Topic Editors

Department of Industrial Engineering and Mathematical Sciences, Università Politecnica delle Marche, Via Brecce Bianche 12, 60131 Ancona, Italy
Department of Industrial, Electronic and Mechanical Engineering, Università degli Studi Roma Tre, Via della Vasca Navale, 79, Rome, Italy

Additive Manufacturing: Design, Opportunities, and Applications

Abstract submission deadline
closed (31 March 2023)
Manuscript submission deadline
closed (30 June 2023)
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64648

Topic Information

Dear Colleagues,

Additive manufacturing (AM), one of the nine enabling technologies of Industry 4.0, is experiencing rapid growth. Today, there are no industrial sectors that have not employed AM (e.g., aerospace, biomedical, automotive, energy, electronics, cultural heritage, contruction). Nevertheless, the implementation of AM technologies by industries is still limited compared to their intrinsic potential. The main challenges that limit the adoption of such technologies are lack of skills (need to train engineers capable of designing and managing these new technologies), sustainability of new processes (need to develop cost and environmental models capable of considering economic and environmental sustainability of AM processes and related supply chain) and design (need for innovative design paradigms and design for additive manufacturing (DfAM) software tools).

ASTM ISO/ASTM52910 offers requirements, guidelines, and recommendations for using AM in product design. However, specific methodologies and methods should be conceived to address the peculiar needs of the abovementioned industrial sectors. In recent years, DfAM software tools have advanced rapidly, allowing for the prediction and thus optimizing design for manufacturing. Simulation systems are increasingly supporting designers and production technologists in identifying problems before 3D printing. Nevertheless, designers are still not fully supported by adequate, easy-to-use, and integrated DfAM tools. DfAM methods and tools continuously evolve to manage new production technologies and materials and support design engineers adopting AM.

Future trends that this topic shall address are:

  • Methodologies to support designers in disruptive/innovative rather than incremental design;
  • AM for improving environmental sustainability; methods to evaluate environmental sustainability for multicriteria decision making, product remanufacturing, etc.;
  • Adoption of life cycle costing and assessment approaches to evaluate the sustainability of AM;
  • Extension of and updates to DfAM rules related to the emerging manufacturing technologies and innovative materials;
  • Characterization of complex lattice structures;
  • Improvements to simulation software tools for accurately predicting product performances;
  • Software tools to manage multiple materials, metamaterial design, multiple function design, and multiscalel
  • Knowledge-based 3D CAD systems to automatically model optimized AM shapes;
  • Increased adoption of AM and definition of DfAM rules for thermofluid, optical, and electronic applications.

Dr. Marco Mandolini
Dr. Paolo Cicconi
Topic Editors

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Applied Sciences
applsci
2.7 4.5 2011 16.9 Days CHF 2400
Journal of Manufacturing and Materials Processing
jmmp
3.2 5.5 2017 14.2 Days CHF 1800
Materials
materials
3.4 5.2 2008 13.9 Days CHF 2600
Metals
metals
2.9 4.4 2011 15 Days CHF 2600
Polymers
polymers
5.0 6.6 2009 13.7 Days CHF 2700

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Published Papers (36 papers)

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21 pages, 74169 KiB  
Article
Material Extrusion to Manufacture Carbide-Based Advanced Cutting Tools
by Gonçalo Oliveira, Ana Senos, Cristina Fernandes, Daniel Figueiredo and Teresa Vieira
Materials 2023, 16(21), 6902; https://doi.org/10.3390/ma16216902 - 27 Oct 2023
Viewed by 871
Abstract
Material extrusion (MEX) allows for the production of advanced cutting tools with new internal cooling systems, which are suitable for new machining equipment. To produce cutting tools via this process, hardmetal and cermet feedstock must be prepared for the extrusion of 3D printing [...] Read more.
Material extrusion (MEX) allows for the production of advanced cutting tools with new internal cooling systems, which are suitable for new machining equipment. To produce cutting tools via this process, hardmetal and cermet feedstock must be prepared for the extrusion of 3D printing filaments. After shaping the 3D object (green), debinding and sintering must be performed to achieve densification. Defects and microstructural heterogeneities were studied according to the powder material. The present study shows that, although MEX is a viable solution for hardmetals, it needs to produce homogeneous filaments for cermets. The WC-Co bulk microstructures versus hardness were similar to the ones that were measured with pressing and sintering. While cermet (Ti(CN)/WC-Ni/Co) microstructures were heterogeneous, their hardness, when compared with that from the pressing and sintering manufacturing process, decreased significantly. Full article
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9 pages, 3527 KiB  
Communication
The Effect of IMCs and Segregation on the Microstructure and Mechanical Properties of β-Type Titanium Alloys
by Xi-Long Ma, Bo-Wen Jia, Guo-Quan Nie, Zhi-Feng Shang, Bin-Bin Fu and He Ren
Metals 2023, 13(10), 1676; https://doi.org/10.3390/met13101676 - 30 Sep 2023
Viewed by 556
Abstract
Two new β-type titanium (β-Ti) alloys of Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al and Ti-15.6Cr-12Mn-3.3Zr were designed with the same bond order value 2.79 and different d-orbital energy level values of 2.28 and 2.16, respectively. The effect of intermetallic compounds (IMCs) and the segregation behaviors of β-Ti alloys [...] Read more.
Two new β-type titanium (β-Ti) alloys of Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al and Ti-15.6Cr-12Mn-3.3Zr were designed with the same bond order value 2.79 and different d-orbital energy level values of 2.28 and 2.16, respectively. The effect of intermetallic compounds (IMCs) and the segregation behaviors of β-Ti alloys were discussed by adding excessive and normal alloying elements to alloys under both as-cast and solution-treated conditions. The mono-β phase in the Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al alloy and β+intermetallic compounds (IMCs) in the Ti-15.6Cr-12Mn-3.3Zr alloy were identified and observed. The as-cast and solution-treated alloys showed their ultimate tensile strength and fracture strain; these were 982 and 1002 MPa, with 9.82 and 9.89% for Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al, and 448 and 296 MPa, with 0.12 and 0.11% for Ti-15.6Cr-12Mn-3.3Zr, respectively. Moreover, the Vickers hardness values of the as-cast and solution-treated alloys were 345 and 355 for Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al, and 422 and 466 for Ti-15.6Cr-12Mn-3.3Zr, respectively. Full article
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25 pages, 3848 KiB  
Review
Additive Manufacturing in Australian Small to Medium Enterprises: Vat Polymerisation Techniques, Case Study and Pathways to Industry 4.0 Competitiveness
by Kimberley Rooney, Yu Dong, Alokesh Pramanik and Animesh Kumar Basak
J. Manuf. Mater. Process. 2023, 7(5), 168; https://doi.org/10.3390/jmmp7050168 - 14 Sep 2023
Cited by 1 | Viewed by 1899
Abstract
The advent of additive manufacturing (AM) in Australian small and medium-sized enterprises offers the direct benefits of time-saving and labour cost-effectiveness for Australian manufacturing to be highly competitive in global markets. Australian local businesses can tailor their products to a diverse range of [...] Read more.
The advent of additive manufacturing (AM) in Australian small and medium-sized enterprises offers the direct benefits of time-saving and labour cost-effectiveness for Australian manufacturing to be highly competitive in global markets. Australian local businesses can tailor their products to a diverse range of customers with a quicker lead time on the sophisticated design and development of products under good quality control in the whole advanced manufacturing process. This review outlines typical AM techniques used in Australian manufacturing, which consist of vat polymerisation (VP), environmentally friendly AM, and multi-material AM. In particular, a practical case study was also highlighted in the Australian jewellery industry to demonstrate how manufacturing style is integrated into their manufacturing processes for the purpose of reducing lead time and cost. Finally, major obstacles encountered in AM and future prospects were also addressed to be well positioned as a key player in the revolutionised Industry 4.0. Full article
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14 pages, 4942 KiB  
Article
Moisture Effects on Qualities and Properties of Laser Powder Bed Fusion (LPBF) Additive Manufacturing of As-Built 17-4PH Stainless Steel Parts
by Taehwan Kim, Min-Kyeom Kim, Yongjian Fang and Jonghwan Suhr
Metals 2023, 13(9), 1550; https://doi.org/10.3390/met13091550 - 03 Sep 2023
Cited by 1 | Viewed by 1278
Abstract
Laser powder bed fusion (LPBF) has the advantages of high resolution and geometric freedom but can be susceptible to process failures and defects caused by inappropriate process parameters and powder conditions. This study aims to reveal and quantify the moisture effect on the [...] Read more.
Laser powder bed fusion (LPBF) has the advantages of high resolution and geometric freedom but can be susceptible to process failures and defects caused by inappropriate process parameters and powder conditions. This study aims to reveal and quantify the moisture effect on the qualities and properties of as-built parts with various process parameters. The results showed that the density was decreased by 7.86% with humid powder (60.0% relative humidity (RH)) compared to dry powder (3.4%RH). Expectedly, the observed low density led to the property degradation in the hardness, yield strength (YS), and ultimate tensile strength (UTS) of the humid powder by 11.7, 15.02, and 21.25%, respectively, compared to that of dry powder (3.4%RH). Interestingly, the elongation at break of the parts fabricated with humid powder (60.0%RH) was increased by 2.82%, while their YS and UTS were decreased significantly. It seems that the water molecules on the powder surface hindered the reaction between the N2 shielding gas and melted powder, which resulted in the reduction in the austenite (γ) phase by up to 4.05 wt.%. This could be mainly responsible for the decrease in both the YS and UTS of the humid powder by approximately 100 and 150 MPa, respectively. This study demonstrates that the moisture of the metal powder used for LPBF should be carefully controlled to ensure desirable as-built qualities and properties. Full article
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13 pages, 7868 KiB  
Article
Development and Fabrication of Biocompatible Ti-Based Bulk Metallic Glass Matrix Composites for Additive Manufacturing
by Po-Sung Chen, Pei-Hua Tsai, Tsung-Hsiung Li, Jason Shian-Ching Jang, Jacob Chih-Ching Huang, Che-Hsin Lin, Cheng-Tang Pan and Hsuan-Kai Lin
Materials 2023, 16(17), 5935; https://doi.org/10.3390/ma16175935 - 30 Aug 2023
Cited by 2 | Viewed by 692
Abstract
Ti-based metallic glasses have a high potential for implant applications. The feasibility of a new biocompatible Ti-based bulk metallic glass composite for selective laser melting (SLM) had been examined. Therefore, it is necessary to design a high-glass-forming-ability Ti-based metallic glass (∆Tx = [...] Read more.
Ti-based metallic glasses have a high potential for implant applications. The feasibility of a new biocompatible Ti-based bulk metallic glass composite for selective laser melting (SLM) had been examined. Therefore, it is necessary to design a high-glass-forming-ability Ti-based metallic glass (∆Tx = 81 K, γ = 0.427, γm = 0.763), to fabricate a partial glass-formable spherical powder (the volume fraction of the amorphous phase in the atomized Ti-based powders being 73% [size < 25 μm], 61% [25–37 μm], and 50% [37–44 μm]), and establish an SLM parameter (a scan rate of 600 mm/s, a power of 120 W, and an overlap of 10%). The Ti42Zr35Si5Co12.5Sn2.5Ta3 bulk metallic glass composite was successfully fabricated through SLM. This study demonstrates that the TiZrSiCoSnTa system constitutes a promising basis for the additive manufacturing process in terms of preparing biocompatible metallic glass composites into complicated graded foam shapes. Full article
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16 pages, 8144 KiB  
Article
Influence of Carbon on Additively Manufactured Ti-6Al-4V
by Kerstin Winkler, Paul Seidel, Andre Danzig, Lothar Kroll and Andreas Undisz
J. Manuf. Mater. Process. 2023, 7(4), 134; https://doi.org/10.3390/jmmp7040134 - 26 Jul 2023
Viewed by 1135
Abstract
In this study, the Ti-6Al-4V powder material for additive manufacturing was mixed with amorphous carbon and processed by powder bed fusion using a laser beam. The specimens were subjected to mechanical and microstructural analyses to investigate the impact of the organic constituent that [...] Read more.
In this study, the Ti-6Al-4V powder material for additive manufacturing was mixed with amorphous carbon and processed by powder bed fusion using a laser beam. The specimens were subjected to mechanical and microstructural analyses to investigate the impact of the organic constituent that may become introduced unintentionally as an impurity along the powder handling chain. It is documented that hardness and tensile strength increase with increasing carbon content up to 0.2 wt.%. Above this carbon concentration, extensive crack formation in the samples prevents successful procession. Full article
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14 pages, 5680 KiB  
Article
Lauroylated, Acetylated, and Succinylated Agave tequilana Fructans Fractions: Structural Characterization, Prebiotic, Antibacterial Activity and Their Effect on Lactobacillus paracasei under Gastrointestinal Conditions
by Dafne I. Díaz-Ramos, Rosa I. Ortiz-Basurto, Oscar García-Barradas, Martina A. Chacón-López, Efigenia Montalvo-González, Luz A. Pascual-Pineda, Uri Valenzuela-Vázquez and Maribel Jiménez-Fernández
Polymers 2023, 15(14), 3115; https://doi.org/10.3390/polym15143115 - 21 Jul 2023
Cited by 2 | Viewed by 893
Abstract
The effect of chemical modification of fractions of native agave fructans (NAF), high performance (HPAF), and a high degree of polymerization (HDPAF) by lauroylation, acetylation, and succinylation reactions on their prebiotic activity, antibacterial properties were evaluated and survival of L. paracasei in a [...] Read more.
The effect of chemical modification of fractions of native agave fructans (NAF), high performance (HPAF), and a high degree of polymerization (HDPAF) by lauroylation, acetylation, and succinylation reactions on their prebiotic activity, antibacterial properties were evaluated and survival of L. paracasei in a simulated gastrointestinal system. The characterization of the reactions was confirmed by NMR and FTIR. The lauroylated and succinylated fructan fractions showed higher antibacterial activity against pathogenic bacteria such as Escherichia coli, Enterococcus faecalis and Staphylococcus aureus than the unmodified ones. Analyses with L. paracasei showed that the acetylated fructan fractions had a greater prebiotic effect, and simulated gastrointestinal tests demonstrated that the acetylated and succinylated fractions favored the survival of L. paracasei during the gastrointestinal phase. The effect of modifying the agave fructans fractions on the evaluated properties depended on the structure, size, and polarity of each incorporated functional group, as well as the degree of polymerization and substitution of each fraction. These results show that the chemical modification of the fructan fractions analyzed improves their functional properties, offering an alternative in the food and pharmaceutical industry. Full article
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23 pages, 4328 KiB  
Article
Modeling of Energy Consumption and Print Time for FDM 3D Printing Using Multilayer Perceptron Network
by Mohamed Achraf El youbi El idrissi, Loubna Laaouina, Adil Jeghal, Hamid Tairi and Moncef Zaki
J. Manuf. Mater. Process. 2023, 7(4), 128; https://doi.org/10.3390/jmmp7040128 - 07 Jul 2023
Viewed by 1481
Abstract
Given the recognized advantages of additive manufacturing (AM) printing systems in comparison with conventional subtractive manufacturing systems, AM technology has become increasingly adopted in 3D manufacturing, with usage rates increasing dramatically. This strong growth has had a significant and direct impact not only [...] Read more.
Given the recognized advantages of additive manufacturing (AM) printing systems in comparison with conventional subtractive manufacturing systems, AM technology has become increasingly adopted in 3D manufacturing, with usage rates increasing dramatically. This strong growth has had a significant and direct impact not only on energy consumption but also on manufacturing time, which in turn has generated significant costs. As a result, this problem has attracted the attention of industry actors and the research community, and several studies have focused on predicting and reducing energy consumption and additive manufacturing time, which has become one of the main objectives of research in this field. However, there is no effective model yet for predicting and optimizing energy consumption and printing time in a fused deposition modeling (FDM) process while taking into account the correct part orientation that minimizes both of these costs. In this paper, a neural-network-based model has been proposed to solve this problem using experimental data from isovolumetrically shaped mechanical parts. The data will serve as the basis for proposing the appropriate model using a specific methodology based on five performance criteria with the following statistical values: R2-squared > 99%, explained variance > 99%, MAE < 0.99%, MSE < 0.02% and RMSE < 1.36%. These values show just how effective the proposed model will be in estimating energy consumption and FDM printing time, taking into account the best choice of part orientation for the lowest cost. This model provides a global understanding of the primary energy and time requirements for manufacturing while also improving the system’s cost efficiency. The results of this work can be extended and applied to other additive manufacturing processes in future work. Full article
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18 pages, 15552 KiB  
Article
Influence of Ni Contents on Microstructure and Mechanical Performance of AlSi10Mg Alloy by Selective Laser Melting
by Hui Wang, Like He, Qingyong Zhang and Yiqing Yuan
Materials 2023, 16(13), 4679; https://doi.org/10.3390/ma16134679 - 28 Jun 2023
Cited by 5 | Viewed by 1092
Abstract
To improve the tensile strength and wear resistance of AlSi10Mg alloys, a novel in situ synthesis method of selective laser melting (SLM) was used to fabricate the Ni-reinforced AlSi10Mg samples. The eutectic Si networks formed around the α-Al crystals by diffusion and [...] Read more.
To improve the tensile strength and wear resistance of AlSi10Mg alloys, a novel in situ synthesis method of selective laser melting (SLM) was used to fabricate the Ni-reinforced AlSi10Mg samples. The eutectic Si networks formed around the α-Al crystals by diffusion and transportation via Marangoni convection in the SLM process. Moreover, the XRD and TEM results verified that the Al3Ni nanoparticles were created by the in situ reaction of the Ni and aluminum matrix in the Ni/AlSi10Mg samples. Therefore, the microstructure of the Ni-containing alloys was constituted by the α-Al + Si network + Al3Ni phases. The dislocations accumulated at the continuous Si network boundaries and cannot transmit across the dislocation walls inside the Si network. SEM results revealed that the continuity and size of eutectic Si networks can be tailored by adjusting the Ni contents. Furthermore, the Al matrix also benefited from the Al3Ni nanoparticles against the dislocation movement due to their excellent interfacial bonding. The 3Ni-AlSi10Mg sample exhibited high mechanical properties due to the continuous Si networks and Al3Ni nanoparticles. The tensile strength, elongation, Vickers hardness, friction coefficient, and wear volumes of the 3Ni-AlSi10Mg samples were 401.15 ± 7.97 MPa, 6.23 ± 0.252%, 144.06 ± 0.81 HV, 0.608, 0.11 mm3, respectively, which outperformed the pure AlSi10Mg samples (372.05 ± 1.64 MPa, 5.84 ± 0.269%, 123.22 ± 1.18 HV, 0.66, and 0.135 mm3). Full article
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15 pages, 8319 KiB  
Article
A Material-Recycling Unit for the Fused Deposition Modelling of Three-Dimensional Printing Systems
by Mohammed Nuwaid Nattukallingal, Ziying Ran and Ahmed Abass
Appl. Sci. 2023, 13(13), 7515; https://doi.org/10.3390/app13137515 - 26 Jun 2023
Viewed by 1667
Abstract
Fused deposition modelling (FDM) three-dimensional (3D) printing technology is one of the most common additive manufacturing (AM) technologies due to the relatively low cost of the printing units and materials. Although cost-effective, this technology is not conceived to convert 100% of the raw [...] Read more.
Fused deposition modelling (FDM) three-dimensional (3D) printing technology is one of the most common additive manufacturing (AM) technologies due to the relatively low cost of the printing units and materials. Although cost-effective, this technology is not conceived to convert 100% of the raw material into a complete product, creating a potential plastic waste problem. To recycle the plastic waste from the FDM machine into reusable filaments, the concept of a 3D printer material-recycling machine (3DP-MRM) was developed using CREO Parametric 9.0 software. A prototype with four systems, including a spooler system, extruder system, display system, and filament-positioning system, was manufactured in-house with complete run experiments. The tests of the 3DP-MRM were applied, and the machine worked successfully among all the designed functions with minor issues. Full article
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21 pages, 17290 KiB  
Article
In Situ Analysis of Curling Defects in Powder Bed Fusion of Polyamide by Simultaneous Application of Laser Profilometry and Thermal Imaging
by Victor Klamert, Lukas Schiefermair, Mugdim Bublin and Andreas Otto
Appl. Sci. 2023, 13(12), 7179; https://doi.org/10.3390/app13127179 - 15 Jun 2023
Cited by 1 | Viewed by 1103
Abstract
Additive manufacturing (AM) is one of the key technologies in the global manufacturing market within various application sectors. The unique capabilities of AM enable high structural and part complexity, low material waste, and benefits in productivity by reducing design cycles and time to [...] Read more.
Additive manufacturing (AM) is one of the key technologies in the global manufacturing market within various application sectors. The unique capabilities of AM enable high structural and part complexity, low material waste, and benefits in productivity by reducing design cycles and time to market. Efficient real-time quality control is still an important challenge in AM. In this paper, a real-time and in situ approach for monitoring the process in powder bed fusion of polyamide (PBF-LB/P/PA12) is proposed using the simultaneous application of two individual sensors, enabling the overlay and direct comparison of independent output data. An industrial grade laser profilometer and a thermal infrared (IR) camera were successfully integrated into a commercial system for PBF-LB/P. Artificially created curling defects were induced in a reproducible way by the manipulation of process parameters. The radiometric data was evaluated and processed into 3D topology and profile measurements to highlight peaks and curling progression. The results measured using different powder bed conditions were contrasted with corresponding thermographic data to prove the thermal visibility of curling and the influence of inhomogeneous temperature distribution on geometrical powder surface defects. The experimental setup enables the measuring of the entire powder bed surface inside the machine, with no limitations to sub-areas. Results indicate the measurable presence of curling and related temperature influences. When curling reached maximum values, inverted warpage into the negative z-direction was detected at part center as a further effect. These results can be used for improving real-time quality control in AM. Full article
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14 pages, 12913 KiB  
Article
Effect of Infill Pattern on Impact Toughness, Microstructure, and Surface Roughness of Inconel 625 Built via Filament-Based Material Extrusion Additive Manufacturing
by Gandjar Kiswanto, Ahmad Kholil and Jos Istiyanto
J. Manuf. Mater. Process. 2023, 7(3), 114; https://doi.org/10.3390/jmmp7030114 - 11 Jun 2023
Cited by 3 | Viewed by 1709
Abstract
Filament-based material extrusion additive manufacturing (FMEAM) is an additive manufacturing technique that uses 3D printing. Additive manufacturing could build parts with infill variations. Solid or triangular infill pattern could be selected as needed. The solid pattern will have the maximum material volume, while [...] Read more.
Filament-based material extrusion additive manufacturing (FMEAM) is an additive manufacturing technique that uses 3D printing. Additive manufacturing could build parts with infill variations. Solid or triangular infill pattern could be selected as needed. The solid pattern will have the maximum material volume, while the triangular pattern will contain a triangular lattice structure that fills the voids in the volume so the material requirement is reduced. This is valuable in optimizing the requirements of metallic materials for mechanical properties without changing the surface shape. The alloy Inconel 625, which is very popular in the aerospace industry have been developed as a feed material of FMEAM. However, for developing rotating parts, such as turbine blades, impact toughness, surface roughness and microstructure need to be investigated. This research was conducted to determine the effect of the infill pattern on the impact toughness, morphology of surface fracture, microstructure of side surface and surface roughness with Inconel 625 material built using FMEAM. The Charpy impact test, s ASTM 23, with v-notch testing method and SEM with EDS were performed. The results showed that the impact toughness for solids was higher than the value for the triangular infill pattern. It was discovered that the cavities in the triangular lattice structure within the specimen reduced the impact toughness to 57.6%. Micropores and residual polymer trapped on the surface reduce impact toughness. However, the same surface shape on solid and triangular infill patterns with surface roughness of 2.44 and 10.03 µm is still feasible for manufacture. Full article
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16 pages, 9584 KiB  
Article
In Situ Inclusion Detection and Material Characterization in an Electron Beam Powder Bed Fusion Process Using Electron Optical Imaging
by Martin Gardfjell, Marcel Reith, Martin Franke and Carolin Körner
Materials 2023, 16(12), 4220; https://doi.org/10.3390/ma16124220 - 07 Jun 2023
Cited by 1 | Viewed by 894
Abstract
Electron Beam Powder Bed Fusion (PBF-EB) is an Additive Manufacturing (AM) method that utilizes an electron beam to melt and consolidate metal powder. The beam, combined with a backscattered electron detector, enables advanced process monitoring, a method termed Electron Optical Imaging (ELO). ELO [...] Read more.
Electron Beam Powder Bed Fusion (PBF-EB) is an Additive Manufacturing (AM) method that utilizes an electron beam to melt and consolidate metal powder. The beam, combined with a backscattered electron detector, enables advanced process monitoring, a method termed Electron Optical Imaging (ELO). ELO is already known to provide great topographical information, but its capabilities regarding material contrast are less studied. In this article the extents of material contrast using ELO are investigated, focusing mainly on identifying powder contamination. It will be shown that an ELO detector is capable of distinguishing a single 100 μm foreign powder particle, during an PBF-EB process, if the backscattering coefficient of the inclusion is sufficiently higher than its surroundings. Additionally, it is investigated how the material contrast can be used for material characterization. A mathematical framework is provided to describe the relationship between the signal intensity in the detector and the effective atomic number Zeff of the imaged alloy. The approach is verified with empirical data from twelve different materials, demonstrating that the effective atomic number of an alloy can be predicted to within one atomic number from its ELO intensity. Full article
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22 pages, 2673 KiB  
Article
Additive Manufacturing in Bespoke Interactive Devices—A Thematic Analysis
by Philip Farrugia, Glenn Cassar, Pierre Vella, Edward Abela, Andrew Wodehouse and Francesco Tamburrino
Appl. Sci. 2023, 13(11), 6627; https://doi.org/10.3390/app13116627 - 30 May 2023
Viewed by 1113
Abstract
Additive Manufacturing (AM) facilitates product development due to the various native advantages of AM when compared to traditional manufacturing processes. Efficiency, customisation, innovation, and ease of product modifications are a few advantages of AM. This manufacturing process can therefore be applied to fabricate [...] Read more.
Additive Manufacturing (AM) facilitates product development due to the various native advantages of AM when compared to traditional manufacturing processes. Efficiency, customisation, innovation, and ease of product modifications are a few advantages of AM. This manufacturing process can therefore be applied to fabricate customisable devices, such as bespoke interactive devices for rehabilitation purposes. In this context, a two-day workshop titled Design for Additive Manufacturing: Future Interactive Devices (DEFINED) was held to discuss the design for AM issues encountered in the development of an innovative bespoke controller and supporting platform, in a Virtual Reality (VR)-based environment, intended for people with limited dexterity in their hands. The workshop sessions were transcribed, and a thematic analysis was carried out to identify the main topics discussed. The themes were Additive Manufacturing, Generative Design Algorithms, User-Centred Design, Measurement Devices for Data Acquisition, Virtual Reality, Augmented Reality, and Haptics. These themes were then discussed in relation to the available literature. The main conclusion of this workshop was that a coherent design for AM tools is needed by designers to take AM considerations throughout the design process, since they lack the AM knowledge required to develop bespoke interactive devices. Full article
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2 pages, 593 KiB  
Correction
Correction: Dimopoulos et al. Multi-Response Optimization of Ti6Al4V Support Structures for Laser Powder Bed Fusion Systems. J. Manuf. Mater. Process. 2023, 7, 22
by Antonios Dimopoulos, Ilias Zournatzis, Tat-Hean Gan and Panagiotis Chatzakos
J. Manuf. Mater. Process. 2023, 7(3), 85; https://doi.org/10.3390/jmmp7030085 - 26 Apr 2023
Viewed by 873
Abstract
In the original publication [...] Full article
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15 pages, 3061 KiB  
Article
Ablation Characteristics Research in Solid Rocket Motor’s Combustion Chamber Produced by 3D Printing
by Weihua Hui, Yun Hu, Yang Liu, Qiang Cai and Weijie Zhao
Materials 2023, 16(8), 3021; https://doi.org/10.3390/ma16083021 - 11 Apr 2023
Cited by 1 | Viewed by 1503
Abstract
A polyamide 12(PA12) reinforced with glass beads (GBs) solid rocket motor (SRM) produced by 3D Printing is proposed in the paper. The ablation research of the combustion chamber is studied by simulating the motor’s operating environment through ablation experiments. The results show that [...] Read more.
A polyamide 12(PA12) reinforced with glass beads (GBs) solid rocket motor (SRM) produced by 3D Printing is proposed in the paper. The ablation research of the combustion chamber is studied by simulating the motor’s operating environment through ablation experiments. The results show that the maximum ablation rate for the motor was 0.22 mm/s, which occurred at the location where the combustion chamber meets the baffle. The closer to the nozzle, the greater its ablation rate. Through the microscopic appearance analysis of the composite material from the inner wall surface to the outer wall surface in several directions before and after the ablation experiments, it was found that the GBs with weak or no interfacial adhesion to PA12 may make the mechanical properties of the material degrade. The ablated motor had a large number of holes and some deposits on the inner wall surface. Also by evaluating the surface chemistry of the material, it was found that the composite material underwent thermal decomposition. Moreover, it underwent a complex chemical reaction with the propellant. Full article
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15 pages, 3828 KiB  
Article
Design and Characterization of Baricitinib Incorporated PLA 3D Printed Pills by Fused Deposition Modeling: An Oral Pill for Treating Alopecia Areata
by Mohammed Muqtader Ahmed, Farhat Fatima, Aisha Alnami, Mohammad Alsenaidy, Alhussain H. Aodah, Mohammed F. Aldawsari, Bjad Almutairy, Md. Khalid Anwer and Mohammed Jafar
Polymers 2023, 15(8), 1825; https://doi.org/10.3390/polym15081825 - 08 Apr 2023
Cited by 2 | Viewed by 1465
Abstract
This study aimed to develop three-dimensional (3D) baricitinib (BAB) pills using polylactic acid (PLA) by fused deposition modeling. Two strengths of BAB (2 and 4% w/v) were dissolved into the (1:1) PEG-400 individually, diluting it with a solvent blend of [...] Read more.
This study aimed to develop three-dimensional (3D) baricitinib (BAB) pills using polylactic acid (PLA) by fused deposition modeling. Two strengths of BAB (2 and 4% w/v) were dissolved into the (1:1) PEG-400 individually, diluting it with a solvent blend of acetone and ethanol (27.8:18:2) followed by soaking the unprocessed 200 cm~6157.94 mg PLA filament in the solvent blend acetone—ethanol. FTIR spectrums of the 3DP1 and 3DP2 filaments calculated and recognized drug encapsulation in PLA. Herein, 3D-printed pills showed the amorphousness of infused BAB in the filament, as indicated by DSC thermograms. Fabricated pills shaped like doughnuts increased the surface area and drug diffusion. The releases from 3DP1 and 3DP2 were found to be 43.76 ± 3.34% and 59.14 ± 4.54% for 24 h. The improved dissolution in 3DP2 could be due to the higher loading of BAB due to higher concentration. Both pills followed Korsmeyer–Peppas’ order of drug release. BAB is a novel JAK inhibitor that U.S. FDA has recently approved to treat alopecia areata (AA). Therefore, the proposed 3D printed tablets can be easily fabricated with FDM technology and effectively used in various acute and chronic conditions as personalized medicine at an economical cost. Full article
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11 pages, 22642 KiB  
Article
Suitableness of SLM Manufactured Turbine Blade for Aerodynamical Tests
by Janusz Telega, Piotr Kaczynski, Małgorzata A. Śmiałek, Piotr Pawlowski and Ryszard Szwaba
Materials 2023, 16(7), 2866; https://doi.org/10.3390/ma16072866 - 04 Apr 2023
Viewed by 1029
Abstract
This paper describes some insights on applicability of a Selective Laser Melting and Direct Metal Laser Sintering technology-manufactured turbine blade models for aerodynamic tests in a wind tunnel. The principal idea behind this research was to assess the possibilities of using ‘raw’ DLMS [...] Read more.
This paper describes some insights on applicability of a Selective Laser Melting and Direct Metal Laser Sintering technology-manufactured turbine blade models for aerodynamic tests in a wind tunnel. The principal idea behind this research was to assess the possibilities of using ‘raw’ DLMS printed turbine blade models for gas-flow experiments. The actual blade, manufactured using the DLMS technology, is assessed in terms of surface quality (roughness), geometrical shape and size (outline), quality of counterbores and quality of small diameter holes. The results are evaluated for the experimental aerodynamics standpoint. This field of application imposes requirements that have not yet been described in the literature. The experimental outcomes prove the surface quality does not suffice to conduct quantitative experiments. The holes that are necessary for pressure measurements in wind tunnel experiments cannot be reduced below 1 mm in diameter. The dimensional discrepancies are on the level beyond acceptable. Additionally, the problem of ‘reversed tolerance’, with the material building up and distorting the design, is visible in elements printed with the DLMS technology. The results indicate the necessity of post-machining of the printed elements prior their experimental usage, as their features in the ‘as fabricated’ state significantly disturb the flow conditions. Full article
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23 pages, 8064 KiB  
Article
CFD Investigation of an Innovative Additive Manufactured POCS Substrate as Electrical Heated Solution for After-Treatment Systems
by Loris Barillari, Augusto Della Torre, Gianluca Montenegro and Angelo Onorati
Appl. Sci. 2023, 13(6), 4017; https://doi.org/10.3390/app13064017 - 22 Mar 2023
Viewed by 1156
Abstract
In the last decade, additive manufacturing (AM) techniques have been progressively applied to the manufacturing of many mechanical components. Compared to traditional techniques, this technology is characterized by disruptive potential in terms of the complexity of the objects that can be produced. This [...] Read more.
In the last decade, additive manufacturing (AM) techniques have been progressively applied to the manufacturing of many mechanical components. Compared to traditional techniques, this technology is characterized by disruptive potential in terms of the complexity of the objects that can be produced. This opens new frontiers in terms of design flexibility, making it possible to create new components with optimized performances in terms of mechanical properties and weight. In this work, the focus is on a specific field of application: the development of novel porous media structures which can be the basis of advanced after-treatment systems for internal combustion engines. In particular, the possibility to design periodic open cellular structures (POCSs) that can be applied as catalytic substrates opens new perspectives in terms of flexibility and integrated functionalities. The present study investigates an innovative solution where the catalytic substrates are located in the pipes of the exhaust manifolds of a high-performance engine. A preliminary characterization of the pressure drop induced by the POCS structure is carried out, with a particular focus on the impact of the backpressure on the engine performances. Moreover, each POCS integrates an electrical circuit which is used to promote the heating of the device, with beneficial effects on the light-off of the catalytic reactions. An advanced CFD model is applied to evaluate the potential of the solution, comparing the pollutant conversion with that of the baseline configuration equipped with a standard after-treatment system solution. Full article
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19 pages, 6544 KiB  
Article
Weldability of 316L Parts Produced by Metal Additive Manufacturing
by Hamdi Selmi, Jean Brousseau, Gabriel Caron-Guillemette, Stéphane Goulet, Jacques Desjardins and Claude Belzile
J. Manuf. Mater. Process. 2023, 7(2), 71; https://doi.org/10.3390/jmmp7020071 - 20 Mar 2023
Cited by 2 | Viewed by 2510
Abstract
The processes of metal additive manufacturing (AM) are no longer confined to rapid prototyping applications and are seeing increasing use in many fields for the production of tools and finished products. The ability to design parts with practically zero waste, high precision, complex [...] Read more.
The processes of metal additive manufacturing (AM) are no longer confined to rapid prototyping applications and are seeing increasing use in many fields for the production of tools and finished products. The ability to design parts with practically zero waste, high precision, complex geometry, and on-demand fabrication are among the advantages of this manufacturing approach. One of the drawbacks of this technique is the productivity rate, as the parts are made layer by layer, which also increases the production cost. Moreover, even the working space is limited, especially for the powder bed fusion technique. In view of these disadvantages and in order to guarantee the profitability of this process, it should be oriented to the production of complex components that have a limited volume with a design adapted to additive manufacturing. One solution with which to circumvent these drawbacks is to combine the 3D printing process with conventional manufacturing processes. When designing products, one may choose to use additive manufacturing to create locally complex parts and assemble them with parts produced by conventional processes. On the other hand, and due to the limited AM printing chamber space, it may be necessary to print large parts in multiple smaller parts and then assemble them. In order to investigate the weldability of stainless steel 316L parts produced by laser powder bed fusion (L-PBF), the mechanical behavior of different welding assemblies is tested. Five configurations are studied: non-welded AM specimens, two AM parts welded together, one AM part and one laser cut part welded together, two laser-cut parts welded together, and non-welded laser cut specimens. Welding is performed using the Pulsed Gas Metal Arc Welding process (GMAW-P). Specimen strength is assessed through static and fatigue tests. The results demonstrate that 316L AM parts are weldable, and the tensile and fatigue properties of L-PBF 316L welded components and welded laser cut components are comparable. GMAW-P welding led to lower fatigue results for AM components than for other configurations, but the difference is not important. It was observed that welding defects may have a direct impact on mechanical properties. Full article
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16 pages, 7582 KiB  
Article
Investigation of LCD 3D Printing of Carbon Fiber Composites by Utilising Central Composite Design
by Raveen Mohammed Salih, Abdulkader Kadauw, Henning Zeidler and Rezo Aliyev
J. Manuf. Mater. Process. 2023, 7(2), 58; https://doi.org/10.3390/jmmp7020058 - 04 Mar 2023
Viewed by 2561
Abstract
The technology of additive manufacturing (AM) has transformed the fields of machinery, aerospace, and electronics. Adopting cost-effective, precise, and rapid procedures in AM is one of the major concerns of today’s industry. Stereolithography is a promising AM technique that is thought to meet [...] Read more.
The technology of additive manufacturing (AM) has transformed the fields of machinery, aerospace, and electronics. Adopting cost-effective, precise, and rapid procedures in AM is one of the major concerns of today’s industry. Stereolithography is a promising AM technique that is thought to meet these requirements. However, the fact that materials printed with stereolithography do not have good mechanical properties limits their application, such as in biomedicine and aerospace. Previous studies have shown the shortcomings of stereolithography printers. This research focuses on enhancing the mechanical characteristics of the polymer resin used in stereolithography (SLA)-like liquid crystal display (LCD) 3D printers by fabricating a new AM composite material with carbon fibers. For this reason, chopped carbon fibers (0.1 mm size) at amounts of 0.25 wt% and 0.5 wt% have been used with Acrylonitrile butadiene styrene (ABS)-like photopolymer transparent resin during the printing process, and three different print layer thicknesses were tested. For the design of the experiment (DoE), Q-DAS software was used to analyze the resulting data. A tensile-testing machine was utilized to determine the ultimate strength using the ASTM D638 standard. The results show an increase in the ultimate strength by adding carbon fiber to some extent, but after a certain percentage of carbon fiber added, the strength drops off. Full article
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16 pages, 3141 KiB  
Article
Melt Pool Shape Evaluation by Single-Track Experiments and Finite-Element Thermal Analysis: Balling and Lack of Fusion Criteria for Generating Process Window of Inconel738LC
by Jun Katagiri, Masahiro Kusano, Satoshi Minamoto, Houichi Kitano, Koyo Daimaru, Masakazu Tsujii and Makoto Watanabe
Materials 2023, 16(4), 1729; https://doi.org/10.3390/ma16041729 - 20 Feb 2023
Cited by 3 | Viewed by 1641
Abstract
Defects occur in laser powder bed fusion (L-PBF) such as the keyholing, lack of fusion, and the balling depending on the laser power (P) and the scan speed (V). The figure shows that the occupied regions of each defect [...] Read more.
Defects occur in laser powder bed fusion (L-PBF) such as the keyholing, lack of fusion, and the balling depending on the laser power (P) and the scan speed (V). The figure shows that the occupied regions of each defect are the process window and are essentially important to fabricate a high-quality part. This paper is a study of process window generation using single-track experiments and finite-element method simulation of thermal conduction for Inconel738LC alloy. A series of single-track experiments were conducted varying the range of P and V and the results were classified into keyholing, lack of fusion, balling, and good track. A series of simulations were conducted and validated by comparison with the experiments. To quantitively identify the balling, the isolines from the contour map generated by the results of simulations and the balling criteria of the ratio of melt pool length and the depth (L/D) of 7.69 were determined considering the past theoretical studies. The lack of fusion criteria: the ratio of the overlap depth in fabrication using multi-scan (Dov) and powder layer thickness (t) of 0.1 was obtained. Using the criteria obtained from the experiments and simulation, the process window was generated. Full article
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30 pages, 5481 KiB  
Review
A Review—Additive Manufacturing of Intermetallic Alloys Based on Orthorhombic Titanium Aluminide Ti2AlNb
by Anatoliy G. Illarionov, Stepan I. Stepanov, Inna A. Naschetnikova, Artemiy A. Popov, Prasanth Soundappan, K. H. Thulasi Raman and Satyam Suwas
Materials 2023, 16(3), 991; https://doi.org/10.3390/ma16030991 - 20 Jan 2023
Cited by 3 | Viewed by 2690
Abstract
Titanium alloys based on orthorhombic titanium aluminide Ti2AlNb are promising refractory materials for aircraft engine parts in the operating temperature range from 600–700 °C. Parts made of Ti2AlNb-based alloys by traditional technologies, such as casting and metal forming, have [...] Read more.
Titanium alloys based on orthorhombic titanium aluminide Ti2AlNb are promising refractory materials for aircraft engine parts in the operating temperature range from 600–700 °C. Parts made of Ti2AlNb-based alloys by traditional technologies, such as casting and metal forming, have not yet found wide application due to the sensitivity of processability and mechanical properties in chemical composition and microstructure compared with commercial solid-solution-based titanium alloys. In the last three decades, metal additive manufacturing (MAM) has attracted the attention of scientists and engineers for the production of intermetallic alloys based on Ti2AlNb. This review summarizes the recent achievements in the production of O-phase-based Ti alloys using MAM, including the analysis of the feedstock materials, technological processes, machines, microstructure, phase composition and mechanical properties. Powder bed fusion (PBF) and direct energy deposition (DED) are the most widely employed MAM processes to produce O-phase alloys. MAM provides fully dense, fine-grained material with a superior combination of mechanical properties at room temperature. Further research on MAM for the production of critical parts made of Ti2AlNb-based alloys can be focused on a detailed study of the influence of post-processing and chemical composition on the formation of the structure and mechanical properties, including cyclic loading, fracture toughness, and creep resistance. Full article
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16 pages, 5192 KiB  
Article
Multi-Response Optimization of Ti6Al4V Support Structures for Laser Powder Bed Fusion Systems
by Antonios Dimopoulos, Ilias Zournatzis, Tat-Hean Gan and Panagiotis Chatzakos
J. Manuf. Mater. Process. 2023, 7(1), 22; https://doi.org/10.3390/jmmp7010022 - 13 Jan 2023
Cited by 4 | Viewed by 2534 | Correction
Abstract
Laser Powder Bed Fusion (LPBF) is one of the most commonly used and rapidly developing metal Additive Manufacturing (AM) technologies for producing optimized geometries, complex features, and lightweight components, in contrast to traditional manufacturing, which limits those characteristics. However, this technology faces difficulties [...] Read more.
Laser Powder Bed Fusion (LPBF) is one of the most commonly used and rapidly developing metal Additive Manufacturing (AM) technologies for producing optimized geometries, complex features, and lightweight components, in contrast to traditional manufacturing, which limits those characteristics. However, this technology faces difficulties with regard to the construction of overhang structures and warping deformation caused by thermal stresses. Producing overhangs without support structures results in collapsed parts, while adding unnecessary supports increases the material required and post-processing. The purpose of this study was to evaluate the various support and process parameters for metal LPBF, and propose optimized support structures to minimize Support Volume, Support Removal Effort, and Warping Deformation. The optimization approach was based on the Design of Experiments (DOE) methodology and multi-response optimization, by 3D printing and studying overhang geometries from 0° to 45°. For this purpose, EOS Titanium Ti64 Grade 5 powder was used, a Ti6Al4V alloy commonly employed in LPBF. For 0° overhangs, the optimum solution was characterized by an average Tooth Height, large Tooth Top Length, low X, Y Hatching, and high Laser Speed, while for 22.5° and 45° overhangs, it was characterized by large Tooth Height, low Tooth Top Length, high X, Y Hatching, and high Laser Speed. Full article
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15 pages, 4054 KiB  
Article
Development of a Novel Tape-Casting Multi-Slurry 3D Printing Technology to Fabricate the Ceramic/Metal Part
by Cho-Pei Jiang, Yulius Shan Romario and Ehsan Toyserkani
Materials 2023, 16(2), 585; https://doi.org/10.3390/ma16020585 - 06 Jan 2023
Cited by 5 | Viewed by 2349
Abstract
Printing ceramic/metal parts increases the number of applications in additive manufacturing technology, but printing different materials on the same object with different mechanical properties will increase the difficulty of printing. Multi-material additive manufacturing technology is a solution. This study develops a novel tape-casting [...] Read more.
Printing ceramic/metal parts increases the number of applications in additive manufacturing technology, but printing different materials on the same object with different mechanical properties will increase the difficulty of printing. Multi-material additive manufacturing technology is a solution. This study develops a novel tape-casting 3D printing technology that uses bottom-up photopolymerization to fabricate the green body for low-temperature co-fired ceramics (LTCC) that consist of ceramic and copper. The composition of ceramic and copper slurries is optimized to allow printing without delamination and sintering without cracks. Unlike traditional tape-casting processing, the proposed method deposits two slurries on demand on a transparent film, scrapes it flat, then photopolymerization is induced using a liquid crystal displayer to project the layer pattern beneath the film. The experimental results show that both slurries have good bonding strength, with a weight ratio of powder to resin of 70:30, and print a U-shaped copper volume as a circuit within the LTCC green body. A three-stage sintering parameter is derived using thermogravimetric analysis to ensure good mechanical properties for the sintered part. The SEM images show that the ceramic/copper interface of the LTCC sintered part is well-bonded. The average hardness and flexural strength of the sintered ceramic are 537.1 HV and 126.61 MPa, respectively. Volume shrinkage for the LTCC slurry is 67.97%, which is comparable to the value for a copper slurry of 68.85%. The electrical resistance of the printed copper circuit is 0.175 Ω, which is slightly greater than the theoretical value, hence it has good electrical conductivity. The proposed tape-casting 3D printer is used to print an LTCC benchmark. The sintered benchmark part is validated for the application in the LTCC application. Full article
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15 pages, 2502 KiB  
Article
Underlying Methodology for a Thermal Process Monitoring System for Wire and Arc Additive Manufacturing
by Daniel Baier, Tobias Weckenmann, Franz Wolf, Andreas Wimmer and Michael F. Zaeh
J. Manuf. Mater. Process. 2023, 7(1), 10; https://doi.org/10.3390/jmmp7010010 - 28 Dec 2022
Cited by 1 | Viewed by 1908
Abstract
The Wire and Arc Additive Manufacturing (WAAM) process has a high potential for industrial applications in aviation. The interlayer temperatures influence the dimensions and geometric deviations of the part. Monitoring the absolute interlayer temperature values is necessary for quantifying these influences. This paper [...] Read more.
The Wire and Arc Additive Manufacturing (WAAM) process has a high potential for industrial applications in aviation. The interlayer temperatures influence the dimensions and geometric deviations of the part. Monitoring the absolute interlayer temperature values is necessary for quantifying these influences. This paper presents an approach for determining the absolute values of the interlayer temperatures during the process using Ti-6Al-4V. The emissivity and transmittance are determined and calibrated, enabling precise thermographic measuring during the WAAM process. The recorded thermographic data are then compared to signals of thermocouples so that the absolute temperature values can be aligned. The methodology is validated by its transfer to measure the interlayer temperature at different regions of interest. The effect of a heat accumulation using Ti-6Al-4V in WAAM was determined. The methodology enables a reproducible and non-tactile measurement of the interlayer temperature during the WAAM process. The results show that with an interlayer temperature of 200 °C, a heat accumulation occurs within a layer. The heat accumulates in the center of the layer because the free ends of the layer cool down faster than the center of the layer. Full article
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13 pages, 2107 KiB  
Article
Investigations on Factors Affecting 3D-Printed Holes Dimensional Accuracy and Repeatability
by Diana Popescu, Cătălin Gheorghe Amza, Rodica Marinescu, Mariana Cristiana Iacob and Nicoleta Luminiţa Căruţaşu
Appl. Sci. 2023, 13(1), 41; https://doi.org/10.3390/app13010041 - 21 Dec 2022
Cited by 6 | Viewed by 2153
Abstract
This paper investigates the impact of several factors related to manufacturing, design, and post-processing on the dimensional accuracy of holes built in the additively manufactured parts obtained by material extrusion process (MEX). Directly fabricated holes in the 3D prints are commonly used for [...] Read more.
This paper investigates the impact of several factors related to manufacturing, design, and post-processing on the dimensional accuracy of holes built in the additively manufactured parts obtained by material extrusion process (MEX). Directly fabricated holes in the 3D prints are commonly used for joining with other parts by means of mechanical fasteners, thus producing assemblies or larger parts, or have other functional purposes such as guiding the drill in the case of patient-personalized surgical guides. However, despite their spread use and importance, the relationship between the 3D-printed holes’ accuracy and printing settings is not well documented in the literature. Therefore, in this research, test parts were manufactured by varying the number of shells, printing speed, layer thickness, and axis orientation angles for evaluating their effect on the dimensional accuracy of holes of different diameters. In the same context of limited existing information, the influence of material, 3D printer, and slicing software is also investigated for determining the dimensional accuracy of hole-type features across different manufacturing sites, a highly relevant aspect when using MEX to produce spare or end-use parts in a delocalized production paradigm. The results of this study indicated that the layer thickness is the most relevant influence factor for the diameter accuracy, followed by the number of shells around the holes. Considering the tested values, the optimal set of values found as optimizing the accuracy and printing time was 0.2 mm layer thickness, two shells, and 50 mm/s printing speed for the straight holes. Data on the prints manufactured on different MEX equipment and slicers indicated no statistically significant difference between the diameters of the holes. The evaluation of 3D-printed polylactic acid test parts mimicking a surgical template device with inclined holes showed that the medical decontamination process had more impact on the holes’ dimensional variability than on their dimensional accuracy. Full article
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14 pages, 3622 KiB  
Article
An Approach to Improve the Resolution of DLP 3D Printing by Parallel Mechanism
by Junjie Huang, Bowen Zhang, Junfeng Xiao and Qinlei Zhang
Appl. Sci. 2022, 12(24), 12905; https://doi.org/10.3390/app122412905 - 15 Dec 2022
Cited by 3 | Viewed by 2831
Abstract
For 3D printing based on Digital Light Processing (DLP) technology, the tradeoff of size and resolution remains challenging due to the limitations of the existing techniques. Therefore, we propose an approach to improve the feature resolution without sacrificing the part size. It is [...] Read more.
For 3D printing based on Digital Light Processing (DLP) technology, the tradeoff of size and resolution remains challenging due to the limitations of the existing techniques. Therefore, we propose an approach to improve the feature resolution without sacrificing the part size. It is achieved by changing the projection distance and then adjusting the projection resolution and format, which is different from the previous printing principle of fixed resolution. To achieve this process, the tripteron 3-Degree-of-Freedom (3-DoF) parallel mechanism is innovatively applied to the DLP 3D printing structure, which simplifies the control process. Since the projection is fixed on the motion platform, the projection distance changes as the platform moves in space. Then the PLC-based program is developed according to the motion process, which successfully runs on the established prototype. Finally, the experiments are designed through the orthogonal method to optimize the molding process parameters. The effectiveness of the approach is verified by the feature forming comparison experiment. The results show that it can reduce the size of features by about 1.3 times through adjusting the projection resolution under the same size parts. Our method provides a new way for solving the contradiction, but more research needs to be done. Full article
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18 pages, 9584 KiB  
Article
The Effect of Silicon Phase Morphology on Microstructure and Properties of AlSi10Mg Alloys Fabricated by Selective Laser Melting
by Liyun Wu, Zhanyong Zhao, Peikang Bai, Zhen Zhang, Yuxin Li, Minjie Liang and Wenbo Du
Materials 2022, 15(24), 8786; https://doi.org/10.3390/ma15248786 - 09 Dec 2022
Cited by 3 | Viewed by 1590
Abstract
This paper investigated the effect of silicon phase morphology and size on microstructure, mechanical properties, and corrosion resistance of the AlSi10Mg alloys fabricated by selective laser melting (SLM). Using different heat treatment conditions for SLM-fabricated alloys, the microstructure characteristics and mechanical properties are [...] Read more.
This paper investigated the effect of silicon phase morphology and size on microstructure, mechanical properties, and corrosion resistance of the AlSi10Mg alloys fabricated by selective laser melting (SLM). Using different heat treatment conditions for SLM-fabricated alloys, the microstructure characteristics and mechanical properties are analyzed. The corrosion behavior analysis is also performed using potentiodynamic polarization, electrochemical and immersion tests. Results show that the AlSi10Mg alloy directly fabricated by SLM has a continuous eutectic silicon network, which has a small driving force for corrosion and facilitates the deposition of corrosion products and generates a dense protective film. On the contrary, the formation of large isolated and uniformly distributed silicon particles produces a greater corrosion driving force after heat treatment, which makes most of the corrosion products transfer to the solution. The corrosion resistance of AlSi10Mg alloy directly fabricated by SLM is better than that of the alloys with heat treatment. Moreover, the heat treatment reduces the hardness of AlSi10Mg alloys due to the decrease in the solid solution strengthening effect. Full article
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32 pages, 10962 KiB  
Review
Recent Advances in Multi-Material 3D Printing of Functional Ceramic Devices
by Hui Chen, Liang Guo, Wenbo Zhu and Chunlai Li
Polymers 2022, 14(21), 4635; https://doi.org/10.3390/polym14214635 - 31 Oct 2022
Cited by 6 | Viewed by 6146
Abstract
In recent years, functional ceramic devices have become smaller, thinner, more refined, and highly integrated, which makes it difficult to realize their rapid prototyping and low-cost manufacturing using traditional processing. As an emerging technology, multi-material 3D printing offers increased complexity and greater freedom [...] Read more.
In recent years, functional ceramic devices have become smaller, thinner, more refined, and highly integrated, which makes it difficult to realize their rapid prototyping and low-cost manufacturing using traditional processing. As an emerging technology, multi-material 3D printing offers increased complexity and greater freedom in the design of functional ceramic devices because of its unique ability to directly construct arbitrary 3D parts that incorporate multiple material constituents without an intricate process or expensive tools. Here, the latest advances in multi-material 3D printing methods are reviewed, providing a comprehensive study on 3D-printable functional ceramic materials and processes for various functional ceramic devices, including capacitors, multilayer substrates, and microstrip antennas. Furthermore, the key challenges and prospects of multi-material 3D-printed functional ceramic devices are identified, and future directions are discussed. Full article
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15 pages, 3103 KiB  
Article
SLA Resins Modification by Liquid Mixing with Ceramic Powders Aiming at Mechanical Property and Thermal Stability Enhancement for Rapid Tooling Applications
by Anna Karatza, Panagiotis Zouboulis, Iakovos Gavalas, Dionisis Semitekolos, Artemis Kontiza, Melpo Karamitrou, Elias P. Koumoulos and Costas Charitidis
J. Manuf. Mater. Process. 2022, 6(6), 129; https://doi.org/10.3390/jmmp6060129 - 26 Oct 2022
Cited by 1 | Viewed by 2098
Abstract
Stereolithography (SL) additive manufacturing process provides increased dimensional precision, smooth surface finish and printing resolution range in the order of magnitude of 100 μm, allowing to obtain intricate 3D geometries. The incorporation of ceramic-based inclusions within liquid resins enhances the thermal and mechanical [...] Read more.
Stereolithography (SL) additive manufacturing process provides increased dimensional precision, smooth surface finish and printing resolution range in the order of magnitude of 100 μm, allowing to obtain intricate 3D geometries. The incorporation of ceramic-based inclusions within liquid resins enhances the thermal and mechanical properties of the final 3D printed component while improving the surface finishing of the final parts; in this way, it expands the range of process applications and reduces the post-processing steps. The proposed approach investigates the bulk modification of commercial SLA resins mixed with ceramic powders of Al2O3 (grain size 1–10 μm) and SiO2 (grain size 55–75 nm) aiming to improve 3D printed parts performance in terms of mechanical properties, dimensional stability and surface finishing compared with pure, unmodified resins. The produced materials were used for the development of inserts for injection moulding and were examined for their performance during the injection moulding process. The addition of particles in the nano- and micro-range is being employed to improve parts performance for rapid tooling applications whilst maintaining 3D printing accuracy, thermal and mechanical properties as well as achieving a smooth surface finishing compared with unmodified resins. Full article
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11 pages, 3276 KiB  
Article
Benefits of Printed Graphene with Variable Resistance for Flexible and Ecological 5G Band Antennas
by Alexander G. Cherevko, Alexey S. Krygin, Artem I. Ivanov, Regina A. Soots and Irina V. Antonova
Materials 2022, 15(20), 7267; https://doi.org/10.3390/ma15207267 - 18 Oct 2022
Cited by 6 | Viewed by 1083
Abstract
The possibility of creating antennas of the 5G standard (5.2–5.9 GHz) with specified electrodynamic characteristics by printing layers of variable thickness using a graphene suspension has been substantiated experimentally and by computer simulation. A graphene suspension for screen printing on photographic paper and [...] Read more.
The possibility of creating antennas of the 5G standard (5.2–5.9 GHz) with specified electrodynamic characteristics by printing layers of variable thickness using a graphene suspension has been substantiated experimentally and by computer simulation. A graphene suspension for screen printing on photographic paper and other flexible substrates was prepared by means of exfoliation from graphite. The relation between the graphene layer thickness and its sheet resistance was studied with the aim of determining the required thickness of the antenna conductive layer. To create a two-sided dipole, a technology has been developed for the double-sided deposition of graphene layers on photographic paper. The electrodynamic characteristics of graphene and copper antennas of identical design are compared. The antenna design corresponds to the operating frequency of 2.4 GHz. It was found that the use of graphene as a conductive layer made it possible to suppress the fundamental (first) harmonic (2.45 GHz) and to observe radiation at the second harmonic (5.75 GHz). This effect is assumed to observe in the case when the thickness of graphene is lower than that of the skin depth. The result indicates the possibility of changing the antenna electrodynamic characteristics by adjusting the graphene layer thickness. Full article
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11 pages, 2278 KiB  
Article
Advanced Dye Sorbents from Combined Stereolithography 3D Printing and Alkali Activation of Pharmaceutical Glass Waste
by Mokhtar Mahmoud, Jozef Kraxner, Hamada Elsayed, Dušan Galusek and Enrico Bernardo
Materials 2022, 15(19), 6823; https://doi.org/10.3390/ma15196823 - 01 Oct 2022
Cited by 6 | Viewed by 1953
Abstract
Additive manufacturing (AM) technologies enable the fabrication of objects with complex geometries in much simpler ways than conventional shaping methods. With the fabrication of recyclable filters for contaminated waters, the present work aims at exploiting such features as an opportunity to reuse glass [...] Read more.
Additive manufacturing (AM) technologies enable the fabrication of objects with complex geometries in much simpler ways than conventional shaping methods. With the fabrication of recyclable filters for contaminated waters, the present work aims at exploiting such features as an opportunity to reuse glass from discarded pharmaceutical containers. Masked stereolithography-printed scaffolds were first heat-treated at relatively low temperatures (680 and 730 °C for 1 h) and then functionalized by alkali activation, with the formation of zeolite and sodium carbonate phases, which worked as additional adsorbing centers. As-sintered and activated scaffolds were characterized in terms of the efficiency of filtration and removal of methylene blue, used as a reference dye. The adsorption efficiency of activated printed glass was 81%. The 3D-printed adsorbent can be easily separated from the solution for reuse. Full article
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8 pages, 1571 KiB  
Communication
Significant Shear Failure Difference among Additively Manufactured Polymers Using Different Techniques
by Luoyu Roy Xu, Qinglin Wang, Yinxu Ni, Gonghe Zhang, Fenghua Liu, Xiaodong Zheng and Yang Liu
Polymers 2022, 14(19), 4028; https://doi.org/10.3390/polym14194028 - 26 Sep 2022
Cited by 4 | Viewed by 1327
Abstract
Because additively manufactured materials are increasingly being used in load-bearing structures, strength research has become critical. Surprisingly, numerous studies have reported the tensile strength measurements, but only a few studies have presented meaningful results for the shear strength measurements of additively manufactured polymers. [...] Read more.
Because additively manufactured materials are increasingly being used in load-bearing structures, strength research has become critical. Surprisingly, numerous studies have reported the tensile strength measurements, but only a few studies have presented meaningful results for the shear strength measurements of additively manufactured polymers. Hence, this paper proposes a combined experimental and numerical investigation of a new interlayer shear strength measurement approach, and it targeted the applications of the same polyamide (PA12) specimens made with fused deposition modeling (FDM) and selective laser sintering (SLS). A necking-shaped shear specimen was developed to measure the pure shear strengths with the aid of a three-dimensional (3D) finite element analysis. The results showed that the specimens made with FDM and SLS exhibited totally different shear failure behaviors. The ultimate shear strength of the FDM-PA specimens had more than a 32% increase over that of the SLS-PA specimens. An interface mechanics assumption was employed to explore the different shear failure mechanisms with the support of a fractography analysis. Full article
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17 pages, 2732 KiB  
Article
Closed-Loop Temperature and Force Control of Additive Friction Stir Deposition
by Glen R. Merritt, Malcolm B. Williams, Paul G. Allison, James B. Jordon, Timothy W. Rushing and Christian A. Cousin
J. Manuf. Mater. Process. 2022, 6(5), 92; https://doi.org/10.3390/jmmp6050092 - 24 Aug 2022
Cited by 9 | Viewed by 2646
Abstract
Additive Friction Stir Deposition (AFSD) is a recent innovation in non-beam-based metal additive manufacturing that achieves layer-by-layer deposition while avoiding the solid-to-liquid phase transformation. AFSD presents numerous benefits over other forms of fusion-based additive manufacturing, such as high-strength mechanical bonding, joining of dissimilar [...] Read more.
Additive Friction Stir Deposition (AFSD) is a recent innovation in non-beam-based metal additive manufacturing that achieves layer-by-layer deposition while avoiding the solid-to-liquid phase transformation. AFSD presents numerous benefits over other forms of fusion-based additive manufacturing, such as high-strength mechanical bonding, joining of dissimilar alloys, and high deposition rates. To improve, automate, and ensure the quality, uniformity, and consistency of the AFSD process, it is necessary to control the temperature at the interaction zone and the force applied to the consumable feedstock during deposition. In this paper, real-time temperature and force feedback are achieved by embedding thermocouples into the nonconsumable machine tool-shoulder and estimating the applied force from the motor current of the linear actuator driving the feedstock. Subsequently, temperature and force controllers are developed for the AFSD process, ensuring that the temperature at the interaction zone and the force applied to the feedstock track desired command values. The temperature and force controllers were evaluated separately and together on setpoints and time-varying trajectories. For combined temperature and force control with setpoints selected at a temperature of 420 °C and a force of 2669 N, the average temperature and force tracking errors are 5.4 ± 6.5 °C (1.4 ± 1.6%) and 140.1 ± 213.5 N (5.2 ± 8.0%), respectively. Full article
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18 pages, 7614 KiB  
Article
Numerical Investigation of the Cycling Loading Behavior of 3D-Printed Poly-Lactic Acid (PLA) Cylindrical Lightweight Samples during Compression Testing
by Ako Karimi, Nikolaj Mole and Tomaž Pepelnjak
Appl. Sci. 2022, 12(16), 8018; https://doi.org/10.3390/app12168018 - 10 Aug 2022
Cited by 4 | Viewed by 1564
Abstract
The additive technologies widely used in recent years provide enormous flexibility in the production of cellular structures. Material extrusion (MEX) technology has become very popular due to the increasing availability of relatively inexpensive desktop 3D printers and the capability of fabricating parts with [...] Read more.
The additive technologies widely used in recent years provide enormous flexibility in the production of cellular structures. Material extrusion (MEX) technology has become very popular due to the increasing availability of relatively inexpensive desktop 3D printers and the capability of fabricating parts with complex geometries. Poly-lactic acid (PLA) is a biodegradable and commonly applied thermoplastic material in additive manufacturing (AM). In this study, using a simulation method based on the user subroutine titled “user subroutine to redefine field variables at a material point” (USDFLD) in the finite element method (FEM) ABAQUS software, the elastic stiffness (ES) of a cylindrical lightweight cellular PLA sample with a 2.4 mm infill line distance (ILD), which was designed as a layered structure similar to the laboratory mode with a MEX method and was subjected to cyclic compressive loading, was investigated by considering the variation of the Young’s modulus depending on the variation of the equivalent plastic strain (PEEQ). It was observed that the PLA sample’s elastic stiffness increases during cyclic loading. This increase is high in the initial cycles and less in the subsequent cycles. It was also observed that the simulation results are in good agreement with the experimental results. Full article
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