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Electron Beam Melting (EBM) mechanism (Source: arcam.com) 

Electron Beam Melting (EBM) mechanism (Source: arcam.com) 

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Additive manufacturing (AM), also known as 3D Printing, is a revolutionary manufacturing technique which has been developing rapidly in the last 30 years. The evolution of this precision manufacturing process from rapid prototyping to ready-to-use parts has significantly alleviated manufacturing constraints and design freedom has been outstandingly...

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... field acts as a magnetic lens and helps the beam to focus to desired diameter, whereas the second field deflects the focused beam to the build platform at a desired point. In EBM printer, as shown in Figure 3, the machine spreads a layer of powder material on the build platform. The electron beam melts the material powder per the data provided to it. ...

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In the early stages of the additive manufacturing technology, its application is mainly focused in rapid prototyping. This is primarily because during those times, the range of layering material used is limited to plastics. But because of its foreseeable application in different fields, exploration of different materials for different applications...

Citations

... Additive manufacturing has evolved as an economically viable alternative to conventional manufacturing as it does not require any special tool or fixture [6]. Selective laser melting (SLM) is one among the laser powder bed fusion (L-PBF) manufacturing processes [7]. ...
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In this paper, a tool life test was performed using PVD-coated insert on Inconel 718 (IN718) samples in milling machining. A single cutting condition was considered with two machining environments. The tool life was tested on an IN718 workpiece fabricated through conventional (cast and wrought) and additive (selective laser melting) process routes. The as-built SLM samples were subjected to two heat treatments such as hot isostatic pressing (HIP) and aeronautic heat treatment (AHT). This study aimed to evaluate the machining behavior of C&W and SLM IN718 from the machining point of view such as tool wear, chip appearance, surface roughness, and residual stresses. The tool life tests were performed under two machining environments, such as dry and near dry environment using minimum quantity lubrication (MQL). Meanwhile, the tool wear propagation under different cutting conditions is also explored. Under both the cutting conditions, flank wear and fracture of the cutting edge are the most predominant failure modes minimizing the tool life. The microhardness, surface roughness, and residual stress measurements were analyzed. The result indicates that the microstructural difference between the C&W and SLM has more influence on the tool life compared to the machining environment. On machining, the SLM sample has 80% and 43% more tool life than the C&W in dry and MQL machining. Comparing the dry and MQL machining of SLM, on using MQL, the tool life is 30% less compared to the dry machining.
... However, 3D printing, also called additive manufacturing (AM), could break the above limits. AM is a fabrication process that builds an object layer-by-layer, which promotes complex structures that cannot be achieved by subtractive machining [3,4]. In particular, selective laser melting (SLM) is a well-developed high-efficiency AM technology for the fabrication of metal parts with complex geometries [5]. ...
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Three-dimensional printing, also called additive manufacturing (AM), offers a new vision for optical components in terms of weight reduction and strength improvement. A truss, which is a triangulated system of members that are structured and connected in such a way that they mainly bear axial force, is commonly used in steel structures to improve stiffness and reduce weight. Combining these two technologies, an extremely lightweight truss-structured mirror was proposed. First, the finite element analyses (FEA) on surface shape deviation and modal properties were carried out. Results showed that the mirrors had sufficient stiffness and a high weight reduction of up to 85%. In order to verify their performance, the truss-structured mirror blanks were fabricated with AM technology. After that, both the preprocessing and the postprocessing of the mirrors were carried out. The results show that without NiP coating, a surface shape deviation of 0.353λ (PV) and 0.028 λ (RMS) (λ = 632.8 nm) with a roughness of Ra 2.8 nm, could be achieved. Therefore, the truss-structured mirrors in this study have the characteristics of being extremely lightweight and having improved stiffness as well as strong temperature stability.
... It also reviewed how additive parts were different from wrought parts. Azam et al. (2018) proposed an in-depth review on additive manufacturing techniques of metals. This paper gave an insight to the available metal AM techniques and compared mechanical and physical properties of the produced parts with conventional parts (Azam et al., 2018). ...
... Azam et al. (2018) proposed an in-depth review on additive manufacturing techniques of metals. This paper gave an insight to the available metal AM techniques and compared mechanical and physical properties of the produced parts with conventional parts (Azam et al., 2018). A study by Ngo et al. (2018) gave a deep insight on methods, applications, and challenges of additive manufacturing techniques. ...
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Additive manufacturing is center of attention now days in innovative research specially because of industrial revolutionization and commercialization. It has a number of advantages, including mass customization, design freedom, waste minimization, and rapid prototyping in breakthrough applications such as aerospace, biomedical, constructions, buildings, and even food, health, and fashion. Metals, polymers, ceramics, and composites are among the materials used, as are smart materials, biomaterials, and nanomaterials. 3D printing is gaining a lot of traction these days, and it has made huge strides in the realm of additive manufacturing. A variety of software is also being used to assist the phenomenon of 3D printing. The basic types of 3D printing, the materials utilized for 3D printing, and applications are discussed in this review study.
... Additive manufacturing technologies are critical drivers for innovation and offer potential business benefits to the industrial sector (Azam et al. 2018;Mueller 2012;Santos et al. 2006). High value manufacturing companies aim to produce additively manufactured parts that form critical components for numerous industries. ...
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Metal powder-bed fusion additive manufacturing technologies offer numerous benefits to the manufacturing industry. However, the current approach to printability analysis, determining which components are likely to build unsuccessfully, prior to manufacture, is based on ad-hoc rules and engineering experience. Consequently, to allow full exploitation of the benefits of additive manufacturing, there is a demand for a fully systematic approach to the problem. In this paper we focus on the impact of geometry in printability analysis. For the first time, we detail a machine learning framework for determining the geometric limits of printability in additive manufacturing processes. This framework consists of three main components. First, we detail how to construct strenuous test artefacts capable of pushing an additive manufacturing process to its limits. Secondly, we explain how to measure the printability of an additively manufactured test artefact. Finally, we construct a predictive model capable of estimating the printability of a given artefact before it is additively manufactured. We test all steps of our framework, and show that our predictive model approaches an estimate of the maximum performance obtainable due to inherent stochasticity in the underlying additive manufacturing process.
... Melting (SLM), Electron Beam Melting (EBM) and Laser Engineered Net Shaping (LENS) methods, the final part is formed by allowing the metal powder to melt completely and solidify into the desired form. (Azam et al., 2018). Optimized processes are known to be able to produce parts with more than 90% density compared to indirect AM methods such as Binder Jetting processes and Selective Laser Sintering (SLS) necessitating post-processing infiltration operations (Yang et al., 2017). ...
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As an emerging and innovative industrial production technology, Additive Manufacturing (AM) allows for realization of three-dimensional shapes with complex geometries based on a layer-by-layer incremental manufacturing concept with high degrees of customization compared to traditional metal manufacturing processes such as forming, cutting and casting. However, despite the numerous advantages associated with additive manufacturing, the use of different combinations and the presence of a large number of process parameters, as well as their complex effects on product performance are a major obstacle to the use of these processes in many applications. Due to the use of non-optimized process parameters, part failure rates can be quite high especially during the first-time production of 3D metal parts Therefore, to successfully manufacture metal parts at the very first attempt, it is imperative that metal additive manufacturing processes are made predictable and reliable by eliminating costly and time-consuming trial and error attempts. To prevent wastage of both metal material and machine operating time as a result of repetitive production of faulty parts, it is therefore critical to simulate potential defects or cracks that may exceed the recommended tolerances for a particular part before initiating the printing process. In this work, a modelling study using Autodesk Netfabb Simulation Utility software was carried out to predict the extent at which changes in the magnitude of Selective Layer Melting (SLM) process parameters affect the distribution and formation of thermal gradients, temperatures, residual stresses and deformation solely by simulation without actually producing the part itself. Since the results of this study could not be verified experimentally, the model used was verified using results obtained from previously validated experimental studies as well as literature from validated work in which similar modelling techniques and simulation software were used. Keywords: Additive Manufacturing, Selective Laser Melting, Process Parameters, Process Modelling, Simulation Utility for Netfabb.
... SLM maximizes the utilization of material since un-melted powder can be re-used for fabrication [38]. It is an accurate and fast manufacturing process compared to other AM technologies and is able to achieve approximately 100% density, producing stronger part and eliminating the postprocessing constraints such as infiltration [39]. Additionally, with post heat treatment on SLM fabricated parts, fatigue life is increased, and energy absorption is enhanced by four-point bending test [40]. ...
Chapter
Aseptic loosening and stress shielding are the most common causes of implant failure after total knee and hip arthroplasty. Failure is due to difference in mechanical properties of natural bone and artificial implants. Porous structures provide the solution to this problem and are being used in implants to avoid failure. The purpose of this research is to determine an optimum porous structure that gives similar mechanical properties as natural bone and can be used in implants. Four different structures have been analyzed for their mechanical properties at different pore sizes and orientation. Finite element analysis is performed in all designs using the ANSYS structural module mimicking ISO standard testing (ISO 13314). All of the structures give optimum porosity to be used as implants, but only some instances show similar Young’s modulus and yield strength to mimic bone’s mechanical properties. The analysis of the porous structures gives promising results for application in orthopedic implants. Application of optimum structure to implants can reduce the premature failure of implants and increase the reliability.
... The additive manufacturing of metals, which has become an area of extensive research work, is transforming many industrial sectors by reducing component lead time and material waste. Many different industries using metallic materials, such as aerospace, automotive, tooling, and health care, among others, are already taking advantage of AM [1,2]. Nevertheless, metallic parts produced by AM are susceptible to various defects, property degradation and compositional changes that need to be addressed [3]. ...
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Ever-increasing demands of industrial manufacturing regarding mechanical properties require the development of novel alloys designed towards the respective manufacturing process. Here, we consider wire arc additive manufacturing. To this end, Al alloys with additions of Zn, Mg and Cu have been designed considering the requirements of good mechanical properties and limited hot cracking susceptibility. The samples were produced using the cold metal transfer pulse advanced (CMT-PADV) technique, known for its ability to produce lower porosity parts with smaller grain size. After material simulations to determine the optimal heat treatment, the samples were solution heat treated, quenched and aged to enhance their mechanical performance. Chemical analysis, mechanical properties and microstructure evolution were evaluated using optical light microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray fluorescence analysis and X-ray radiography, as well as tensile, fatigue and hardness tests. The objective of this research was to evaluate in detail the mechanical properties and microstructure of the newly designed high-performance Al–Zn-based alloy before and after ageing heat treatment. The only defects found in the parts built under optimised conditions were small dispersed porosities, without any visible cracks or lack of fusion. Furthermore, the mechanical properties are superior to those of commercial 7xxx alloys and remarkably independent of the testing direction (parallel or perpendicular to the deposit beads). The presented analyses are very promising regarding additive manufacturing of high-strength aluminium alloys.
... In LPBF, a common metal additive manufacturing (AM) process, a thin layer of precursor powder is selectively melted by tracing a high power laser to create a single, solid layer, followed by the spread of the next layer of powder for melting, and so on to build a part layer-by-layer [1][2][3][4][5][6][7][8][9][10][11][12][13][14] . This approach offers a number of distinct advantages over conventional metal fabrication, including rapid prototyping, efficient material utilization, fabrication of complex geometries incompatible with machining or molding techniques, and applicability to materials which may exhibit machining difficulties, such as titanium 4,8-12,14 . ...
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Laser powder bed fusion (LPBF) is a method of additive manufacturing characterized by the rapid scanning of a high powered laser over a thin bed of metallic powder to create a single layer, which may then be built upon to form larger structures. Much of the melting, resolidification, and subsequent cooling take place at much higher rates and with much higher thermal gradients than in traditional metallurgical processes, with much of this occurring below the surface. We have used in situ high speed X-ray diffraction to extract subsurface cooling rates following resolidification from the melt and above the β-transus in titanium alloy Ti-6Al-4V. We observe an inverse relationship with laser power and bulk cooling rates. The measured cooling rates are seen to correlate to the level of residual strain borne by the minority β-Ti phase with increased strain at slower cooling rates. The α-Ti phase shows a lattice contraction which is invariant with cooling rate. We also observe a broadening of the diffraction peaks which is greater for the β-Ti phase at slower cooling rates and a change in the relative phase fraction following LPBF. These results provide a direct measure of the subsurface thermal history and demonstrate its importance to the ultimate quality of additively manufactured materials.
... SLM maximizes the utilization of material since un-melted powder can be re-used for fabrication [38]. It is an accurate and fast manufacturing process compared to other AM technologies and is able to achieve approximately 100% density, producing stronger part and eliminating the postprocessing constraints such as infiltration [39]. Additionally, with post heat treatment on SLM fabricated parts, fatigue life is increased, and energy absorption is enhanced by four-point bending test [40]. ...
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Porous metal structures have emerged as a promising solution in repairing and replacing damaged bone in biomedical applications. With the advent of additive manufacturing technology, fabrication of porous scaffold architecture of different unit cell types with desired parameters can replicate the biomechanical properties of the natural bone, thereby overcoming the issues, such as stress shielding effect, to avoid implant failure. The purpose of this research was to investigate the influence of cube and gyroid unit cell types, with pore size ranging from 300 to 600 µm, on porosity and mechanical behavior of titanium alloy (Ti6Al4V) scaffolds. Scaffold samples were modeled and analyzed using finite element analysis (FEA) following the ISO standard (ISO 13314). Selective laser melting (SLM) process was used to manufacture five samples of each type. Morphological characterization of samples was performed through micro CT Scan system and the samples were later subjected to compression testing to assess the mechanical behavior of scaffolds. Numerical and experimental analysis of samples show porosity greater than 50% for all types, which is in agreement with desired porosity range of natural bone. Mechanical properties of samples depict that values of elastic modulus and yield strength decreases with increase in porosity, with elastic modulus reduced up to 3 GPa and yield strength decreased to 7 MPa. However, while comparing with natural bone properties, only cube and gyroid structure with pore size 300 µm falls under the category of giving similar properties to that of natural bone. Analysis of porous scaffolds show promising results for application in orthopedic implants. Application of optimum scaffold structures to implants can reduce the premature failure of implants and increase the reliability of prosthetics.
Book
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Preface The present book volume, Metal Matrix Composites: Fabrication, Production, and 3D Printing will provide great support and basic knowledge of MMCs to readers undergoing different programs related to Mechanical and Materials Technology, irrespective of the stream they opt for. All the engineers and designers are directly or indirectly involved in the manufacturing of metal matrix composites and its related processes. In general, Composites are made of two or more materials with a combination of required properties and are used by both manufacturers and industrialists. Moreover, understanding their manufacturing processes is paramount as these processes vary as do the materials. Hence, engineers and researchers opting for this profession should have deep knowledge about the materials and preparation of MMCs. The users can provide the best feedback and if they happen to be engineers, their feedback may help in better design, cost reduction, alternative material, and the process of making a part or machine or structure. The present book intends to provide in-depth knowledge for easy understanding of concepts. This book brings in the elements of the manufacturing of metal matrix composites with a detailed focus on its fabrication, production, and 3D printing. Real-life examples have also been used in the text rather than just describing the process. Also, the different authors have tried to explain the concepts and reasons in the best possible way.