Journal of Manufacturing and Materials Processing

14 pages, 4227 KB

Open AccessArticle

Effects of Compaction Rotation Speed and Compaction Thickness in Roller-Compaction-Assisted Binder Jetting Additive Manufacturing

by Wenchao Du, Mohammadamin Moghadasi, Xingjian Wei, Zhijian Pei and Chao Ma

J. Manuf. Mater. Process. 2026, 10(3), 97; https://doi.org/10.3390/jmmp10030097 - 12 Mar 2026

Abstract

Powder bed compaction can be used to control powder bed density in binder jetting additive manufacturing. Applying a forward-rotating roller to the powder bed is one of the methods for powder bed compaction. Both the compaction rotation speed and compaction thickness are critical [...] Read more.

Powder bed compaction can be used to control powder bed density in binder jetting additive manufacturing. Applying a forward-rotating roller to the powder bed is one of the methods for powder bed compaction. Both the compaction rotation speed and compaction thickness are critical parameters affecting the powder packing density and resultant printed sample integrity. However, their joint effects have not been investigated for roller-compaction-assisted binder jetting. This paper reports an experimental study to investigate the effects of the compaction rotation speed and the compaction thickness on powder bed density and the printed sample quality (in terms of distortion and cracks). The experimental results showed that powder bed density was not affected by changing compaction rotation speed but was enhanced by increasing compaction thickness. Small compaction thickness did not cause any observable distortions or cracks in the printed samples at any compaction rotation speed. Large compaction thickness caused printed samples to distort and crack under specific conditions. At large compaction thickness, compaction rotation speed significantly affected both the direction and extent of the printed sample distortion. Samples with improved density and integrity were achieved in the center of the build platform at large compaction thickness and at a compaction circumferential speed larger than the compaction traverse speed. These results can help optimize binder jetting additive manufacturing for printed sample quality. Full article

(This article belongs to the Special Issue Next-Generation Material Designs and Processes for Additive Manufacturing)

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23 pages, 4782 KB

Open AccessArticle

Development of Simplified Mechanical Model for Welding Deformation in Multi-Pass Welding

by Wenda Wang, Shintaro Maeda, Kazuki Ikushima and Masakazu Shibahara

J. Manuf. Mater. Process. 2026, 10(3), 96; https://doi.org/10.3390/jmmp10030096 - 12 Mar 2026

Abstract

This paper proposes a simplified mechanical model to estimate transverse shrinkage and angular distortion in multi-pass butt welding. The simplified mechanical model is first derived for an I-groove joint by representing the heated weld region with one-dimensional bar elements and by enforcing force [...] Read more.

This paper proposes a simplified mechanical model to estimate transverse shrinkage and angular distortion in multi-pass butt welding. The simplified mechanical model is first derived for an I-groove joint by representing the heated weld region with one-dimensional bar elements and by enforcing force equilibrium to obtain closed-form expressions for pass-by-pass deformation increments and cumulative deformation. For non-I-groove joints, the same simplified mechanical model is applied by updating the layer partition and geometric parameters for each pass based on the pass-wise high-temperature region; the inherent shrinkage of each pass is evaluated from the heat input and an equivalent heated-layer thickness. The simplified mechanical model is validated for V-groove multi-pass joints by comparison with thermo-elastic-plastic finite element (FE) analyses and available experimental data, and for X-groove multi-pass joints by comparison with thermo-elastic-plastic FE analyses. In addition, a parametric study on the V-groove angle (40°–70°) for SUS316L demonstrates that the model captures the increasing trend of final transverse shrinkage with groove angle without a pronounced degradation in prediction accuracy. The results show that the simplified mechanical model reproduces both deformation histories and final values with good accuracy while using only a small set of input parameters and negligible computational cost, making it useful for early-stage welding procedure planning and quick parameter studies. Full article

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13 pages, 3835 KB

Open AccessArticle

Nanotexturing onto Laser-Microtextured Surface via Nickel Wet-Plating for IR-Emissivity Control

by Tatsuhiko Aizawa, Hiroki Nakata and Takeshi Nasu

J. Manuf. Mater. Process. 2026, 10(3), 95; https://doi.org/10.3390/jmmp10030095 - 11 Mar 2026

Abstract

Short-pulse laser machining was employed to transform the flat copper sheet into a microtextured specimen. This specimen was further nanotextured using the nickel wet-plating to build up the IR (InfraRed)-emission metallic device with fractal-like surface. Four-unit cells were designed and fabricated as a [...] Read more.

Short-pulse laser machining was employed to transform the flat copper sheet into a microtextured specimen. This specimen was further nanotextured using the nickel wet-plating to build up the IR (InfraRed)-emission metallic device with fractal-like surface. Four-unit cells were designed and fabricated as a micro-/nanotextured specimen by varying the microtextured unit cell structure. The IR-emissivity of these four specimens was measured using the thermographic microscopy with FT-IR (Fourier Transform InfraRed). The bare copper and nickel-nanotextured copper specimens were utilized as a reference. The micro-/nanotextured copper specimen had higher IR-emissivity than 0.8 in the wide wavelength range from 2 μm to 14 μm. Full article

(This article belongs to the Special Issue Laser Surface Modification: Advances and Applications)

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19 pages, 5603 KB

Open AccessArticle

The Influence of Heat and Holding Time on the Warm Forming of Al–Mg–Si Alloys

by Vasco Simões, Marta Oliveira, Hervé Laurent and Luis Menezes

J. Manuf. Mater. Process. 2026, 10(3), 94; https://doi.org/10.3390/jmmp10030094 - 11 Mar 2026

Abstract

Warm forming of heat-treatable aluminium alloys can induce significant changes in their initial heat treatment, affecting both the forming process and the final in-service properties. This work aims to systematically investigate the influence of heat-holding time on the thermo-mechanical behaviour and post-forming properties [...] Read more.

Warm forming of heat-treatable aluminium alloys can induce significant changes in their initial heat treatment, affecting both the forming process and the final in-service properties. This work aims to systematically investigate the influence of heat-holding time on the thermo-mechanical behaviour and post-forming properties of Al–Mg–Si alloys (EN AW 6016-T4 and EN AW 6061-T6), with a focus on optimizing process parameters to enhance formability and minimize springback. The study combines uniaxial tensile tests, cylindrical cup forming, hardness measurements, and springback evaluation, at room temperature (RT) and 200 °C, for different heat-holding times. The results show that short heat-holding times improve formability and reduce springback, while longer times promote artificial ageing, increasing strength and hardness but reducing ductility, especially in the EN AW 6016-T4 alloy. The EN AW 6061-T6 alloy exhibits greater thermal stability. The findings provide practical guidelines for industrial warm forming of Al–Mg–Si alloys, highlighting the critical role of heat-holding time in balancing formability, strength, and dimensional accuracy. Full article

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17 pages, 4367 KB

Open AccessArticle

On the Ultrasonic Atomization of SS316L Parts Manufactured via Laser Powder Bed Fusion for the Closed-Loop Production

by Olga Bashmakova, Leonid Fedorenko, Andrey Vasilev, Boris Zotov, Andrey Urzhumtsev, Ali Kavousi Sisi, Maria Lyange, Ivan Pelevin, Mikhail Gilvitinov, Ksenia Petukhova, Ekaterina Zinovyeva and Stanislav Chernyshikhin

J. Manuf. Mater. Process. 2026, 10(3), 93; https://doi.org/10.3390/jmmp10030093 - 10 Mar 2026

Abstract

Sustainable feedstock management remains a major challenge in laser beam powder bed fusion (PBF-LB), where conventional reuse strategies are typically limited to sieving and blending rather than full material regeneration. Ultrasonic atomization (UA) offers a fundamentally different powder production route based on capillary-wave [...] Read more.

Sustainable feedstock management remains a major challenge in laser beam powder bed fusion (PBF-LB), where conventional reuse strategies are typically limited to sieving and blending rather than full material regeneration. Ultrasonic atomization (UA) offers a fundamentally different powder production route based on capillary-wave instabilities induced at the surface of a molten metal by high-frequency vibrations. In contrast to turbulence-driven atomization, droplet formation in UA is primarily governed by ultrasonic frequency and intrinsic thermophysical properties of the melt, enabling quasi-deterministic particle formation with high sphericity and reduced satellite formation. In this study, ultrasonic atomization was investigated as a closed-loop route for converting PBF-LB-manufactured 316L stainless steel parts into reusable powder. Printed rods were remelted and atomized under controlled variation of electric current and vibration amplitude. The resulting powders were characterized in terms of morphology, internal microstructure, particle size distribution, chemical composition, and gas impurity content. UA produced highly spherical particles with reduced internal porosity and improved flowability compared to the initial gas-atomized powder, while preserving the principal alloying elements. An increase in oxygen content was observed after recycling, attributed to selective high-temperature oxidation under residual oxygen in nominally inert conditions. The results establish a mechanistic framework for transforming consolidated PBF-LB material into secondary feedstock and identify key parameters governing structural and compositional stability in closed-loop recycling. Full article

(This article belongs to the Special Issue Recent Advances in Optimization of Additive Manufacturing Processes)

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31 pages, 5554 KB

Open AccessArticle

Process–Design Co-Optimisation of Laser Powder Bed Fusion Titanium Gyroid Lattices via Deep Learning

by Alexander Dawes, Ali Abdelhafeez Hassan, Hany Hassanin and Khamis Essa

J. Manuf. Mater. Process. 2026, 10(3), 92; https://doi.org/10.3390/jmmp10030092 - 9 Mar 2026

Abstract

Laser powder bed fusion (LPBF) enables controlled gyroid lattices, but mapping both process and design to performance remains challenging when datasets are small and interactions are non-linear. In this study, data-driven models that link energy density and lattice geometry to Young’s modulus and [...] Read more.

Laser powder bed fusion (LPBF) enables controlled gyroid lattices, but mapping both process and design to performance remains challenging when datasets are small and interactions are non-linear. In this study, data-driven models that link energy density and lattice geometry to Young’s modulus and yield strength were established for sheet and network gyroid architectures. To stabilise small-data learning, stacked-autoencoder pre-training was benchmarked against greedy layer-wise pre-training. Compression characterisation data at under-represented energy-density conditions were added to fill data gaps and validate predictions. The models support property-driven design in which given modulus and yield strength targets inform a method that returns feasible combinations of laser powder bed fusion settings and gyroid density and size. Pre-trained models reduced error and captured the relationship between stiffness and density and between strength and density, with yield strength prediction errors of 3.51% for sheet architectures and 8.76% for network architectures. Young’s modulus showed a higher variability that is consistent with sensitivities in LPBF such as surface roughness and thin walls. This work contributes an artificial intelligence method for manufacturing datasets using stacked autoencoder pre-training with fine-tuning, and an inverse-design workflow that maps energy density and gyroid geometry to Young’s modulus and yield strength in titanium lattices. Full article

(This article belongs to the Special Issue Digital Twinning for Manufacturing)

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16 pages, 6279 KB

Open AccessArticle

Joinability and Performance of Double-Flush Riveted and Resistance-Welded Lap Joints in High-Strength Steel Sheets

by Rui F. V. Sampaio, João P. M. Pragana, Ivo M. F. Bragança, Carlos M. A. Silva and Paulo A. F. Martins

J. Manuf. Mater. Process. 2026, 10(3), 91; https://doi.org/10.3390/jmmp10030091 - 4 Mar 2026

Abstract

The applicability of two different joining processes for producing lap joints from high-strength steel sheets is investigated, reflecting their increasing use in advanced lightweight structures with demanding performance requirements. The work is primarily focused on the joining-by-forming process known as double-flush riveting, evaluated [...] Read more.

The applicability of two different joining processes for producing lap joints from high-strength steel sheets is investigated, reflecting their increasing use in advanced lightweight structures with demanding performance requirements. The work is primarily focused on the joining-by-forming process known as double-flush riveting, evaluated in two variants: one utilizing forged holes and the other employing machined holes. The performance of these two variants is compared with conventional fusion-based resistance spot welding using lap joints fabricated from 2 mm high-strength low-alloy S500MC steel sheets under varying geometric and process conditions, with support from finite element modelling. Results indicate that both double-flush riveting variants produce similar joint cross-sectional geometries, but the machined hole variant simplifies sheet preparation and eliminates the need for a progressive tooling system. Tensile lap-shear and peel test results reveal that double-flush riveted joints with forged holes exhibit superior strength, attributed to strain hardening in the forged regions. Furthermore, for nuggets and rivets of equivalent size, both double-flush riveting variants surpass resistance spot welding in terms of the mechanical strength of the final joints. These results suggest that double-flush riveting represents a promising alternative for assembling high-strength steel sheets in lightweight structural applications. Full article

(This article belongs to the Special Issue Innovative Approaches in Metal Forming and Joining Technologies)

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13 pages, 6394 KB

Open AccessArticle

Effect of Rapid Solidification on the Structure and Properties of Ag–Cu–(Ti,Zr) Brazing Alloys for Metal–Ceramic Joining

by Sofya Terekhova, Alexander Ivannikov, Anton Abramov, Veronika Kirillova, Vladimir Mikhalchik, Alexander Bazhenov, Pavel Morokhov, Ivan Fedotov, Ivan Klyushin, Nikita Popov and Oleg Sevryukov

J. Manuf. Mater. Process. 2026, 10(3), 90; https://doi.org/10.3390/jmmp10030090 - 3 Mar 2026

Abstract

Four compositions of rapidly quenched ribbon brazing alloys based on Ag–Cu–Ti (Ag–26.5Cu–1.5Ti, Ag–25Cu–5Ti) and Ag–Cu–Zr (Ag–26.5Cu–1.5Zr, Ag–25Cu–5Zr) systems were produced. Initial ingots were synthesized by arc melting. Rapidly solidified ribbons, 50–100 μm thick, were then fabricated from homogenized ingots using a “Crystall-702” facility. [...] Read more.

Four compositions of rapidly quenched ribbon brazing alloys based on Ag–Cu–Ti (Ag–26.5Cu–1.5Ti, Ag–25Cu–5Ti) and Ag–Cu–Zr (Ag–26.5Cu–1.5Zr, Ag–25Cu–5Zr) systems were produced. Initial ingots were synthesized by arc melting. Rapidly solidified ribbons, 50–100 μm thick, were then fabricated from homogenized ingots using a “Crystall-702” facility. A comparative analysis of the microstructure and phase composition of both the ingots and ribbons was conducted using scanning electron microscopy and X-ray diffraction. The analysis revealed the presence of Cu₄Ti and CuTi intermetallic compounds in the Ag–Cu–Ti alloys, and AgCu₄Zr and Zr₂Cu in the Ag–Cu–Zr alloys. Rapid quenching was found to produce metastable structures and significantly refine the intermetallic phases. Microhardness measurements of the ingot and ribbon states demonstrated a substantial influence of the processing route on the mechanical properties. The tensile strength of the ingots was also evaluated. The wetting angles of the rapidly quenched alloy melts on 99% Al₂O₃ (alumina) ceramic substrates under vacuum were determined. All produced ribbons, except for the Ag–26.5Cu–1.5Zr composition, demonstrated adequate wettability. Thus, these materials are considered promising for further research into heat-resistant metal–ceramic joints. Full article

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17 pages, 26160 KB

Open AccessArticle

New Insight into Mechanical, Microstructural and Failure Features of Lap-Fillet Autogenous Laser-Welded Similar and Dissimilar Joints of Ultra-Thin Steel Sheets

by Mihaela Iordachescu, Patricia Santos, Andrés Valiente, Maricely de Abreu and Elena Scutelnicu

J. Manuf. Mater. Process. 2026, 10(3), 89; https://doi.org/10.3390/jmmp10030089 - 2 Mar 2026

Abstract

This research work addresses the mechanical and metallurgical characterisation, as well as the failure features, of two types of lap-fillet autogenous laser-welded joints made of ultra-thin sheets by applying an appropriate welding technology for producing sound welds and flawless joints. Both welded samples, [...] Read more.

This research work addresses the mechanical and metallurgical characterisation, as well as the failure features, of two types of lap-fillet autogenous laser-welded joints made of ultra-thin sheets by applying an appropriate welding technology for producing sound welds and flawless joints. Both welded samples, one made only of stainless steel (SS-SS) sheets, and the other made of stainless steel and carbon steel (SS-CS) plates, were subjected to tensile–shear loads that are representative of the in-service conditions. The experimental research was focused on determining, by the digital image correlation (VIC-2D) method, the strain field and the rotation angle of the welded joints that were developed during loading tests of the welded specimens. Comparing to the classical testing method applied to study the joint overall mechanical properties, the novelty of this research consists of local mechanical behaviour assessment of relevant zones from similar and dissimilar welded joints, by using the innovative technique VIC-2D. Based on the analysis of the experimental results, it was found that the maximum rotation angle is 2.5 times higher in the SS-SS similar welded joint, in comparison with the SS-CS dissimilar welded joint. Despite this finding, the SS-CS specimen failed in the CS base material, far from the weld, with the failure phenomenon being preceded by the material yielding and necking. This failure mode is consistent with the detected strength mismatch of the SS-CS joint, with respect to the CS base material. In contrast, the quasi-ductile fracture of the SS-SS welded joint occurred by plastic exhaustion at the boundary between the narrow Heat-Affected Zone (HAZ) of SS and the Fuzion Zone (FZ). These outcomes are consistent with the hardness profile, microstructural heterogeneities found in the lap-fillet welded joints, and the load versus elongation curves that are determined and discussed in this paper. This research provides new insight and original information on the materials’ response to the autogenous laser welding, which will contribute to improving the knowledge on the ultra-thin lap-fillet welded similar and dissimilar steels. Full article

(This article belongs to the Special Issue Advances in Dissimilar Metal Joining and Welding, 2nd Edition)

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14 pages, 3444 KB

Open AccessArticle

Scan-Strategy Dependent Microstructural Modulation in L-PBF Ti-6Al-4V Components Through Selective Rescanning

by Kalyan Nandigama, Bharath Bhushan Ravichander, Yash Parikh and Golden Kumar

J. Manuf. Mater. Process. 2026, 10(3), 88; https://doi.org/10.3390/jmmp10030088 - 2 Mar 2026

Abstract

Laser Powder Bed Fusion (L-PBF) can enable in situ microstructural tailoring of metallic components by precisely controlling the layer-wise processing parameters. Layer rescanning is one such strategy used to induce localized microstructural modification. In this study, we investigated the effect of a lattice-based [...] Read more.

Laser Powder Bed Fusion (L-PBF) can enable in situ microstructural tailoring of metallic components by precisely controlling the layer-wise processing parameters. Layer rescanning is one such strategy used to induce localized microstructural modification. In this study, we investigated the effect of a lattice-based selective rescanning approach applied to different base scan strategies for Ti-6Al-4V samples. The lattice regions were selectively rescanned at 50% reduced laser power relative to the initial scan along the same laser path. Relative density, porosity, martensitic α′ morphology, phase fraction, and Vickers microhardness were compared with those of non-rescanned reference counterparts. Different scan strategies, including unidirectional, stripes, and chess, exhibited distinct responses to selective rescanning, resulting in localized variations in martensitic phase formation and hardness values. The extent of localized microstructural modification and hardness enhancement was strongly governed by the underlying scan strategy. Selective rescanning using the stripes strategy yielded the largest contrast between non-rescanned and rescanned regions. The unidirectional strategy showed strong effects of rescanning, but the heat-affected zones extended to the non-rescanned regions. In contrast, the chess strategy exhibited comparatively moderate changes owing to its inherent thermal-management characteristics. These findings demonstrate that selective rescanning can provide an effective, localized approach for tailoring microstructure and hardness enhancement in L-PBF Ti-6Al-4V, with its effectiveness strongly dependent on the underlying scan strategy. Full article

(This article belongs to the Special Issue Advances in Metal Additive Manufacturing: Processes, Materials, and Applications)

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39 pages, 31180 KB

Open AccessArticle

A Segmental Joining Method for Large-Scale Additive Components: Case Study on a Fan Blade

by Ronald Bastovansky, Matus Veres, Rudolf Madaj, Robert Kohar and Peter Weis

J. Manuf. Mater. Process. 2026, 10(3), 87; https://doi.org/10.3390/jmmp10030087 - 27 Feb 2026

Abstract

This study presents a case-specific joining method for modular, large-scale components manufactured using Selective Laser Sintering (SLS). A T-slot joint reinforced with a pultruded carbon fiber rod was developed to enable the segmental assembly of polymer fan blades that exceed the build volume [...] Read more.

This study presents a case-specific joining method for modular, large-scale components manufactured using Selective Laser Sintering (SLS). A T-slot joint reinforced with a pultruded carbon fiber rod was developed to enable the segmental assembly of polymer fan blades that exceed the build volume of common SLS printers. Through an iterative design process, five joint variations were investigated, focusing on the optimization of slot geometry (fillet radii and wall thickness) and the integration of carbon fiber reinforcements to create a high-strength hybrid connection. The experimental findings were validated using a non-linear finite element analysis (FEA) utilizing an iteratively calibrated Young’s modulus of 710 MPa, which accounts for the 50/50 virgin-to-reused PA2200 powder ratio employed in the study. The numerical model identified that the primary sites for crack initiation were the fillet radii of the female slot, where localized equivalent plastic strains reached critical levels of up to 84% in tension and 78% in bending. The final design achieved an average tensile strength of 27.6 MPa, exceeding the design threshold of 21.9 MPa with a safety factor of 2.5. While unreinforced joints showed a 73.4% reduction in bending strength compared to solid specimens, the addition of an 8 mm carbon rod increased performance by 238.7%, restoring over 90% of the monolithic material’s strength. Numerical results confirmed that the reinforcement assumed the primary load-bearing role, effectively mitigating stresses in the polymer matrix below the ultimate tensile strength. Failure analysis clarified that the observed audible failure originated from internal fiber breakage within the rod at stresses between 900–1050 MPa. This work demonstrates that a segmental, reinforcement-based joining method can effectively overcome size constraints in polymer additive manufacturing, providing a robust and repeatable solution for rotating components subject to complex loading conditions. Full article

(This article belongs to the Special Issue Advanced Design and Materials for Additive Manufacturing)

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16 pages, 2560 KB

Open AccessArticle

Investigation of Wire EDM Dressing of Metal-Bond Diamond Grinding Wheels and Its Impact on Grinding Performance

by Jan Wittenburg, Marcel Olivier, Tim Herrig, Timm Petersen, Thomas Bergs, Christian Wrobel, Rainer Harter and Eugen Großmann

J. Manuf. Mater. Process. 2026, 10(3), 86; https://doi.org/10.3390/jmmp10030086 - 27 Feb 2026

Abstract

Grinding wheel conditioning is critical for maintaining cutting efficiency and surface quality, yet conventional mechanical dressers struggle with metal-bonded superabrasive wheels. In this study, wire electrical discharge machining (WEDM) dressing was evaluated on metal-bond diamond wheels of two grit sizes (D54 and D91) [...] Read more.

Grinding wheel conditioning is critical for maintaining cutting efficiency and surface quality, yet conventional mechanical dressers struggle with metal-bonded superabrasive wheels. In this study, wire electrical discharge machining (WEDM) dressing was evaluated on metal-bond diamond wheels of two grit sizes (D54 and D91) and compared to standard mechanical dressing. Dressing was performed on a WEDM machine using varied discharge currents, open-circuit voltages, and duty factors; subsequently, each wheel ground twelve grooves in tungsten carbide under identical parameters. Performance was assessed via maximum spindle power, tangential and normal forces, surface roughness (Ra), radial wheel wear, and edge radius. WEDM-dressed wheels exhibited up to 56% lower peak spindle power and 40–50% lower forces than mechanically dressed wheels. Compared to mechanically dressed wheels, WEDM-conditioned wheels exhibited markedly lower radial wear and maintained substantially sharper, more stable edge radii throughout the grinding cycles. Surface roughness converged after an initial break-in, matching mechanical methods. By selectively eroding the bond without damaging grains, WEDM dressing extends dressing intervals by approximately fivefold and reduces maintenance. Full article

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19 pages, 5217 KB

Open AccessArticle

Experimental Characterization and Numerical Optimization of 3D-Printed PA6-CF External Fixator Rings

by Ion Badea, Tudor-George Alexandru, Diana Popescu and Florin Baciu

J. Manuf. Mater. Process. 2026, 10(3), 85; https://doi.org/10.3390/jmmp10030085 - 27 Feb 2026

Abstract

This research investigated the feasibility of 3D-printed external fixator (EF) rings made from carbon fiber reinforced polyamide 6 (PA6-CF) as an alternative to the conventional metallic counterpart. The study integrated tensile testing with digital image correlation (DIC) in as-printed and cold plasma-sterilized conditions, [...] Read more.

This research investigated the feasibility of 3D-printed external fixator (EF) rings made from carbon fiber reinforced polyamide 6 (PA6-CF) as an alternative to the conventional metallic counterpart. The study integrated tensile testing with digital image correlation (DIC) in as-printed and cold plasma-sterilized conditions, finite-element analysis (FEA) under wire loading, topology optimization for material and energy reduction, and evaluation of printability limits for large PA6-CF rings. The average Young’s modulus was 4.76 GPa and the maximum tensile strength was 60.5 MPa for as-printed samples, decreasing by 6.4% and 10.4% after sterilization, respectively. Using these properties as model inputs, FEA predicted safety factors larger than 1.42 for all configurations under 1000 N wire pretension, while topology optimization targeted up to 50% mass reduction without compromising ring stiffness. The study also revealed challenges in the printability of PA6-CF for large and thin components, including dimensional contraction, significant warping and moisture-induced defects, requiring an experienced 3D printer operator. Full article

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21 pages, 8264 KB

Open AccessArticle

Defects, Microstructure, and Hardness of As-Built and Heat-Treated 13 Hot Work Tool Steel and 17-4 PH Stainless Steel Obtained by Fused Filament Fabrication

by Morgane Mokhtari, Chirag Khandivar, Yannick Balcaen, David López-Bolaños, Miren Aristizabal and Joël Alexis

J. Manuf. Mater. Process. 2026, 10(3), 84; https://doi.org/10.3390/jmmp10030084 - 27 Feb 2026

Abstract

Fused Filament Fabrication (FFF) is a low-cost additive manufacturing process that produces metallic parts from printing with a metal-polymer filament, followed by a debinding–sintering process. It presents an opportunity for the tooling sector to improve performance by geometrical optimization while keeping costs low. [...] Read more.

Fused Filament Fabrication (FFF) is a low-cost additive manufacturing process that produces metallic parts from printing with a metal-polymer filament, followed by a debinding–sintering process. It presents an opportunity for the tooling sector to improve performance by geometrical optimization while keeping costs low. This study investigates the possibility of producing a molding core for plastic injection by FFF technology. This research aimed to characterize 17-4 PH stainless steel and H13 hot work tool steels produced through this process. Their heat treatment behavior was investigated using dilatometry, which led to the obtention of a Continuous Cooling Transformation (CCT) diagram. Results show that for as-sintered materials, martensitic steel with some residual austenite is present in 17-4 PH, and a pearlitic microstructure is observed in H13. Porosity (around 4%) falls within the reported range in the literature and can be removed by hot isostatic pressing. CCT diagrams do not show significant differences with conventional materials. The low hardness of as-sintered H13 (around 175 HV1) is improved (>500 HV1) by suitable heat treatment. Finally, both materials meet the requirements for this specific industrial application, and demonstrators were produced. Full article

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20 pages, 5349 KB

Open AccessArticle

The Effect of Si and Zr on the Formation of Al₃X and V-Phase in a 6005A Alloy with Sc—Part 1: Alloy Design and Heat Treatment Selection

by Eli Harma, Timothy Langan and Paul Sanders

J. Manuf. Mater. Process. 2026, 10(3), 83; https://doi.org/10.3390/jmmp10030083 - 27 Feb 2026

Abstract

Adding Sc to 6xxx series alloys has led to inconsistent results due to the formation of the high-temperature, thermodynamically stable V-phase (AlSc₂Si₂). Thermo-Calc single-axis equilibrium and phase diagram calculations were employed to identify V-phase formation with varying Si and [...] Read more.

Adding Sc to 6xxx series alloys has led to inconsistent results due to the formation of the high-temperature, thermodynamically stable V-phase (AlSc₂Si₂). Thermo-Calc single-axis equilibrium and phase diagram calculations were employed to identify V-phase formation with varying Si and Zr concentrations, indicating that increasing Zr and decreasing Si lowered the V-phase equilibrium volume fraction. Increasing Zr also shifted the V-phase equilibrium to higher Si concentrations. To access real-world influences of Zr and Si, four compositions were cast with different Si and Zr concentrations: a high-Si, low-Zr alloy; a medium-Si, medium-Zr alloy; a low-Si, high-Zr alloy; and a baseline alloy without Zr and Sc. The compositions were DC-cast followed by multi-step isochronal and isothermal heat treatments, which revealed that increasing Zr concentration did not influence the formation of V-phase but did result in higher hardness at high temperatures, likely due to Al₃Zr precipitation. In contrast, higher Si and lower Zr concentrations produced higher hardness in the peak-aged condition but lower hardness at homogenization temperatures in the 400 °C to 520 °C range. Given these conclusions, a new alloy and a multi-step homogenization process are proposed to further develop Sc- and Zr-containing 6xxx extrusion alloys. Full article

(This article belongs to the Special Issue Design and Manufacturing of Lightweight Materials Process and Structures)

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17 pages, 5996 KB

Open AccessArticle

Optimization of the Operating Behavior of Spur Gears Through Machine Hammer Peening

by Mohammad Dadgar, Sebastian Sklenak, Martina Müller, Tim Herrig, René Greschert, Dieter Mevissen, Christian Brecher and Thomas Bergs

J. Manuf. Mater. Process. 2026, 10(3), 82; https://doi.org/10.3390/jmmp10030082 - 26 Feb 2026

Abstract

Gear systems operate under high mechanical and tribological loads, making their surfaces vulnerable to wear and fatigue. Improving surface durability requires finishing processes that improve near-surface properties and extend service life. Since machine hammer peening (MHP) offers such potential, this study investigates its [...] Read more.

Gear systems operate under high mechanical and tribological loads, making their surfaces vulnerable to wear and fatigue. Improving surface durability requires finishing processes that improve near-surface properties and extend service life. Since machine hammer peening (MHP) offers such potential, this study investigates its influence on the performance of case-hardened spur gears and evaluates its suitability as an alternative to shot peening as a conventional finishing method. Analog specimens with simplified geometries were treated using various MHP parameters to identify effective process settings. These optimized settings were then applied to real spur gears to assess performance under practical conditions. The experiments showed that MHP can significantly modify surface integrity, achieving surface roughness reductions of up to 55%, surface hardness increases of up to 30%, and compressive residual stresses exceeding −1400 MPa with stability to depths of 200 µm. These modifications resulted in improved wear and fatigue performance, with increases in load cycle number in the tooth flank up to 99% and an increase in load amplitude in the tooth root of more than 5%. For comparison, specimens were also treated with shot peening. Although MHP induced stronger surface integrity modifications, shot peening achieved higher overall load-carrying capacity because several critical areas could not be fully accessed by MHP, limiting its effectiveness. Overall, MHP shows promise as a finishing process, but its full potential depends on overcoming accessibility limitations in complex gear geometries. Full article

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15 pages, 1668 KB

Open AccessArticle

Dynamic Reuleaux Venturi with Boundary-Imposed Swirl

by Lorenzo Albanese

J. Manuf. Mater. Process. 2026, 10(3), 81; https://doi.org/10.3390/jmmp10030081 - 26 Feb 2026

Abstract

In-line cavitation is relevant to many continuous processes; however, its intensity depends on flow rate, available pressure, temperature, fluid properties, and plant conditions, complicating the maintenance of a repeatable regime within a prescribed band. This paper presents the DVRA, an actuated Venturi module [...] Read more.

In-line cavitation is relevant to many continuous processes; however, its intensity depends on flow rate, available pressure, temperature, fluid properties, and plant conditions, complicating the maintenance of a repeatable regime within a prescribed band. This paper presents the DVRA, an actuated Venturi module with a Reuleaux triangular cross-section for in-operation regulation of hydrodynamic cavitation through device configuration. The novelty lies in combining two degrees of freedom—an in-operation adjustable hydraulic throat and boundary-imposed swirl forcing—within a compact in-line device: all rotation is confined to the module, and no rotation of the process line is required. The hydraulic throat is tuned via an actuated elastomeric liner, while swirl is generated by external end collars. Reproducible operational conventions are introduced together with a normalized input set and a configuration-space formalism that distinguishes admissible from achievable configurations. Regulation is cast as a control-oriented inverse mapping given a target band for an in-line estimated cavitation indicator and standard industrial measurements of flow rate, pressure, and temperature; configuration commands are selected to keep the indicator within bounds. The contribution is methodological and provides an implementable basis; comprehensive validation and performance benchmarking are outside the scope of this paper and will be reported separately. Full article

(This article belongs to the Special Issue Technological Advances and Industrial Applications in Intelligent Manufacturing)

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16 pages, 1868 KB

Open AccessArticle

Effects of Dispense Delay and Recoat Speed on Green Part Density and Powder Bed Density in Binder Jetting Additive Manufacturing

by Fahim Khan, Zhijian Pei, Md Shakil Arman, Steven Kuntzendorf and Yi-Tang Kao

J. Manuf. Mater. Process. 2026, 10(3), 80; https://doi.org/10.3390/jmmp10030080 - 26 Feb 2026

Abstract

This study investigates the effects of two process parameters (dispense delay and recoat speed) on green part density and powder bed density in binder jetting additive manufacturing using silicon carbide powder. These two process parameters control the amount of powder dispensed on the [...] Read more.

This study investigates the effects of two process parameters (dispense delay and recoat speed) on green part density and powder bed density in binder jetting additive manufacturing using silicon carbide powder. These two process parameters control the amount of powder dispensed on the powder bed for each powder layer. Experiments were conducted at three levels of dispense delay (0.2, 1, and 5 s) and three levels of recoat speeds (5, 10, and 20 mm/s). The one-way Analysis of Variance (ANOVA) results reveal that both dispense delay and recoat speed have statistically significant effects on green part density and powder bed density. Experimental results show that increasing dispense delay or decreasing recoat speed leads to higher green part density and powder bed density. These findings provide useful insights into optimizing binder jetting additive manufacturing process parameters to achieve the desired green part density without employing powder bed compaction. Full article

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23 pages, 3596 KB

Open AccessArticle

Analysis and Characterization of Axially Joined Friction-Welded Ti6Al4V Alloy Rods

by Mthobisi Zulu, Peter Madindwa Mashinini, Tshepo Ntsoane, Andrew Venter, Ryno van der Merwe and Deon Marais

J. Manuf. Mater. Process. 2026, 10(3), 79; https://doi.org/10.3390/jmmp10030079 - 26 Feb 2026

Abstract

The effect of process inputs in the friction welding of Ti6Al4V alloy rods was investigated through the analysis of residual stresses, microstructure, chemical phases and hardness testing of the weld joints. The rods were welded using different combinations of process inputs. The results [...] Read more.

The effect of process inputs in the friction welding of Ti6Al4V alloy rods was investigated through the analysis of residual stresses, microstructure, chemical phases and hardness testing of the weld joints. The rods were welded using different combinations of process inputs. The results revealed variations in residual stresses, hardness and microstructure of the weld joints when weld inputs were varied. Peak compressive residual stresses were obtained at the centre of the weld interface, where the grains were very fine. The joints with a greater volume fraction of martensitic grains had elevated residual stress values. The maximum compressive residual stress values were obtained at the weld interface, with high hardness results. A further investigation was conducted to study the relationship between the residual stresses, microstructure and mechanical properties of the weld joint. Full article

(This article belongs to the Special Issue Advances in Additive Manufacturing of Metal Alloys: Microstructure, Mechanical Behavior, and Surface Performance)

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