Additive Manufacturing: Design, Opportunities, and Applications

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.838	3.7	2011	14.9 Days	2300 CHF	Submit
Journal of Manufacturing and Materials Processing jmmp	-	4.8	2017	13.5 Days	1600 CHF	Submit
Materials materials	3.748	4.7	2008	13.9 Days	2300 CHF	Submit
Metals metals	2.695	3.8	2011	16.9 Days	2000 CHF	Submit
Polymers polymers	4.967	5.7	2009	12.4 Days	2400 CHF	Submit

Open AccessArticle

Additive Manufacturing in Bespoke Interactive Devices—A Thematic Analysis

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Appl. Sci. 2023, 13(11), 6627; https://doi.org/10.3390/app13116627 - 30 May 2023

Viewed by 244

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessCorrection

Correction: Dimopoulos et al. Multi-Response Optimization of Ti6Al4V Support Structures for Laser Powder Bed Fusion Systems. J. Manuf. Mater. Process. 2023, 7, 22

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J. Manuf. Mater. Process. 2023, 7(3), 85; https://doi.org/10.3390/jmmp7030085 - 26 Apr 2023

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Abstract

In the original publication [...] Full article

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Ablation Characteristics Research in Solid Rocket Motor’s Combustion Chamber Produced by 3D Printing

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Materials 2023, 16(8), 3021; https://doi.org/10.3390/ma16083021 - 11 Apr 2023

Cited by 1 | Viewed by 643

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Design and Characterization of Baricitinib Incorporated PLA 3D Printed Pills by Fused Deposition Modeling: An Oral Pill for Treating Alopecia Areata

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Mohammed Muqtader Ahmed

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Mohammed F. Aldawsari

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Bjad Almutairy

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Md. Khalid Anwer

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Mohammed Jafar

Polymers 2023, 15(8), 1825; https://doi.org/10.3390/polym15081825 - 08 Apr 2023

Viewed by 606

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Suitableness of SLM Manufactured Turbine Blade for Aerodynamical Tests

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Janusz Telega

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Piotr Kaczynski

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Małgorzata A. Śmiałek

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Piotr Pawlowski

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Ryszard Szwaba

Materials 2023, 16(7), 2866; https://doi.org/10.3390/ma16072866 - 04 Apr 2023

Viewed by 517

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

CFD Investigation of an Innovative Additive Manufactured POCS Substrate as Electrical Heated Solution for After-Treatment Systems

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Appl. Sci. 2023, 13(6), 4017; https://doi.org/10.3390/app13064017 - 22 Mar 2023

Viewed by 681

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Weldability of 316L Parts Produced by Metal Additive Manufacturing

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Hamdi Selmi

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Jean Brousseau

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Gabriel Caron-Guillemette

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Stéphane Goulet

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Jacques Desjardins

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Claude Belzile

J. Manuf. Mater. Process. 2023, 7(2), 71; https://doi.org/10.3390/jmmp7020071 - 20 Mar 2023

Viewed by 1092

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Investigation of LCD 3D Printing of Carbon Fiber Composites by Utilising Central Composite Design

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Raveen Mohammed Salih

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Abdulkader Kadauw

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Henning Zeidler

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Rezo Aliyev

J. Manuf. Mater. Process. 2023, 7(2), 58; https://doi.org/10.3390/jmmp7020058 - 04 Mar 2023

Viewed by 1087

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

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

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Materials 2023, 16(4), 1729; https://doi.org/10.3390/ma16041729 - 20 Feb 2023

Viewed by 850

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 (D_ov) 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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessReview

A Review—Additive Manufacturing of Intermetallic Alloys Based on Orthorhombic Titanium Aluminide Ti₂AlNb

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Anatoliy G. Illarionov

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Stepan I. Stepanov

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Inna A. Naschetnikova

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Materials 2023, 16(3), 991; https://doi.org/10.3390/ma16030991 - 20 Jan 2023

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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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Multi-Response Optimization of Ti6Al4V Support Structures for Laser Powder Bed Fusion Systems

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J. Manuf. Mater. Process. 2023, 7(1), 22; https://doi.org/10.3390/jmmp7010022 - 13 Jan 2023

Cited by 1 | Viewed by 1489 | 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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Development of a Novel Tape-Casting Multi-Slurry 3D Printing Technology to Fabricate the Ceramic/Metal Part

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Cho-Pei Jiang

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Yulius Shan Romario

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Ehsan Toyserkani

Materials 2023, 16(2), 585; https://doi.org/10.3390/ma16020585 - 06 Jan 2023

Viewed by 949

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Underlying Methodology for a Thermal Process Monitoring System for Wire and Arc Additive Manufacturing

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J. Manuf. Mater. Process. 2023, 7(1), 10; https://doi.org/10.3390/jmmp7010010 - 28 Dec 2022

Viewed by 1236

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Investigations on Factors Affecting 3D-Printed Holes Dimensional Accuracy and Repeatability

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Diana Popescu

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Cătălin Gheorghe Amza

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Rodica Marinescu

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Mariana Cristiana Iacob

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Nicoleta Luminiţa Căruţaşu

Appl. Sci. 2023, 13(1), 41; https://doi.org/10.3390/app13010041 - 21 Dec 2022

Cited by 2 | Viewed by 1091

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

An Approach to Improve the Resolution of DLP 3D Printing by Parallel Mechanism

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Appl. Sci. 2022, 12(24), 12905; https://doi.org/10.3390/app122412905 - 15 Dec 2022

Cited by 1 | Viewed by 1155

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

The Effect of Silicon Phase Morphology on Microstructure and Properties of AlSi10Mg Alloys Fabricated by Selective Laser Melting

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Materials 2022, 15(24), 8786; https://doi.org/10.3390/ma15248786 - 09 Dec 2022

Viewed by 851

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessReview

Recent Advances in Multi-Material 3D Printing of Functional Ceramic Devices

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Polymers 2022, 14(21), 4635; https://doi.org/10.3390/polym14214635 - 31 Oct 2022

Cited by 1 | Viewed by 2729

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

SLA Resins Modification by Liquid Mixing with Ceramic Powders Aiming at Mechanical Property and Thermal Stability Enhancement for Rapid Tooling Applications

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J. Manuf. Mater. Process. 2022, 6(6), 129; https://doi.org/10.3390/jmmp6060129 - 26 Oct 2022

Cited by 1 | Viewed by 1158

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Benefits of Printed Graphene with Variable Resistance for Flexible and Ecological 5G Band Antennas

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Alexander G. Cherevko

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Materials 2022, 15(20), 7267; https://doi.org/10.3390/ma15207267 - 18 Oct 2022

Cited by 2 | Viewed by 609

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Advanced Dye Sorbents from Combined Stereolithography 3D Printing and Alkali Activation of Pharmaceutical Glass Waste

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Materials 2022, 15(19), 6823; https://doi.org/10.3390/ma15196823 - 01 Oct 2022

Cited by 1 | Viewed by 1195

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessCommunication

Significant Shear Failure Difference among Additively Manufactured Polymers Using Different Techniques

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Polymers 2022, 14(19), 4028; https://doi.org/10.3390/polym14194028 - 26 Sep 2022

Cited by 2 | Viewed by 809

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Closed-Loop Temperature and Force Control of Additive Friction Stir Deposition

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J. Manuf. Mater. Process. 2022, 6(5), 92; https://doi.org/10.3390/jmmp6050092 - 24 Aug 2022

Cited by 3 | Viewed by 1584

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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Open AccessArticle

Numerical Investigation of the Cycling Loading Behavior of 3D-Printed Poly-Lactic Acid (PLA) Cylindrical Lightweight Samples during Compression Testing

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Ako Karimi

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Nikolaj Mole

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Tomaž Pepelnjak

Appl. Sci. 2022, 12(16), 8018; https://doi.org/10.3390/app12168018 - 10 Aug 2022

Cited by 3 | Viewed by 972

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

(This article belongs to the Topic Additive Manufacturing: Design, Opportunities, and Applications)

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