramic parts, offering fast molding speeds and a diverse range of material options. However, it still faces significant precision challenges due to the incorporation of inorganic ceramic particles, which alters the propagation path of the incident light and affects the region where the polymerization reaction occurs. Herein, we regulate the polymerization reaction kinetics by introducing reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization into ceramic stereolithography, successfully reducing the minimum printable feature size of Al₂O₃ photosensitive slurry to 200 μm and achieving over 86.7 % fidelity across all tested feature sizes. The RAFT-based ceramic stereolithography system enhances the uniformity of the polymer network and reduces the formation of high cross-link density microgels with a high refractive index. Additionally, incorporating RAFT agents increases the critical energies in both depth and width directions, mitigating out-of-target area curing caused by radical diffusion. Furthermore, the RAFT formulation significantly reduces the attenuation length in the width direction, broadening the printing operational window and improving dimensional stability. Finally, the cross-section exposure distribution simulations under varying conditions suggest that RAFT-slurry reduces the broadening of the cure diameter caused by scattering effects and enhances inter-layer interactions during printing. This work presents a new technological approach for the advanced manufacturing of fine ceramic structures.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"103 ","pages":"Article 104757"},"PeriodicalIF":10.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739660","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}

{"title":"Investigate mechanisms of different printing parameters on the mechanical anisotropy of 3D concrete printing elements by using computed tomography scan and computational fluid dynamics methods","authors":"Zhenbang Liu ,&nbsp;Mingyang Li ,&nbsp;Xiangyu Wang ,&nbsp;Teck Neng Wong ,&nbsp;Ming Jen Tan","doi":"10.1016/j.addma.2025.104760","DOIUrl":"10.1016/j.addma.2025.104760","url":null,"abstract":"<div><div>3D concrete printing (3DCP) elements show significant mechanical anisotropy. Printing parameters can affect the mechanical anisotropy of 3DCP elements. However, most studies have focused on the effects of printing parameters on the interlayer bond strength at a macroscale level. The mechanisms of printing parameters on the mechanical anisotropy of 3DCP elements remain unclear. To fill research gaps, computed tomography (CT) scans, computational fluid dynamics (CFD) numerical simulations, and uniaxial compression tests (UCTs) were conducted with the printing parameters of the expansion state of the nozzle flow channel, overflow ratio, stand-off distance, and flow rate involved. The results of CT scans, CFD simulations, and UCTs revealed the mechanism that the printing parameters affect porosity distribution and pore anisotropy by influencing the normalized local pressure at interlayer and fluid velocity gradients, respectively, which further results in the modification of the mechanical anisotropy of 3DCP elements.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"103 ","pages":"Article 104760"},"PeriodicalIF":10.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734905","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}

{"title":"Printing dense and low-resistance copper microstructures via highly directional laser-induced forward transfer","authors":"Jiangyou Long ,&nbsp;Yujun Zhou ,&nbsp;Jinghao Lin ,&nbsp;Bingjun Luo ,&nbsp;Zhiheng Wu ,&nbsp;Xinhong Su","doi":"10.1016/j.addma.2025.104755","DOIUrl":"10.1016/j.addma.2025.104755","url":null,"abstract":"<div><div>Laser-induced forward transfer (LIFT) can be used to print micrometer-scale metallic three-dimensional (3D) structures. However, the structures produced by this method exhibit high porosity and poor electrical properties due to the non-vertical ejection and loose stacking of transfer particles. In this study, we replace the conventional copper (Cu) monolayer donor film with a chromium-copper (Cr-Cu) bilayer film. We demonstrate that this bilayer enhances laser absorption and improves glass-metal adhesion through the spontaneous formation of a CrO_<em>x</em> interlayer. The improved laser absorption reduces the optimal pulse energy required for transfer, while the interlayer stabilizes the transfer process, promoting more vertical ejection of material. This enhanced directionality leads to denser structures, even when the donor and receiver are placed at a larger distance. The resulting structures exhibit a porosity of 4.8 % and a specific resistance 2.9 times that of bulk copper. Cross-sectional electron microscopy is employed to investigate the microstructure and elucidate the mechanisms behind the reduced resistance. Additionally, we demonstrate the application of this 3D printing method in creating high aspect ratio microstructures and repairing open defects on printed circuit boards (PCBs).</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"103 ","pages":"Article 104755"},"PeriodicalIF":10.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715396","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}

{"title":"Analytical prediction of lack-of-fusion porosity including uncertainty and variable melt pools for powder bed fusion","authors":"Brodan Richter ,&nbsp;Joshua D. Pribe ,&nbsp;George R. Weber ,&nbsp;Vamsi Subraveti ,&nbsp;Caglar Oskay","doi":"10.1016/j.addma.2025.104733","DOIUrl":"10.1016/j.addma.2025.104733","url":null,"abstract":"<div><div>Powder bed fusion (PBF) additive manufacturing (AM) technology has greatly matured in recent years driven by numerous industrial applications. However, lack-of-fusion (LoF) porosity is a significant challenge during PBF, and LoF pores can form even when processing with optimized deposition parameters. This paper proposes an analytical approach for simulating LoF porosity during PBF AM on the basis of a semi-elliptical model of the melt pool cross-section. Melted area, reference area, and LoF area fraction calculations are developed for the case where only one layer melts the reference area because of a shallow melt pool. In more complex cases where two layers melt a portion of the initial layer, the melted volume, reference volume, and LoF volume fraction calculations are developed using a change of coordinate system and integration. Finally, the model is extended to an arbitrary number of layers by assuming LoF porosity exponentially decays as the number of interacting layers increases. The analytical model predicts LoF porosity for both identical and variable melt pools and enables uncertainty analysis for LoF porosity calculations through the rapid sampling of a large number of experimentally-determined melt pool geometries. The model is used to calculate porosity fraction across the melt pool depth, melt pool width, hatch spacing, and layer thickness processing space. The accuracy of the model is demonstrated through comparisons with experimental data, and the effect of melt pool geometric uncertainty on the PBF process window is demonstrated through experimental comparisons. A new LoF porosity criterion for variable melt pools is proposed that simplifies to a previously defined, widely used LoF porosity criterion in the case of identical melt pools. Overall, the new approach presented provides a straightforward, low computational cost method for calculating LoF porosity that incorporates uncertainty for PBF AM processing.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"103 ","pages":"Article 104733"},"PeriodicalIF":10.3,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739409","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}

{"title":"I-wi: Multifunctional 3D-printable stretchable ionogel and ionic eutectogel wires with AC and DC signal transmission","authors":"Sergey Nechausov,&nbsp;Yi Jiang,&nbsp;Aslan Miriyev","doi":"10.1016/j.addma.2025.104743","DOIUrl":"10.1016/j.addma.2025.104743","url":null,"abstract":"<div><div>Recent advances in technologies based on soft matter functionality have spurred the demand for flexible and stretchable conductors. However, state-of-the-art stretchable conductors suffer from trade-offs between material compositions, design and scale factors, electrical properties, durability, and precise fabrication methods, thus sacrificing critical parameters and hindering performance. The longstanding challenge in the field has been co-developing reliable, stretchable, and highly electrically conductive bulk elastomers with precise fabrication methods for transferring diverse signals over distances, while both at rest and in a stretched state under both DC and AC conditions. In this study, we developed, characterized, and showcased i-wi (ionic wires) — soft, stretchable, and 3D-printable ionogels and ionic eutectogels designed for applications in soft stretchable electronics under both DC and AC. We combined imidazolium-based ionic liquids (ILs) or ethaline and glyceline deep eutectic solvents (DESs) with photopolymer compositions to obtain ionogels or eutectogels, respectively, that combine elastic deformation with high ionic conductivity and that can be precisely 3D-printed using the vat photopolymerization method. We showed that i-wi can transfer both DC and AC signals in various implementation scenarios, extending the horizon for myriad applications. We demonstrated the multifunctionality of i-wi in multimaterial connectors, which conducted signals to light LEDs, play music, and perform electric guitar, while both at rest and under stretching, and which functioned as precise temperature and strain sensors. We suggest that i-wi may become a core component of physically intelligent systems, including morphological computing, advanced wearable and medical devices, and the broader field of soft robotic systems.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"104 ","pages":"Article 104743"},"PeriodicalIF":10.3,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}