Challenges In Additive Manufacturing Research Articles

Full-composition-gradient in-situ alloying of Cu–Ni through laser powder bed fusion

Multi-material laser powder bed fusion has long been a challenge in additive manufacturing, especially in terms of controlling spatial variations and joining multiple materials. The challenge is even greater when multi-material components have different physical properties (e.g., different thermal expansions, thermal conductivities and laser reflectivities). The aforementioned scenario is applicable to copper–nickel (Cu–Ni) alloy. The simultaneous printing and controllable mixing of pure Cu and pure Ni within a single print have not been accomplished due to the substantial disparity in the physical properties of pure Cu and pure Ni. In this work, a full composition with different mixing proportions (100 % Cu to 100 % Ni) was fabricated in a single printing process through in-situ alloying based on our process of micro laser powder bed fusion. A transition from a columnar grain to a quasi-equiaxed grain morphology with texture variation from <110> to <111> was found in the full–composition–gradient of the Cu–Ni alloy. Microstructural variations, such as fine grain strengthening and grain boundary strengthening, greatly affected the mechanical properties of the alloys: the ultimate tensile strength ranged from 303 to 488 MPa and the yield strength ranged from 231 to 445 MPa. Moreover, the electrical conductivity of the alloys with a compositional gradient ranged from 3.6 % IACS to 96 % IACS due to the electron scattering induced by lattice distortion. In summary, a full-composition Cu–Ni gradient alloy was fabricated through in-situ alloying adopting micro laser powder bed fusion for the first time, enabling the investigation of the evolution of the microstructure and properties of the alloy as the alloy composition varies.

MitM attacks on intellectual property and integrity of additive manufacturing systems: A security analysis

Additive Manufacturing (AM) was originally invented to reduce the cost of the prototyping process. Over time, the technology evolved to be faster, more accurate, and affordable. These factors, in addition to the potential use of AM in parts production, have helped rapidly drive the growth of AM in both industrial and personal uses. Thus, there is an accompanying demand to understand the cybersecurity implications of such systems. In our research, we present an in-depth security review of Stratasys Dimension Elite and show how manufacturers of such high-end 3D printers failed to protect the confidentiality and integrity of the printed 3D models. Revealing the intricate dimensions of cyber threats within the realm of AM and laying the foundation for understanding the multifaceted nature of attacks, offering insights into vulnerabilities and potential consequences. Moreover, we demonstrate the massive impact network attacks can have on 3D printers' communication channels. Our sniffing attack stole transmitted models with a minimal overhead of 0.015 seconds to evade detection. The developed replacement attack targeted and replaced specific models with offline-prepared models. Also, we automated a sabotaging attack to alter the interior model structure on the fly with minimal visual but significant strength differences. By revealing these attacks, this research not only improves the security posture of 3D printers but also enhances the understanding of security challenges in additive manufacturing as a whole.

Legal challenges of additive manufacturing on the Moon

Additive manufacturing (AM) is promising for supporting sustainable human presence on the Moon as it reduces costs and dependency on the Earth. It has been incorporated into several lunar programs. Nonetheless, AM on the Moon is legally challenging. First, the legal field most challenged by AM is intellectual property (IP) law, and the peculiar location of AM on the Moon complicates the issue. Deciding the State to exercise jurisdiction and extend its IP protection to the Moon encounters difficulties. Second, AM on the Moon is most valuable when it uses lunar regolith as a source of printing material, which may face similar legal problems to in situ resource utilization, including determining the legality of the activity, deciding the State to exercise the jurisdiction and control over it, the protection of the lunar environment, and so forth. Lunar in situ AM using lunar regolith (LISAMUR), meaning using lunar regolith as raw materials to manufacture objects on the Moon through AM technologies, renders these problems more imminent and substantial. The article delves into the two categories of legal issues ignited by AM on the Moon and reveals that three reasons lead to the legal dilemma: the ambiguous terminology of the space treaties, the abstract principles, and the lacunae in space law. It suggests that as international legislation is slow, temporary approaches of coordinating the understanding of critical notions and relevant principles in space law and updating the registration regime through international cooperation on multilateral platforms would be more viable for coping with the legal challenges of AM on the Moon.

A review on critical challenges in additive manufacturing via laser-induced forward transfer

A review on critical challenges in additive manufacturing via laser-induced forward transfer

Future Prospects and Challenges in Additive Manufacturing for Complete Dentures: A Narrative Review

The utilization of computer-assisted design and computer-assisted manufacturing (CAD/CAM) techniques in the creation of complete dentures (CDs) has piqued the interest of many people. This article seeks to provide a comprehensive, critical, and objective analysis of the current knowledge of CDs and related technology. The aim of this study is to assess existing literature concerning 3D-printed complete dentures, covering aspects like innovative biomaterials, manufacturing methods and processes, workflow, and clinical effectiveness. The design of the current study included an initial review of 172 titles, an appraisal of abstracts, and finally a selection of articles for rigorous textual analysis. Inconsistencies discovered throughout the selection process were amicably resolved through discourse, culminating in the identification of 65 items. The publications retrieved from a thorough search of the PubMed, Scopus, and Embase databases spanned the years 1994 to 2023. Contemporary digital technology provides evident advantages, but its successful incorporation necessitates meticulous preparation. In the realm of dental healthcare, the digital workflow showcases versatility and a range of applications.

Rheology in Product Development: An Insight into 3D Printing of Hydrogels and Aerogels.

Rheological characterisation plays a crucial role in developing and optimising advanced materials in the form of hydrogels and aerogels, especially if 3D printing technologies are involved. Applications ranging from tissue engineering to environmental remediation require the fine-tuning of such properties. Nonetheless, their complex rheological behaviour presents unique challenges in additive manufacturing. This review outlines the vital rheological parameters that influence the printability of hydrogel and aerogel inks, emphasising the importance of viscosity, yield stress, and viscoelasticity. Furthermore, the article discusses the latest developments in rheological modifiers and printing techniques that enable precise control over material deposition and resolution in 3D printing. By understanding and manipulating the rheological properties of these materials, researchers can explore new possibilities for applications such as biomedicine or nanotechnology. An optimal 3D printing ink requires strong shear-thinning behaviour for smooth extrusion, forming continuous filaments. Favourable thixotropic properties aid viscosity recovery post-printing, and adequate yield stress and G' are crucial for structural integrity, preventing deformation or collapse in printed objects, and ensuring high-fidelity preservation of shapes. This insight into rheology provides tools for the future of material design and manufacturing in the rapidly evolving field of 3D printing of hydrogels and aerogels.

Artificial Neural Networks for Predicting Mechanical Properties of Crystalline Polyamide12 via Molecular Dynamics Simulations.

Predicting material properties of 3D printed polymer products is a challenge in additive manufacturing due to the highly localized and complex manufacturing process. The microstructure of such products is fundamentally different from the ones obtained by using conventional manufacturing methods, which makes the task even more difficult. As the first step of a systematic multiscale approach, in this work, we have developed an artificial neural network (ANN) to predict the mechanical properties of the crystalline form of Polyamide12 (PA12) based on data collected from molecular dynamics (MD) simulations. Using the machine learning approach, we are able to predict the stress-strain relations of PA12 once the macroscale deformation gradient is provided as an input to the ANN. We have shown that this is an efficient and accurate approach, which can provide a three-dimensional molecular-level anisotropic stress-strain relation of PA12 for any macroscale mechanics model, such as finite element modeling at arbitrary quadrature points. This work lays the foundation for a multiscale finite element method for simulating semicrystalline polymers, which will be published as a separate study.

A Review of Additive Manufacturing of Soft Magnetic Materials in Electrical Machines

This paper presents a review of the main advantages and challenges of Additive Manufacturing (AM) applied in the production of soft magnetic components for electrical machines. Firstly, a general introduction about additive manufacturing is made, considering all of its possibilities of application, then the authors focused on the electrical machine application field, in particular the AM of soft ferromagnetic materials. The soft ferromagnetic materials are fundamental for the production of electrical machines, and currently, there are more and more requests for designed ad hoc geometries, which can be difficult to produce with conventional manufacturing technologies. With this purpose, AM can be used to produce the desired geometries.

In Situ Analysis of Curling Defects in Powder Bed Fusion of Polyamide by Simultaneous Application of Laser Profilometry and Thermal Imaging

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.

Crystalline and Hairy Nanocelluloses for 3D Printed Hydrogels and Strongly Structured Cryogels

This work addresses two main challenges in additive manufacturing of cellulosic hydrogels and cryogels. They are (1) the rheological properties of suspensions of electrosterically stabilized nanocrystalline cellulose (ENCC, a member of the family of hairy nanocelluloses) are inadequate for 3D printing of hydrogels and (2) 3D printed cellulose nanocrystal (CNC) cryogels have poor mechanical properties. The above limitations are effectively addressed by hybridization of CNC/ENCC in the presence of a salt at an optimized weight ratio. Controlling the CNC/ENCC weight ratio leads to high tunability of the rheological properties of the hybrid systems, resulting in high-fidelity printing of 3D hydrogels. Similarly, high tunability in the mechanical performance of the cryogels, obtained upon freeze drying of the printed hydrogels, is achieved by manipulating the CNC/ENCC ratio. Compared to neat CNC cryogels, the compressive strength of the CNC/ENCC (1:1) cryogels is 78% higher. Combined, CNC bestows high printability on the cryogels, while the presence of ENCC leads to the strengthening of the corresponding super porous solid materials. Our findings open new opportunities for sustainable, biocompatible, and lightweight cellulosic structured scaffolds that can be tailored for a broad spectrum of applications.

Three-dimensional characterization of the pore structures in SiC formed by binder jet 3D printing, polymer infiltration and pyrolysis (PIP)

Processing of binder jet printed refractory ceramics, including SiC, to high density remains a major challenge in additive manufacturing. Polymer Infiltration and Pyrolysis (PIP) has been applied to SiC made with large particle sizes and low sinterability, but the PIPed material struggles to reach high density even after many infiltration cycles. In this work, binder jetted α-SiC powders were PIPed up to 8 cycles and characterized after each cycle. By comparison with an exclude volume model, the infiltrated density showed a plateauing after 8 cycles. X-ray micro-computer tomography (μCT) was used to characterize the microstructure evolution in 3D. The reconstructed cross-sectional image indicated that large cracks, attributed to gas pressure build-up in burn-out, were formed as the number of infiltration cycles increased. Additionally, quantitative 3D data extracted from μCT images showed a large pore network existed in the interior of all samples and remained mostly open, even after 8 PIP cycles.

Novel solid-state metal powder surface modification process for additive manufacturing of metal matrix composites and alloys

Although metal additive manufacturing has been widely studied owing to its flexible product shape design, the material selection window for metal additive manufacturing remains narrow owing to limited feedstocks. To address the challenges in additive manufacturing, an innovative metal powder fabrication process was developed in this study. This process is known as surface modification and reinforcement transplantation (SMART), and it efficiently produces surface-modified feedstock powders, such as spheroidized, surface-alloyed, surface-coated, or composite powders, which facilitate the exploration of new alloys and composites via additive manufacturing. In this study, the working principles of the SMART process were established, and some practical applications of the SMART process were considered by fabricating specialized metal additive manufacturing feedstocks such as carbon nanotube-coated, Mo alloyed, and TiC particle-reinforced Inconel 625 powders. Furthermore, Mo-alloyed and TiC particle-reinforced powders were utilized in the directed energy deposition process to validate the performance of the SMART powder by fabricating Mo-controlled alloy and TiC particle-reinforced composites. The SMART process was compared with the existing processes and proved to be advantageous. Therefore, this study provides a novel method for producing feedstock powders for additive manufacturing.

Opportunities and challenges of additive manufacturing toward magnetic refrigeration

Opportunities and challenges of additive manufacturing toward magnetic refrigeration

Modelling of the design process challenges in additive manufacturing using PROMETHEE

Design process-related challenges have caused significant limitations to the innovations that can be brought to additive manufactured parts. These challenges pose a barrier to development that can be implemented in the additive manufacturing field. Few challenges to be named are the surface roughness, formation of build angles, and residual stresses that have created a barrier to the easy manufacturing of the additive manufacturing parts. PROMETHEE multi criteria decision making tool helps to compare alternatives of manufacturing techniques regarding the criteria, being the challenges of design process in additive manufacturing. PROMETHEE gives the most preferred alternative using both PROMETHEE – I and PROMETHEE – II to give the most accurate option taking into account all challenges. It uses various preference ranking functions to judge between alternatives in consideration to the criteria. The data was collected using the Likert scale to simplify the data collection process and get the most effective analysis. The design process in additive manufacturing has various challenges, and these challenges being modelled will give industrialists a better understanding of how to overcome and make changes to adapt to these challenges.

Formidable Challenges in Additive Manufacturing of Solid Oxide Electrolyzers (SOECs) and Solid Oxide Fuel Cells (SOFCs) for Electrolytic Hydrogen Economy toward Global Decarbonization

Solid oxide electrolysis cells (SOECs) and solid oxide fuel cells (SOFCs) are the leading high-temperature devices to realize the global “Hydrogen Economy”. These devices are inherently multi-material (ceramic and cermets). They have multi-scale, multilayer configurations (a few microns to hundreds of microns) and different morphology (porosity and densification) requirements for each layer. Adjacent layers should exhibit chemical and thermal compatibility and high-temperature mechanical stability. Added to that is the need to stack many cells to produce reasonable power. The most critical barriers to widespread global adoption of these devices have been their high cost and issues with their reliability and durability. Given their complex structure and stringent requirements, additive manufacturing (AM) has been proposed as a possible technological path to enable the low-cost production of durable devices to achieve economies of scale. However, currently, there is no single AM technology capable of 3D printing these devices at the complete cell level or, even more difficult, at the stack level. This article provides an overview of challenges that must be overcome for AM to be a viable path for the manufacturing of SOECs and SOFCs. A list of recommendations is provided to facilitate such efforts.

A comparative evaluation of sepiolite and nano-montmorillonite on the rheology of cementitious materials for 3D printing

• The use of fibrous sepiolite as a rheology modifier in printable cement-based materials was investigated. • A comparative analysis of its use with a commonly used nano clay was established. • A sustainable printable mortar mix design was obtained by only using limited dosage of superplasticizer. • Incorporation of clays increased the dynamic yield stress and time-dependent evolution of static yield stress. • Addition of clays improved the thixotropic behavior of cement-based systems, particularly those containing fly-ash. • The sepiolite was found to be more effective compared to nano-montmorillonite in terms of improving thixotropy, structural build-up and recovery. Through the last decade, methods of digital manufacturing of concrete gained a significant interest compared to conventional concrete. The main challenge in additive manufacturing (3D printing) is to design a highly thixotropic cementitious system. This study aims to investigate the use of sepiolite as a rheology modifier as a novel approach to improve the thixotropic behavior and adapt cementitious systems to 3D printing. To understand the influence of sepiolite on rheological properties, a comparative evaluation with nano-montmorillonite was established. The effectiveness of clay addition was also investigated in fly-ash amended cement-based materials. The rheological analysis was done on cement-paste samples containing both clays in terms of their effects on thixotropy, structural build-up, and recovery. A preliminary printability assessment was done with a lab scale printer having a ram extruder. The results show that the incorporation of clays increased the dynamic yield stress and time-dependent evolution of static yield stress. Moreover, the addition of clays improved the thixotropic behavior of cement-based systems, particularly those containing fly-ash. Herein, the sepiolite was found to be more effective compared to nano-montmorillonite in terms of improving thixotropy, structural build-up and recovery. The results showed that use of fly-ash enhances the printability of the mix for the specified extruder and the samples containing 1% nano-montmorillonite or 0.5% sepiolite can be printed. The positive effects of sepiolite were attributed to opposing surface charges of the clay layers and its micro-fibrous microstructure. The findings in this study enabled an in-depth understanding of the rheology and printability of fly-ash amended clay containing printable cement-based mortars.

Influence of process parameters on the particle–matrix interaction of WC-Co metal matrix composites produced by laser-directed energy deposition

The prediction of the in-service behaviour of metal-matrix composites produced by laser-directed energy deposition is a fundamental challenge in additive manufacturing. The interaction between the reinforcement phase and the matrix has a major impact on the micro and macroscopic properties of these materials. This interaction is fostered by the exposition of the materials to high temperatures. Hence, it is highly influenced by the thermal cycle of the manufacturing process. In this work, an experimental approach is adopted to determine the influence of the main process parameters on the properties of metal-matrix composites. Statistical regression models are employed to consider the role of the most relevant parameters, from exploration to exploitation. The obtained trends are further corroborated by the corresponding microstructural, SEM, and EDS analyses. In terms of surface hardness, the DOE reveals different trends of the response depending on the composition of the feedstock employed. It is concluded that the strengthening behaviour of the material varies throughout the experimental domain studied. When high WC% feedstocks are employed, the main strengthening mechanism responsible for the increase of hardness is the solid-solution of tungsten and carbide precipitation. On the contrary, when low WC%s are employed, grain refinement becomes the main strengthening mechanism.

A Recent Trend on Additive Manufacturing Sustainability with Supply Chain Management Concept, Multicriteria Decision Making Techniques

In the past 3 decades, the emerging technology in manufacturing sector other than conventional manufacturing is additive manufacturing (AM). The additive manufacturing principle was completely born from the research gaps of conventional manufacturing concepts such that the elimination of wastage and produce the component layer upon layer. Every new technology obtains the sustainability that may consider in the supply chain management principle of the raw material to finished products and decision-making techniques are to reach the consumer or customer as properly and periodically but these things are addressed challenges in additive manufacturing. This review paper aims to narrate the common research gaps on additive manufacturing, the structure of the supply chain management on AM, MCDM tools/techniques, AM application in different fields, challenges of selection of additive manufacturing, AM processes, and its application. The traditional method of literature review has been used for this review. The outcome of this review has helped the new researcher’s decision making on the AM various problems as easily and the new researchers may give the experimental solution for explored research gaps.

A novel methodology to manufacture complex metallic sudden overhangs in weld-deposition based additive manufacturing

PurposeAmongst various additive manufacturing (AM) techniques for realizing the complex metallic objects, weld-deposition (arc)-based directed energy AM technique is attaining more focus over commercially available powder bed fusion techniques. This is because of the capability of high deposition rates, high power and material utilization, simpler setup and less initial investment of arc-based AM. Nevertheless, realization of sudden overhanging features through arc-based weld-deposition techniques is still a challenging task because of the necessity of support structures. This paper aims to describe a novel methodology for producing complex metallic objects with sudden overhangs without using supports.Design/methodology/approachThe realization of complex metallic objects with sudden overhangs (without using supports) is possible by reorienting the workpiece and/or deposition head at every instance using higher order kinematics (5-axis setup) to make sure the overhanging feature is in line to the deposition direction.FindingsIn the absence of universally applicable support mechanism, deposition of overhanging features remains one of the main challenges in AM. A separate support structure is often necessary for depositing the overhanging features. Small overhang features are usually possible by a little overextension from the previous layer. Nevertheless, deposition of large gradually varying overhangs and sudden overhangs with complex features without support structures is a challenging task in any AM process. This demands higher order kinematics which calls for inclined and/or orthogonal slicing and area filling.Originality/valueThe unique aspect of this paper is the identification of sudden overhang feature from a tessellated computer-aided design (.stl) file and generates an orthogonal tool path for deposition for sudden overhangs. An in-house MATLAB routine has been developed and presented for performing the same. This methodology helps in realization of sudden overhangs without use of supports. To validate proposed technique, various illustrative case studies have been taken up for deposition.

Opportunities and challenges in additive manufacturing used in space sector: a comprehensive review

PurposeThe purpose of this study is to explore the applications of 3D printing in space sectors. The authors have highlighted the potential research gap that can be explored in the current field of study. Three-dimensional (3D) printing is an additive manufacturing technique that uses metallic powder, ceramic or polymers to build simple/complex parts. The parts produced possess good strength, low weight and excellent mechanical properties and are cost-effective. Therefore, efforts have been made to make the adoption of 3D printing successful in space so that complex parts can be manufactured in space. This saves a considerable amount of both time and carrying cost. Thereof the challenges and opportunities that the space sector holds for additive manufacturing is worth reviewing to provide a better insight into further developments and prospects for this technology.Design/methodology/approachThe potentiality of 3D printing for the manufacturing of various components under space conditions has been explained. Here, the authors have reviewed the details of manufactured parts used for zero-gravity missions, subjected to onboard international space station conditions and with those manufactured on earth. Followed by the major opportunities in 3D printing in space which include component repair, material characterization, process improvement and process development along with the new designs. The challenges like space conditions, availability of power in space, the infrastructure requirements and the quality control or testing of the items that are being built in space are explained along with their possible mitigation strategies.FindingsThese components are well comparable with those prepared on earth which enables a massive cost saving. Other than the onboard manufacturing process, numerous other components as well as a complete robot/satellite for outer space applications were manufactured by additive manufacturing. Moreover, these components can be recycled onboard to produce feedstock for the next materials. The parts produced in space are bought back and compared with those built on earth. There is a difference in their nature, i.e. the flight specimen showed a brittle nature, and the ground specimen showed a denser nature.Originality/valueThis review discusses the advancements of 3D printing in space and provides numerous examples of the applications of 3D printing in space and space applications. This paper is solely dedicated to 3D printing in space. It provides a breakthrough in the literature as a limited amount of literature is available on this topic. This paper aims at highlighting all the challenges that additive manufacturing faces in the space sector and also the future opportunities that await development.