Overview of current additive manufacturing technologies and selected applications.

Additive manufacturing (AM) refers to the method of manufacturing new parts or components by adding materials in successive layers as opposed to the traditional subtractive approach to remove materials to create new parts. Major advantages of AM include faster and cost-efficient fabrication, ability to produce intricate parts, and tenability of properties based on the raw materials. AM techniques have proven to help engineers ease the strenuous design cycle and avoid costly errors. Generally, AM is synonymous with three-dimensional printing (313P); however, AM or 313P is an umbrella term that includes several other techniques depending on the methodology. In this chapter, a concise account of the different AM categories and the most commonly used AM techniques is given. The future prospect of AM is also touched in the end.

Additionally known as three-dimensional (3D) printing, additive manufacturing has made major advancements possible in the fields of engineering, business, the arts, education, and medical. Thanks to recent developments, it is now possible to print three-dimensional to create complex, useful living tissues, biocompatible substances, cells, and supporting structures are combined. Regenerative medicine is utilizing 3D bioprinting. Additive manufacturing technology, or 3D printing, has been labelled the “next big thing” and is predicted to overtake cell phones in popularity. 3D printers use digital templates to produce actual, three-dimensional items. Adding layers to a print, commonly referred to as additive manufacturing, allows for the use of more than a hundred different materials, including nylon, metal, and plastic. Applications for 3D printing can be found in many different industries, such as industrial design, manufacturing, dental, automotive, aerospace, civil engineering, education, jewellery, footwear, and geographic information systems. It has shown to be a simple and affordable solution for a variety of use cases. Using computer-aided design tools and programming, three-dimensional printing is a sophisticated technique that adds material to a base surface to create three-dimensional things. Additive layer manufacturing, also referred to as 3D printing, is the technique of creating three-dimensional things by depositing or solidifying material one layer at a time. Using a computer-aided design module, pharmaceutical components are organized in a three-dimensional pattern. Afterwards, the constituents are converted into a machine-readable format resembling the surface of a three-dimensional dosage form. 3D printing has been used for jewelry, shoe-making, architecture, engineering & construction, the automotive industry as well as the aerospace field, dentistry and medicine, plus geographic information systems (GIS), civil engineering and education. After that stage of the process is completed, the surface transferred to the machine is then printed in different layers. Bioprinting is an interdisciplinary domain that integrates additive manufacturing with biology and material sciences to manufacture threedimensional structures representative of living organisms. The ability to create biological tissues and organs has attracted considerable attention in biomedical research owing to the rising demand for personalized medicine. This scenario propelled bioprinting forward which received much interest thus triggering comprehensive research efforts by various players such as companies, universities as well as research institutes. The goal of this book is to provide a thorough analysis of the complex and rapidly evolving field of bioprinting by critically analyzing and evaluating the existing scientific literature.

Additive manufacturing, or three-dimensional (3D) printing, refers to a layer-based production technology. A product is created through layers that are melted together. The layer-based manufacturing means that new surfaces can be shaped with complex forms created and combined in a single manufacturing process. It leads to components or entire products being printed locally. As a technology, it infers extensive changes for (a) product and production design, (b) supply chain options, and (c) business models. It does so because additive manufacturing opens opportunities not only for new product designs but also for firm operations and offerings. More specifically, additive manufacturing enables advanced organic designs manufactured as one piece, local on-demand printing of spare parts, and the printing of full-scaled prototypes to fit and test with final solutions. Movable parts can be printed as one single product and through one single production process. The local manufacturing reduces the need for transportations and subsuppliers. New business models include firms specializing in additive manufacturing for others, such as fab labs and printing houses. Through these changes, additive manufacturing challenges manufacturers of tools and parts as well as demand for logistics solutions. Customization, higher product precision, and increased sustainability are positive consequences of additive manufacturing. Meanwhile, additive manufacturing raises concerns about who owns the product design and who carries responsibilities for the product. Additive manufacturing affects product and production design, supply chains, and business models, and businesses face several ethical dilemmas regarding this new technology. Examples are provided to illustrate additive manufacturing practices.

3D Printing and Industrial Ecology

Overview of 3D additive manufacturing (AM) and corresponding AM composites

Additive Manufacturing (AM) enables the manufacture of three-dimensional components and products out of raw materials and three-dimensional design data. AM is also known as 3D printing is a set of emerging technologies that can be seen as a future of manufacturing. The ability of additive manufacturing in manufacturing complex products makes it more popular. Nowadays, many companies like aerospace, automotive, and healthcare industries are moving towards additive manufacturing for assembling their products. Many researches are being conducted in additive manufacturing to increase its efficiency. This chapter is a comprehensive study on future trends and technologies in additive manufacturing. Also, shows a comparison between additive manufacturing and subtractive manufacturing on different grounds. The article highlights the techniques that are currently being used in additive manufacturing and its future trends. The techniques include photopolymer, deposition, lamination, powder-based, etc. The trends in a number of papers published in additive manufacturing are shown. Both local and overseas research activities on additive manufacturing have been focusing on new processes, new materials, new software capabilities, and new applications of the emerging additive manufacturing technology. The article also includes predictions on the market value of additive manufacturing in its different sectors like hardware, software, materials, post-processing, etc.

Additive manufacturing (AM), also known as three-dimensional (3D) printing, is a manufacturing technology that constructs objects by sequentially adding material layer by layer. AM encompasses a range of different techniques capable of working with very different materials from metals and alloys to polymers and composites. As an advanced fabrication technology, AM is characterized by strong design flexibility, the ability to create intricate structures, and cost-effectiveness when compared to conventional fabrication methods. AM technology is widely employed in various sectors such as aerospace, healthcare, and industrial manufacturing, and its application is increasingly expanding into agricultural manufacturing. This study provides a comprehensive review and analysis of the current status of AM technology applied in the five main agricultural manufacturing aspects such as the application of AM technology in the manufacturing of agricultural equipment parts, its use in agricultural sensors, its role in the utilization of agricultural waste, its application in the field of plant growth mechanisms and in phytoremediation tissues. The current existing problems of AM technology and future development trends are also included to provide the implications for researchers. The adoption of AM technology in agriculture offers significant advantages, including enhanced production efficiency, cost reduction, innovation facilitation, and environmental protection. From initial prototyping to custom production today, AM technology provides more flexible, efficient and sustainable solutions for agricultural manufacturing. Especially in the fields of agricultural machinery, planting facilities and agricultural biomaterials, the application of AM technology has shown great potential and advantages. With the continuous advancement in technology and the reduction of costs, AM technology will become more popular and play a more vital role in agricultural manufacturing. In the future, we can foresee that AM will realize the manufacturing of agricultural products with higher precision, a more complex structure and more functions, providing more intelligent and personalized solutions for agricultural production. As such, it is emerging as a critical driving force in the advancement of precision agriculture.

Manufacturing processes are typically divided into three categories: formative, subtractive, and additive. While formative and subtractive manufacturing processes are considered more traditional, additive manufacturing (AM) is a family of evolving technologies that are rapidly growing with techniques and constraints yet to be explored. In this paper, a life cycle assessment comparison of casting (formative), machining (subtractive), and three AM methods, namely, binder jetting (BJ), powder bed fusion (PBF), and novel bound powder extrusion (BPE) has been performed. To compare each method from the sustainability standpoint, a life cycle assessment was conducted on a double cardan H-yoke, as a case study, focusing on environmental metrics such as water consumption, energy requirements, and CO2 emissions. This study focuses on the environmental effects of the novel BPE process with respect to current traditional manufacturing and AM methods. The case study was divided into two scenarios of the original and topology-optimized H-yoke to investigate the potential environmental footprint reduction by utilizing the capability of AM in generating complex geometries. The results proved that casting, as a formative manufacturing process, is the most environmentally friendly option for large-scale production of the investigated processes. Among the AM technologies that have been studied, PBF was the most environmentally friendly choice when coupled with renewable energy, reducing the total CO2 emission by 9.2% when compared to casting. In contrast, BJ was more environmentally friendly when fossil fuel was assumed as the main source of energy, showing only an 8.7% increase in CO2 emissions. The novel BPE preformed equal to or just short of BJ in all metrics, showing only a 9.4% increase of CO2 emission using fossil fuel compared to the 41.7% increase seen by PBF, with respect to BJ. AM environmental metrics were significantly improved when the topology-optimized part was employed. Machining, as a subtractive method, performed the worst from the environmental perspective due to the initial billet size and the amount of material to be removed (wasted). The production time for each process was analyzed to display the feasibility of producing the cast study part in a mass manufacturing scenario. The LCA case study proves that the increased number of BPE manufacturing steps does not negatively affect the environmental impact of the process, based on current LCA data. However, the BPE process is the most time-consuming process and must be considered when selecting the method of manufacture.

Purpose of study: Additive manufacturing processes taking the basic information form computer-aided design (CAD) file to convert into the stereolithography (STL) data file. Today additive layer manufacturing processes are playing a very vital role in manufacturing parts with high rate of effectiveness and accuracy. CAD software is approximated to sliced containing information of each layer by layer that is printed. The main purpose of the study is to discuss the scientific and technological challenges of additive layer manufacturing processes for making polymer components production through various technological parameters and problem-solving techniques of layer manufacturing processes.
 Main findings: Additive layer manufacturing is simply another name for 3D printing or rapid prototyping. As 3D printing has evolved as a technology, it has moved beyond prototyping and into the manufacturing space, with small runs of finished components now being produced by 3D printing machines around the world. Additive layer manufacturing (ALM) is the opposite of subtractive manufacturing, in which material is removed to reach the desired shape
 Methodology Used: The continuous and increasing growth of additive layer manufacturing processes to discuss with different experimental behavior through simulations and graphical representations. In ALM, 3D parts are built up in successive layers of material under computer control. In its early days, 3D printing was used mainly for rapid prototyping, but it is now frequently used to make finished parts the automotive and aerospace sectors, amongst many others.
 The originality of study: At the present time, the technologies of additive manufacturing are not just using for making models with the plastics but using polymer materials. It is possible to make finished products developed with high accuracy and save a lot of time and there is the possibility of testing more models.

The growing interest in multi-functional metallic biomaterials for bone substitutes challenges the current additive manufacturing (AM, =3D printing) technologies. It is foreseeable that advances in multi-material AM for metallic biomaterials will not only allow for complex geometrical designs, but also improve their multi-functionalities by tuning the types or compositions of the underlying base materials, thereby presenting unprecedented opportunities for advanced orthopedic treatments. AM technologies are yet to be extensively explored for the fabrication of multi-functional metallic biomaterials, especially for bone substitutes. The aim of this review is to present the viable options of the state-of-the-art multi-material AM for Ti-, Mg-, and Fe-based biomaterials to be used as bone substitutes. The review starts with a brief review of bone tissue engineering, the design requirements, and fabrication technologies for metallic biomaterials to highlight the advantages of using AM over conventional fabrication methods. Five AM technologies suitable for metal 3D printing are compared against the requirements for multi-material AM. Of these AM technologies, extrusion-based multi-material AM is shown to have the greatest potential to meet the requirements for the fabrication of multi-functional metallic biomaterials. Finally, recent progress in the fabrication of Ti-, Mg-, and Fe-based biomaterials including the utilization of multi-material AM technologies is reviewed so as to identify the knowledge gaps and propose the directions of further research for the development of multi-material AM technologies that are applicable for the fabrication of multi-functional metallic biomaterials. Statement of SignificanceAddressing a critical bone defect requires the assistance of multi-functional porous metallic bone substitutes. As one of the most advanced fabrication technology in bone tissue engineering, additive manufacturing is challenged for its viability in multi-material fabrication of metallic biomaterials. This article reviews how the current metal additive manufacturing technologies have been and can be used for multi-material fabrication of Ti-, Mg-, and Fe-based bone substitutes. Progress on the Ti-, Mg-, and Fe-based biomaterials, including the utilization of multi-material additive manufacturing, are discussed to direct future research for advancing the multi-functional additively manufactured metallic bone biomaterials.

Purpose A review on additive manufacturing (AM) of shape memory polymer composites (SMPCs) is put forward to highlight the progress made up to date, conduct a critical review and show the limitations and possible improvements in the different research areas within the different AM techniques. The purpose of this study is to identify academic and industrial opportunities. Design/methodology/approach This paper introduces the reader to three-dimensional (3 D) and four-dimensional printing of shape memory polymers (SMPs). Specifically, this review centres on manufacturing technologies based on material extrusion, photopolymerization, powder-based and lamination manufacturing processes. AM of SMPC was classified according to the nature of the filler material: particle dispersed, i.e. carbon, metallic and ceramic and long fibre reinforced materials, i.e. carbon fibres. This paper makes a distinction for multi-material printing with SMPs, as multi-functionality and exciting applications can be proposed through this method. Manufacturing strategies and technologies for SMPC are addressed in this review and opportunities in the research are highlighted. Findings This paper denotes the existing limitations in the current AM technologies and proposes several directions that will contribute to better use and improvements in the production of additive manufactured SMPC. With advances in AM technologies, gradient changes in material properties can open diverse applications of SMPC. Because of multi-material printing, co-manufacturing sensors to 3D printed smart structures can bring this technology a step closer to obtain full control of the shape memory effect and its characteristics. This paper discusses the novel developments in device and functional part design using SMPC, which should be aided with simple first stage design models followed by complex simulations for iterative and optimized design. A change in paradigm for designing complex structures is still to be made from engineers to exploit the full potential of additive manufactured SMPC structures. Originality/value Advances in AM have opened the gateway to the potential design and fabrication of functional parts with SMPs and their composites. There have been many publications and reviews conducted in this area; yet, many mainly focus on SMPs and reserve a small section to SMPC. This paper presents a comprehensive review directed solely on the AM of SMPC while highlighting the research opportunities.

To review the current metal-based additive manufacturing (AM) technologies, namely powder bed fusion (PBF) technologies, and their current prosthodontic applications. The PBF technologies reviewed are selective laser sintering (SLS), selective laser melting (SLM), and electron beam melting (EBM). The literature on metal AM technologies was considered, and the AM procedures and their current applications in prosthodontics were collated and described. Published articles about AM metal in dental care were searched (MEDLINE, EMBASE, EBSCO, and Web of Science). All studies related to the description, analysis, and evaluation of prosthodontic applications using metal AM technologies. AM technologies are reliable for many applications in dentistry, including metal frameworks for removable partial dentures (RPDs), overdentures, tooth- and implant-supported fixed dental prostheses (FDPs), and metal frameworks for splinting implant impression abutments. However, further studies are needed in future to evaluate the accuracy, reproducibility, and clinical outcome throughout function of AM technologies.

Additive manufacturing involves a new class of cyber-physical systems that manufacture 3D objects incrementally by depositing and fusing together thin layers of source material. In 2015, the global additive manufacturing industry had $5.165 billion in revenue, with 32.5% of all manufactured objects used as functional parts. Because of their reliance on computerization, additive manufacturing devices (or 3D printers) are susceptible to a broad range of attacks. The rapid adoption of additive manufacturing in aerospace, automotive and other industries makes it an attractive attack target and a critical asset to be protected. This chapter compares emerging additive manufacturing and traditional subtractive manufacturing from the security perspective. While the discussion compares the two manufacturing technologies, the emphasis is on additive manufacturing due to its expected dominance as the manufacturing technology of the future. The chapter outlines the additive and subtractive manufacturing workflows, proposes a framework for analyzing attacks on or using additive manufacturing systems and presents the major threat categories. In order to compare the two manufacturing paradigms from the security perspective, the differences between the two workflows are identified and the attack analysis framework is applied to demonstrate how the differences translate into threats. The analysis reveals that, while there is significant overlap with regard to security, fundamental differences in the two manufacturing paradigms require a separate investigation of additive manufacturing security.

Additive manufacturing is a new, rapidly emerging technique in the industrial sector. This is the process of creating parts by adding layer by layer material, hence it is called as 'Layer Manufacturing Process.’ This process is also called ‘Rapid Prototyping’ or ‘3DPrinting.’ This is a tool-less manufacturing method that produces parts in less time and with high precision. This process provides freedom for designing the parts and their complexity. Additive manufacturing has many advantages over conventional manufacturing processes like low production cost, no residual stresses, no wastage of material, etc. Nowadays, so much research work is going on in this additive manufacturing field. This manufacturing technology is going to replace the conventional manufacturing techniques in the upcoming days. In this paper, we discuss about the various additive manufacturing methods, its principles, applications, advantages, and challenges to industrial use.

Additive manufacturing (AM) has gained notoriety for offering advantages over traditional manufacturing methods, such as increased design complexity and flexibility. However, it has not found widespread use beyond rapid prototyping. One hindrance to the acceptance of AM processes in industry is the time and cost of fabrication per component. While metal AM by itself can be inexpensive, extra manufacturing steps in the form of subtractive manufacturing (SM) may need to be performed to reach final part tolerances, leading to hybrid additive-subtractive manufacturing (HASM) of a part, which increases time and cost. A potential area to reduce cost is through increasing the efficiency of the HASM process by conducting additive and subtractive manufacturing simultaneously. Usually, HASM is performed in a process where AM is completed in one machine or cell and transferred to another machine or cell for SM in a sequential assembly line process. This efficiency decreases part cost, but high aspect ratio parts or parts with internal geometry that require interleaved additive deposition and machining cannot be produced. One unexplored solution to simultaneous HASM that allows for interleaved operations is to operate the deposition head and machining spindle concurrently within the same machine envelope, known as concurrent HASM (CHASM). In this type of process, both AM and SM occur simultaneously on a batch of small parts or a single large part, maintaining a high efficiency without sacrificing the full range of complex geometries that AM allows for. A potential approach to the single-machine method could be to combine a robot and mill within the same envelope. A challenge to this approach, however, is control of both systems. Most machine controllers have limited external communication or, if a robot has been integrated, only offer movement of either the robot or mill at any given time. As a result, systems must pause either the AM or SM process to switch between them rather than working simultaneously. The present work investigates the positional accuracy of such a CHASM system comprised of a robotic arm and a 3-axis mill. Open-loop tests with limited communication between machines are performed on the system to verify positional error during concurrent robot-mill movements. Under certain conditions, it is demonstrated that position error can stay within 2 mm for the duration of a single layer; however, these tests show that, generally, the open-loop positioning performance of the system is inadequate for CHASM without part-specific hand-tuning of parameters. Based on these results, a set of requirements for successful robot-CNC CHASM is proposed for future integrations.