Journal of Manufacturing and Materials Processing

14 pages, 4754 KiB

Open AccessArticle

Optimizing the Material Extrusion Process for Investment Casting Mould Production

by Pablo Rodríguez-González, Pablo Zapico, Sofía Peláez-Peláez, María Ángeles Castro-Sastre and Ana Isabel Fernández-Abia

J. Manuf. Mater. Process. 2024, 8(6), 265; https://doi.org/10.3390/jmmp8060265 - 23 Nov 2024

Abstract

This study investigates the optimization of the Material Extrusion (MEX) process for producing polylactic acid (PLA) patterns used in investment casting moulds, specifically targeting the casting of non-ferrous alloys such as brass. Key MEX process parameters—layer thickness, wall thickness, infill density, and post-processing [...] Read more.

This study investigates the optimization of the Material Extrusion (MEX) process for producing polylactic acid (PLA) patterns used in investment casting moulds, specifically targeting the casting of non-ferrous alloys such as brass. Key MEX process parameters—layer thickness, wall thickness, infill density, and post-processing with dichloromethane vapour for surface enhancement—were systematically analyzed for their impact on mould quality. Results indicate that an optimized combination of MEX parameters yields moulds with high dimensional accuracy, low surface roughness, and minimal pattern residue within the mould cavity. These optimized moulds were subsequently used in brass casting, with the final cast parts evaluated for dimensional precision and surface finish. The study concludes that PLA patterns manufactured via optimized MEX parameters provide a precise, cost-effective, and easy-to-implement solution for industry applications. Additionally, this process is environmentally friendly and presents clear advantages over other pattern-making methods, offering a sustainable alternative for producing complex metal parts with reduced environmental impact. The findings underscore the significant role of post-processing in enhancing mould quality and, consequently, the quality of the cast parts. Full article

(This article belongs to the Special Issue Advances in Additive Manufacturing and Material Characterization Techniques)

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14 pages, 13014 KiB

Open AccessArticle

A Design Strategy for Surface Modification and Decarburization to Achieve Enhanced Mechanical Properties in Additively Manufactured Stainless Steel

by Soumya Sridar, Noah Sargent, Stephanie Prochaska, Mitra Shabani, Owen Hildreth and Wei Xiong

J. Manuf. Mater. Process. 2024, 8(6), 264; https://doi.org/10.3390/jmmp8060264 - 20 Nov 2024

Abstract

Post-processing of additively manufactured components, including the removal of support structures and the reduction in surface roughness, presents significant challenges. Conventional milling struggles to access internal cavities, while the Self-Terminating Etching Process (STEP) offers a promising solution. STEP effectively smooths surfaces and dissolves [...] Read more.

Post-processing of additively manufactured components, including the removal of support structures and the reduction in surface roughness, presents significant challenges. Conventional milling struggles to access internal cavities, while the Self-Terminating Etching Process (STEP) offers a promising solution. STEP effectively smooths surfaces and dissolves supports without substantial changes in geometry. However, it can lead to compositional changes and precipitation, affecting the material properties and necessitating a design strategy to mitigate them. In this study, STEP is applied to stainless steel 316L (SS316L) produced via laser powder bed fusion, reducing surface roughness from 7 to 2 μm. After STEP, the surface carbon exhibited a threefold increase, leading to the formation of M₂₃C₆ clusters. This significantly impacted the yield strength, resulting in a 37% reduction compared to the as-built condition. The key to overcoming this challenge was using computational simulations, which guided the determination of the decarburization conditions: 1000 °C for 60 min, ensuring maximum M₂₃C₆ dissolution and surface carbon reduction with minimal grain coarsening. Following these conditions, the yield strength of SS316L was restored to the level observed in the as-built condition. These findings underscore the potential of the proposed design strategy to enhance the mechanical performance of additively manufactured components significantly. Full article

(This article belongs to the Special Issue Advances in Additive Manufacturing and Material Characterization Techniques)

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23 pages, 7016 KiB

Open AccessArticle

Build Orientation-Driven Anisotropic Fracture Behaviour in Polymer Parts Fabricated by Powder Bed Fusion

by Karthik Ram Ramakrishnan and Jagan Selvaraj

J. Manuf. Mater. Process. 2024, 8(6), 263; https://doi.org/10.3390/jmmp8060263 - 20 Nov 2024

Abstract

Additive manufacturing (AM) enables fabricating intricate objects with complex geometries previously unattainable through conventional methods. This process encompasses various techniques, including powder bed fusion (PBF), such as selective laser sintering (SLS) and multi-jet fusion (MJF). These techniques involve selectively melting powdered polymer material, [...] Read more.

Additive manufacturing (AM) enables fabricating intricate objects with complex geometries previously unattainable through conventional methods. This process encompasses various techniques, including powder bed fusion (PBF), such as selective laser sintering (SLS) and multi-jet fusion (MJF). These techniques involve selectively melting powdered polymer material, predominantly utilizing engineering thermoplastics layer by layer to create solid components. Although their mechanical properties have been extensively characterised, very few works have addressed the influence of additive manufacturing on fracture behaviour. In this context, we present our work demonstrating the presence of anisotropy in fracture behaviour due to the build orientation as well as the PBF methods. To evaluate this anisotropy, the fracture behaviour of polyamide 12 polymer manufactured by SLS and MJF were investigated with experiments and numerical modelling of Mode I compact tension (CT) specimens. Experiments were monitored by digital image correlation (DIC) and infra-red thermography (IRT). Additionally, the fractured surfaces are analysed using scanning electron microscopy. Comparative analyses between SLS and MJF technologies unveiled dissimilar trends in mechanical strength, build-orientation effects, and fracture properties. Full article

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11 pages, 6390 KiB

Open AccessArticle

Development of Polymer Hydrophobic Surfaces Through Combined Laser Ablation and Hot Embossing Processes

by Esmaeil Ghadiri Zahrani, Amirmohmmad Fakharzadeh Jahromi and Bahman Azarhoushang

J. Manuf. Mater. Process. 2024, 8(6), 262; https://doi.org/10.3390/jmmp8060262 - 20 Nov 2024

Abstract

The development of hydrophobicity on polymer surfaces in mass production is one of the most critical challenges in the plastic industry. This paper deals with a novel combined hot embossing process in which femtosecond laser ablation is utilized to texture the embossing stamps. [...] Read more.

The development of hydrophobicity on polymer surfaces in mass production is one of the most critical challenges in the plastic industry. This paper deals with a novel combined hot embossing process in which femtosecond laser ablation is utilized to texture the embossing stamps. By controlling the process temperature and axial forces, the laser textures were transferred to polymer surfaces, successfully resulting in hydrophobicity. Four different polymers, including ABS, PP, PA, and PC, along with two different laser textures, namely ball and pyramid, were tested. The laser and hot embossing parameters under which the textures were transferred to the polymers are introduced. The critical micro- and nano-features of the transferred textures that resulted in high hydrophobic contact angles are also discussed. The results indicate that PP and ABS have higher contact angles, respectively, while under the given parameters, PA and PC did not exhibit hydrophobic surfaces. Full article

(This article belongs to the Topic Advanced Manufacturing and Surface Technology)

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17 pages, 8481 KiB

Open AccessReview

A Review of Magnetic Abrasive Finishing for the Internal Surfaces of Metal Additive Manufactured Parts

by Liaoyuan Wang, Yuli Sun, Zhongmin Xiao, Fanxuan Yang, Shijie Kang, Yanlei Liu and Dunwen Zuo

J. Manuf. Mater. Process. 2024, 8(6), 261; https://doi.org/10.3390/jmmp8060261 - 16 Nov 2024

Abstract

With the rapid development of high-end manufacturing industries such as aerospace and national defense, the demand for metal additive manufactured parts with complex internal cavities has been steadily increasing. However, the finishing of complex internal surfaces, especially for irregularly shaped parts, remains a [...] Read more.

With the rapid development of high-end manufacturing industries such as aerospace and national defense, the demand for metal additive manufactured parts with complex internal cavities has been steadily increasing. However, the finishing of complex internal surfaces, especially for irregularly shaped parts, remains a significant challenge due to their intricate geometries. Through a comparative analysis of common finishing methods, the distinctive characteristics and applicability of magnetic abrasive finishing (MAF) are highlighted. To meet the finishing needs of complex metal additive manufactured parts, this paper reviews the current research on magnetic abrasive finishing devices, processing mechanisms, the development of magnetic abrasives, and the MAF processes for intricate internal cavities. Future development trends in MAF for complex internal cavities in additive manufactured parts are also explored; these are (1) investigating multi-technology composite magnetic abrasive finishing equipment designed for complex internal surfaces; (2) studying the dynamic behavior of multiple magnetic abrasive particles in complex cavities and their material removal mechanisms; (3) developing high-performance magnetic abrasives suitable for demanding conditions; and (4) exploring the MAF process for intricate internal surfaces. Full article

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18 pages, 7690 KiB

Open AccessArticle

A Comparison of the Microstructure and Mechanical Properties of RSW and RFSSW Joints in AA6061-T4 for Automotive Applications

by Damon Gale, Taylor Smith, Yuri Hovanski, Kate Namola and Jeremy Coyne

J. Manuf. Mater. Process. 2024, 8(6), 260; https://doi.org/10.3390/jmmp8060260 - 14 Nov 2024

Abstract

To reduce vehicle weight and improve energy efficiency, automotive manufacturers are increasingly using aluminum body panels. However, the traditional joining method, Resistance Spot Welding (RSW), presents challenges like weld porosity and electrode degradation when used with aluminum. These issues have driven the industry [...] Read more.

To reduce vehicle weight and improve energy efficiency, automotive manufacturers are increasingly using aluminum body panels. However, the traditional joining method, Resistance Spot Welding (RSW), presents challenges like weld porosity and electrode degradation when used with aluminum. These issues have driven the industry to explore alternative, more effective methods for joining aluminum in vehicle manufacturing such as Refill Friction Stir Spot Welding (RFSSW). This research reports on a comparison of the microstructure and mechanical properties of welds made with RSW and RFSSW in AA6061-T4 automotive sheets. This comparison includes CT scanning, optical and SEM imaging, statistical microscopy, hardness testing, tensile testing, and fatigue testing. The results showed that RFSSW produced fully consolidated welds with a refined, equiaxed grain structure that outperformed RSW’s dendritic grain structure by as much as 73% in tensile testing and 2600% in fatigue testing. These results suggest that future designs utilizing RFSSW could incorporate fewer joints, reducing processing time, energy consumption, and tool wear. Cost studies also found that RFSSW consumes 2.5% of the energy that RSW does per joint, demonstrating that RFSSW is positioned as the preferred method for joining aluminum automotive sheets. Full article

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13 pages, 12590 KiB

Open AccessArticle

Stainless Steel 316L Fabricated by Fused Deposition Modeling Process: Microstructure, Geometrical and Mechanical Properties

by Maria Zaitceva, Anton Sotov, Anatoliy Popovich and Vadim Sufiiarov

J. Manuf. Mater. Process. 2024, 8(6), 259; https://doi.org/10.3390/jmmp8060259 - 14 Nov 2024

Abstract

Additive manufacturing (AM) methods are widely used to produce metal products. However, the cost of equipment for processes based on material melting is high. In this paper, a promising, less expensive method of producing metal products from metal-filled Ultrafuse 316L filament by FDM [...] Read more.

Additive manufacturing (AM) methods are widely used to produce metal products. However, the cost of equipment for processes based on material melting is high. In this paper, a promising, less expensive method of producing metal products from metal-filled Ultrafuse 316L filament by FDM was investigated. The aim of this work was to compare the debinding methods and investigate the microstructure, phase composition, and geometric and mechanical properties. The results showed that catalytic debinding can be replaced by thermal debinding as no significant effect on the structure and properties was found. In addition, a filament study was performed and data on the particle size distribution, morphology, and phase composition of the metal particles were obtained. Thermodynamic modeling was performed to better understand the phase distribution at the sintering stage. The δ-Fe fraction influencing the corrosion properties of the material was estimated. The conformity of geometric dimensions to the original 3D models was evaluated using 3D scanning. The applied printing and post-processing parameters allowed us to obtain a density of 98%. The material and technology represent a promising direction for applications in the field of lightweight engineering in the manufacturing of parts with bioinspired designs, shells, and sparse filler structures with useful porosity designs (like helicoidal structures). Full article

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24 pages, 6347 KiB

Open AccessArticle

Effect of Different Annealing Methods on ULTEM 9085 Parts Manufactured by Material Extrusion

by Javaid Butt, Habib Afsharnia, Md Ashikul Alam Khan and Vahaj Mohaghegh

J. Manuf. Mater. Process. 2024, 8(6), 258; https://doi.org/10.3390/jmmp8060258 - 14 Nov 2024

Abstract

A common practice of improving the performance of parts manufactured by material extrusion is annealing. In this work, ULTEM 9085 parts were subjected to three different annealing methods to compare their effectiveness in terms of dimensional stability, hardness, surface roughness, tensile strength, microstructure [...] Read more.

A common practice of improving the performance of parts manufactured by material extrusion is annealing. In this work, ULTEM 9085 parts were subjected to three different annealing methods to compare their effectiveness in terms of dimensional stability, hardness, surface roughness, tensile strength, microstructure and flexural strength. The annealing methods involved heating ULTEM 9085 parts inside an oven in three different ways: direct oven annealing by placing the parts on a tray, fluidized bed annealing with sharp sand surrounding the parts and sandwiching the parts between metal plates. Annealing for all three methods was conducted at temperatures of 180 °C, 190 °C and 200 °C with time intervals of 1 h, 2 h and 3 h. The results showed that direct oven annealing provides consistent results under all scenarios. Better dimensional accuracies were observed with fluidized bed annealing, and metal plate annealing is better suited to ensuring an improved surface finish and higher hardness values. For the tensile test, direct oven annealing yielded the most consistent and optimal results with an increase of up to 28.1% in tensile strength, whereas the other two methods performed better at lower temperatures. Direct oven annealing also led to improved ductility and higher elongation at break. Moreover, microstructural analysis of the fracture surfaces indicated enhanced coalescence for direct oven annealing. In terms of flexural testing, metal plate annealing proved to be more effective, with an increase of up to 13.9% in flexural strength. The other two methods demonstrated consistent results, with direct oven annealing showing slightly higher values compared with unannealed ULTEM 9085 samples. This work provides a useful comparison among different annealing methods that can be used to enhance the performance of ULTEM 9085 parts for different engineering applications. Full article

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12 pages, 2990 KiB

Open AccessArticle

The Effects of Cutting Parameters on Cutting Force and Tribological Properties of Machined Surface Under Dry Turning of AISI304L Austenitic Stainless Steel

by Gábor Kónya, Béla Csorba, Norbert Szabó and Zsolt F. Kovács

J. Manuf. Mater. Process. 2024, 8(6), 257; https://doi.org/10.3390/jmmp8060257 - 14 Nov 2024

Abstract

In this study, the effects of cutting speed and feed rate on the roughness parameters R_a, R_z, R_sk, R_ku, R_pk, R_vk, and A₂ were examined during machining with coated carbide [...] Read more.

In this study, the effects of cutting speed and feed rate on the roughness parameters R_a, R_z, R_sk, R_ku, R_pk, R_vk, and A₂ were examined during machining with coated carbide tools in a dry environment. The authors introduced the R_vk/R_pk ratio, a coefficient that facilitates a simpler evaluation of surface wear resistance. Specifically, if this ratio is greater than 1, the surface is more wear-resistant, while values less than 1 indicate a higher tendency for surface wear. The Taguchi OA method was used to analyze and identify the significance of technological parameters on output characteristics. Based on the results, it was established that feed rate has the greatest impact on all output characteristics. The highest cutting force was measured at a cutting speed of 60 m/min and a feed rate of 0.15 mm/rev, attributed to the fact that at lower cutting speeds, the base material does not soften while the cross-sectional area of the chip increases. To achieve the lowest R_a and R_z surface roughness, a cutting speed of 100 m/min and a feed rate of 0.05 mm/rev are recommended. If the goal is to enhance surface wear resistance and improve oil retention capability, machining with a cutting speed of 80–100 m/min and a feed rate of 0.15 mm/rev is advisable, as the coarser machining increases both the R_vk/R_pk ratio and the oil-retaining pocket size, which together improve the wear resistance of the machined surface. Full article

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20 pages, 21860 KiB

Open AccessArticle

Geometric and Mechanical Properties of Ti6Al4V Skeletal Gyroid Structures Produced by Laser Powder Bed Fusion for Biomedical Implants

by Cong Hou, Max Goris, Dries Rosseel, Bey Vrancken and Kathleen Denis

J. Manuf. Mater. Process. 2024, 8(6), 256; https://doi.org/10.3390/jmmp8060256 - 13 Nov 2024

Abstract

Skeletal gyroid structures possess promising applications in biomedical implants, owing to their smooth and continuously curved surfaces, open porosity, and customisable mechanical properties. This study simulated the geometric properties of Ti6Al4V skeletal gyroid structures, with relative densities ranging from 1.83% to 98.17%. The [...] Read more.

Skeletal gyroid structures possess promising applications in biomedical implants, owing to their smooth and continuously curved surfaces, open porosity, and customisable mechanical properties. This study simulated the geometric properties of Ti6Al4V skeletal gyroid structures, with relative densities ranging from 1.83% to 98.17%. The deformation behaviour of these structures was investigated through a combination of uniaxial compression tests and simulations, within a relative density range of 13.33% to 50% (simulation) and 15.19% to 41.69% (experimental tests). The results established explicit analytical correlations of pore size and strut diameter with the definition parameters of the structures, enabling precise control of these dimensions. Moreover, normalised Young’s modulus (ranging from 1.05% to 20.77% in simulations and 1.65% to 15.53% in tests) and normalised yield stress (ranging from 1.75% to 17.39% in simulations and 2.09% to 13.95% in tests) were found to be power correlated with relative density. These correlations facilitate the design of gyroid structures with low stiffness to mitigate the stress-shielding effect. The presence of macroscopic 45° fractures in the gyroid structures confirmed that the primary failure mechanism is induced by shear loads. The observed progressive failure and plateau region proved the bending-dominant behaviour and highlighted their excellent deformability. Additionally, the anisotropy of gyroid structures was confirmed through variations in stress and strain concentrations, deformation behaviour, and Young’s modulus under different loading directions. Full article

(This article belongs to the Special Issue Recent Advances in 3D Printing Technologies in Bioengineering with Selected Papers from the 29th Congress of the European Society of Biomechanics (ESB 2024))

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22 pages, 6236 KiB

Open AccessArticle

An Experimental Investigation into the Enhancement of Surface Quality of Inconel 718 Through Axial Ultrasonic Vibration-Assisted Grinding in Dry and MQL Environments

by Sreethul Das, Pandivelan Chinnaiyan, Joel Jayaseelan, Jeyapandiarajan Paulchamy, Andre Batako and Ashwath Pazhani

J. Manuf. Mater. Process. 2024, 8(6), 255; https://doi.org/10.3390/jmmp8060255 - 13 Nov 2024

Abstract

Ultrasonic vibration-assisted grinding (UVAG) has proven to be beneficial for grinding difficult-to-machine materials. This work attempts to enhance the grinding performance of Inconel 718 through a comprehensive study of UVAG characteristics. Grinding experiments were performed in both dry and Minimum Quantity Lubrication (MQL) [...] Read more.

Ultrasonic vibration-assisted grinding (UVAG) has proven to be beneficial for grinding difficult-to-machine materials. This work attempts to enhance the grinding performance of Inconel 718 through a comprehensive study of UVAG characteristics. Grinding experiments were performed in both dry and Minimum Quantity Lubrication (MQL) environments, and assessment of the grinding forces, specific energy, residual stress, and surface topography was done. A substantial reduction of both surface roughness and grinding force components was observed in UVAG compared to conventional grinding (CG). Utilizing UVAG with MQL at the maximum vibration amplitude led to a 64% reduction in tangential grinding force and a 51% decrease in roughness parameter, R_a, when compared to CG conducted in a dry environment. The high-frequency indentations of the abrasives in UVAG generated compressive residual stresses on the ground surface. Surface parameters pointed to uniform texture and SEM images showed widening of abrasive grain tracks on the workpiece surface during UVAG. The utilization of UVAG under MQL produced a synergistic impact and resulted in the lowest grinding forces, specific energy, and optimal surface quality among all the grinding conditions investigated. Overall analysis of the results indicated that the axial configuration of the vibration set-up is favorable for UVAG, and the high-frequency periodic separation-cutting characteristic of the process improves lubricating efficiency and grinding performance. Full article

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11 pages, 4564 KiB

Open AccessArticle

Managing Residual Heat Effects in Femtosecond Laser Material Processing by Pulse-on-Demand Operation

by Jaka Petelin, Matevž Marš, Jaka Mur and Rok Petkovšek

J. Manuf. Mater. Process. 2024, 8(6), 254; https://doi.org/10.3390/jmmp8060254 - 12 Nov 2024

Abstract

Femtosecond laser processing combines highly accurate structuring with low residual heating of materials, low thermal damage, and nonlinear absorption processes, making it suitable for the machining of transparent brittle materials. However, with high average powers and laser pulse repetition rates, residual heating becomes [...] Read more.

Femtosecond laser processing combines highly accurate structuring with low residual heating of materials, low thermal damage, and nonlinear absorption processes, making it suitable for the machining of transparent brittle materials. However, with high average powers and laser pulse repetition rates, residual heating becomes relevant. Here, we present a study of the femtosecond laser pulse-on-demand operation regime, combined with regular scanners, aiming to improve throughput and quality of processing regardless of the scanner’s capabilities. We developed two methods to define the needed pulse-on-demand trigger sequences that compensate for the initial accelerating scanner movements. The effects of pulse-on-demand operation were studied in detail using direct process monitoring with a fast thermal camera and indirect process monitoring with optical and topographical surface imaging of final structures, both showing clear advantages of pulse-on-demand operation in precision, thermal effects, and structure shape control. The ability to compensate for irregular scanner movement is the basis for simplified, cheaper, and faster femtosecond laser processing of brittle and heat-susceptible materials. Full article

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14 pages, 5716 KiB

Open AccessArticle

Improving the Quality of Reshaped EoL Components by Means of Accurate Metamodels and Evolutionary Algorithms

by Antonio Piccininni, Angela Cusanno, Gianfranco Palumbo, Giuseppe Ingarao and Livan Fratini

J. Manuf. Mater. Process. 2024, 8(6), 253; https://doi.org/10.3390/jmmp8060253 - 12 Nov 2024

Abstract

The reshaping of End-of-Life (EoL) components by means of the sheet metal forming process has been considered largely attractive, even from the social and economic point of view. At the same time, EoL parts can often be characterized by non-uniform thicknesses or alternation [...] Read more.

The reshaping of End-of-Life (EoL) components by means of the sheet metal forming process has been considered largely attractive, even from the social and economic point of view. At the same time, EoL parts can often be characterized by non-uniform thicknesses or alternation of work-hardened/undeformed zones as the result of the manufacturing process. Such heterogeneity can hinder a proper reshaping of the EoL part, and residual marks on the reformed blanks can still be present at the end of the reshaping step. In a previous analysis, the authors evaluated the effectiveness of reshaping a blank with a deep-drawn feature by means of the Sheet Hydroforming (SHF) process: it was demonstrated that residual marks were still present if the deep-drawn feature was located in a region not enough strained during the reshaping step. Starting from this condition and adopting a numerical approach, additional investigations were carried out, changing the profile of the load applied by the blank holder and the maximum oil pressure. Numerical results were collected in terms of overall strain severity and residual height of the residual marks from the deep-drawn feature at the end of the reshaping step. Data were then fitted by accurate Response Surfaces trained by means of interpolant Radial Basis Functions and anisotropic Kriging algorithms, subsequently used to carry out a virtual optimization managed by multi-objective evolutionary algorithms (MOGA-II and NSGA-II). Optimization results, subsequently validated via experimental trials, provided the optimal working conditions to achieve a remarkable reduction of the marks from the deep-drawn feature without the occurrence of rupture. Full article

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18 pages, 2833 KiB

Open AccessArticle

Performance Analysis of FFF-Printed Carbon Fiber Composites Subjected to Different Annealing Methods

by Javaid Butt, Md Ashikul Alam Khan, Muhammad Adnan and Vahaj Mohaghegh

J. Manuf. Mater. Process. 2024, 8(6), 252; https://doi.org/10.3390/jmmp8060252 - 11 Nov 2024

Abstract

Annealing is a popular post-process used to enhance the performance of parts made by fused filament fabrication. In this work, four different carbon-fiber-based composites were subjected to two different annealing methods to compare their effectiveness in terms of dimensional stability, surface roughness, tensile [...] Read more.

Annealing is a popular post-process used to enhance the performance of parts made by fused filament fabrication. In this work, four different carbon-fiber-based composites were subjected to two different annealing methods to compare their effectiveness in terms of dimensional stability, surface roughness, tensile strength, hardness, and flexural strength. The four materials include PLA-CF, PAHT-CF, PETG-CF, and ABS-CF. The annealing methods involved heating the printed composites inside an oven in two different ways: placed on a tray and fluidized bed annealing with sharp sand. Annealing was conducted for a one-hour time interval at different annealing temperatures selected as per the glass transition temperatures of the four materials. The results showed that oven annealing provides better results under all scenarios except dimensional stability. PETG-CF and ABS-CF composites were significantly affected by oven annealing with expansion along the z-axis as high 8.42% and 18% being observed for PETG-CF and ABS-CF, respectively. Oven annealing showed better surface finish due to controlled and uniform heating, whereas the abrasive nature of sand and contact with sand grains caused inconsistencies on the surface of the composites. Sand annealing showed comparable hardness values to oven annealing. For tensile and flexural testing, sand annealing showed consistent values for all cases but lower than those obtained by oven annealing. However, oven annealing values started to decrease at elevated temperatures for PETG-CF and ABS-CF. This work offers a valuable comparison by highlighting the limitations of conventional oven annealing in achieving dimensional stability. It provides insights that can be leveraged to fine-tune designs for optimal results when working with different FFF-printed carbon-fiber-based composites, ensuring better accuracy and performance across various applications. Full article

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14 pages, 5250 KiB

Open AccessArticle

Thermal Management of Friction-Drilled A356 Aluminum Alloy: A Study of Preheating and Drilling Parameters

by Ahmed Abdalkareem, Rasha Afify, Nadia Hamzawy, Tamer S. Mahmoud and Mahmoud Khedr

J. Manuf. Mater. Process. 2024, 8(6), 251; https://doi.org/10.3390/jmmp8060251 - 8 Nov 2024

Abstract

Friction drilling is a non-conventional process that generates heat through the interaction between a rotating tool and a workpiece, forming a hole with a bushing. In this study, the effect of the preheating temperature, rotational speed, and feed rate on the induced temperature [...] Read more.

Friction drilling is a non-conventional process that generates heat through the interaction between a rotating tool and a workpiece, forming a hole with a bushing. In this study, the effect of the preheating temperature, rotational speed, and feed rate on the induced temperature during the friction drilling of A356 aluminum alloy was investigated. This study aimed to analyze the influence of friction-drilling parameters on the thermal conditions in the induced bushing, where it focused on the relationship between preheating and the resulting heat generation. The analysis of variance (ANOVA) approach was carried out to optimize the friction-drilling parameters that contributed most to the induced temperature during the friction-drilling processing. Experiments were conducted at various preheating temperatures (100 °C, 150 °C, 200 °C), rotational speeds (2000 rpm, 3000 rpm, 4000 rpm), and feed rates (40 mm/min, 60 mm/min, 80 mm/min). The induced temperature during the process was recorded using an infrared camera, where the observed temperatures ranged from a minimum of 154.4 °C (at 2000 rpm, 60 mm/min, and 100 °C preheating) to a maximum of 366.8 °C (at 4000 rpm, 40 mm/min, and 200 °C preheating). The results show that preheating increased the peak temperature generated in the bushing during friction drilling, especially at lower rotational speeds. The rotational speed rise led to an increase in the induced temperature. However, the increase in the feed rate resulted in a decrease in the observed temperature. The findings provide insights into optimizing friction-drilling parameters for enhanced thermal management in A356 aluminum alloy. Full article

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17 pages, 8436 KiB

Open AccessArticle

Impact of Combined Zr, Ti, and V Additions on the Microstructure, Mechanical Properties, and Thermomechanical Fatigue Behavior of Al-Cu Cast Alloys

by Peng Hu, Kun Liu, Lei Pan and X.-Grant Chen

J. Manuf. Mater. Process. 2024, 8(6), 250; https://doi.org/10.3390/jmmp8060250 - 6 Nov 2024

Abstract

The effects of minor additions of the transition elements Zr, Ti, and V on the microstructure, mechanical properties, and out-of-phase thermomechanical fatigue behavior of 224 Al-Cu alloys were investigated. The results revealed that the introduction of the transition elements led to a refined [...] Read more.

The effects of minor additions of the transition elements Zr, Ti, and V on the microstructure, mechanical properties, and out-of-phase thermomechanical fatigue behavior of 224 Al-Cu alloys were investigated. The results revealed that the introduction of the transition elements led to a refined grain size and a finer and much denser distribution of θ″/θ′ precipitates compared to that of the base alloy, which enhanced the tensile strength but reduced the elongation at both room temperature and 300 °C. Constitutive analyses based on theoretical strength calculations indicated that precipitation strengthening was the primary mechanism contributing to the strength of both tested alloys at room temperature and 300 °C. The out-of-phase thermomechanical fatigue test results showed that the addition of transition elements caused a slight decrease in the fatigue lifetime, which was mainly attributed to the reduced ductility and higher peak tensile stress at low temperatures. During the fatigue process, the transition element-added alloy exhibited a lower coarsening ratio, indicating higher thermal stability, which mitigated the negative impact of the reduced ductility on the fatigue performance to some extent. Considering their various properties, the addition of Zr, Ti, and V is recommended to improve the overall performance of Al-Cu 224 cast alloys. Full article

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26 pages, 31631 KiB

Open AccessArticle

A Study of Fit and Friction Force as a Function of the Printing Process for FFF 3D-Printed Piston–Cylinder Assembly

by Philippe A. Passeraub, Quentin Allen, Elizabeth Clark, Michael Miles, Siddartha Berns, Maija Pearson, Sterling Allred, Jonah Brooks and Sylvain Hugon

J. Manuf. Mater. Process. 2024, 8(6), 249; https://doi.org/10.3390/jmmp8060249 - 6 Nov 2024

Abstract

Current 3D printing processes for polymer material extrusion are limited in their accuracy in terms of dimension, form, and position. For precise results, post-processing is recommended, like with assembled parts such as pistons and cylinders wherein axial mobility is desired with low friction [...] Read more.

Current 3D printing processes for polymer material extrusion are limited in their accuracy in terms of dimension, form, and position. For precise results, post-processing is recommended, like with assembled parts such as pistons and cylinders wherein axial mobility is desired with low friction force and limited radial play. When no post-processing step of the printed parts is accomplished, the fit and the friction force behavior are strongly dependent on the process performances. This paper presents a study on parameters of significance and their effects on sliding and running fits as well as their friction forces for fused filament fabrication of such assemblies. A series of experiments were performed with multiple factors and levels, including the position or layout of printed objects, their layer thickness, the material used, the use of aligned or random seam, and the printer type. Piston–cylinder pairs were printed, measured, assembled, and tested using a tensile test frame. A mathematical model was developed to describe the oscillating friction force behavior observed. This study presents the feasibility and limitations of producing piston–cylinder assemblies with reduced play and friction when using appropriate conditions. It also provides recommendations to obtain and better control a desired running and sliding fit. Full article

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12 pages, 7783 KiB

Open AccessArticle

Influence of Interpass Temperature on the Simulated Coarse-Grained Heat-Affected Zone of a Circumferentially Welded 2.25Cr-1Mo Steel Pipe Joint

by Paulo Henrique Grossi Dornelas, João da Cruz Payão Filho, Victor Hugo Pereira Moraes e Oliveira and Francisco Werley Cipriano Farias

J. Manuf. Mater. Process. 2024, 8(6), 248; https://doi.org/10.3390/jmmp8060248 - 6 Nov 2024

Abstract

To reduce manufacturing costs, energy companies aim to maximize the deposition rate during welding operations by increasing the interpass temperature (IT), thereby minimizing the cooling time. However, IT can significantly affect weldment performance, particularly its Charpy V-notch (CVN) impact energy (toughness). The present [...] Read more.

To reduce manufacturing costs, energy companies aim to maximize the deposition rate during welding operations by increasing the interpass temperature (IT), thereby minimizing the cooling time. However, IT can significantly affect weldment performance, particularly its Charpy V-notch (CVN) impact energy (toughness). The present study investigates the effect of increasing IT beyond the limit specified by the ASME B31.3 (315 °C) on the CVN impact energy (−30 °C) of the simulated coarse-grained heat-affected zone (CGHAZ) of a 2.25Cr-1Mo steel submerged arc welded (SAW). The CGHAZ thermal cycles were obtained through finite element method simulations and physically replicated using a Gleeble machine. The increase in IT beyond the ASME-specified limit significantly reduces the CVN impact energy of the CGHAZ. However, the values obtained remained above the minimum required threshold (NORSOK M630, 42 J). The main effect of increased IT was grain coarsening. Additionally, an inverse linear relationship was observed between effective grain size (EGS) and CVN impact energy. The steel’s microstructure showed non-significant sensitivity to variations in IT within the studied range. These findings suggest that, under the conditions studied, increasing IT could be a viable option for optimizing production by reducing welding time and potentially lowering costs. Full article

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23 pages, 3823 KiB

Open AccessArticle

Machining-Induced Burr Suppression in Edge Trimming of Carbon Fibre-Reinforced Polymer (CFRP) Composites by Tool Tilting

by Tamás Sándor Tima and Norbert Geier

J. Manuf. Mater. Process. 2024, 8(6), 247; https://doi.org/10.3390/jmmp8060247 - 5 Nov 2024

Abstract

Several challenges arise during edge trimming of carbon fibre-reinforced polymer (CFRP) composites, such as the formation of machining-induced burrs and delamination. In a recent development, appropriate-quality geometric features in CFRPs can be machined using special cutting tools and optimised machining parameters. However, these [...] Read more.

Several challenges arise during edge trimming of carbon fibre-reinforced polymer (CFRP) composites, such as the formation of machining-induced burrs and delamination. In a recent development, appropriate-quality geometric features in CFRPs can be machined using special cutting tools and optimised machining parameters. However, these suitable technologies quickly become inappropriate due to the accelerated tool wear. Therefore, the main aim of our research was to find a novel solution for maintaining the machined edge quality even if the tool condition changed significantly. We developed a novel mechanical edge-trimming technology inspired by wobble milling, i.e., the composite plate compression is governed by the proper tool tilting. The effectiveness of the novel technology was tested through mechanical machining experiments and compared with that of conventional edge-trimming technology. Furthermore, the influences of the tool tilting angle and the permanent chamfer size on the burr characteristics were also investigated. A one-fluted solid carbide end mill with a helix angle of 0° was applied for the experiments. The machined edges were examined trough stereomicroscopy and scanning electron microscopy. The images were evaluated through digital image processing. Our results show that multi-axis edge-trimming technology produces less extensive machining-induced burrs than conventional edge trimming by an average of 50%. Furthermore, we found that the tool tilting angle has a significant impact on burr size, while permanent chamfer does not influence it. These findings suggest that multi-axis edge trimming offers a strong alternative to conventional methods, especially when using end-of-life cutting tools, and highlight the importance of selecting the optimal tool tilting angle to minimize machining-induced burrs. Full article

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Journal of Manufacturing and Materials Processing

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