Additive manufacturing最新文献

{"title":"Measuring thermomechanical response of large-format printed polymer composite structures via digital image correlation","authors":"Tyler M. Corum ,&nbsp;Johnna C. O’Connell ,&nbsp;James C. Brackett ,&nbsp;Ahmed Arabi Hassen ,&nbsp;Chad E. Duty","doi":"10.1016/j.addma.2024.104479","DOIUrl":"10.1016/j.addma.2024.104479","url":null,"abstract":"<div><div>Large-format additive manufacturing (LFAM) is a branch of additive manufacturing (AM) research with the ability to create large structures typically measuring several meters in scale. LFAM is advantageous for tooling applications, not only because it offers the ability to create complex geometries not easily made using subtractive manufacturing processes, but the cost savings of pelletized feedstock used by these systems result in larger parts printed at faster speeds than traditional AM systems. Fiber reinforced polymer (FRP) is a commonly used feedstock material in LFAM structures because it reduces the distortion experienced during printing. However, FRP introduces highly anisotropic thermomechanical properties and contributes to a nonhomogeneous microstructure that can result in critical distortion of dimensions during tooling. Measuring the global thermomechanical response of LFAM structures requires a more representative method that accounts for not only anisotropic properties but also the nonhomogeneous nature of the final part. This is where traditional techniques to measure thermomechanical response, such as thermomechanical analysis (TMA), fall short as they assume homogeneity. This study evaluated the coefficient of thermal expansion (CTE) of LFAM structures as measured by TMA as compared to a novel digital image correlation oven (DIC Oven) system. The LFAM structures were made from 20 % by weight carbon fiber reinforced acrylonitrile butadiene styrene (CF-ABS). TMA measurements showed significant variations in CTE across a single LFAM bead, confirming the need for a global technique that captures overall thermomechanical response. The CTE values measured using the DIC Oven compared well to average TMA values obtained from localized measurements across the sample. The DIC Oven was also used to quantify the effects of different layer orientations on thermomechanical properties, which cannot be easily captured using TMA. A predictive model was also developed by using localized TMA values across an LFAM bead to predict the overall thermomechanical response of an LFAM structure.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104479"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442116","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":"4D Printed shape memory polymers in focused ultrasound fields","authors":"Hrishikesh Kulkarni ,&nbsp;Jiaxin Xi ,&nbsp;Ahmed Sallam ,&nbsp;Phoenix Lee ,&nbsp;David Safranski ,&nbsp;Reza Mirzaeifar ,&nbsp;Shima Shahab","doi":"10.1016/j.addma.2024.104465","DOIUrl":"10.1016/j.addma.2024.104465","url":null,"abstract":"<div><div>4D Printing is a new area of additive manufacturing that extends the possibilities of 3D printing by including the dimension of time. This cutting-edge technique entails creating elaborate structures out of intelligent materials, specifically shape memory polymers (SMPs), which may dynamically change shape or functionality in response to external inputs. The purpose of this study is to conduct a rigorous spatiotemporal characterization into the potential of focused ultrasound (FUS) in actuating 4D-printed SMPs as well as to evaluate the impacts of different printing parameters on shape recovery. Experiments demonstrate that FUS is a unique and non-invasive method that can cause localized heating, activate several intermediate shapes, and accomplish full shape recovery in SMPs. Moreover, by optimizing sample size, ultrasound frequency, exposure time, intensity, and the location of ultrasound focusing, FUS possesses an enhanced capacity for temporal and spatial control of shape recovery. We determine the effects of various 3D printing parameters, including printing temperature, printing speed, infill density, and infill structures, on the thermo-mechanical shape recovery properties of a thermoplastic polyurethane. Shape recovery ratios ranged from 50% to 80% across different printing parameters. The study demonstrated that increasing acoustic field intensity can maximize shape recovery to over 95%, although this may cause to material degradation depending on sample thickness. The findings also revealed that these printing parameters significantly influence storage modulus, loss modulus, and glass transition temperature, highlighting their impact on thermo-mechanical properties. Furthermore, this study uses acoustical principles and thermo-mechanical experimental data to show a systematic relationship between additive manufacturing settings and SMP viscoelastic deformation properties. Lastly, a dynamic transition of a 4D-printed functional gripper-like structure, exhibiting both opening and closing motions upon exposure to FUS irradiation, was demonstrated using the optimized parameters. This research paves the way for FUS to accurately spatiotemporal and localized actuation of SMPs, particularly in medical applications.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104465"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552416","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":"A heterogeneous pore design algorithm for material extrusion additive manufacturing","authors":"Huawei Qu ,&nbsp;Kaizheng Liu ,&nbsp;Juan Liu ,&nbsp;Chongjian Gao ,&nbsp;Changshun Ruan","doi":"10.1016/j.addma.2024.104449","DOIUrl":"10.1016/j.addma.2024.104449","url":null,"abstract":"<div><div>Material extrusion additive manufacturing offers great potential for customizing matters with complex external contours, and filament diameter-adjustable 3D (FDA-3D) printing strategy provides fresh impetus to create heterogeneous porous structures inside these complex matters. However, the absence of supporting algorithms to implement FDA-3D printing severely hinders its widespread use. In this paper, we develop a heterogeneous pore design (HPD) algorithm aimed at advancing the development of FDA-3D printing for producing heterogeneous porous matters. The HPD algorithm consists of three sub-algorithms: model design, collapse compensation, and fabrication file (G-codes) generation. As proofs of concept, we utilize this algorithm to 3D print radial gradient and letter-embedded gradient materials following specific steps: (1) designing the heterogeneous porous models with collapse compensation in Grasshopper® and displaying them in Rhinocores®; (2) customizing and writing the corresponding G-codes files by following the material extrusion 3D printer's control rules; (3) upgrading a commercial extrusion printer to FDA-3D print the design models via the customized G-codes. Micro-computed tomography-based 3D reconstruction and quantified pore size maps for the fabricated objects demonstrate the high capability of this HPD algorithm. Overall, the HPD algorithm holds the potential to revolutionize material extrusion 3D printers cost-effectively, creating new possibilities for material extrusion of heterogeneous materials.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104449"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358176","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":"Multi-fidelity surrogate with heterogeneous input spaces for modeling melt pools in laser-directed energy deposition","authors":"Nandana Menon,&nbsp;Amrita Basak","doi":"10.1016/j.addma.2024.104440","DOIUrl":"10.1016/j.addma.2024.104440","url":null,"abstract":"<div><div>Multi-fidelity (MF) modeling is a powerful statistical approach that can intelligently blend data from varied fidelity sources. This approach finds a compelling application in predicting melt pool geometry for laser-directed energy deposition (L-DED). One major challenge in using MF surrogates to merge a hierarchy of melt pool models is the variability in input spaces. To address this challenge, this paper introduces a novel approach for constructing an MF surrogate for predicting melt pool geometry by integrating models of varying complexity, that operate on heterogeneous input spaces. The first thermal model incorporates five input parameters i.e., laser power, scan velocity, powder flow rate, carrier gas flow rate, and nozzle height. In contrast, the second thermal model can only handle laser power and scan velocity. A mapping is established between the heterogeneous input spaces so that the five-dimensional space can be morphed into a pseudo two-dimensional space. Predictions are then blended using a Gaussian process-based co-kriging method. The resulting heterogeneous multi-fidelity Gaussian process (Het-MFGP) surrogate not only improves predictive accuracy but also offers computational efficiency by reducing evaluations required from the high-dimensional, high-fidelity thermal model. The tested Het-MFGP yields an <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of 0.975 for predicting melt pool depth. This surpasses the comparatively modest <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of 0.592 achieved by a GP trained exclusively on high-dimensional, high-fidelity data. Similarly, in the prediction of melt pool width, the Het-MFGP excels with an <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of 0.943, outshining the GP's performance, which registers a lower <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of 0.588. The results underscore the benefits of employing Het-MFGP for modeling melt pool behavior in L-DED. The framework successfully demonstrates how to leverage multimodal data and handle scenarios where certain input parameters may be difficult to model or measure.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104440"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142318867","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":"Inhibition of interfacial cracks in 304L-Inconel718 bimetal fabricated via laser powder bed fusion","authors":"Yinghui Li ,&nbsp;Zhuangzhuang Liu ,&nbsp;Zhengyu Wei ,&nbsp;Pengfei Hu ,&nbsp;Jiawang Chen ,&nbsp;Lijing Liu ,&nbsp;Guogang Shu ,&nbsp;Jianxin Xie","doi":"10.1016/j.addma.2024.104463","DOIUrl":"10.1016/j.addma.2024.104463","url":null,"abstract":"<div><div>Multi-material additive manufacturing is crucial for intricate component fabrication, yet challenges, such as interfacial cracks and weak bonding, persist. This work investigated the laser powder bed fusion (L-PBF) of bimetallic components (stainless steel 304L-nickel-based alloy Inconel718) crucial in aerospace and nuclear applications. It is found that the interfacial cracks predominantly occur within the compositional transition zone where the proportion of 304 L is between 45 wt% and 75 wt%, characterized by brittle Laves phases along grain boundaries. Experimental and finite element simulations of melt pool reveal that a higher ratio of temperature gradient (<span><math><mover><mrow><mi>G</mi></mrow><mo>̅</mo></mover></math></span>) to the grain growth rate (<span><math><mover><mrow><mi>R</mi></mrow><mo>̅</mo></mover></math></span>) (<span><math><mover><mrow><mi>G</mi></mrow><mo>̅</mo></mover></math></span>/<span><math><mover><mrow><mi>R</mi></mrow><mo>̅</mo></mover></math></span>) results in straight grain boundaries with underdeveloped secondary dendrites. This leads to the formation of continuous liquid film and strip-like Laves phase at grain boundaries, causing interfacial cracks during L-PBF. To suppress these cracks, this work proposes manipulating grain boundaries into a tortuous morphology through promoting the growth of secondary dendrites. By controlling the <span><math><mover><mrow><mi>G</mi></mrow><mo>̅</mo></mover></math></span>/<span><math><mover><mrow><mi>R</mi></mrow><mo>̅</mo></mover></math></span> ratios below the critical value (&lt;147.9×10⁶ K∙s/m²) and combining with a high cooling rate (<span><math><mover><mrow><mi>G</mi></mrow><mo>̅</mo></mover></math></span>×<span><math><mover><mrow><mi>R</mi></mrow><mo>̅</mo></mover></math></span>) during L-PBF, a well-developed secondary dendritic structure and grain refinement are achieved, significantly enhancing grain boundary tortuosity and forming discretely distributed Laves phases. As a result, interfacial cracks are completely suppressed, enabling the successful manufacturing of crack-free 304L-Inconel718 bimetallic components. The approach of tailoring the distribution of brittle precipitates through manipulating grain boundary morphology proposed in this work provides a novel and practical pathway for inhibiting cracks in multi-material additive manufacturing.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104463"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423467","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":"A mechanical characteristic capture method considering printing configurations for buildability modeling in concrete 3D printing","authors":"Yuning Chen ,&nbsp;Kailun Xia ,&nbsp;Enlai Dong ,&nbsp;Ruilin Cao ,&nbsp;Yueyi Gao ,&nbsp;Yamei Zhang","doi":"10.1016/j.addma.2024.104462","DOIUrl":"10.1016/j.addma.2024.104462","url":null,"abstract":"<div><div>The structure failure modeling of 3D printing concrete (3DPC) during production is crucial for structure design, manufacturing process control and optimization. Serving as model inputs, the accuracy of 3DPC fresh material properties measurement highly affects the model prediction performance. The measured mechanical properties of freshly printed concrete strongly depend on the geometry, deformation and hardening process of used samples in testing. Herein, we propose an all-in-one method (AIOM) that synchronously considers these key factors (layer geometry, deformation, and hardening process) to more accurately capture the early-age mechanical performance distribution in printed structures. Different parametric-mechanical buckling models and two printable cementitious materials with distinct hardening characteristics (printable cement and printable geopolymer) were used to validate the performance of AIOM, with the traditional testing method, uniaxial unconfined compression test (UUCT), as the reference. Compared with UUCT, AIOM can improve the buildability prediction accuracy by 11.9 % to 50.8 % for different validation scenarios. This novel testing method for 3DPC fresh material properties contributes to improving the accuracy of 3DPC structure failure models, thereby facilitating a better production phase control for 3DPC.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104462"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423468","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":"Obtaining excellent mechanical properties with additively manufactured short fiber reinforced polyether-ether-ketone thermoplastics through simultaneous vacuum and infrared heating","authors":"Recep Gümrük ,&nbsp;Bahri Barış Vatandaş ,&nbsp;Altuğ Uşun","doi":"10.1016/j.addma.2024.104491","DOIUrl":"10.1016/j.addma.2024.104491","url":null,"abstract":"<div><div>Additive manufacturing of short fiber reinforced thermoplastic composite with high-performance engineering thermoplastics is important in various industrial sectors because of their ability to manufacture complex and lightweight products. Although extensive studies in the literature are aimed at enhancing the mechanical performance of additively manufactured short fiber reinforced thermoplastics through methods like refining printing parameters, enhancing fiber fractions, and optimizing printing parameters, their mechanical performance remains limited. In this study, the individual effects of vacuum-assisted printing and infrared pre-heater-assisted printing and their combined effects were investigated to substantially increase the mechanical properties, interlaminar performance, and crystallinity ratios. The polyether ether ketone (PEEK) samples were printed with vacuum-assisted, infrared-assisted, and a combination of vacuum and infrared-assisted environments were subjected to three-point bending tests to evaluate their mechanical properties. Synergistic vacuum and infrared-assisted printing significantly enhanced the mechanical properties as the flexural strength increased by 54.58 % compared to printing under vacuum alone. Moreover, the flexural strength and elasticity modulus of samples printed with vacuum-infrared-assisted manufacturing increased by 324.48 % and 239.77 %, respectively, when compared to printing under atmospheric pressure without additional heating. Thermal and structural characterizations of the printed parts revealed that this significant improvement was attributed to reduced porosity ratios and increased crystallinity.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104491"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533983","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":"Near-surface microstructures convolute mechanical properties in additively manufactured metals","authors":"Kaitlynn M. Fitzgerald ,&nbsp;Jay D. Carroll ,&nbsp;Dale E. Cillessen ,&nbsp;Anthony Garland ,&nbsp;Timothy J. Ruggles ,&nbsp;Kyle L. Johnson ,&nbsp;Brad L. Boyce","doi":"10.1016/j.addma.2024.104477","DOIUrl":"10.1016/j.addma.2024.104477","url":null,"abstract":"<div><div>Kovar specimens were additively manufactured with 180 variations in process conditions. Three distinct geometries (two tensile geometries and a Charpy specimen) were evaluated for each set of process conditions. Tensile specimens additively manufactured to net shape had less porosity, more uniform material properties, higher average ductility, and they consistently failed via ductile rupture. Tensile specimens harvested via electric discharge machining from larger additively manufactured blocks often contained lack of fusion voids throughout the cross section - those pre-existing pores drove pre-mature failure. As-printed specimens, on the other hand, were more representative of the outer border properties rather than the interior of large printed parts. The properties of the specimens cut from the larger block of additively manufactured material were more representative of the inner hatch properties but were stochastic, depending on the size and location of present voids. Using a high-throughput methodology, the results from over 800 tensile tests are reported here. This extensive statistical sampling allows the effects of specimen type and location to be clearly distinguished from other intentional variables (process parameter variations) and stochastic material variability.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104477"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534041","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":"Mechanical properties of Ti-6Al-4V thin walls fabricated by laser powder bed fusion","authors":"Junghoon Lee ,&nbsp;Arif Hussain ,&nbsp;Jeonghong Ha ,&nbsp;Youngsam Kwon ,&nbsp;Rae Eon Kim ,&nbsp;Hyoung Seop Kim ,&nbsp;Dongsik Kim","doi":"10.1016/j.addma.2024.104484","DOIUrl":"10.1016/j.addma.2024.104484","url":null,"abstract":"<div><div>Laser powder bed fusion (PBF-LB/M) has recently garnered considerable attention for fabricating thin walls owing to its potential for producing lightweight structures. However, knowledge of the mechanical properties of thin walls with high surface-to-volume ratios remains insufficient. Specifically, no studies have been conducted for thin walls with a thickness less than 400 µm, making the size effect unclear. Therefore, the main objective of this work is to reveal the effect of thicknesses on the mechanical properties of Ti-6Al-4V samples as thin as 195 µm. To achieve this, the fabrication process was optimized to maximize the aspect ratio and properties of samples. In addition, the microstructure and surface roughness were examined to understand the size effect. The results demonstrated that the ultimate tensile strength of the thin-wall samples was similar to that of bulk Ti-6Al-4V samples fabricated via PBF-LB/M, regardless of the thickness. By contrast, the elongation of the thin-wall samples decreased with thickness, indicating a significant size effect. This size effect on elongation can be attributed to the strong influence of surface and internal defects.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104484"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533981","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":"Molten pool behaviors and printability of tungsten anti-scattering grids with extremely thin wall thickness fabricated via laser powder bed fusion","authors":"Meng Wang ,&nbsp;Changjun Han ,&nbsp;Menglong Jiang ,&nbsp;Vyacheslav Trofimov ,&nbsp;Yongqiang Yang ,&nbsp;Chao Yang ,&nbsp;Yongwei Feng ,&nbsp;Ming Yan ,&nbsp;Shaochong Wei ,&nbsp;Di Wang","doi":"10.1016/j.addma.2024.104487","DOIUrl":"10.1016/j.addma.2024.104487","url":null,"abstract":"<div><div>It is challenging for laser powder bed fusion (LPBF) technique to fabricate metal parts with a wall thickness below 100 μm. This work investigated the critical conditions for achieving extremely thin wall thickness in tungsten grids fabricated via LPBF. Specifically, the impact of low energy density on the printability of tungsten single tracks and grids via LPBF was comprehensively examined. A computational fluid dynamics approach was employed to develop a thermal fluid flow model for single tracks with multilayers in LPBF. The findings demonstrate that at low energy densities, single tracks exhibit four different morphologies, i.e., balling, discontinuity and winding, discontinuity but straightness, as well as continuity and straightness. The simulation model effectively elucidates the continuity of single tracks and provides insights into the governing mechanism of molten pool defects. Due to high thermal diffusion properties of tungsten, the continuity of its track relies on the connection of neighboring molten pools and is sensitive to scanning speed. The tungsten molten pools with low energy density can be categorized into shallow flows affected by surface morphology and deep flows influenced by internal voids of the powder bed. After multi-layer stacking, the track fluctuations and defects in single tracks accumulated into greater surface roughness and deteriorate thin-walled morphology. The critical conditions required for printing extremely thin walls were achieved, ensuring minimal merging of tracks between two layers by maintaining the energy density of 57 J/mm³. Based on these findings, an ultra-thin-walled anti-scattering tungsten grid with a wall thickness of 86 μm and a wall roughness below 3.3 μm (<em>Ra</em>) was fabricated by LPBF. This work provides valuable theoretical insights and presents a viable methodology for determining the minimum energy density threshold and wall thickness essential for LPBF processing of thin-walled components.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104487"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533987","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}