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3 pages, 150 KiB

Open AccessEditorial

Additive Manufacturing—Process Optimisation

by Muhannad Ahmed Obeidi

Designs 2024, 8(2), 34; https://doi.org/10.3390/designs8020034 - 10 Apr 2024

Viewed by 1097

Abstract

The realm of Additive Manufacturing (AM), often referred to as 3D printing, encompasses a broad spectrum of applications and methodologies, each contributing distinctively to the progress of this dynamic field [...] Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

Research

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13 pages, 5742 KiB

Open AccessArticle

Enhancement of Fatigue Life of Polylactic Acid Components through Post-Printing Heat Treatment

by Moises Jimenez-Martinez, Julio Varela-Soriano, Rafael Carrera-Espinoza, Sergio G. Torres-Cedillo and Jacinto Cortés-Pérez

Designs 2024, 8(1), 7; https://doi.org/10.3390/designs8010007 - 11 Jan 2024

Cited by 1 | Viewed by 1682

Abstract

To reduce the carbon footprint of manufacturing processes, it is necessary to reduce the number of stages in the development process. To this end, integrating additive manufacturing processes with three-dimensional (3D) printing makes it possible to eliminate the need to use tooling for [...] Read more.

To reduce the carbon footprint of manufacturing processes, it is necessary to reduce the number of stages in the development process. To this end, integrating additive manufacturing processes with three-dimensional (3D) printing makes it possible to eliminate the need to use tooling for component manufacturing. Furthermore, using 3D printing allows the generation of complex models to optimize different components, reducing the development time and realizing lightweight structures that can be applied in different industries, such as the mobility industry. Printing process parameters have been studied to improve the mechanical properties of printed items. In this regard, although the failure of most structural components occurs under dynamic load, the majority of the evaluations are quasistatic. This work highlights an improvement in fatigue strength under dynamic loads in 3D-printed components through heat treatment. The fatigue resistance was improved regarding the number of cycles and the dispersion of results. This allows 3D-printed polylactic acid components to be structurally used, and increasing their reliability allows their evolution from a prototype to a functional component. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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29 pages, 4284 KiB

Open AccessEditor’s ChoiceArticle

Development and Performance Evaluation of Fibrous Pseudoplastic Quaternary Cement Systems for Aerial Additive Manufacturing

by Barrie Dams, Paul Shepherd and Richard J. Ball

Designs 2023, 7(6), 137; https://doi.org/10.3390/designs7060137 - 27 Nov 2023

Cited by 2 | Viewed by 1779

Abstract

Aerial additive manufacturing (AAM) represents a paradigm shift in using unmanned aerial vehicles (UAVs, often called ‘drones’) in the construction industry, using self-powered and untethered UAVs to extrude structural cementitious material. This requires miniaturisation of the deposition system. Rheological properties and known hydration [...] Read more.

Aerial additive manufacturing (AAM) represents a paradigm shift in using unmanned aerial vehicles (UAVs, often called ‘drones’) in the construction industry, using self-powered and untethered UAVs to extrude structural cementitious material. This requires miniaturisation of the deposition system. Rheological properties and known hydration times are important material parameters. Calcium aluminate cement (CAC) systems can be advantageous over purely ordinary Portland cement (OPC) binders as they promote hydration and increase early strength. A quaternary OPC/pulverised fuel ash (PFA)/CAC/calcium sulphate (CS) system was combined with polyvinyl alcohol (PVA) fibres and pseudoplastic hydrocolloids to develop a novel AAM material for miniaturised deposition. CAC hydration is affected by environmental temperature. Intending material to be extruded in situ, mixes were tested at multiple temperatures. OPC/PFA/CAC/CS mixes with PVA fibres were successfully extruded with densities of ≈1700 kg/m

^{3}

, yield stresses of 1.1–1.3 kPa and a compressive strength of 25 MPa. Pseudoplastic OPC/PFA/CAC/CS quaternary cementitious systems are demonstrated to be viable for AAM, provided mixes are modified with retarders as temperature increases. This study can significantly impact industry by demonstrating structural material which can be extruded using UAVs in challenging or elevated in situ construction, reducing safety risks. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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22 pages, 8629 KiB

Open AccessEditor’s ChoiceArticle

Rheological Behaviour of ABS/Metal Composites with Improved Thermal Conductivity for Additive Manufacturing

by Vicente F. Moritz, Harald Prévost, Janaína S. Crespo, Carlos A. Ferreira and Declan M. Devine

Designs 2023, 7(6), 133; https://doi.org/10.3390/designs7060133 - 17 Nov 2023

Cited by 2 | Viewed by 2223

Abstract

Metal-reinforced polymer composites are suitable materials for applications requiring special thermal, electrical or magnetic properties. Three-dimensional printing technologies enable these materials to be quickly shaped in any design directly and without the need for expensive moulds. However, processing data correlating specific information on [...] Read more.

Metal-reinforced polymer composites are suitable materials for applications requiring special thermal, electrical or magnetic properties. Three-dimensional printing technologies enable these materials to be quickly shaped in any design directly and without the need for expensive moulds. However, processing data correlating specific information on how the metal particles influence the rheological behaviour of such composites is lacking, which has a direct effect on the processability of these composites through melt processing additive manufacturing. This study reports the compounding and characterisation of ABS composites filled with aluminium and copper particulates. Experimental results demonstrated that the tensile modulus increased with the incorporation of metal particles; however, there was also an intense embrittling effect. Mechanical testing and rheological analysis indicated poor affinity between the fillers and matrix, and the volume fraction proved to be a crucial factor for complex viscosity, storage modulus and thermal conductivity. However, a promising set of properties was achieved, paving the way for polymer–metal composites with optimised processability, microstructure and properties in melt processing additive manufacturing. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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14 pages, 2846 KiB

Open AccessArticle

Effects of Raster Angle on the Elasticity of 3D-Printed Polylactic Acid and Polyethylene Terephthalate Glycol

by Mohammed Aqeel Albadrani

Designs 2023, 7(5), 112; https://doi.org/10.3390/designs7050112 - 29 Sep 2023

Cited by 2 | Viewed by 1837

Abstract

Because of its numerous advantages, 3D printing is widely employed for a variety of purposes. The mechanical characteristics of 3D-printed items are quite important. 3D-printed polylactic acid (PLA) is a common thermoplastic polymer due to its excellent characteristics and affordable cost. Because of [...] Read more.

Because of its numerous advantages, 3D printing is widely employed for a variety of purposes. The mechanical characteristics of 3D-printed items are quite important. 3D-printed polylactic acid (PLA) is a common thermoplastic polymer due to its excellent characteristics and affordable cost. Because of its enhanced characteristics, polyethylene terephthalate glycol (PETG) has recently received a lot of attention. Despite PETG’s potential appeal in the 3D-printing field, little research has been conducted to explore its qualities, such as the impacts of raster angle on elasticity, which could lead to the development of more accurate guidelines for inspection and assessment. In this regard, this study examines the mechanical characteristics of polylactic acid (PLA) and polyethylene terephthalate glycol (PETG) 3D-printing specimens with different raster angles. Test specimens with raster angles of 15° and 30° were printed, and the stress–strain responses were recorded and compared with the simulated profiles generated using ANSYS software. The results showed that the raster angle significantly affected the mechanical properties of both types of materials. The simulated profile matched well with the experimental profile only in the case of PLA printed with a raster angle of 15°. These findings imply that extra effort should be made to ensure that the raster angle is tailored to yield the optimal mechanical properties of 3D-printed products. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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35 pages, 13372 KiB

Open AccessEditor’s ChoiceArticle

A Structural and Thermal Comparative Review of 3D-Printed Wall Shapes

by Nicholas D. Bello and Ali M. Memari

Designs 2023, 7(3), 80; https://doi.org/10.3390/designs7030080 - 19 Jun 2023

Cited by 2 | Viewed by 1944

Abstract

This article explores several aspects of the three-dimensional concrete printing (3DCP) industry. More specifically, it begins with a literature review discussing the background of this technology. This literature review also explores several of the challenges that the industry is currently facing. In this [...] Read more.

This article explores several aspects of the three-dimensional concrete printing (3DCP) industry. More specifically, it begins with a literature review discussing the background of this technology. This literature review also explores several of the challenges that the industry is currently facing. In this way, a knowledge gap is identified. More specifically, there are few studies that have explored the structural and thermal performance of typical walls printed in this industry. Therefore, we used the simulation tool in SolidWorks to examine the structural behavior of several different wall types when pressure was applied to the exterior face. In addition to this, the thermal performance of different wall types was also studied in SolidWorks by applying a temperature difference between the exterior and interior faces of each wall. For example, one wall shape in this study had minimum factor of safety of approximately 100 due when a load was applied, and the same wall lost approximately 212 W due to the temperature difference applied in this study. Finally, SolidWorks was used to calculate the moment of inertia of the cross sections of several of these walls, which helped to provide a better understanding of each wall’s structural rigidity. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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18 pages, 10680 KiB

Open AccessArticle

A Novel Feature-Based Manufacturability Assessment System for Evaluating Selective Laser Melting and Subtractive Manufacturing Injection Moulding Tool Inserts

by Mennatallah F. El Kashouty, Allan E. W. Rennie and Mootaz Ghazy

Designs 2023, 7(3), 68; https://doi.org/10.3390/designs7030068 - 22 May 2023

Cited by 1 | Viewed by 1562

Abstract

Challenges caused by design complexities during the design stages of a product must be coordinated and overcome by the selection of a suitable manufacturing approach. Additive manufacturing (AM) is capable of fabricating complex shapes, yet there are limiting aspects to surface integrity, dimensional [...] Read more.

Challenges caused by design complexities during the design stages of a product must be coordinated and overcome by the selection of a suitable manufacturing approach. Additive manufacturing (AM) is capable of fabricating complex shapes, yet there are limiting aspects to surface integrity, dimensional accuracy, and, in some instances, design restrictions. Therefore, the goal is essentially to establish the complex areas of a tool during the design stage to achieve the desired quality levels for the corresponding injection moulding tool insert. When adopting a manufacturing approach, it is essential to acknowledge limitations and restrictions. This paper presents the development of a feature-based manufacturability assessment system (FBMAS) to demonstrate the feasibility of integrating selective laser melting (SLM), a metal-based AM technology, with subtractive manufacturing for any given part. The areas on the tool inserts that hold the most geometrical complexities to manufacture are focused on the FBMAS and the design features that are critical for the FBMAS are defined. Furthermore, the structural approach used for developing the FBMAS graphical user interface is defined while explaining how it can be operated effectively and in a user-friendly approach. The systematic approach established is successful in capturing the benefits of SLM and subtractive methods of manufacturing, whilst defining design limitations of each manufacturing method. Finally, the FBMAS developed was validated and verified against the criteria set by experts in the field, and the system’s logic was proven to be accurate when tested. The decision recommendations proved to correlate with the determined recommendations of the field experts in evaluating the feature manufacturability of the tool inserts. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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9 pages, 1946 KiB

Open AccessArticle

By Visualizing the Deformation with Mechanoluminescent Particles, Additive Manufacturing Offers a Practical Alternative to Stress and Strain Simulation

by Ernests Einbergs, Agnese Spustaka, Virginija Vitola and Aleksejs Zolotarjovs

Designs 2023, 7(2), 54; https://doi.org/10.3390/designs7020054 - 7 Apr 2023

Cited by 2 | Viewed by 1862

Abstract

The use of stress–strain analysis in structural design or mechanical components is critical for avoiding or investigating structural failures. In the case of complicated designs, mathematical full-field stress modeling produces imprecise predictions. Experimental analysis can be used as a replacement for mathematical modeling, [...] Read more.

The use of stress–strain analysis in structural design or mechanical components is critical for avoiding or investigating structural failures. In the case of complicated designs, mathematical full-field stress modeling produces imprecise predictions. Experimental analysis can be used as a replacement for mathematical modeling, but with the use of currently available strain gauges, it is cumbersome and impossible in the case of moving parts. Mechanoluminescent materials transform mechanical energy into visible light and can be used as a replacement for strain gauges to monitor strain/stress. Three-dimensional printing technology has made major advances in terms of additive manufacturing. In this article, we describe a method to produce an ML 3D print. The fabricated samples are precise and versatile and satisfy the need for easy and non-destructible spatial stress analysis. A 3D printed photopolymer sample with SrAl₂O₄: Eu, Dy particle addition only to the final layers was tested, and the number of layers was optimized. It was determined that the optimal number of layers for easy detection is in the range of 10 to 20 layers. It opens the possibility for the real-time evaluation of complex uneven forces on complex parts, thus having a good potential for commercialization. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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16 pages, 11387 KiB

Open AccessArticle

Dimensional Accuracy of Electron Beam Powder Bed Fusion with Ti-6Al-4V

by Eric Bol and Mamidala Ramulu

Designs 2023, 7(2), 53; https://doi.org/10.3390/designs7020053 - 6 Apr 2023

Cited by 6 | Viewed by 1986

Abstract

While much of additive manufacturing (AM) research is focused on microstructure, material properties, and defects, there is much less research in regards to understanding how well the part coming out of the machine matches the 3D model it is based on, as well [...] Read more.

While much of additive manufacturing (AM) research is focused on microstructure, material properties, and defects, there is much less research in regards to understanding how well the part coming out of the machine matches the 3D model it is based on, as well as what are the key process parameters an engineer needs to care about when they are optimizing for AM. The purpose of this study was to understand the dimensional accuracy of the electron beam powder bed fusion (EB-PBF) process using specimens of different length scales from Ti-6Al-4V. Metrology of the specimens produced was performed using fringe projection, or laser scanning, to characterize the as-built geometry. At the meso-scale, specimen geometry and hatching history play a critical role in dimensional deviation. The effect of hatching history was further witnessed at the macro-scale while also demonstrating the effects of thermal expansion in EB-PBF. These results make the case for further process optimization in terms of dimensional accuracy in order to reduce post-processing costs and flow time. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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13 pages, 23905 KiB

Open AccessArticle

Caffeine–Acrylic Resin DLP-Manufactured Composite as a Modern Biomaterial

by Dorota Tomczak, Radosław Wichniarek and Wiesław Kuczko

Designs 2023, 7(2), 49; https://doi.org/10.3390/designs7020049 - 26 Mar 2023

Cited by 3 | Viewed by 1899

Abstract

Materials based on photocurable resins and pharmaceutically active agents (APIs) are gaining interest as a composite drug delivery system. In this study, a composite of caffeine with acrylic resin was obtained using an additive manufacturing method of digital light processing (DLP) as a [...] Read more.

Materials based on photocurable resins and pharmaceutically active agents (APIs) are gaining interest as a composite drug delivery system. In this study, a composite of caffeine with acrylic resin was obtained using an additive manufacturing method of digital light processing (DLP) as a potential material for transdermal drug delivery. The mechanical properties of the composites and the ability to release caffeine from the resin volume in an aqueous environment were investigated. The amount of caffeine in the resulting samples before and after release was evaluated using a gravimetric method. The global thresholding method was also evaluated for its applicability in examining caffeine release from the composite. It was shown that as the caffeine content increased, the strength properties worsened and the ability to release the drug from the composite increased, which was caused by negligible interfacial interactions between the hydrophilic filler and the hydrophobic matrix. The global thresholding method resulted in similar caffeine release rate values compared to the gravimetric method but only for samples in which the caffeine was mainly located near the sample surface. The distribution of caffeine throughout the sample volume made it impossible to assess the caffeine content of the sample using global thresholding. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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22 pages, 13850 KiB

Open AccessArticle

An Assembly-Oriented Design Framework for Additive Manufacturing

by Germain Sossou, Frédéric Demoly, Samuel Gomes and Ghislain Montavon

Designs 2022, 6(1), 20; https://doi.org/10.3390/designs6010020 - 18 Feb 2022

Cited by 5 | Viewed by 3636

Abstract

The shape complexity capability of additive manufacturing (AM) is currently the main thrust of the design for AM (DFAM) research. In order to aid designers embracing that complexity-for-free characteristics of AM, many design approaches have been put forth. However, AM does not only [...] Read more.

The shape complexity capability of additive manufacturing (AM) is currently the main thrust of the design for AM (DFAM) research. In order to aid designers embracing that complexity-for-free characteristics of AM, many design approaches have been put forth. However, AM does not only benefit parts’ designs: its capability can be harnessed at assembly level to design performant and innovative products. Most of the few contributions on the topic are concerned with part consolidation of existing assemblies, but other advantages such as assembly-free mechanisms, multi-material components, or even component embedding can also improve product design complexity. This paper aims to put forth a thorough DFAM framework for new product development (made of multiple parts) and which consider all the assembly-related characteristics of AM. It considers what can be called AM-based architecture minimization, which includes, among others, part consolidation and assembly-free mechanisms as well. Within context of an ‘AM-factory’, in which the most appropriate machine(s) is/are selected for easing a whole assembly manufacturing before the detailed geometric definition is committed. For the sake of completeness, a methodology based on functional flows has also been investigated for the parts’ design. A gripper as case study has been introduced to illustrate the framework. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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Review

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20 pages, 4648 KiB

Open AccessEditor’s ChoiceReview

A Review of the Current State of the Art of Polyether Ether Ketone (PEEK) Composite Based 3D-Printed Biomedical Scaffolds

by Rajesh Surendran, Sithara Sreenilayam Pavithran, Anugop Balachandran, Sony Vijayan, Kailasnath Madanan and Dermot Brabazon

Designs 2023, 7(6), 128; https://doi.org/10.3390/designs7060128 - 10 Nov 2023

Cited by 2 | Viewed by 2525

Abstract

Three-dimensional printing or additive manufacturing (AM) has enabled innovative advancements in tissue engineering through scaffold development. The use of scaffolds, developed by using AM technology for tissue repair (like cartilage and bone), could enable the growth of several cell types on the same [...] Read more.

Three-dimensional printing or additive manufacturing (AM) has enabled innovative advancements in tissue engineering through scaffold development. The use of scaffolds, developed by using AM technology for tissue repair (like cartilage and bone), could enable the growth of several cell types on the same implant. Scaffolds are 3D-printed using polymer-based composites. polyether ether ketone (PEEK)-based composites are ideal for scaffold 3D printing due to their excellent biocompatibility and mechanical properties resembling human bone. It is therefore considered to be the next-generation bioactive material for tissue engineering. Despite several reviews on the application of PEEK in biomedical fields, a detailed review of the recent progress made in the development of PEEK composites and the 3D printing of scaffolds has not been published. Therefore, this review focuses on the current status of technological developments in the 3D printing of bone scaffolds using PEEK-based composites. Furthermore, this review summarizes the challenges associated with the 3D printing of high-performance scaffolds based on PEEK composites. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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32 pages, 4311 KiB

Open AccessEditor’s ChoiceReview

Design for Additive Manufacturing: Recent Innovations and Future Directions

by Paul F. Egan

Designs 2023, 7(4), 83; https://doi.org/10.3390/designs7040083 - 29 Jun 2023

Cited by 10 | Viewed by 8077

Abstract

Design for additive manufacturing (DfAM) provides a necessary framework for using novel additive manufacturing (AM) technologies for engineering innovations. Recent AM advances include shaping nickel-based superalloys for lightweight aerospace applications, reducing environmental impacts with large-scale concrete printing, and personalizing food and medical devices [...] Read more.

Design for additive manufacturing (DfAM) provides a necessary framework for using novel additive manufacturing (AM) technologies for engineering innovations. Recent AM advances include shaping nickel-based superalloys for lightweight aerospace applications, reducing environmental impacts with large-scale concrete printing, and personalizing food and medical devices for improved health. Although many new capabilities are enabled by AM, design advances are necessary to ensure the technology reaches its full potential. Here, DfAM research is reviewed in the context of Fabrication, Generation, and Assessment phases that bridge the gap between AM capabilities and design innovations. Materials, processes, and constraints are considered during fabrication steps to understand AM capabilities for building systems with specified properties and functions. Design generation steps include conceptualization, configuration, and optimization to drive the creation of high-performance AM designs. Assessment steps are necessary for validating, testing, and modeling systems for future iterations and improvements. These phases provide context for discussing innovations in aerospace, automotives, construction, food, medicine, and robotics while highlighting future opportunities for design services, bio-inspired design, fabrication robots, and machine learning. Overall, DfAM has positively impacted diverse engineering applications, and further research has great potential for driving new developments in design innovation. Full article

(This article belongs to the Special Issue Additive Manufacturing – Process Optimisation)

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