Journal of Manufacturing and Materials Processing

19 pages, 9207 KiB

Open AccessArticle

Effect of Heat Treatments on the Microstructure, Corrosion Resistance and Wear Behaviour of Bainitic/Martensitic Ductile Iron Under Dry Sliding Friction

by Nugzar Khidasheli, Salome Gvazava, Garegin Zakharov, Mikheil Chikhradze, Andre Danonu Lignamnateh Batako, Juan Ignacio Ahuir-Torres, Ashwath Pazhani and Micheal Anthony Xavior

J. Manuf. Mater. Process. 2025, 9(5), 145; https://doi.org/10.3390/jmmp9050145 - 28 Apr 2025

Abstract

The development of high-strength cast irons with multiphase metal matrix structures is one of the new areas of modern materials science and mechanical engineering. This is so because of the high dissipative properties of such materials, which, in turn, ensure an improvement in [...] Read more.

The development of high-strength cast irons with multiphase metal matrix structures is one of the new areas of modern materials science and mechanical engineering. This is so because of the high dissipative properties of such materials, which, in turn, ensure an improvement in their functional characteristics. It is known that one of the effective methods for obtaining alloys with a heterogeneous structure is a multi-stage heat treatment. Therefore, this study aimed to enhance the corrosion and friction properties of high-strength cast irons by combining different processing methods to create a bainite-martensitic matrix. High-strength cast irons with high ductility micro-alloyed with boron were chosen as the object for research. The experiments studied the effect of various types of multi-stage heat treatment on the structural features, tribological properties, hardness and corrosion resistance. The cast irons were quenched in water or liquid nitrogen after a controlled duration of isothermal exposure at different temperatures. It was established that cooling of isothermally hardened samples in liquid nitrogen makes it possible to effectively engineer the morphology and amount of the formed martensitic phase. It was observed that the high-strength cast irons with 10–15% lower bainite, residual austenite and martensite have the best frictional characteristics. This innovative method allowed the quenching of cast iron directly into liquid nitrogen without violent cracking. Full article

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23 pages, 8345 KiB

Open AccessArticle

Design of the Dual-Path Cold Spray Nozzle to Improve Deposition Efficiency

by Hongjun Li, Yongqi Le, Hao Xu and Ziyao Li

J. Manuf. Mater. Process. 2025, 9(5), 144; https://doi.org/10.3390/jmmp9050144 - 28 Apr 2025

Abstract

This paper designs a Dual path cold spray nozzle and studies its performance during the cold spray process through numerical simulations and optimization experiments. The gas flow field inside the nozzle and the particle acceleration process were simulated using Fluent software2020R1. The orthogonal [...] Read more.

This paper designs a Dual path cold spray nozzle and studies its performance during the cold spray process through numerical simulations and optimization experiments. The gas flow field inside the nozzle and the particle acceleration process were simulated using Fluent software2020R1. The orthogonal experimental method was used to analyze the effects of five geometric parameters on the nozzle performance, determining the optimal design parameter combination. Modeling and simulation calculations based on the optimal parameter combination showed that the average particle impact velocity increased by nearly 17 m/s, the number of particles exceeding the theoretical critical velocity increased by nearly 100, and the theoretical deposition efficiency improved by 10%. Experimental results indicated that compared to the single-channel nozzle, the deposition efficiency increased from 20.22% to 28.26%, the porosity improved from 10.51% to 9.12%, and the deposition microhardness also increased. The experimental test data were in good agreement with the previous numerical simulation results, validating the accuracy of the simulation model and providing an important theoretical reference for the optimization and improvement of subsequent process parameters. Full article

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22 pages, 3812 KiB

Open AccessArticle

Dynamic Dwell Time Adjustment in Wire Arc-Directed Energy Deposition: A Thermal Feedback Control Approach

by Md Munim Rayhan, Abderrachid Hamrani, Fuad Hasan, Tyler Dolmetsch, Arvind Agarwal and Dwayne McDaniel

J. Manuf. Mater. Process. 2025, 9(5), 143; https://doi.org/10.3390/jmmp9050143 - 27 Apr 2025

Abstract

Precise thermal management remains a critical challenge in Wire Arc-Direct Energy Deposition (W-DED) processes due to significant temperature fluctuations that can adversely impact part quality, dimensional accuracy, and process reliability. To address these issues, this study introduces a novel Hybrid Interlayer Hysteresis Controller [...] Read more.

Precise thermal management remains a critical challenge in Wire Arc-Direct Energy Deposition (W-DED) processes due to significant temperature fluctuations that can adversely impact part quality, dimensional accuracy, and process reliability. To address these issues, this study introduces a novel Hybrid Interlayer Hysteresis Controller (HIHC) designed specifically for W-DED, which integrates real-time thermal feedback and adaptive dwell time control. The system implements a dual-mode cooling strategy based on a temperature threshold, utilizing optical character recognition-based temperature monitoring and a rolling buffer system for stability. Experimental validation demonstrated improvements in thermal management, with the dynamic control system maintaining an average temperature undershoot of 1.38% while achieving 96.29% optimal temperature window compliance. Surface quality analysis revealed an 8.67% improvement in front face smoothness and a 5.15% enhancement in top surface quality. The dynamic control system also exhibited superior dimensional accuracy, producing thin walls with widths of 61.98 mm versus 66.43 mm in fixed dwell time samples, relative to the intended 60 mm specification. This study advances the field of additive manufacturing by establishing a robust framework for precise thermal management in W-DED processes, contributing to enhanced part quality, reduced post-processing requirements, and improved process reliability. Despite these advances, limitations include the system’s dependence on external optical monitoring hardware, potential scalability constraints for complex geometries, and limited testing across diverse material systems. Future work should focus on integrating multi-axis thermal sensors, extending the framework to multi-material deposition scenarios and implementing machine learning algorithms for predictive thermal modeling. Full article

(This article belongs to the Special Issue Advances in Directed Energy Deposition Additive Manufacturing)

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23 pages, 9237 KiB

Open AccessArticle

Tailoring Thermal Energy Supply Towards the Advanced Control of Deformation Mechanisms in 3D Forming of Paper and Board

by Leonard Vogt and Marek Hauptmann

J. Manuf. Mater. Process. 2025, 9(5), 142; https://doi.org/10.3390/jmmp9050142 - 27 Apr 2025

Abstract

The temperature of the tools and the moisture content of the material play a significant role in the 3D forming of paperboard in terms of the degree of forming and the quality of the formed part. It is known that different forming mechanisms [...] Read more.

The temperature of the tools and the moisture content of the material play a significant role in the 3D forming of paperboard in terms of the degree of forming and the quality of the formed part. It is known that different forming mechanisms act within the paperboard in different areas of the deep drawing tools during the deep drawing of paperboard and that the success of the forming process is also based on a dynamic interaction between material moisture and tool surface temperature. However, it has not yet been investigated how the forming parameters can be influenced by an individually adjustable temperature for the individual tool areas and how they influence the complex interaction with the moisture content of the paperboard during the forming process. Due to the inhomogeneity of the natural fiber network of paperboard, rapid and directed temperature changes of the tools are also of interest in order to be able to react quickly to variations of material properties in order to prevent frequent process failure within a continuous production. In this paper, test tools with individually controllable heating zones were developed and the use of different heating technologies to improve the rate of temperature change was analyzed. These tools were used to investigate the influence of temperature in the individual sections of the deep drawing process and how the moisture content can be specifically controlled during the process. It was found that with modern heating technology, the deep-drawing tools can be tempered significantly faster and that a temperature difference between the blank holder zone and the drawing cavity zone has a positive influence on the formability and the fixation of the shape of the part produced. This effect was further enhanced by the fact that, thanks to the temperature tailored tool, it was possible to work with a very high moisture content of the paperboard. Full article

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Graphical abstract

22 pages, 14262 KiB

Open AccessArticle

Comparison of the Self-Healing Behaviour of 60Sn40Pb and 99.3Sn0.7Cu Solder Alloy Reinforced Al6061 MMCs’

by Subrahmanya Ranga Viswanath Mantha, Gonal Basavaraja Veeresh Kumar, Ramakrishna Pramod, Chilakalapalli Surya Prakasha Rao, Mohd Shahneel Saharudin and Santosh Kumar Sahu

J. Manuf. Mater. Process. 2025, 9(5), 141; https://doi.org/10.3390/jmmp9050141 - 24 Apr 2025

Abstract

The self-healing characteristics of Al6061 reinforced with CuO have been examined experimentally. The solder alloys 60Pb40Sn and 99.3Sn0.7Cu with low melting points are incorporated to strengthen the Al6061 MMCs’; the self-healing properties have been investigated. Developed self-healing samples have undergone testing for hardness, [...] Read more.

The self-healing characteristics of Al6061 reinforced with CuO have been examined experimentally. The solder alloys 60Pb40Sn and 99.3Sn0.7Cu with low melting points are incorporated to strengthen the Al6061 MMCs’; the self-healing properties have been investigated. Developed self-healing samples have undergone testing for hardness, tensile, and impact characteristics in accordance with ASTM standard test protocols. The findings demonstrate how the solder filling affects the mechanical characteristics of self-healed Al6061 alloy and its MMCs’. The results showed that the composites formed a decent bond between the solder and matrix, confirming successful fabrication. Pb-Sn filled samples demonstrated higher self-healing efficiency for tensile and impact of 90.02% and 90.30% with 6 wt.% of CuO, respectively, and Sn-Cu filled samples witnessed higher self-healing efficiency for tensile and impact of 91.81% and 91.09% with 6 wt.% of CuO respectively. However, the self-healed composite did not split in two when subjected to Charpy impact and tensile strength tests, and the healing efficiency of Sn-Cu-filled composites is higher than that of the Pb-Sn-filled composites. Full article

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

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24 pages, 10416 KiB

Open AccessArticle

Improved Mechanical Performance of Carbon–Kevlar Hybrid Composites with TiO₂ Nanoparticle Reinforcement for Structural Applications

by Vignesh Nagarajan Jawahar, Rajesh Jesudoss Hynes Navasingh, Krzysztof Stebel, Radosław Jasiński and Adam Niesłony

J. Manuf. Mater. Process. 2025, 9(5), 140; https://doi.org/10.3390/jmmp9050140 - 24 Apr 2025

Abstract

Carbon–Kevlar hybrid composites are being increasingly recognized as suitable materials for aerospace, automotive, and construction applications due to their unique combination of strength, toughness, and safety. Prior to their use, extensive testing and validation are essential to ensure that these composites meet the [...] Read more.

Carbon–Kevlar hybrid composites are being increasingly recognized as suitable materials for aerospace, automotive, and construction applications due to their unique combination of strength, toughness, and safety. Prior to their use, extensive testing and validation are essential to ensure that these composites meet the specific safety and performance standards required by each industry. In this study, the mechanical performance and behavior of five different types of Carbon–Kevlar hybrid composites were investigated. In addition to microstructural investigations, mechanical tests were also carried out, including tensile, bending, impact, and micro-hardness tests. The investigated composites were Carbon–Kevlar hybrids without orientation, with a symmetrical orientation, and with the addition of TiO₂ nanoparticles at weight percentages of 3%, 4%, and 5%. The results showed that the mechanical properties of these composites could be significantly influenced by different fiber orientations and the addition of TiO₂ nanoparticles. In particular, the addition of TiO₂ nanoparticles increased the tensile strength, hardness, toughness, and breaking strength. Of the composites tested, the composite reinforced with 5% TiO₂ nanoparticles exhibited the highest mechanical performance, with a 79.8 Shore D hardness, 406 MPa tensile strength, 398 N/mm² flexural strength, and 10.1 J impact energy. These results indicate that Carbon–Kevlar hybrid composites reinforced with TiO₂ nanoparticles have excellent mechanical properties that make them highly suitable for armor plating, helmets, and vehicle armoring in particular and a wide range of other industrial applications in general. Full article

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

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17 pages, 4101 KiB

Open AccessArticle

Design and Manufacture of a Flexible Adaptive Fixture for Precision Grinding of Thin-Walled Bearing Rings

by Yao Shi, Yu He, Jun Zha, Bohao Chen, Chaoyu Shi and Ming Wu

J. Manuf. Mater. Process. 2025, 9(5), 139; https://doi.org/10.3390/jmmp9050139 - 22 Apr 2025

Abstract

Addressing the issues of easy deformation and difficult-to-control machining accuracy of thin-walled bearing rings during precision grinding due to clamping forces, existing research mainly employs methods such as elastic clamping, hydraulic control, pneumatic control, and vacuum adsorption to tackle the clamping problem. However, [...] Read more.

Addressing the issues of easy deformation and difficult-to-control machining accuracy of thin-walled bearing rings during precision grinding due to clamping forces, existing research mainly employs methods such as elastic clamping, hydraulic control, pneumatic control, and vacuum adsorption to tackle the clamping problem. However, these methods still suffer from problems such as uneven clamping force, insufficient adaptability, and limited machining accuracy. In this paper, a novel fixture suitable for precision grinding of thin-walled bearing rings is designed. By analyzing the working principle of the fixture and considering the processing characteristics of thin-walled bearing rings, the fixture structure is designed and optimized to enhance its clamping stability and machining accuracy. Modal analysis and stress-displacement analysis are conducted to verify the stability and performance of the new fixture during the machining process. The research results show that the fixture can effectively reduce the deformation of thin-walled bearing rings, improve machining quality and efficiency, and provide a feasible solution for high-precision grinding of thin-walled bearing rings. Full article

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

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18 pages, 2112 KiB

Open AccessArticle

Additive vs. Subtractive Manufacturing: A Comparative Life Cycle and Cost Analyses of Steel Mill Spare Parts

by Luis Segovia-Guerrero, Nuria Baladés, Juan J. Gallardo-Galán, Antonio J. Gil-Mena and David L. Sales

J. Manuf. Mater. Process. 2025, 9(4), 138; https://doi.org/10.3390/jmmp9040138 - 19 Apr 2025

Abstract

In the context of growing environmental concerns and the demand for more sustainable manufacturing practices, this study evaluates the environmental and economic performance of two production routes for a stainless steel support block used in steel mills. A comparative Life Cycle Assessment (LCA) [...] Read more.

In the context of growing environmental concerns and the demand for more sustainable manufacturing practices, this study evaluates the environmental and economic performance of two production routes for a stainless steel support block used in steel mills. A comparative Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) were conducted to assess a conventional subtractive manufacturing process based on Computer Numerical Control (CNC) machining versus a hybrid approach that combines Plasma Arc-Wire Arc Additive Manufacturing (PA-WAAM) with CNC finishing. The LCA was carried out using ReCiPe 2016 Midpoint and Endpoint methodologies in SimaPro, while the LCC employed a cradle-to-gate cost model. Results showed that the hybrid WAAM-CNC route reduced average environmental impacts by 49% across 18 categories and decreased steel consumption by approximately 70% due to near-net-shape fabrication. Although the hybrid method incurred an approximate 3.5 times increase in unit production cost, this was primarily attributed to equipment investment. In contrast, operational costs such as labor, materials, and consumables were significantly lower—by 66%, 28%, and 45%, respectively. These findings support the hybrid approach as a more sustainable manufacturing alternative with the potential for long-term cost optimization as additive technologies mature. Full article

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Graphical abstract

25 pages, 5232 KiB

Open AccessArticle

An Advanced Compression Molding Simulation and Validation of a Thick-Walled Carbon Fiber Sheet Molding Compound Brake Caliper

by Andreas Kapshammer, Severin Huemer-Kals, Kepa Zulueta, Peter Fischer and Zoltan Major

J. Manuf. Mater. Process. 2025, 9(4), 137; https://doi.org/10.3390/jmmp9040137 - 19 Apr 2025

Abstract

This study introduces a methodology for characterizing and modeling the viscosity and specific volume–pressure–temperature (pvT) behavior of sheet molding compound (SMC) materials, based on the use of specialized testing equipment. Conventional rheometers are inadequate for such materials due to the presence of long [...] Read more.

This study introduces a methodology for characterizing and modeling the viscosity and specific volume–pressure–temperature (pvT) behavior of sheet molding compound (SMC) materials, based on the use of specialized testing equipment. Conventional rheometers are inadequate for such materials due to the presence of long fibers, necessitating the use of specialized equipment like squeeze flow rheometers and pvT dilatometers. Our findings demonstrate that traditional oscillatoric rheometer measurements underestimate the viscosity of CF-SMCs, highlighting the need for advanced, albeit non-standardized, testing methods. Additionally, we found that standard Tait models failed to capture the temperature-dependent porosity of CF-SMCs at low pressures, whereas models based on thermodynamic state variables (TSVs) provided accurate predictions across a broader range of conditions. The study also addressed the complexities introduced by fiber–flow coupling and the fiber orientation in measuring the viscosity, revealing limitations in conventional modeling approaches. The numerical analysis showed that a power law-based anisotropic viscosity model (PL-IISO) combined with a TSV model offered the best predictive performance in finite volume flow simulations, especially for thick-walled regions. However, the current modeling approaches have limited predictive capabilities for the fiber orientation in thin-walled regions. This research underscores the challenges in accurately modeling CF-SMC materials in terms of the fiber orientation, whereas the compression forces needed from the pressing machine could be predicted accurately within an average error of 6.5% in the squeeze flow experiments. Full article

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12 pages, 4385 KiB

Open AccessArticle

Effects of Compaction Thickness on Density, Integrity, and Microstructure of Green Parts in Binder Jetting Additive Manufacturing of Silicon Carbide

by Mostafa Meraj Pasha, Md Shakil Arman, Zhijian Pei, Fahim Khan, Jackson Sanders and Stephen Kachur

J. Manuf. Mater. Process. 2025, 9(4), 136; https://doi.org/10.3390/jmmp9040136 - 19 Apr 2025

Abstract

Binder jetting additive manufacturing (BJAM) of silicon carbide (SiC) has been reported in the literature. In the reported studies, the effects of the compaction thickness on the properties of SiC green parts printed by BJAM have largely been unexamined. This study aims to [...] Read more.

Binder jetting additive manufacturing (BJAM) of silicon carbide (SiC) has been reported in the literature. In the reported studies, the effects of the compaction thickness on the properties of SiC green parts printed by BJAM have largely been unexamined. This study aims to fill this gap in the literature by investigating the effects of the compaction thickness on the density, integrity, and microstructure of SiC green parts printed by BJAM. In this study, experiments were conducted using four levels of compaction thickness at two levels of layer thickness. The results indicate that increasing the compaction thickness enhances the green part density, reaching 1.85 g/cm³ at a layer thickness of 45 µm and 1.87 g/cm³ at a layer thickness of 60 µm, respectively. However, a higher compaction thickness might also introduce defects in green parts, such as cracks. Scanning electron microscopy (SEM) analysis confirmed the improved particle packing and reduced porosity with the increased compaction thickness. These findings underscore a trade-off between density and defect formation, providing critical insights for optimizing BJAM process variables for fabricating SiC parts. Full article

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13 pages, 3162 KiB

Open AccessArticle

Effect of Varying Layer Thickness by Interlayer Machining on Microstructure and Mechanical Properties in Wire Arc Additive Manufacturing

by G. Ganesan, Neel Kamal Gupta, S. Siddhartha, Shahu R. Karade, Henning Zeidler, K. Narasimhan and K. P. Karunakaran

J. Manuf. Mater. Process. 2025, 9(4), 135; https://doi.org/10.3390/jmmp9040135 - 18 Apr 2025

Abstract

This study investigates the influence of varying layer thickness through interlayer machining in Wire Arc Additive Manufacturing (WAAM) and its impact on microstructural evolution, mechanical properties, and residual stress distribution. It compares four types of WAAM samples: As-built with uneven layer thickness without [...] Read more.

This study investigates the influence of varying layer thickness through interlayer machining in Wire Arc Additive Manufacturing (WAAM) and its impact on microstructural evolution, mechanical properties, and residual stress distribution. It compares four types of WAAM samples: As-built with uneven layer thickness without interlayer machining and uniform layer thicknesses of 2 mm, 1.5 mm, and 1 mm achieved through interlayer machining. As-built components exhibited coarse columnar grains and uneven deposition, adversely affecting hardness and strength. Interlayer machining at reduced layer thickness refined grains, restricted growth, and induced plastic deformation, leading to enhanced mechanical properties. Grain refinement achieved reductions of 62.7% (top), 77.6% (middle), and 64.3% (bottom), significantly improving microstructural uniformity. Microhardness increased from 150 to 180 HV (as-built) to 210 to 230 HV (machined to maintain 1 mm layer thickness), marking a 40–43% improvement. Tensile strength was enhanced, with UTS increasing from 494.72 MPa to 582.11 MPa (17.6%) and YS from 371 MPa to 471 MPa (26.9%), although elongation decreased from 59% to 46% (22% reduction). Residual stress was reduced by 55–60%, improving structural integrity. These findings highlight interlayer machining as a key strategy for optimizing WAAM-fabricated components while balancing mechanical performance and manufacturing efficiency. Full article

(This article belongs to the Special Issue Design, Processes and Materials for Additive Manufacturing: 2nd Edition)

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21 pages, 5818 KiB

Open AccessArticle

Influence of Infill Geometry and Density on the Mechanical Properties of 3D-Printed Polylactic Acid Structure

by Jozef Jaroslav Fekiač, Lucia Kakošová, Michal Krbata, Marcel Kohutiar, Maroš Eckert, Zbynek Studeny and Andrej Dubec

J. Manuf. Mater. Process. 2025, 9(4), 134; https://doi.org/10.3390/jmmp9040134 - 18 Apr 2025

Abstract

Additive manufacturing of polymer composites, also known as 3D printing, is one of the progressive technologies in material engineering. It enables the production of parts with complex geometries while optimizing material efficiency. Polylactide (PLA) is a widely used material in additive manufacturing due [...] Read more.

Additive manufacturing of polymer composites, also known as 3D printing, is one of the progressive technologies in material engineering. It enables the production of parts with complex geometries while optimizing material efficiency. Polylactide (PLA) is a widely used material in additive manufacturing due to its biodegradability and suitable mechanical properties. However, its brittleness and limited thermal stability require further modifications, such as modifying the filler structure or adding reinforcing materials. This paper focuses on analyzing the influence of different filler geometries and densities on the mechanical properties of PLA parts manufactured by the fused filament deposition (FFF) method. Three basic filler structures—cubic, gyroid and rectilinear—were investigated at different density levels from 20%, 40%, 60% and 80%. Experimental tests were performed according to ASTM D638 to determine the strength characteristics of the material. In addition to mechanical tests, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TG) were performed to better understand the influence of the filling geometry on the thermal stability and viscoelastic behavior of the material. Experimental tests according to ASTM D638 showed that higher filling density improves mechanical properties. At 80% filling, the tensile strength reached 21.06 MPa (cubic), 20.53 MPa (gyroid) and 20.84 MPa (linear). The elastic modulus was highest with cubic filling (1414.19 MPa). The yield strength reached 15.59 MPa (cubic), 15.52 MPa (gyroid) and 14.30 MPa (linear). Full article

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39 pages, 8029 KiB

Open AccessReview

Recent Advances in In Situ 3D Surface Topographical Monitoring for Additive Manufacturing Processes

by Vignesh Suresh, Badrinath Balasubramaniam, Li-Hsin Yeh and Beiwen Li

J. Manuf. Mater. Process. 2025, 9(4), 133; https://doi.org/10.3390/jmmp9040133 - 18 Apr 2025

Abstract

Additive manufacturing (AM) has revolutionized production across industries, yet persistent challenges in defect detection and process reliability necessitate advanced in situ monitoring solutions. While non-destructive evaluation (NDE) techniques such as X-ray computed tomography, thermography, and ultrasonic testing have been widely adopted, the critical [...] Read more.

Additive manufacturing (AM) has revolutionized production across industries, yet persistent challenges in defect detection and process reliability necessitate advanced in situ monitoring solutions. While non-destructive evaluation (NDE) techniques such as X-ray computed tomography, thermography, and ultrasonic testing have been widely adopted, the critical role of 3D surface topographic monitoring remains underutilized for real-time anomaly detection. This work comprehensively reviews the 3D surface monitoring of AM processes, such as Laser powder bed fusion, directed energy deposition, material extrusion, and material jetting, highlighting the current state and challenges. Furthermore, the article discusses the state-of-the-art advancements in closed-loop feedback control systems, sensor fusion, and machine learning algorithms to integrate 3D surface data with various process signatures to dynamically adjust laser parameters and scan strategies. Guidance has been provided on the best 3D monitoring technique for each of the AM processes. Motivated by manufacturing labor shortages, the high skill required to operate and troubleshoot some of these additive manufacturing techniques, and zero-defect manufacturing goals, this paper also explores the metamorphosis towards autonomous AM systems and adaptive process optimization and explores the role and importance of real-time 3D monitoring in that transition. Full article

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27 pages, 14022 KiB

Open AccessArticle

Personalizing Industrial Maintenance Operation Using the Model of Hierarchical Complexity

by Gonçalo Raposo, Nuno Araújo, Marco Parente, António M. Lopes, Adriano Santos, Filipe Pereira, Sofia Leite and António Ramos Silva

J. Manuf. Mater. Process. 2025, 9(4), 132; https://doi.org/10.3390/jmmp9040132 - 15 Apr 2025

Abstract

The rapid advancement of Industry 4.0 technologies has transformed industrial maintenance operations, introducing digital work instructions as a critical tool for improving efficiency and reducing errors. However, existing digitalization approaches often fail to account for variations in worker expertise, leading to cognitive overload, [...] Read more.

The rapid advancement of Industry 4.0 technologies has transformed industrial maintenance operations, introducing digital work instructions as a critical tool for improving efficiency and reducing errors. However, existing digitalization approaches often fail to account for variations in worker expertise, leading to cognitive overload, frustrations, and overall inefficiency. This study proposes a novel methodology for dynamically personalizing digital work instructions by structuring task instructions based on complexity levels and worker proficiency. Using the Model of Hierarchical Complexity (MHC) as a framework ensures that operators receive guidance tailored to their cognitive and skill capabilities. The methodology is implemented and evaluated in an industrial maintenance environment, where digital work instructions are adapted based on worker profiles. The results show significant improvements in maintenance operations, including a reduction in task completion time, a decrease in error rates, and enhanced worker engagement. Comparative analysis with conventional static instructions reveals that personalized digital work instructions contribute to a more effective knowledge transfer process, reducing cognitive strain and enhancing procedural adherence. Additionally, integrating predictive maintenance strategies with personalized work instructions could further enhance operational efficiency by enabling proactive decision-making. Addressing potential challenges, such as worker resistance to adaptive technologies and data privacy concerns, will be crucial for widespread implementation. In conclusion, leveraging the Model of Hierarchical Complexity to personalize digital work instructions represents a significant step toward optimizing industrial maintenance workflows. Tailoring instructional content to individual skill levels and cognitive abilities enhances workforce productivity, reduces errors, and contributes to the broader objectives of Industry 4.0. Full article

(This article belongs to the Special Issue Haptic-Robotic Systems in Industrial Design, Manufacturing, Assembly, Simulation, and Training)

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16 pages, 10278 KiB

Open AccessReview

Ag/Au Bimetallic Core–Shell Nanostructures: A Review of Synthesis and Applications

by Shuyue He, Ziyu Tang, Tianhang Huo, Di Wu and Jasper H. Tang

J. Manuf. Mater. Process. 2025, 9(4), 131; https://doi.org/10.3390/jmmp9040131 - 15 Apr 2025

Abstract

Silver/gold (Ag/Au) core–shell nanostructures exhibit tunable plasmonic properties and enhanced catalytic performance, enabling applications across sensing, biomedicine, and environmental remediation. This review presents representative synthetic strategies for fabricating Ag/Au bimetallic core–shell nanostructures with three distinct morphologies: nanospheres, nanocubes, and nanowires. For each architecture, [...] Read more.

Silver/gold (Ag/Au) core–shell nanostructures exhibit tunable plasmonic properties and enhanced catalytic performance, enabling applications across sensing, biomedicine, and environmental remediation. This review presents representative synthetic strategies for fabricating Ag/Au bimetallic core–shell nanostructures with three distinct morphologies: nanospheres, nanocubes, and nanowires. For each architecture, we cover the representative synthetic approaches, such as seed-mediated growth, one-pot synthesis, and evaporation deposition methods, along with their corresponding applications. This review provides discussions on the synthesis methods and applications through specific examples, offering researchers guidance for fabricating Ag/Au core–shell nanostructures with tailored morphologies while addressing major challenges in controlling bimetallic formation. Full article

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13 pages, 18986 KiB

Open AccessArticle

Thermal Modelling of Metals and Alloys Irradiated by Pulsed Electron Beam: Focus on Rough, Heterogeneous and Multilayered Materials

by Andrea Lucchini Huspek, Valentina Mataloni, Ali Mohtashamifar, Luca Paterlini and Massimiliano Bestetti

J. Manuf. Mater. Process. 2025, 9(4), 130; https://doi.org/10.3390/jmmp9040130 - 15 Apr 2025

Abstract

Low-Energy High-Current Electron Beam (LEHCEB) is an innovative vacuum technology employed for the surface modification of conductive materials. Surface treatments by means of LEHCEB allow the melting and rapid solidification of a thin layer (up to ~10 μm) of material. The short duration [...] Read more.

Low-Energy High-Current Electron Beam (LEHCEB) is an innovative vacuum technology employed for the surface modification of conductive materials. Surface treatments by means of LEHCEB allow the melting and rapid solidification of a thin layer (up to ~10 μm) of material. The short duration of each pulse (2.5 μs) allows for the generation of high thermal rates, up to 10⁹ K/s. Due to the peculiar features of LEHCEB source, in situ temperature monitoring inside the vacuum chamber is unfeasible, even with the most rapid IR pyrometers available on the market. Therefore, multiphysics simulations serve as a tool for predicting and assessing the thermal effects induced by electron beam irradiation. COMSOL Multiphysics was employed to study the thermal behaviour of metals and alloys at the sub-microsecond time scale by implementing both experimental power time profiles and semi-empirical electron penetration functions. Three case studies were considered: (a) 17-4 PH steel produced by Binder Jetting, (b) biphasic Al-Si13 alloy, and (c) Magnetron Sputtering Nb films on Ti substrate. The influence on the thermal effects of electron accelerating voltage and number of pulses was investigated, as well as the role of the physicochemical properties of the materials. Full article

(This article belongs to the Special Issue New Trends in Precision Machining Processes)

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38 pages, 4194 KiB

Open AccessReview

Recent Trends and Future Directions in 3D Printing of Biocompatible Polymers

by Maryam Aftab, Sania Ikram, Muneeb Ullah, Niyamat Khan, Muhammad Naeem, Muhammad Amir Khan, Rakhmonov Bakhrombek Bakhtiyor o’g’li, Kamalova Sayyorakhon Salokhiddin Qizi, Oribjonov Otabek Erkinjon Ugli, Bekkulova Mokhigul Abdurasulovna and Oribjonova Khadisakhon Abdumutallib Qizi

J. Manuf. Mater. Process. 2025, 9(4), 129; https://doi.org/10.3390/jmmp9040129 - 14 Apr 2025

Abstract

Three-dimensional (3D) bioprinting using biocompatible polymers has emerged as a revolutionary technique in tissue engineering and regenerative medicine. These biopolymers mimic the extracellular matrix (ECM) and enhance cellular behavior. The current review presents recent advancements in additive manufacturing processes including Stereolithography (SLA), Fused [...] Read more.

Three-dimensional (3D) bioprinting using biocompatible polymers has emerged as a revolutionary technique in tissue engineering and regenerative medicine. These biopolymers mimic the extracellular matrix (ECM) and enhance cellular behavior. The current review presents recent advancements in additive manufacturing processes including Stereolithography (SLA), Fused Filament Fabrication (FFF), Selective Laser Sintering (SLS), and inkjet printing. It also explores the fundamentals of 3D printing and the properties of biocompatible polymers for 3D bioprinting. By mixing biopolymers, enhancing rheological characteristics, and adding bioactive components, further advancements have been made for organ transplantation, drug development, and tissue engineering. As research progresses, the potential for 3D bioprinting to fundamentally transform the healthcare system is becoming obvious and clear. However, the therapeutic potential of printed structures is hindered by issues such as material anisotropy, poor mechanical properties, and the need for more biocompatible and biodegradable architectures. Future research should concentrate on optimizing the 3D bioprinting process using sophisticated computational techniques, systematically examining the characteristics of biopolymers, customizing bioinks for different cell types, and exploring sustainable materials. Full article

(This article belongs to the Special Issue Advances in 3D Printing Technologies: Materials, Processes, and Applications)

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15 pages, 8253 KiB

Open AccessArticle

An Investigation of the Fatigue Behavior and Dislocation Substructures of Friction-Stir-Welded SSM 6063 Aluminum Alloy

by Kittima Sillapasa, Konkrai Nakowong, Siriporn Khantongkum and Chaiyoot Meengam

J. Manuf. Mater. Process. 2025, 9(4), 128; https://doi.org/10.3390/jmmp9040128 - 14 Apr 2025

Abstract

In this study, we examine the evolution of dislocation substructures influenced by the fatigue behavior of SSM 6063 aluminum alloy processed through friction stir welding (FSW). The findings indicate that dislocation substructures have a significant impact on fatigue life. Cyclic loading induced recrystallization [...] Read more.

In this study, we examine the evolution of dislocation substructures influenced by the fatigue behavior of SSM 6063 aluminum alloy processed through friction stir welding (FSW). The findings indicate that dislocation substructures have a significant impact on fatigue life. Cyclic loading induced recrystallization in the stir zone (SZ), the advancing-side thermomechanically affected zone (AS-TMAZ), and the retreating-side thermomechanically affected zone (RS-TMAZ). The transformation of the α-primary aluminum matrix phase into an S/S’ structure and the precipitation of Al₅FeSi intermetallic compounds into the T-phase were observed. Furthermore, the precipitation of Si and Mg, the primary alloying elements, was observed in the Guinier–Preston (GP) zone within the SZ. Transmission electron microscopy (TEM) analysis revealed small rod-like particles in the T-phase, measuring approximately 10–20 nm in width and 20–30 nm in length in the SZ. In the AS-TMAZ, these rod-like structures ranged from 10 to 120 nm in width and 20 to 180 nm in length, whereas in the RS-TMAZ, they varied between 10 and 70 nm in width and from 20 to 110 nm in length. The dislocation substructures influenced the stress amplitude, which was 42.46 MPa in the base metal (BM) and 33.12 MPa in the FSW-processed SSM 6063 aluminum alloy after undergoing more than 2 × 10⁶ loading cycles. The endurance limit was 42.50 MPa for BM and 32.40 MPa for FSW. Fractographic analysis of the FSW samples revealed distinct laminar crack zones and shear fracture surface zones, differing from those of other regions. Both brittle and ductile fracture characteristics were identified. Full article

(This article belongs to the Special Issue Deformation and Mechanical Behavior of Metals and Alloys)

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15 pages, 4008 KiB

Open AccessArticle

Optimization of Process Parameters in Electropolishing of SS 316L Utilizing Taguchi Robust Design

by Muhammad Kemal Syahputra, Kartika Nur ‘Anisa’, Rizky Astari Rahmania, Farazila Yusof, Pradeep Dixit, Muslim Mahardika and Gunawan Setia Prihandana

J. Manuf. Mater. Process. 2025, 9(4), 127; https://doi.org/10.3390/jmmp9040127 - 11 Apr 2025

Abstract

In electropolishing, the material removal rate is frequently neglected, as this process is primarily focused on surface finish, and yet, it is crucial for manufacturing metallic sheets. Solutions are required to enhance the material removal rate while maintaining surface quality. This work introduces [...] Read more.

In electropolishing, the material removal rate is frequently neglected, as this process is primarily focused on surface finish, and yet, it is crucial for manufacturing metallic sheets. Solutions are required to enhance the material removal rate while maintaining surface quality. This work introduces an electropolishing technique that involves suspending ethanol in an electrolyte solution and employing a magnetic field during machining processes. The Taguchi approach is utilized to determine the ideal process parameters for enhancing the material removal rate of SS 316L electropolishing through a L9 orthogonal array. Pareto analysis of variance (ANOVA) is utilized to examine the four parameters of the machining process: applied voltage, ethanol concentration, machining gap variation, and the magnetic field of the electrolyte. The results demonstrate that the applied voltage, the incorporation of ethanol in electropolishing, and a reduced machining gap significantly increase the material removal rate; however, the introduction of a magnetic field did not notably increase the material removal rate. Full article

(This article belongs to the Topic Advanced Manufacturing and Surface Technology, 2nd Edition)

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