Additive manufacturing最新文献_第6页

Audio-visual cross-modality knowledge transfer for machine learning-based in-situ monitoring in laser additive manufacturing

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-05 DOI: 10.1016/j.addma.2025.104692

Jiarui Xie , Mutahar Safdar , Lequn Chen , Seung Ki Moon , Yaoyao Fiona Zhao

Various machine learning (ML)-based in-situ monitoring systems have been developed to detect anomalies and defects in laser additive manufacturing (LAM) processes. While multimodal fusion, which integrates data from visual, audio, and other modalities, can improve monitoring performance, it also increases hardware, computational, and operational costs. This paper introduces a cross-modality knowledge transfer (CMKT) methodology for LAM in-situ monitoring, which transfers knowledge from a source modality to a target modality. CMKT enhances the representativeness of the features extracted from the target modality, allowing the removal of source modality sensors during prediction. This paper proposes three CMKT methods: semantic alignment, fully supervised mapping, and semi-supervised mapping. The semantic alignment method establishes a shared encoded space between modalities to facilitate knowledge transfer. It employs a semantic alignment loss to align the distributions of identical groups (e.g., visual and audio defective groups) and a separation loss to distinguish different groups (e.g., visual defective and audio defect-free groups). The two mapping methods transfer knowledge by deriving features from one modality to another using fully supervised and semi-supervised learning approaches. In a case study for LAM in-situ defect detection, the proposed CMKT methods were compared with multimodal audio-visual fusion. The semantic alignment method achieved an accuracy of 98.6 % while removing the audio modality during the prediction phase, which is comparable to the 98.2 % accuracy obtained through multimodal fusion. Using explainable artificial intelligence, we discovered that semantic alignment CMKT can extract more representative features while reducing noise by leveraging the inherent correlations between modalities.

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引用次数: 0

UV-curable, 3D printable, thermally conductive polysiloxane composites for thermal interface devices

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-05 DOI: 10.1016/j.addma.2025.104658

Hao Jin , Xingxing Zhong , Chucheng Zhong , Wensheng Dai , Hongping Xiang , Lanyue Zhang

Thermally conductive polysiloxane composites play an important role in 5 G electronics to efficiently dissipate accumulated heat. However, these polysiloxane composites are still challenged by long curing time, high energy consumption and huge amounts of waste from traditional subtractive manufacturing processes. In this work, UV-curable, 3D printable, thermally conductive polysiloxane composites are developed using mercaptopropyl-functionalized polydimethylsiloxane (PDMS-SH) and 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane (V₄) as matrix, and different sized spherical Al₂O₃ and BN particles as thermally conductive fillers. Using V₄ instead of the common vinyl-terminated polydimethylsiloxane (PDMS-Vi) can greatly reduce the viscosity to fill more fillers (6 wt% BN and 76 wt% Al₂O₃) for higher thermal conductivity (2.02 ± 0.02 W/mK). The rational combination of larger particle size BN (200 μm) with different sizes of Al₂O₃ (5 and 90 μm) has a fast gelation behavior (within 5 s) and low critical exposure energy (3 mJ/cm²). Furthermore, the composites developed can be 3D printed into thermally conductive devices with complex 3D structures, and the 3D objects show outstanding heat conduction and dissipation capabilities. Therefore, these UV-curable, 3D printable, thermally conductive polysiloxane composites will be used in 3D thermal interfacial objects with high production efficiency, low energy consumption and customization.

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引用次数: 0

A novel 3D printing scheme for lunar construction with extremely low binder utilization

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-05 DOI: 10.1016/j.addma.2025.104657

Zifan Geng , Zhiwen Wu , Xiangyu Wang , Lizhi Zhang , Wei She , Ming Jen Tan

Lunar construction has become a multidisciplinary, cutting-edge, and strategic topic worldwide with additive manufacturing as a key technology to build required structures. Targeting the low strength or excessive terrestrial materials utilization in current lunar 3D printing, a novel printing scheme is proposed herein to balance the processability and strength using minimal binders. A printing system was designed based on powder extrusion and passive roll-pressing. Therein, a screw-blade module with 73 % of full blade length can efficiently extrude dry and damp powders. An adjustable roller-spring module is applied to reveal the significance of harder lunar regolith, larger roller and stiffer spring on the powder printing. Using the roller with 50 mm of diameter and 78 N of pressure, a dense print layer can be obtained with > 2 mm of layer thickness and 2–5 MPa of flexural strength. Through experimental results and mechanical analysis a quantitative powder-roller interaction is established. Also, this printing system supports both premix printing and dry printing. The former can use fewer binders as low as 4 wt%, while the latter enables 2.6 times and 3.8 times higher flexural and bonding strength respectively. This low-binder powder 3D printing scheme will bring more prospects and advancements for future lunar constructions.

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引用次数: 0

Vat photopolymerization of zirconia suspensions continuously blended by in-line static mixing for strength-gradient zirconia

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-05 DOI: 10.1016/j.addma.2025.104675

Gyu-Nam Kim , Young-Hag Koh

Vat photopolymerization (VP) of ceramics has demonstrated great promises for manufacturing dental crowns made of partially stabilized zirconia (PSZ) ceramics with excellent dimensional accuracy, outstanding mechanical properties, and good esthetics. However, close mimicking of gradually changing optical translucency of natural teeth still remains challenging. We herein propose functionally graded (FG)-digital light processing (DLP) for manufacturing PSZ objects with gradually varying compositions and mechanical/optical properties using an in-line static mixing system. In this study, 4 mol% and 5 mol% yttria (Y₂O₃) PSZ, denoted as “4Y-PSZ and 5Y-PSZ”, respectively, were employed as models due to their different mechanical strengths and optical transmittances. Predetermined amounts of 4Y-PSZ and 5Y-PSZ suspensions were fed individually into an in-line static mixer using computer-controlled extrusion systems. This FG-DLP process enabled construction of five gradients with varying 4Y-PSZ/5Y-PSZ compositions (5Y-PSZ content = 0 vol%, 25 vol%, 50 vol%, 75 vol%, and 100 vol%). For uniform blending, as-received 4Y-PSZ and 5Y-PSZ granules were calcined at 1000 °C for 1 h and then crushed into fine particles by ball-milling. In addition, UV curing time for different gradients were optimized individually due to different photopolymerization behaviors of 4Y-PSZ and 5Y-PSZ suspensions. After sintering at 1500 °C for 2 h, all gradients were almost fully densified and strongly bonded together. When the content of 5Y-PSZ increased from 0 vol% to 100 vol%, flexural strength decreased from 865 ± 80 MPa to 613 ± 56 MPa and optical % transmittance increased remarkably from 24.1 ± 0.4 % to 31.9 ± 0.3 %.

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引用次数: 0

Additive manufacturing of γ' precipitate-strengthened nickel-based superalloy UNS N07001 by electron beam melting: Effects of post-heat treatment on microstructure and mechanical properties

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-04 DOI: 10.1016/j.addma.2025.104690

Ryo Takakuwa , Motoki Sakaguchi , Yuante Chin , Hiroaki Nakamoto , Manabu Noguchi , Hirotsugu Inoue

The γ' precipitate-strengthened nickel-based superalloy UNS N07001 is widely used in gas turbines because of its high-temperature strength and corrosion resistance. In this paper, optimal process parameters of electron beam melting were determined to shorten the lead time of UNS N07001. In addition, the effects of post-heat treatment on the microstructure and mechanical properties of UNS N07001 were evaluated. The optimal process parameters were determined by evaluating the appearance, surface roughness, relative density, and Brinell hardness of UNS N07001 blocks built with 32 different parameter combinations. The UNS N07001 sample produced using the optimal parameters was subjected to hot isotropic pressing (HIP) and solution treatment and aging (STA). Microstructural observation, precipitate analysis, and tensile tests of the resulting specimens were conducted. Microstructural observations and precipitate analysis revealed that the as-built specimen contained cracks and pores. These defects disappeared after HIP treatment. Additionally, STA after HIP treatment resulted in a high content of fine γ'-phase precipitate. Tensile tests revealed that the mechanical properties of the specimen were barely changed by HIP treatment, whereas STA after HIP markedly improved the mechanical properties of the specimen to a level comparable to the requirements for the wrought material. The beneficial mechanical properties of the specimen treated by HIP and STA may be attributed to the high content of fine γ' precipitates.

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引用次数: 0

Mechanical improvement of basalt fiber reinforced cementitious material for binder jetting 3D printing

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-04 DOI: 10.1016/j.addma.2025.104688

Guowei Ma , Chaoyu Dou , Li Wang , Fang Wang , Zhijian Li

Binder jetting 3D printing (BJ3DP) of cementitious material exhibits remarkable dexterity in printing complex or customer-tailored architectural components due to the support of powder. The length distribution and content of basalt fibers are optimized to achieve uniform dispersion of long fibers in cement powder and the synergy between printability and mechanical enhancement of composite materials. A high-speed mixer is used to break and disperse fibers into cement powder. Effect of working parameters, such as the mixing time, original fiber length and content, on printability and mechanical properties are exploited. Different post-processing methods are attempted to enhance the strength of the printed specimens. The successful printing of highly complex hollow thin-wall structures demonstrates the dexterity and high accuracy of BJ3DP using fiber reinforced cementitious materials. Test results show that higher fiber content and fiber length tend to negate spreadability of powders and the dimensional accuracy of printed specimens. The directional alignment of fibers is more remarkable for longer fibers. The printed specimens with 12 mm fibers (1.5 %) show maximum flexural strength of 13.52 MPa, which is 62.5 % higher than non-reinforced control specimens. The basalt fiber-reinforced specimens show obvious anisotropy in compressive strength and ultrasonic wave velocity due to basalt fiber orientation. The post-processing method of SiO₂ particles in silica sol impregnation adhere each other and fill voids in the matrix and result in a denser material, thus effectively enhancing the flexural and compressive strengths to 14.27 MPa and 37.67 MPa, respectively.

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引用次数: 0

Design and 3D printing of soft optical waveguides towards monolithic perceptive systems

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-03 DOI: 10.1016/j.addma.2025.104687

Petr Trunin , Diana Cafiso , Lucia Beccai

Integrating sensors into soft systems poses significant challenges in fabrication, assembly, and integration. Optical sensors represent a valuable solution due to their rapid response, minimal wiring, and negligible electromagnetic susceptibility. Still, developing optical soft sensing via additive manufacturing, like stereolithography (SLA), remains underexplored. Indeed, there’s a strong potential to unlock the fabrication of intricate and integrated perceptive structures, eliminating the need for assembly processes or multi-material interfaces that can compromise durability and signal accuracy. This study introduces a novel and versatile approach for developing soft optical bending sensors with enhanced performance by SLA. We systematically investigate the role of printed layers’ orientation for the mechanical and optical properties of the material, focusing on its effect on light attenuation in optical waveguides. The high resolution and design freedom of SLA are leveraged to finely incorporate superficial pattern (or wells) with precisely tunable dimensions, leading to light scattering phenomena. The optical loss and signal linearity trade-off was investigated by Finite Element Method (FEM) simulations, and the experimental results indicate the optimal design for sensors printed at different orientations, e.g., 1.2 mm × 1 mm × 1.55 mm rectangular wells for waveguides printed orthogonally to the building platform. To demonstrate the potential of this approach for developing fully integrated sensorized architectures, we present a proof-of-concept consisting of three sensors printed monolithically in a lattice structure. The versatility and scalability of our method contributes to the field of additive manufacturing by enabling the creation of smart soft systems with embedded soft sensors, suitable for a wide range of applications that benefit from responsive and flexible sensing capabilities.

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引用次数: 0

Automated toolpath design of 3D concrete printing structural components

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-01 DOI: 10.1016/j.addma.2025.104662

Yefan Zhi , Hua Chai , Teng Teng , Masoud Akbarzadeh

3D concrete printing (3DCP) structural components for construction assemblies are known for reduced material use and enhanced efficiency and design freedom. This article investigates the limitations in the geometrical and toolpath design of 3DCP structural components and presents an automated and comprehensive approach to their toolpath design and optimization. It exploits hierarchical geometric data structures and graph algorithms to achieve the following features: (1) By analyzing the overhang of toolpaths, the method offers quantitative criteria for determining the buildability of the components and predicting failure, thus assisting design decisions. (2) It provides toolpath offsetting and filleting methods that can enhance the dimensional accuracy of the print concerning layer line textures and overfills. (3) For branching and porous geometries, the method creates as-continuous-as-possible toolpaths with minimal stop-starts based on their topologies, thus reducing seam defects. (4) It converts the toolpath into efficient visualization meshes representing layer line textures and toolpath meshes compatible with finite elements analysis. The proposed method is implemented as a plug-in software within the environment of Grasshopper® for Rhino® to facilitate designers and engineers working with 3DCP. The effectiveness and versatility of the tool are demonstrated through the toolpath design and printing of four sets of examples. The tool reduces the number of toolpaths by 90% for a typical 80 mm nozzle and takes 0.21 s per meter of toolpath to slice, analyze overhang, generate continuous printing toolpaths, and visualize the print.

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引用次数: 0

Crystallization-coalescence relationships in laser powder bed fusion: Moving beyond the “sintering window”

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-02-01 DOI: 10.1016/j.addma.2025.104668

Camden A. Chatham

Laser-based polymer powder bed fusion (PBF-LB/P) additive manufacturing (AM) creates objects through layerwise repetition of selective consolidation of polymer powder particles. The specific molecular- and meso-scale mechanisms responsible for consolidation are important to understand to rapidly identify potential new materials for PBF-LB and correctly attribute observed failures, defects, and deviancy to either feedstock issues or process issues for quality assurance. Such understanding must draw from both material science principles and a deep comprehension of how automated hardware interacts with the feedstock during the manufacturing process. The so-called “Sintering Window” or “PBF Processing Window” is a prevalent tool claimed by many to adequately and rapidly summarize these key relationships between feedstock properties and the manufacturing process. This tool has been common parlance in PBF-LB/P research since the early days of commercialized PBF-LB/P (a.k.a., Selective Laser Sintering, SLS) in the mid 1990’s. The author argues in the present work that lack of progression beyond the rudimentary Sintering Window is hampering advancement of this AM modality as it elevates secondary factors (e.g., crystallization) above primary factors (e.g., coalescence) and does so in a manner disconnected from the real manufacturing environment. The present work outlines four issues with the overuse of the Sintering Window in fundamental research and provides alternative methodologies for reconciling the present body of fundamental polymer science with the present understanding of PBF-LB process physics. Namely, an increased emphasis on coalescing flow behavior that is ultimately arrested by crystallization at the point of physical gelation is recommended for investigating potential suitability of the typical semicrystalline polymer for PBF-LB. Six varieties of nylon-12 and one commercially available polypropylene material are used as exemplars.

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引用次数: 0

Rapid prediction and tailoring on compressive behavior of origami-inspired hierarchical structure

IF 10.3 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-01-31 DOI: 10.1016/j.addma.2025.104686

Wenzhen Huang , Junhong Lin , Muhong Jiang , Xiaoli Xu , Lili Tang , Xiang Xu , Yong Zhang

Thin-walled structures with tailorable compressive behavior offer a promising solution for achieving desired mechanical properties across multi-scenario applications. Therefore, this paper develops a novel thin-walled structure with high programmability through an origami-inspired hierarchical strategy. The origami-inspired hierarchical structure (OIHS) is fabricated using Laser Powder Bed Fusion. The compressive testing reveals that the deformation of OIHS strictly adheres to the pre-set crease, resulting in a stable load-bearing process. Numerical simulations are further conducted to investigate the programmable capacity of OIHS. The results display that the folding angle θ can enhance the deformation stability of OIHS, but is not conducive to the load-bearing level. The module number M effectively tailors the number and wavelength of folding lobes in OIHS, thus improving the energy absorption and load-bearing stability. As the M increases from 4 to10, the SEA and CFE of OIHS increase by 36.55 % and 17.81 %, respectively. The increasing edge length of sub-cell and wall thickness contribute to the interactive effect and material utilization, respectively, which facilitate its energy absorption. Compared to the vertex-based hierarchical structures, the OIHS demonstrates a 15.78 % increase in load-bearing stability without compromising its energy absorption capacity. Ultimately, artificial neural network-based machine learning models are developed to establish forward and inverse relationships between the mechanical curves and configuration parameters of OIHS, enabling rapid prediction and tailoring of the desired compressive behavior with an error of less than 8 %.

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引用次数: 0