Journal of Manufacturing and Materials Processing

16 pages, 2826 KiB

Open AccessArticle

Online Tool Wear Monitoring via Long Short-Term Memory (LSTM) Improved Particle Filtering and Gaussian Process Regression

by Hui Xu, Hui Xie and Guangxian Li

J. Manuf. Mater. Process. 2025, 9(5), 163; https://doi.org/10.3390/jmmp9050163 (registering DOI) - 17 May 2025

Abstract

Accurate prediction of tool wear plays a vital role in improving machining quality in intelligent manufacturing. However, traditional Gaussian Process Regression (GPR) models are constrained by linear assumptions, while conventional filtering algorithms struggle in noisy environments with low signal-to-noise ratios. To address these [...] Read more.

Accurate prediction of tool wear plays a vital role in improving machining quality in intelligent manufacturing. However, traditional Gaussian Process Regression (GPR) models are constrained by linear assumptions, while conventional filtering algorithms struggle in noisy environments with low signal-to-noise ratios. To address these challenges, this paper presents an innovative tool wear prediction method that integrates a nonlinear mean function and a multi-kernel function-optimized GPR model combined with an LSTM-enhanced particle filter algorithm. The approach incorporates the LSTM network into the state transition model, utilizing its strong time-series feature extraction capabilities to dynamically adjust particle weight distributions, significantly enhancing the accuracy of state estimation. Experimental results demonstrate that the proposed method reduces the mean absolute error (MAE) by 47.6% and improves the signal-to-noise ratio by 15.4% compared to traditional filtering approaches. By incorporating a nonlinear mean function based on machining parameters, the method effectively models the coupling relationships between cutting depth, spindle speed, feed rate, and wear, leading to a 31.09% reduction in MAE and a 42.61% reduction in RMSE compared to traditional linear models. The kernel function design employs a composite strategy using a Gaussian kernel and a 5/2 Matern kernel, achieving a balanced approach that captures both data smoothness and abrupt changes. This results in a 58.7% reduction in MAE and a 64.5% reduction in RMSE. This study successfully tackles key challenges in tool wear monitoring, such as noise suppression, nonlinear modeling, and non-stationary data handling, providing an efficient and stable solution for tool condition monitoring in complex manufacturing environments. Full article

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22 pages, 20072 KiB

Open AccessReview

Analyzing Joinery for Furniture Designed for Disassembly

by Maciej Sydor and Kacper Stańczyk

J. Manuf. Mater. Process. 2025, 9(5), 162; https://doi.org/10.3390/jmmp9050162 - 15 May 2025

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Abstract

End-users can design personalized furnishing products using remote web-based CAD systems. However, if these designs fail to incorporate design for disassembly (DfD) principles, the furniture’s subsequent repair, reconfiguration, recycling, and disposal can be significantly hindered. To address this drawback, this study supports DfD, [...] Read more.

End-users can design personalized furnishing products using remote web-based CAD systems. However, if these designs fail to incorporate design for disassembly (DfD) principles, the furniture’s subsequent repair, reconfiguration, recycling, and disposal can be significantly hindered. To address this drawback, this study supports DfD, a strategy that enables the creation of easily repairable, reusable, and recyclable furniture to reduce waste and environmental impact. Consequently, this review aims to classify and evaluate available furniture joinery systems for their suitability within DfD frameworks, ultimately promoting their implementation within CAD environments. To this end, various solutions were evaluated, including traditional joints, dowel/biscuit, hammered, directly screwed, snap-on, expandable, and cam/bolt fasteners. Based on a literature review and practical observations, the analyzed joinery systems were categorized into non-disassemblable, conditionally disassemblable, and fully disassemblable categories. Only the fully disassemblable solutions effectively align with DfD principles. The study postulates a preference for expandable and cam/bolt fasteners in furniture designs, noting that although snap-on fasteners can potentially support DfD, this outcome is not always ensured. To guarantee that the designed furniture adheres to the DfD principles, the following eight furniture design guidelines were formulated: develop web-accessible disassembly instructions, prioritize access to fast-wearing components, prioritize modularity, standardize parts in modules, label components, enable independent component removal, use materials that withstand repeated disassembly, and employ fully disassemblable joints. Full article

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12 pages, 7004 KiB

Open AccessArticle

Bonding Characteristics in Air of a Decomposable Composite Sheet Containing Sn-3.0Ag-0.5Cu Particles for Formation of a Robust Metallic Solder Joint in Die Attachment

by Hye-Min Lee and Jong-Hyun Lee

J. Manuf. Mater. Process. 2025, 9(5), 161; https://doi.org/10.3390/jmmp9050161 - 15 May 2025

Viewed by 65

Abstract

To address solder paste drawbacks, such as die contamination and flux residue, a polymer-based sheet containing Sn-3.0 (wt%) Ag-0.5Cu solder particles as fillers was fabricated, and its bonding characteristics were analyzed. The reductant in the manufactured sheet evaporated while removing the oxide layers [...] Read more.

To address solder paste drawbacks, such as die contamination and flux residue, a polymer-based sheet containing Sn-3.0 (wt%) Ag-0.5Cu solder particles as fillers was fabricated, and its bonding characteristics were analyzed. The reductant in the manufactured sheet evaporated while removing the oxide layers on the solder and copper finish surfaces during heating. Subsequently, the resin component (polymethyl methacrylate) began to decompose thermally and gradually dissipated. Ultimately, the resulting joint formed a solder interconnection with a small amount of residual resin. This joint is expected to exhibit superior thermal conductivity compared with composite joints with a polymer matrix structure. Die-attach tests were conducted in air using the fabricated sheet between Cu finishes. Results showed that joints formed at 300 °C for 30 s and 350 °C for 10 s provided excellent shear strength values of 48.0 and 44.3 MPa, respectively, along with appropriately developed intermetallic compound (IMC) layers at the bonding interface. In contrast, bonding at 350 °C for 60 s resulted in excessive growth of IMC layers at the interface. When comparing size effects of solder particles, type 6 particles exhibited superior shear strength along with a relatively thinner total IMC layer thickness compared to when type 7 particles were used. Full article

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

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18 pages, 8376 KiB

Open AccessArticle

Knot-TPP: A Unified Deep Learning Model for Process Incidence and Tool Wear Monitoring in Stacked Drilling

by Jiduo Zhang, Robert Heinemann and Otto Jan Bakker

J. Manuf. Mater. Process. 2025, 9(5), 160; https://doi.org/10.3390/jmmp9050160 - 14 May 2025

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Abstract

In drilling Carbon-Fibre-Reinforced Polymers (CFRP)/Al stacks, adaptive drilling facilitates the optimisation of cutting parameters for each constituent stack layer and tool wear, thus enhancing cutting efficiency and borehole quality. This study proposed a knot–Temporal Pyramid Pooling (TPP) model aimed at monitoring both process [...] Read more.

In drilling Carbon-Fibre-Reinforced Polymers (CFRP)/Al stacks, adaptive drilling facilitates the optimisation of cutting parameters for each constituent stack layer and tool wear, thus enhancing cutting efficiency and borehole quality. This study proposed a knot–Temporal Pyramid Pooling (TPP) model aimed at monitoring both process incidences and tool wear in the drilling of hybrid stacks, which subsequently informs the machine tool to adjust cutting parameters or, if necessary, replaces the tool. TPP is introduced to remove the restriction of input dimensions, allowing for the acceptance of inputs with arbitrary shapes. On the other hand, a knot structure has been proposed to incorporate the classification of process incidences into the tool wear analysis, thereby enhancing prediction accuracy. The proposed model achieves a process incidence identification accuracy of 99.19% and a Mean Absolute Error (MAE) of 10 μm in tool wear prediction, demonstrating robust performance across a wide range of sampling conditions. This achievement facilitates decision-making and optimisation relating to cutting parameters and tool replacement in the context of adaptive drilling of aerospace materials. Full article

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16 pages, 15439 KiB

Open AccessArticle

Unveiling Surface Roughness Trends and Mechanical Properties in Friction Stir Welded Similar Alloys Joints Using Adaptive Thresholding and Grayscale Histogram Analysis

by Haider Khazal, Azzeddine Belaziz, Raheem Al-Sabur, Hassanein I. Khalaf and Zerrouki Abdelwahab

J. Manuf. Mater. Process. 2025, 9(5), 159; https://doi.org/10.3390/jmmp9050159 - 14 May 2025

Viewed by 225

Abstract

Surface roughness plays a vital role in determining surface integrity and function. Surface irregularities or reduced quality near the surface can contribute to material failure. Surface roughness is considered a crucial factor in estimating the fatigue life of structures welded by FSW. This [...] Read more.

Surface roughness plays a vital role in determining surface integrity and function. Surface irregularities or reduced quality near the surface can contribute to material failure. Surface roughness is considered a crucial factor in estimating the fatigue life of structures welded by FSW. This study attempts to provide a deeper understanding of the nature of the surface formation and roughness of aluminum joints during FSW processes. In order to form more efficient joints, the frictional temperature generated was monitored until reaching 450 °C, where the transverse movement of the tool and the joint welding began. Hardness and tensile tests showed that the formed joints were good, which paved the way for more reliable surface roughness measurements. The surface roughness of the weld joint was measured along the weld line at three symmetrical levels using welding parameters that included a rotational speed of 1250 rpm, a welding speed of 71 mm/min, and a tilt angle of 1.5°. The average hardness in the stir zone was measured at 64 HV, compared to 50 HV in the base material, indicating a strengthening effect induced by the welding process. In terms of tensile strength, the FSW joint exhibited a maximum force of 2.759 kN. Average roughness (Rz), arithmetic center roughness (Ra), and maximum peak-to-valley height (Rt) were measured. The results showed that along the weld line and at all levels, the roughness coefficients (Rz, Ra, and Rt) gradually increased from the beginning of the weld line to its end. The roughness Rz varies from start to finish, ranging between 9.84 μm and 16.87 μm on the RS and 8.77 μm and 13.98 μm on the AS, leveling off slightly toward the end as the heat input stabilizes. The obtained surface roughness and mechanical properties can give an in-depth understanding of the joint surface forming and increase the ability to overcome cracks and defects. Consequently, this approach, using adaptive thresholding image processing coupled with grayscale histogram analysis, yielded significant understanding of the FSW joint’s surface texture. Full article

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

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18 pages, 26273 KiB

Open AccessReview

Recent Applications of Focused Ion Beam–Scanning Electron Microscopy in Advanced Packaging

by Huan Zhang, Mengmeng Ma, Yuhang Liu, Wenwu Zhang and Chonglei Zhang

J. Manuf. Mater. Process. 2025, 9(5), 158; https://doi.org/10.3390/jmmp9050158 - 13 May 2025

Viewed by 225

Abstract

Advanced packaging represents a crucial technological evolution aimed at overcoming limitations posed by Moore’s Law, driving the semiconductor industry from two-dimensional toward three-dimensional integrated structures. The increasing complexity and miniaturization of electronic devices have significantly heightened the challenges associated with failure analysis during [...] Read more.

Advanced packaging represents a crucial technological evolution aimed at overcoming limitations posed by Moore’s Law, driving the semiconductor industry from two-dimensional toward three-dimensional integrated structures. The increasing complexity and miniaturization of electronic devices have significantly heightened the challenges associated with failure analysis during process development. The focused ion beam–scanning electron microscope (FIB-SEM), characterized by its high processing precision and exceptional imaging resolution, has emerged as a powerful solution for the fabrication, defect localization, and failure analysis of micro- and nano-scale devices. This paper systematically reviews the innovative applications of FIB-SEM in the research of core issues, such as through-silicon-via (TSV) defects, bond interfacial failures, and redistribution layer (RDL) electromigration. Additionally, the paper discusses multimodal integration strategies combining FIB-SEM with advanced analytical techniques, such as high-resolution three-dimensional X-ray microscopy (XRM), electron backscatter diffraction (EBSD), and spectroscopy. Finally, it provides a perspective on the emerging applications and potential of frontier technologies, such as femtosecond-laser-assisted FIB, in the field of advanced packaging analysis. Full article

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19 pages, 5719 KiB

Open AccessArticle

Influence of Laser-Wire Metal Deposition Process Parameters on the Mechanical Properties and Microstructure of ER70S-6 Steel

by Daniel Gomez-Lendinez, Jesus Garcia-Moreno-Caraballo, Sergio Corbera and Rafael Barea

J. Manuf. Mater. Process. 2025, 9(5), 157; https://doi.org/10.3390/jmmp9050157 - 9 May 2025

Viewed by 307

Abstract

Low-carbon steels, such as ER70S-6, are typically considered resistant to phase transformations due to their high critical cooling rate. However, this study investigates how the manufacturing process and specimen geometry influence heat dissipation, potentially leading to localized grain size variations that impact mechanical [...] Read more.

Low-carbon steels, such as ER70S-6, are typically considered resistant to phase transformations due to their high critical cooling rate. However, this study investigates how the manufacturing process and specimen geometry influence heat dissipation, potentially leading to localized grain size variations that impact mechanical properties. To analyze these effects, samples were fabricated using Laser Wire-Feed Additive Manufacturing (LWAM) with different geometries, and their hardness and microstructural characteristics were evaluated. Vickers microhardness tests were performed along the specimens to assess local variations, while dilatometry measurements were conducted to determine thermal expansion coefficients for future integration into finite element models (FEMs) of residual stress distribution. The results reveal that differences in heat dissipation during fabrication lead to grain size heterogeneity, affecting hardness at a microscopic scale and overall mechanical performance. These findings highlight the importance of considering thermal history and geometry in LWAM-fabricated components to ensure consistent material properties. Full article

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Graphical abstract

14 pages, 8046 KiB

Open AccessArticle

Evaluation of Laser Structuring in Hard Turning Process of Martensitic Steel

by Esmaeil Ghadiri Zahrani, Amir Alinaghizadeh, Amirmohammad Fakharzadeh Jahromi and Bahman Azarhoushang

J. Manuf. Mater. Process. 2025, 9(5), 156; https://doi.org/10.3390/jmmp9050156 - 9 May 2025

Viewed by 235

Abstract

The hard turning process presents significant challenges compared to conventional turning techniques, particularly in terms of controlling machining forces and dimensional accuracy. This study evaluates the effectiveness of laser structuring in enhancing the hard turning process of martensite steel. A CBN insert with [...] Read more.

The hard turning process presents significant challenges compared to conventional turning techniques, particularly in terms of controlling machining forces and dimensional accuracy. This study evaluates the effectiveness of laser structuring in enhancing the hard turning process of martensite steel. A CBN insert with two distinct approach angles and cutting depths was employed. The research involved the measurement of forces generated during the machining process, together with an analysis of chip formation kinematics. The results demonstrate that laser structuring effectively reduced machining forces so that the laser structuring reduced both tangential and feed forces, with the reduction being more significant for the approach angle κ = 50°. Additionally, the forces decreased further as the structuring density increased. Additionally, the laser structuring showed the potential to optimize surface integrity. Increasing the laser structuring density led to a significant reduction in the residual stress of the final surface. This study confirms the practical benefits of laser structuring in hard turning, particularly in improving surface quality. Full article

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19 pages, 10069 KiB

Open AccessArticle

Quasi-Static Compressive Behavior and Energy Absorption Performance of Polyether Imide Auxetic Structures Made by Fused Deposition Modeling

by Jing Xu, Liubimau Aliaksandr, Hanna Narkevich, Sijia Hao, Yubin Chen, Yuguang He, Junpeng Tian, Shenglong Dai and Cheng Yang

J. Manuf. Mater. Process. 2025, 9(5), 155; https://doi.org/10.3390/jmmp9050155 - 9 May 2025

Viewed by 278

Abstract

Auxetic structures have garnered considerable interest for being lightweight and exhibiting superior properties such as an excellent energy absorption capability. In this paper, re-entrant and missing rib square grid auxetic structures were additively manufactured via the fused deposition modeling technique using two types [...] Read more.

Auxetic structures have garnered considerable interest for being lightweight and exhibiting superior properties such as an excellent energy absorption capability. In this paper, re-entrant and missing rib square grid auxetic structures were additively manufactured via the fused deposition modeling technique using two types of polyether imide materials: ULTEM 9085 and ULTEM 1010. In-plane quasi-static compressive tests were carried out on the proposed structures at different relative densities to investigate the Poisson’s ratio, equivalent modulus, deformation behavior, and energy absorption performance. Finite element simulations of the compression process were conducted, which confirmed the deformation behavior observed in the experiments. It was found that the Poisson’s ratio and normalized equivalent Young’s modulus of ULTEM 9085 and ULTEM 1010 with the same geometries were very close, while the energy absorption of the ductile ULTEM 9085 was significantly higher than that of the brittle ULTEM 1010 structures. Furthermore, a linear correlation exists between the relative density and specific energy absorption of missing rib square grid structures within the investigated relative density range, whereas the relationship for re-entrant structures follows a power law. This study provides a better understanding of how material properties influence the deformation behavior and energy absorption characteristics of auxetic structures. Full article

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23 pages, 32328 KiB

Open AccessArticle

Mechanical and Cellular Evaluations of ACP-Enriched Biodegradable Micromolded PLA/PCL Bone Screws

by Min-Wen Wang, Wei-Young Wang, Chun-Ming Chen and Chun-Chieh Tseng

J. Manuf. Mater. Process. 2025, 9(5), 154; https://doi.org/10.3390/jmmp9050154 - 7 May 2025

Viewed by 201

Abstract

Nanoscale amorphous calcium phosphate (ACP) exhibits superior bioactivity, degradability, and osteoblast adhesion compared to hydroxyapatite (HAp), making it a promising bioactive ceramic material for bone regeneration applications. This study explores the integration of ACP as a bioactive additive in polylactic acid/polycaprolactone (PLA/PCL) composites. [...] Read more.

Nanoscale amorphous calcium phosphate (ACP) exhibits superior bioactivity, degradability, and osteoblast adhesion compared to hydroxyapatite (HAp), making it a promising bioactive ceramic material for bone regeneration applications. This study explores the integration of ACP as a bioactive additive in polylactic acid/polycaprolactone (PLA/PCL) composites. Nanoscale ACP powder was synthesized through low-temperature wet chemical methods without additional reagents. The composite, consisting of 10 wt.% ACP, 80 wt.% PLA, and 20 wt.% PCL, achieved optimal tensile strength (>12 MPa) and elongation (>0.1%). Utilizing the Taguchi experimental design, the microinjection molding parameters were optimized, and they are a material temperature of 190 °C, an injection speed of 50 mm/s, and a holding pressure speed of 30 mm/s. Variance analysis identified the injection speed to be the most significant factor, contributing 50.73% to the overall effect. Immersing ACP in simulated body fluid (SBF) for six hours reduced its calcium ion concentration by 28%, with this concentration stabilizing thereafter. Biocompatibility was confirmed through an MTT assay with NIH-3T3 cells, demonstrating the PLA/PCL/ACP composite’s compatibility. Bone differentiation and mineralization tests showed the enhanced performance of both ACP and the composite material. Degradation tests indicated an initial 0.29% weight increase in the first week, followed by a 2% reduction by the fifth week. These results underscore the PLA/PCL/ACP composite’s excellent mechanical properties, biocompatibility, and suitability for injection molding, positioning it as a strong candidate for biodegradable bone screw applications. Full article

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20 pages, 6608 KiB

Open AccessArticle

Leveraging Intelligent Machines for Sustainable and Intelligent Manufacturing Systems

by Somkiat Tangjitsitcharoen, Nattawut Suksomcheewin and Alessio Faccia

J. Manuf. Mater. Process. 2025, 9(5), 153; https://doi.org/10.3390/jmmp9050153 - 6 May 2025

Viewed by 228

Abstract

This study presents an intelligent machine developed for real-time quality monitoring during CNC turning, aimed at improving cutting efficiency and reducing production energy. A dynamometer integrated into the CNC machine captures decomposed cutting forces using the Daubechies wavelet transform. These force ratios are [...] Read more.

This study presents an intelligent machine developed for real-time quality monitoring during CNC turning, aimed at improving cutting efficiency and reducing production energy. A dynamometer integrated into the CNC machine captures decomposed cutting forces using the Daubechies wavelet transform. These force ratios are correlated with key workpiece dimensions: surface roughness, average roughness, straightness, and roundness. Two predictive models—nonlinear regression and a feed-forward neural network with Levenberg–Marquardt backpropagation—are employed to estimate these parameters under varying cutting conditions. Experimental results indicate that nonlinear regression models outperform neural networks in predictive accuracy. The proposed system offers effective in-process control of machining quality, contributing to shorter cycle times, lower defect rates, and more sustainable manufacturing practices. Full article

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16 pages, 3392 KiB

Open AccessArticle

DED Powder Modification for Single-Layer Coatings on High-Strength Steels

by Unai Garate, Enara Mardaras, Jon Arruabarrena, Garikoitz Artola, Aitzol Lamikiz and Luis Norberto López de Lacalle

J. Manuf. Mater. Process. 2025, 9(5), 152; https://doi.org/10.3390/jmmp9050152 - 6 May 2025

Viewed by 194

Abstract

In the design of L-DED (laser-directed energy deposition) cladding processes, the chemical composition of the metallic powders is typically assumed to match that of the intended coating. However, during the deposition of the first layer, dilution with the substrate alters the weld metal [...] Read more.

In the design of L-DED (laser-directed energy deposition) cladding processes, the chemical composition of the metallic powders is typically assumed to match that of the intended coating. However, during the deposition of the first layer, dilution with the substrate alters the weld metal composition, deviating from the nominal powder chemistry. Although the application of multiple layers can gradually reduce this dilution effect, it introduces additional complexity and processing time. This study proposes an alternative strategy to counteract substrate dilution from the very first deposited layer, eliminating the need for multilayer coatings. Specifically, to achieve a corrosion-resistant monolayer of AISI 316L stainless steel on a high-strength, quenched-and-tempered AISI 4140 steel substrate, a dilution-compensating alloy powder is added to the standard AISI 316L feedstock. Single-layer coatings, both with and without compensation, were evaluated in terms of chemical composition, microstructure, and corrosion resistance. The results show that unmodified coatings suffered a chromium depletion of approximately 2 wt.%, leading to a reduced pitting potential of Ep = 725 ± 6 mV in synthetic seawater. In contrast, the use of the compensation alloy preserved chromium content and significantly improved corrosion resistance, achieving a pitting potential of Ep = 890 ± 9 mV. Full article

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

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15 pages, 3120 KiB

Open AccessArticle

Thermal Curing of Adhesive Joints Enabled by Precision Heating Multi-Material Additive Manufacturing

by Mattia Frascio, Matilde Minuto, Francesco Musiari, Stefano Morchio, Khalid M. Usman, Federico Dittamo, Matteo Zoppi and Massimiliano Avalle

J. Manuf. Mater. Process. 2025, 9(5), 151; https://doi.org/10.3390/jmmp9050151 - 5 May 2025

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Abstract

This study explores the development of adhesive joints incorporating embedded resistive heating elements, fabricated using Multi-Material Additive Manufacturing. By embedding conductive circuits within the adherends, localized heating enables controlled curing of the adhesive, optimizing its mechanical properties according to the specific application. This [...] Read more.

This study explores the development of adhesive joints incorporating embedded resistive heating elements, fabricated using Multi-Material Additive Manufacturing. By embedding conductive circuits within the adherends, localized heating enables controlled curing of the adhesive, optimizing its mechanical properties according to the specific application. This study focused on modifying the stiffness of the adhesive in order to reduce edge effects in the joints and allow for better load distribution. The adherends were made of PLA, the resistive heating elements were fabricated using carbon black-filled conductive PLA, and an epoxy resin served as the adhesive. Thermal and mechanical characterizations were conducted, evaluating the effects of different curing temperatures on joint strength. The tensile strength for joints cured at 120 °C exhibited a 58% increase in maximum breaking force and a 144% increase in elongation at break compared to the joints cured at room temperature. These findings highlight the potential of AM-integrated resistive heating for precise adhesive curing, enabling the local tailoring of the adhesive stiffness in the overlap volume. Full article

(This article belongs to the Special Issue Innovative and Sustainable Advances in Polymer Composites for Additive Manufacturing: Processing, Microstructure, Machining, and Mechanical Properties)

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20 pages, 11285 KiB

Open AccessArticle

Improved Use of the Full Length of Milling-Tool Flutes in Processes of Air-Contour Milling

by César García-Hernández, Juan-Jesús Valdivia-Sánchez, Pedro Ubieto-Artur, Mariano García-Arbués, Anastasios Tzotzis, Juan-José Garde-Barace, Francisco Valdivia-Calvo and José-Luis Huertas-Talón

J. Manuf. Mater. Process. 2025, 9(5), 150; https://doi.org/10.3390/jmmp9050150 - 2 May 2025

Viewed by 375

Abstract

The cutting length of milling tools must be longer than the axial distance of the material to be processed. In fact, in most cases, the cutting length far exceeds the thickness of the material to be removed. Therefore, along the entire length of [...] Read more.

The cutting length of milling tools must be longer than the axial distance of the material to be processed. In fact, in most cases, the cutting length far exceeds the thickness of the material to be removed. Therefore, along the entire length of the milling-tool flutes, only the area farthest from the shank wears out, leaving the rest of the tool practically without any wear, especially in the area closest to the shank. This research analyses a toolpath model to use the complete length of the milling tool flutes, in those machining operations in which it is possible, with the objective of reducing the costs associated with tool wearing and resharpening. This improves the tool performance, which clearly increases the sustainability of the milling process. For this purpose, it is necessary to transform the numerical control programme that performs a flat (2D) toolpath into a helical (3D) one by decomposing the arcs and rectilinear segments into a succession of points within a precision range. A negative aspect of this method is that it can only be applied to bottomless contours in processes of air-contour milling. Full article

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14 pages, 2116 KiB

Open AccessArticle

In Vitro Characterization of 3D-Printed PLA/CPO Oxygen Releasing Scaffolds: Mechanical and Biological Properties for Bone Tissue Engineering

by Abdullah Mohammed, Alice Tirnoveanu, William Richard Webb, Ammar A. Melaibari, Adnan Memić, Mohammad Aslam, Amr Elshaer, Hany Hassanin and Khamis Essa

J. Manuf. Mater. Process. 2025, 9(5), 149; https://doi.org/10.3390/jmmp9050149 - 2 May 2025

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Abstract

The addition of oxygen-releasing biomaterials into 3D-printed scaffolds presents a novel approach to enhancing bone scaffolds, yet no in vitro studies have demonstrated the effect of oxygen-generating filaments on scaffold biological and mechanical properties. This study introduces a polylactic acid (PLA)/calcium peroxide (CPO) [...] Read more.

The addition of oxygen-releasing biomaterials into 3D-printed scaffolds presents a novel approach to enhancing bone scaffolds, yet no in vitro studies have demonstrated the effect of oxygen-generating filaments on scaffold biological and mechanical properties. This study introduces a polylactic acid (PLA)/calcium peroxide (CPO) composite filament, designed for oxygen release, which is a key factor for early-stage bone regeneration. The PLA/CPO composite filament was fabricated via wet-mixing, solvent evaporation, and hot-melt extrusion, followed by fused deposition modeling (FDM) with optimized parameters to achieve high structural fidelity (25% porosity, 0.60mm pore size). In vitro characterization, including mechanical, morphological, and biological assessments, demonstrated that, post-cell culturing, mechanical strength improved, which indicates improved scaffold resilience. The scaffold exhibited gradual oxygen release over a 3-day period, and gene expression analysis confirmed notable upregulation of osteogenic markers RUNX2, SPP1, and SP7 in vitamin D-supplemented conditions. The mechanical strength improved from approximately 2.8 MPa in the control group to 5.0 MPa in scaffolds cultured with osteogenic media. This study provides the first in vitro evidence that oxygen-releasing 3D-printed filaments can improve both mechanical properties and biological response in scaffolds, demonstrating the functional integration of sustained oxygen delivery, enhanced mechanical properties, and increased osteogenic activity in a single 3D-printed scaffold. Full article

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14 pages, 4359 KiB

Open AccessArticle

Optimization of Machining Parameters for the Fixed Pocket Cycle

by Felipe Stein, Nickolas Giacomitti, Gustavo Valério, Jorge Paulo, João Rocha and João Ribeiro

J. Manuf. Mater. Process. 2025, 9(5), 148; https://doi.org/10.3390/jmmp9050148 - 30 Apr 2025

Viewed by 143

Abstract

In a competitive industrial setting, optimizing machining processes is important for enhancing surface quality and productivity. This study focuses on optimizing pocket milling parameters for 5083 H111 aluminum alloy using three toolpath strategies: Zig-Zag, Parallel Spiral, and One-Way. To achieve these goals, the [...] Read more.

In a competitive industrial setting, optimizing machining processes is important for enhancing surface quality and productivity. This study focuses on optimizing pocket milling parameters for 5083 H111 aluminum alloy using three toolpath strategies: Zig-Zag, Parallel Spiral, and One-Way. To achieve these goals, the Taguchi method, Grey Relational Analysis (GRA), ANOVA, and visual amplification were employed to evaluate the influence of cutting speed (V_c), feed per tooth (f_z), and axial depth of cut (a_p) on surface roughness and production rate. For the Zig-Zag and Parallel Spiral tool paths, cutting speed was the most important factor affecting surface roughness. For the One-Way strategy, axial penetration was the most important factor. The Parallel Spiral toolpath, under the V_c of 150 m/min, the f_z of 0.025 mm/tooth, and the a_p of 1.0 mm (A3-B3-C1) configuration, achieved the best balance between surface finish and production rate. Visual analysis also showed significative differences in how rough the wall was along perpendicular and parallel tool paths, which made it clear that finishing passes are needed in some cases. This research shows that using both statistical methods and visual amplification together makes process optimization more organized and effective, which leads to better machining performance. Full article

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27 pages, 22019 KiB

Open AccessArticle

Laser Powder Bed Fusion Processing of UNS C64200 Aluminum–Silicon–Bronze

by Kenzie A. Timmons, Ali Nasiri and Donald P. Bishop

J. Manuf. Mater. Process. 2025, 9(5), 147; https://doi.org/10.3390/jmmp9050147 - 30 Apr 2025

Viewed by 240

Abstract

This research focused on developing the processing parameters required to fabricate UNS C64200 aluminum–silicon–bronze (ASB) using laser powder bed fusion (LPBF) additive manufacturing. A full factorial design of experiments (DOE), followed by a central composite DOE, was employed to statistically optimize the as-built [...] Read more.

This research focused on developing the processing parameters required to fabricate UNS C64200 aluminum–silicon–bronze (ASB) using laser powder bed fusion (LPBF) additive manufacturing. A full factorial design of experiments (DOE), followed by a central composite DOE, was employed to statistically optimize the as-built density while varying laser power, scan speed, and hatch spacing. Parameter sets that yielded high-density (>99.9%) products were then utilized to manufacture specimens to determine mechanical properties in both the as-built and heat-treated states. The as-built samples exhibited high tensile strength but relatively low ductility and absorbed impact energy, owing to the presence of a mixed α/β’ microstructure. Heat treatment at 620 °C eliminated the martensitic β’ phase, which manifested significant gains in ductility and absorbed energy. As such, the final tensile properties and impact toughness exceeded the Defence Standard minimum requirements for conventionally processed ASB. Full article

(This article belongs to the Special Issue Additive Manufacturing of Copper-Based Alloys)

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16 pages, 12342 KiB

Open AccessArticle

Prediction of Milling Deformation for Frame-Type Thin-Walled Parts Considering Workblank Initial Residual Stress and Milling Force

by Lijie Ma, Shijie Ba, Yu Zhang, Hongwen Liu, Leyang Li, Fei Gao, Faping Zhang and Junjin Ma

J. Manuf. Mater. Process. 2025, 9(5), 146; https://doi.org/10.3390/jmmp9050146 - 29 Apr 2025

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Abstract

Machining deformation is a key bottleneck that restricts the improvement of manufacturing accuracy of aviation thin-walled structural components, such as frames, beams, and wall panels. The initial residual stress of the workblank and the cutting load are the direct factors leading to machining [...] Read more.

Machining deformation is a key bottleneck that restricts the improvement of manufacturing accuracy of aviation thin-walled structural components, such as frames, beams, and wall panels. The initial residual stress of the workblank and the cutting load are the direct factors leading to machining deformation. Based on the initial residual stress measurement and the milling force test, a finite element prediction model for milling deformation of frame-type thin-walled parts with integrated consideration of initial residual stress and the milling force was established and experimentally verified in this study. Then, the influence of milling process factors, such as the frame processing sequence (FPS), the cutting path, and the single frame one-time removal depth (SFORD), on the milling deformation of frame-type parts was studied. The results showed that the established prediction model had high reliability and the prediction accuracy was improved by 6.7% compared with that when only considering the initial residual stress. A smaller machining deformation can be achieved through the use of the FPS to prioritize the width, direction, and symmetrical milling, as well as the inner loop cutting path, and the smaller SFORD. This study can provide a technical reference for the prediction and control of milling deformation of aviation thin-walled structural parts, especially frame-type thin-walled parts. Full article

(This article belongs to the Special Issue Advances in High-Performance Machining Operations)

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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

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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

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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

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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

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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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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

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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

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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

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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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J. Manuf. Mater. Process., Volume 9, Issue 5 (May 2025) – 25 articles

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