Additive manufacturing letters最新文献

{"title":"Impact of a typical scanner delay processing parameter on local microstructure in metallic laser-based powder bed fusion","authors":"Brenda Leticia Valadez Mesta ,&nbsp;Pascal Thome ,&nbsp;Marcus C. Lam ,&nbsp;Sammy Tin ,&nbsp;Jorge Mireles ,&nbsp;Ryan B. Wicker","doi":"10.1016/j.addlet.2025.100273","DOIUrl":"10.1016/j.addlet.2025.100273","url":null,"abstract":"<div><div>In laser-based powder bed fusion of metals (PBF-LB/M), variations in laser scanner movements, particularly lesser-studied parameters like scanner delays that control laser directional changes, can influence the microstructure in a part during fabrication as each of typically millions of individual laser vectors impact part thermal history and resulting microstructure. While the impact of commonly researched parameters such as laser power, scan speed, hatch spacing, and layer thickness on part microstructure have been well studied, considerably less attention has been given to scanner delays such as the polygon delay. This study uses electron backscatter diffraction to investigate the microstructural variations caused by polygon delay values ranging from 0 to 450 microseconds, beginning with individual scan tracks. The study then extends single tracks to a simple three-dimensional part to examine if microstructure differences due to polygon delays may be influenced by localized heating and cooling caused by nearby hatch vectors and successive layers. The results reveal that varying polygon delay clearly affects grain morphology during individual scan tracks, although these effects are less clear during a three-dimensional build. Future PBF-LB/M studies should focus more on understanding time-resolved laser beam processing effects to better reduce inconsistencies and improve part quality.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"13 ","pages":"Article 100273"},"PeriodicalIF":4.2,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative analysis of machining and electropolishing for surface quality improvement of shape memory nitinol samples additively manufactured by laser powder bed fusion","authors":"Rodrigo Zapata Martínez ,&nbsp;Shohom Bose-Bandyopadhyay ,&nbsp;Alan Burl ,&nbsp;Óscar Contreras-Almengor ,&nbsp;Carlos Aguilar Vega ,&nbsp;Kyle Saleeby ,&nbsp;Thomas Kurfess ,&nbsp;Andrés Díaz Lantada ,&nbsp;Jon Molina-Aldareguia","doi":"10.1016/j.addlet.2024.100261","DOIUrl":"10.1016/j.addlet.2024.100261","url":null,"abstract":"<div><div>Nickel-titanium (NiTi) or nitinol alloys exhibit high corrosion resistance, mechanical strength, biocompatibility, and smart properties, rendering them ideal materials for active biomedical devices. Traditional manufacturing techniques struggle with these alloys, prompting the adoption of Laser Powder Bed Fusion (L-PBF) as a viable alternative for producing geometrically challenging features. However, L-PBF inherently introduces geometric inconsistencies and surface defects, necessitating post-processing. Electropolishing and chemical etching, while effective for surface smoothing, result in non-conformal material removal, potentially altering the designed geometry. This study examines the use of machining as a post-processing method to achieve uniform material removal and maintain geometric fidelity. Planar spring-shaped actuators were fabricated via L-PBF and subsequently machined to their final geometry using a Computer Numerical Controlled (CNC) system. The actuators were assessed for geometric accuracy and shape memory properties. Machining of the actuators lead to a near homogeneous thickness of 300 µm in all cases, whereas the electropolished + chemically etched samples varied dramatically from &lt;50 µm to over 400 µm in thickness. The findings demonstrate that CNC machining effectively enhances the geometric precision of L-PBF-manufactured NiTi components, while preserving shape memory characteristics. This research underscores the potential of integrating L-PBF with CNC machining to improve the precision and functionality of NiTi-based biomedical devices.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"12 ","pages":"Article 100261"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143179870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resin-dependent mechanical anisotropy in laser vat photopolymerization correlates to the initial rate of polymerization and critical energy","authors":"Dagoberto Torres-Alvarez,&nbsp;Angel Celis-Guzman,&nbsp;Alan Aguirre-Soto","doi":"10.1016/j.addlet.2024.100264","DOIUrl":"10.1016/j.addlet.2024.100264","url":null,"abstract":"<div><div>The degree of mechanical anisotropy in objects printed with laser vat photopolymerization (VPP) remains controversial. It has been stated that objects with a higher degree of mechanical isotropy are produced with VPP as compared to other polymer-based additive manufacturing techniques, such as fused filament fabrication (FFF). However, reports on the evaluation of resin-dependency of the mechanical anisotropy obtained with VPP are scarce. Furthermore, the degree of anisotropy (DA) was quantified using different procedures. Here, six commercial resins were selected to evaluate how the DA correlates to the initial rate of polymerization (R_P0), critical energy (E_C), and penetration depth (D_P) for materials with a broader range of properties. State-of-the-art procedures to calculate the degree of mechanical anisotropy are discussed, and an ideal method is proposed, namely, the ratio of the standard deviations related to the inter- and intra-layer forces: DA=(sd_inter/sd_intra). The elastic modulus (<em>E</em>) was confirmed isotropic with the three resins that were previously reported. However, objects printed with the additional resins that polymerize at higher initial rates (R_P0 =72.1 mM/s) and with lower critical energies (E_C = 0.36 mJ/cm²) appear more anisotropic. A linear trend was obtained for the scaling of the mechanical DA with R_P0. Moreover, a logarithmic correlation between E_C and the DA in <em>E</em> was found, which appears inappropriate for E_C as a function of the DA in the maximum stress (σ_Max). This study aims to spur research on the mechanisms underlying the dependence of the mechanical DA on the resin-curing behavior for objects fabricated by VPP.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"12 ","pages":"Article 100264"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143179871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Micro-X-ray-CT for analysis of particle size segregation during powder spreading in Binder Jet Printing","authors":"Julia G. Behnsen ,&nbsp;Joseph W. Roberts ,&nbsp;Oliver J. Rogan ,&nbsp;James M. McArdle ,&nbsp;Kate Black","doi":"10.1016/j.addlet.2024.100266","DOIUrl":"10.1016/j.addlet.2024.100266","url":null,"abstract":"<div><div>The uniformity of the powder bed in Binder Jet Printing can impact the final properties of additively manufactured components. Granular flow phenomena, such as particle size segregation can influence the uniformity of the powder bed. Due to the 3D nature of the powder bed and the standard requirement for sintering parts following printing, direct experimental observation of the particle distribution and packing density can be difficult. The use of Micro-X-ray-CT however, enables the high-resolution imaging of components manufactured by binder jetting and allows quantification of particle size distribution and packing density throughout the powder bed. This study analyses the periodicity of effects such as in-layer particles size segregation and packing density. The results presented here show that particles segregate by size within each layer of the binder jet printed sample, which resulted in a periodic density change within each layer. The particle size distribution changes over the length of the power-bed, with the volume fraction of smaller particles increased near the front of the powder bed, and the volume fraction of larger particles increased near the back. The insights gained from the Micro-X-ray-CT characterisation approach allow for an enhanced understanding of the powder spreading process in additive manufacturing, paving the way forward for possible part optimisation.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"12 ","pages":"Article 100266"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calibration and compensation of 5-axis 3D-printers for printed electronics","authors":"Daniel Ahlers,&nbsp;Tom Schmolzi,&nbsp;German Junca,&nbsp;Jianwei Zhang,&nbsp;Florens Wasserfall","doi":"10.1016/j.addlet.2024.100265","DOIUrl":"10.1016/j.addlet.2024.100265","url":null,"abstract":"<div><div>5-axis 3D printing presents a promising approach to overcome the limitations of traditional 3-axis methods, particularly in the domain of printed electronics where conformal conductive connections are printed onto the surface of freeform objects. However, this additional freedom comes with a demand for high positioning accuracy, as the rotary movements amplify small axis deviations through the lever effect. This paper presents an approach for an automatically self-calibrating low-cost 5-axis printing system using a built-in 3D touch probe. The calibration data is used to generate a precise kinematic printer model in the Unified Robot Description Format (URDF). Our inverse kinematic solver uses this model in our pathplanning software to generate fully compensated G-code trajectories, maintaining the correct position without needing an expensive high-precision motion system. First results are presented as evaluation which were printed on our low-cost 5-axis system with 3D-printed rotary axes, demonstrating the capability to reliably print circuits on imprecise hardware. The calibration process can be executed quickly and automatically every time the printer is restarted. This approach makes multi-axis 3D printing more accessible and increases potential uses, leading to more precise and cost-effective manufacturing solutions.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"12 ","pages":"Article 100265"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermo-mechanical response of aluminum alloy in the additive friction-stir deposition process","authors":"Chowdhury Sadid Alam ,&nbsp;Vahid Karami ,&nbsp;Shengmin Guo ,&nbsp;M Shafiqur Rahman","doi":"10.1016/j.addlet.2024.100263","DOIUrl":"10.1016/j.addlet.2024.100263","url":null,"abstract":"<div><div>Additive Friction Stir Deposition (AFSD) is an emerging solid-state additive manufacturing (AM) technique that creates fully dense metallic structures with equiaxed fine microstructures. The feedstock material is plasticized via frictional heating and deposited in the solid state. Due to the complex multi-physics nature of the process, an in-depth understanding of the interplay between material flow, temperature variations, and stress distribution within the deposited layers under various process parameters is crucial for achieving desired outcomes. This study focuses on the development of a plasticity-based computational model that employs a coupled Eulerian-Lagrangian (CEL) finite element methodology to analyze the thermo-mechanical response of the AA6061-T6 alloy in the AFSD process. By incorporating essential AFSD process variables namely, tool rotation speed, tool traverse speed, and material deposition rate, the model can accurately forecast the flow of material, temperature fluctuations, and stress distribution across different operational settings. For instance, an optimal solid-state deposition of AA 6061-T6 alloy is achieved with 380 RPM tool rotation speed, 0.9 mm/s tool traverse speed, and 0.3 mm/s material deposition rate for the geometry reported in this study. The CEL model is validated by comparing its results (e.g., peak temperature) with the experimental data and published computational results for the same combination of process parameters, giving the maximum errors of 8 % and 2.8 %, respectively. Through the utilization of this proposed model, a practical and efficient means of predicting process results is established, enabling a rapid and cost-effective optimization of the AFSD process parameters for different scale of the feed material, tool, and substrate. Ultimately, this advancement contributes to the progression of solid-state AM techniques and development of digital twins by streamlining the process with scalability, multifunctionality, and a variety of material selections.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"12 ","pages":"Article 100263"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Liquid-induced heat treatment strategy for eliminating anisotropy of IN718 fabricated by laser powder bed fusion","authors":"Zhuoyu Li ,&nbsp;Xiaogang Hu ,&nbsp;Fan Zhou ,&nbsp;Zhifang Shi ,&nbsp;Zhiwei Lyu ,&nbsp;Zhen Xu ,&nbsp;Yu Li ,&nbsp;Xin Zhao ,&nbsp;Hongxing Lu ,&nbsp;Qiang Zhu","doi":"10.1016/j.addlet.2024.100262","DOIUrl":"10.1016/j.addlet.2024.100262","url":null,"abstract":"<div><div>The laser-based additive manufacturing process often results in highly textured columnar grain structures along the build direction, leading to undesirable anisotropic mechanical properties in most industrial applications. Tailored heat treatments are currently the predominant approach to address anisotropy issues. However, the lack of driving force for recrystallization during the post-heat treatment within laser powder bed fusion (LPBF) makes this method inapplicable to the process. Here, we develop a novel liquid-induced heat treatment (LIHT) post-processing. The intergranular liquid film is introduced to facilitate the columnar-to-equiaxed transition of grains in IN718 alloy fabricated by LPBF. Microstructures and mechanical properties parallel and perpendicular to the build direction have been analyzed. The degree of anisotropy in ultimate strength was reduced from 21.1% to 3.5%. The anisotropy in creep performance also decreased from 52.1% to 11.3%. LIHT is anticipated to be a typical process for eliminating the anisotropy in the mechanical properties of metallic components.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"12 ","pages":"Article 100262"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143179869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructure-sensitive mechanical behavior of an additively manufactured psuedoelastic shape memory alloy","authors":"Patxi Fernandez-Zelaia ,&nbsp;Chris Ledford ,&nbsp;Chris M. Fancher ,&nbsp;Sarah Graham ,&nbsp;Taresh Guleria ,&nbsp;Brad Sampson ,&nbsp;Fred List III ,&nbsp;Jason Mayeur ,&nbsp;Chins Chinnasamy ,&nbsp;Mohammad Elahinia ,&nbsp;Michael M. Kirka","doi":"10.1016/j.addlet.2025.100270","DOIUrl":"10.1016/j.addlet.2025.100270","url":null,"abstract":"<div><div>The additive manufacturing of shape memory alloys into complex geometries enables fabrication of advanced functional systems across a variety of fields and domains. This work presents results focused on the mechanical behavior of additively manufactured shape memory pseudoelastic NiTi. The deformation induced solid state phase transformation from austenite to martensite allows this system to accommodate large recoverable strains. This deformation behavior is fundamentally driven by crystal-scale transformation physics. Laser powder bed fusion processing reveals that the resulting microstructure, both grain morphology and crystallographic texture, is strongly dependent on the manufacturing processing history. Exhaustive mechanical testing demonstrates that these microstructural factors strongly impact both tensile and cyclic stress–strain behavior. Cyclic dissipative behavior, however, is similar across all tested microstructures following an initial transient period. Remarkably, analysis of spatial strain fields during tensile loading reveals two distinctly different localization “modes”. The first is initiation of localized deformation bands which continuously propagate through the tensile bar during loading. In the second mode localization is observed but lacks propagation; instead additional localization cites nucleate during subsequent loading. The latter phenomena is suspected to be driven by grain-scale deformation physics as the localized band morphologies coincide with grain morphologies. These phenomena strongly impact the resulting aggregate stress–strain behavior. Hence, manufacturers and designers of psuedoelastic functional components must at the very least consider the potential variability in properties when considering additive manufacturing processing. More ideally the process–structure–property relations can be used to further tailor and optimize final functional performance.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"13 ","pages":"Article 100270"},"PeriodicalIF":4.2,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on curing strategies for metal binder jetting with Ti-6Al-4V","authors":"Kevin Janzen ,&nbsp;Timo Rieß ,&nbsp;Claus Emmelmann","doi":"10.1016/j.addlet.2025.100272","DOIUrl":"10.1016/j.addlet.2025.100272","url":null,"abstract":"<div><div>Metal binder jetting is a promising manufacturing technology that holds the potential to be a future competition technology to classic laser based additive manufacturing processes. In contrast to these technologies, however, metal binder jetting is much less mature. While sintering and debinding are already well known due to the spread of metal injection molding and powder deposition by laser powder bed fusion and its related processes, the often-neglected curing step represents a major challenge in process control. This study was therefore the first comprehensive investigation into the curing of metal binder jetting green parts from Ti-6Al-4 V powder with a powder size distribution below 25 µm. It was shown that the curing step has only a minor effect on the green part quality (surface roughness and density), but at the same time has a decisive influence on the green strength. In addition, position-dependent effects for the green density were detected, which indicate insufficient curing in the outer areas of the print box.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"13 ","pages":"Article 100272"},"PeriodicalIF":4.2,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on metallurgical interface and grain refinement effect in AlMgSc alloy reinforced with HEAs particles formed by arc-direct energy deposition","authors":"Shihao Shi,&nbsp;Yingying Ren,&nbsp;Shihao Kang,&nbsp;Yongqin Liu,&nbsp;Chenyu Liu,&nbsp;Yaning He,&nbsp;Yinghui Zhou","doi":"10.1016/j.addlet.2025.100271","DOIUrl":"10.1016/j.addlet.2025.100271","url":null,"abstract":"<div><div>On the basis of the AlMgSc alloy formed by Arc-DED (Arc Directed Energy Deposition), we adopted a method of coaxially depositing powder and wire layer by layer to fabricate the AlMgSc alloy enhanced by (HEAs) High Entropy Alloys. The HEAs powder exhibited favorable metallurgical bonding with the α-Al matrix, and the elements such as Co, Fe, and Ni in the HEAs particles obviously diffused towards the matrix at the interface. The addition of HEAs powder significantly refined the microstructure. The average grain size of the AlMgSc alloy was 40.7 ± 13.9 μm, while that of the AlMgSc-HEAs alloy was 14.5 ± 4.9 μm, with a 64 % reduction in grain size. Compared with the AlMgSc alloy, the yield strength (YS) of the AlMgSc-HEAs alloy was increased by 9 %.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"13 ","pages":"Article 100271"},"PeriodicalIF":4.2,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}