Abstract Additive Manufacturing Technologies Research Articles

Business model and methods of evaluation in sustainable manufacturing

Additive manufacturing (AM) enables cost-effective and efficient production toward sustainability. However, a rigorous evaluation method is required to further investigate the measurement method and efficiency before AM can be well-positioned in sustainable manufacturing and become the industry mainstream. Cost savings play a key role in the manufacturing industry. Compared to conventional manufacturing (CM), the cost of AM is volume-independent. In contrast, CM production requires a certain volume to share the initial tooling costs to achieve cost reduction. This constraint limits CM from service on demand and leaves ambiguity in the threshold setting of that critical batch volume. In addition, the invisibility of AM advantages in cost factors blocks AM technologies from appropriate processes and affects its applications. To address these issues, this paper proposes a business model. The major issues encountered by AM are the scaling, speed, and size of products. The enhancement of cost modeling and addressing speed, scale, and size issues are the novelties of this study and provide a breakthrough in AM issues. Generic equations are derived using the convergence effect and cost–volume intersection calculation between AM and CM. Furthermore, the divide-and-conquer approach is proposed to support scaling factors and dependencies for both AM and CM. Consequently, appropriate AM technologies can be compared with the CM convergence threshold to contribute to decision-making. Next, the advantages and weaknesses of AM are identified, and a collaboration pattern is proposed to connect large enterprises, small-and medium-sized enterprises, and home-based manufacturers into an AM society. Through this society, the advantages of AM can be fully exploited, scaling and speed issues can be addressed, and AM's dominant role in sustainable manufacturing can be made feasible.

INTRODUCING NOVEL LEARNING OUTCOMES AND PROCESS SELECTION MODEL FOR ADDITIVE MANUFACTURING EDUCATION IN ENGINEERING

Additive manufacturing (AM) is at the verge of being recognised as one of the main manufacturing methods among the traditional ones. The largest obstacle in using AM in the companies is the lack of knowledge about the possibilities of the technology. One sub-problem caused by this is the lack of qualified machine operators in companies due to the insufficient AM education. This indicates the need for strengthen the current AM education especially in the B.Sc. and M.Sc. levels in engineering education by emphasising the importance of AM in curriculum development. This study presents novel learning outcomes based on the needs of manufacturing industry and companies in Finland. A questionnaire was conducted to work-life representatives in order to map the requirements for AM education in the mechanical engineering degree of the Lapland University of Applied Sciences in Finland. The responds were collected as competences representing different areas of AM knowledge and the learning outcomes were derived from the responds. AM education must also provide a model for selecting the most suitable AM technology in order for students to learn the technological aspects. This study also presents a process selection model which can be used in AM education. The model allows the student to compare different AM technologies from different perspectives such as material, functionality and visual appearance point-of-view.
 
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Internal Surface Quality Enhancement of Selective Laser Melted Inconel 718 by Abrasive Flow Machining

Abstract Additive manufacturing (AM) technology enables a new way for fabricating components with complex internal surfaces. Selective laser melting (SLM), being one of the most common AM techniques, is able to fabricate complex geometries with superior material properties. However, due to the poor surface quality, the fabricated internal surfaces cannot meet the specifications for some real applications. To achieve the required internal surface condition, post-polishing process is essential. As one of the most prominent processes for finishing inaccessible surfaces with a wide range of materials, abrasive flow machining (AFM) shows great potential to polish AM internal surfaces. Hence, this paper presents an analytical and experimental study on the internal surface quality improvement of SLM Inconel 718 by AFM, aiming to verify the feasibility of AFM on internal surface quality improvement. The surface evolution process was modeled, and the effects of process parameters on surface and subsurface quality were evaluated. The results show that good surface roughness was obtained at the medium conditions of high viscosity, large particle size, low extrusion pressure, and low temperature. The surface morphology was greatly affected by the medium particle size which showed consistency with the surface evolution model that small abrasive particles are unable to overcome the width and depth of the valleys, resulting in the formation of craters. The partially melt layer was effectively removed, and no subsurface damage was induced.

Metal Powder and Wire Additive Manufacturing Technology

Additive manufacturing technology can quickly manufacture parts with dense microstructures and excellent mechanical properties, so that it shows a broad application prospect in aerospace and other fields. Additive manufacturing technology was briefly introduced in this paper. On this basis, the technology and characteristics of metal powder and wire additive manufacturing were systematically analyzed and compared, and the development of additive manufacturing technology was prospected.

Design of SLM automatic leveling powder laying mechanism and variable position powder laying movement strategy

Additive Manufacturing technology has aroused widespread attention for free designing and rapid prototyping. Selective Laser Melting technology is one of the metal additive manufacturing technologies, and it has become an important choice for precision manufacturing of metal parts with high performance and complex shape. In the process of selective laser melting, the accuracy and efficiency of laying powders directly affect the quality and time of parts printing. In order to realize laying powder accurately and efficiently in printing process, the mechanical mechanism and movement strategy of the powder laying device are studied in this paper. A powder laying mechanism with automatic leveling function is designed. On the premise of ensuring the powder laying accuracy, a variable position powder laying movement strategy is proposed to improve the powder laying efficiency The case analysis results show that the laying powder efficiency has been increased by 49.2%.

Additive Manufacturing Application to a Ship Propeller Model for Experimental Activity in the Cavitation Tunnel

Additive manufacturing (AM), or three dimensional printing, is a modern way to build objects with possibly a high degree of accuracy and favorable cost/benefit ratio. This approach is widely used by many manufacturing industries and a certain interest for this innovative production technology is also growing in the ship design and production field. To this regard, the experimental activity at the model scale is often necessary for the ship performance assessment in the design phase. In the article, preliminary results of a propeller model for the cavitation tunnel, built with additive technology, are presented, showing the strengths and weaknesses of the printed model. Moreover, as an introductive overview, different AM technologies are briefly described, with the aim to point out potential applicability to ships. 1. Introduction Additive Manufacturing (AM), also known as 3D printing, is a well-known process to shape objects by layering materials under numerical control until the completion of the work. It represents an innovative approach because it is based on the addition of material instead of carving material from a block (like CNC—Computer Numerical Control, i.e. a manufacturing approach relying on mills, drills, and other numerically controlled tools). AM is deemed as an outstanding flywheel for innovation in the productive world, and the shipbuilding industry seems to have started realizing the advantages of this technology, already largely used, e.g., in the automotive, aerospace, biomedical, and energy industries (Shahi 2016; Satish Prakasha et al. 2018). In this perspective, an introductive overview of different AM typologies is presented in the article, to possibly understand how it could be used to improve ship design and production. The overview includes the applicable technologies, focusing on the printing process, the materials, and the mechanical properties of the final printed object. A practical example of AM technology application is presented regarding the printing of the blades of a ship's propeller model for experiments in a cavitation tunnel.

Design Modification of Additive Manufacturing Parts Using Texture Information of 3D Model

Additive manufacturing (AM) has been commonly used for the prototyping of three-dimensional (3D) models. The input model of the AM technology is a triangular model representing the surface shape of an object. The design features on a triangular model are generally not clear as the vertices are irregularly distributed. If design modification is necessary, it is difficult to segment and extract the meshes from the model. The objective of this study is to propose a method for extracting the design features on an object model by using the texture information. A 3D color model including a triangular model representing the object shape and a texture map describing the object texture is employed. The 3D model is generated by using a set of object images captured from different views surrounding the object. A texture mapping algorithm is then employed to generate the texture map corresponding to the 3D model. With both meshes and texture displayed in a texture mode, a region extraction technique is employed to extract the design features. All parts separated can then be fabricated with an AM machine, and assembled for checking the feasibility of design modification. Several products are employed to demonstrate the feasibility of the proposed technique.

Impact of additive manufacturing in different areas of Industry 4.0

Additive manufacturing (AM) technologies are becoming an essential part of tomorrow's smart factories, where software, technologies, and processes are being integrated to deliver world-class results. AM is to provide extensive inputs to smart manufacturing systems using digital design, and specialised software-based manufacturing technology. AM helps to create product innovation, thereby impacting different areas of Industry 4.0. The purpose of this study is to understand how AM can impact various areas of Industry 4.0. A large number of research papers on additive manufacturing in Industry 4.0 and other related articles in the manufacturing field have been studied to identify its fifteen significant impacts and subsequent research direction. In future, AM will create technological advancement in design, manufacturing and provide a maximum contribution in Industry 4.0 to the self-optimise production system. AM helps to reduce a considerable amount of unused inventory and helps fulfil the customised demand of consumer and market. AM creates any customised prototype for specific users in lesser time. It provides innovative product concepts by assessing market demand and minimise the supply chain cost.

Use of Polymer Scaffolding and Electroplating to Create Porous Metal Structures

Additive manufacturing (AM) offers a fabrication process that provides numerous advantages when compared with traditional fabrication methods. Specifically, AM technology allows for the creation of porous media where porosity and permeability can be precisely controlled. When manufacturing metallic artifacts for biomedical use (e.g., bone implants), the investment in a laser sintering machine can be prohibitive for the budget-conscious enterprises limiting the study and use of this technology. Electroforming, electroplating, and electrotyping have been used for decades to replicate the complex shape of unique artifacts and can be viable techniques to create complex metallic shapes starting from a conductive mandrel. We investigated a fabrication technique that combines the stereolithographic additive manufacturing of a polymeric mandrel with electroforming, to obtain porous composites of polymers and metals. The fabrication method to electroform a porous artifact is presented, and an analytical model of the combined properties of the composite material is provided.

Development of light weight multi-rotor UAV structures through synergistic application of design analysis and fused deposition modelling

Additive manufacturing (AM) technologies are gaining acceptance for fabricating end-use parts in several sectors and this study focuses on developing AM-based approach for gainful development of unmanned aerial vehicles (UAVs). Design-freedom and time-compression are synonymous with AM technologies and to realise the same in the development of UAVs, redesigning of the components is imperative. This paper presents a protocol that synergistically combines design iterations and fused deposition modelling (FDM) for developing light-weight structures for multi-rotor UAVs. Rather than employing expensive industry-grade FDM systems, the present study illustrates a fabrication protocol based on desktop 3D printers and affordable FDM filament material of polyactic acid (PLA). Multiple design configurations are analysed and prototyped leading to considerable weight reduction. The resultant operational benefits that are related to lesser part count, lower assembly effort and higher flight duration as compared to the conventional designs are demonstrated through experimental efforts. A customised process for electrochemical deposition of copper-nickel layers over the PLA parts is developed for enhancement in tensile, flexural and impact performance. Findings from this study lead to new vistas for rapid design iterations through an AM centric fabrication process with consequential impact on ever burgeoning UAV domain.

Challenges of additive manufacturing in production systems

Additive Manufacturing (AM) has become indispensable in the context of digitalization and Industry 4.0 and is said to be a mega trend of the 21st century. The technology offers immense opportunities to revolutionize the production of parts and components in all industries. Despite of the outstanding technical possibilities, the industry-wide adaptation rate is low. The current approach of looking at AM from a mostly technological view is a major reason for this. The challenge is to efficiently integrate 3D printing and other additive processes into existing manufacturing processes and systems. AM must be perceived as a multidimensional topic and viewed from different perspectives, two of which are the AM technology and the planning and management of production systems. These two perspectives have to be addressed simultaneously and cross-linked. In order to use AM to tackle some of the most challenging problems in modern manufacturing systems like increasing variant diversity, shorter product lifecycles, the demand for digitized processes and cyber-physical systems, it is necessary to develop interdisciplinary approaches and solutions, because none of the disciplines can reach the necessary performance and cost-efficiency alone.

Laser Powder Bed Fusion: tailoring the microstructure of alloys for biomedical applications

Abstract Additive manufacturing (AM) is particularly attractive for biomedical applications, where complex geometries and a high degree of individualization are required. Laser powder bed fusion (LPBF) is an AM technology exploiting the action of a solid-state laser to locally melt a metal powder according to a computer aided design (CAD) model. In the present study, the EOS Cobalt Chrome SP2 (Co-Cr-Mo-W) and Ti64 (Ti6Al4V) powders were sintered by the system equipped with a Yb fiber laser. During LPBF, the Co-Cr-Mo-W metal powder undergoes total melting followed by rapid cooling, giving rise to athermal martensitic phase transformation from the high-temperature γ (fcc) phase to the low-temperature e (hcp) phase. This produces an intricate network of thin e-lamellae inside the γ phase matrix. After the firing cycle this structure is maintained, and a massive presence of coarse precipitates is also observed. Owing to the rapid cooling taking place during LPBF, in Ti6Al4V sintered samples only the acicular martensitic α’ phase is present. The firing cycle induces the β phase formation at the α plate boundaries and this microstructure leads to reduced values of strength, with respect to those of the as-sintered samples. The highlighted behaviors show that by tuning the post-production heat treatments it is possible to tailor the microstructure and the mechanical properties.

Melting and Solidification Behavior of High-Strength Aluminum Alloy during Selective Laser Melting

Additive manufacturing (AM) technology has been dramatically attracted attention because of advantages in building free-shaped parts and simplification of manufacturing process. Recently the most relevant alloys, such as TiAl6V4, Inconel 718, AlSi10Mg and so on, are able to manufacture the parts using metal AM technology. However high-strength 2024, 6061 and 7075 aluminum alloys are difficult to fabricate using selective laser melting (SLM) owing to solidification cracking during solidification. In this research, the melting and solidification behaviors of AlSi10Mg alloy during SLM process were observed under various fabrication conditions of laser power and scan speed using a high-speed camera. It was found that the melting and solidification behavior of the alloy is greatly different by the fabrication conditions. And also the mechanism of solidification cracking in 2024 and 6061 aluminum alloys is investigated by the observation of the surface morphology and microstructure of the alloys using OM, SEM and EDS, comparing with Al10SiMg alloy. As a result, crack-free 2024 and 6061 aluminum alloy parts can be obtained by fabrication at the higer enrgy density.

Three Dimensional Smart Processing by Ultra Violet Laser Lithography of Ceramic Additive Manufacturing

Additive manufacturing (AM) and three-dimensional printing (3DP) technologies are being developed for use in manufacturing. In this study, a new AM technology, laser stereo-lithography, that enables to fabricate ceramic components in a single process is developed. This method is demonstrated with alumina under various laser conditions.

Tribological properties of 3D printed components

Abstract Additive manufacturing technology is developing in many industries, including aviation, automotive and others. 3D printing offers new possibilities in the field of designing and manufacturing of machines and devices’ components. The paper presents the results of tribological investigations of components produced in FDM printing technology. The authors presented the evaluation of sliding properties of the model friction couple – block on ring type – of available thermoplastic polymers and polymers’ composites under dry friction conditions. The authors assessed the influence of material type and printed structure on resistance to motion of prepared samples.

Simulation-Based Analysis of Additive Manufacturing Systems for Fuel Nozzles

Additive manufacturing technologies have the potential to revolutionize manufacturing, allowing for the production of ever more complex products and supporting the creation of strategic competitive advantages to certain industries. Recent investments in additive manufacturing systems show that operational plants are close to become reality. In this context, the demand for knowledge regarding the behavior of such systems is expected to increase. This research aims to analyze additive manufacturing systems – based on powder bed fusion technologies – applied to aerospace fuel nozzles by modeling and simulating different scenarios regarding the allocation of resources. The amount of time required by the additive step is a key aspect of the plants behavior and, still, there is a limit to the increase in productivity attained by adding more parts per batch. Different combinations of productive resources showed that the optimization of resources utilization is bounded by the number of additive manufacturing machines. Furthermore, total unit costs are mostly driven by the equipment costs as the need for human resources is significantly reduced.

Additive Manufacturing Rectangular Lattice Structure Design Automation

Additive Manufacturing (AM) technology provides new opportunities to automatically fabricate parts with complicated shapes that could not be produced by conventional manufacturing processes, thus enabling unprecedented design flexibilities and application opportunities. The design and analysis of lattice structures manufactured using additive manufacturing technique is a new approach to create lightweight high-strength components. Infill percentage and lattice pattern influence print weight, material usage, strength, print time and sometimes decorative properties. With many types of lattice structure patterns available, This Paper focuses on design of rectangular lattice structure according to required infill percentage. Rectangular beam is considered for application of design methodology and the rectangular lattice structure is generated with infill percentage as an input parameter. The manual process of lattice structure design is tedious and time consuming and requires many iterations to achieve final design. Therefore, the focus of this paper is to develop methodology for automatic lattice structure generation using CAD Application Programming Interface(API). The design process is automated using integration of CAD software packages Creo© parametric 4.0 and Mathcad 4.0.

3D model of filler melting with micro-beam plasma arc based on additive manufacturing technology

Additive manufacturing technology is a systematic process based on discrete-accumulation principle, which is derived by the dimension of parts. Aiming at the dimension mathematical model and slicing problems in additive manufacturing process, the constitutive relations between micro-beam plasma welding parameters and the dimension of part were investigated. The slicing algorithm and slicing were also studied based on the dimension characteristics. By using the direct slicing algorithm according to the geometric characteristics of model, a hollow thin-wall spherical part was fabricated by 3D additive manufacturing technology using micro-beam plasma.

Small Punch Testing of Powder Bed Direct Laser Deposits

Additive Layer Manufacturing (ALM) technologies, such as Powder Bed Direct Laser Deposition (PB-DLD), have gained increasing popularity within the aerospace industry due to the advantages they hold over conventional processing routes. Among the advantages are the ability to produce more sophisticated cross-sectional geometries, a decrease in production lead times and an improvement to the buy-to-fly ratio. However, build quality and microstructural characteristics have a dependency on the process variables such as build direction. In order to understand the influence of grain size and build orientation on tensile behaviour, the Small Punch Tensile (SPT) testing technique has been applied to variants of the nickel based superalloy C263, manufactured using the PB-DLD method. The test technique utilises miniaturised samples, requiring only small volumes of material and is therefore a desirable test method to employ. SPT testing has characterised the mechanical properties between vertically and horizontally built PB-DLD C263 in comparison with the cast material derivative. Differences in mechanical performance between each variant have been revealed and found to be associated with microstructural variations. The deformation behaviour across each material variant have been exposed by interrupted tests. SPT results have also been accompanied by fractography, fracture energy calculations along with comparisons with uniaxial data.

Energy effectiveness achieved by orienting prototype of a laparoscopic instrument handle using polyjet additive manufacturing technology

Additive manufacturing (AM) technology can be considered as an answer to energy effective system as it is capable of reducing manufacturing time. In this research, an attempt is made to find the best among the 64 orientations, which gives minimum energy and material consumption using polyjet AM technology. This study provides an additional benefit to AM towards further reduction of product lead time to market. Orientations 0-0-0, 0-0-30 and 0-0-45 have been slightly higher build time comparing to 0-0-90. Imparting maximum strength to the build parts, 0-0-0 is selected as preferred orientation and build mode as high speed, which consumes 1.05 kWh of energy. This paper provides an outline for a possible way to energy-efficient manufacturing method, and it is recommended that orientations 0-0-0 and 0-0-45 can be used for auto orienting the part in any AM machines.