Wire + Arc Additive Manufacturing Williams, S. W.; Martina, F.; Addison, A. C. ...
Materials science and technology,
05/2016, Volume:
32, Issue:
7
Journal Article
Peer reviewed
Open access
Depositing large components (>10 kg) in titanium, aluminium, steel and other metals is possible using Wire + Arc Additive Manufacturing. This technology adopts arc welding tools and wire as feedstock ...for additive manufacturing purposes. High deposition rates, low material and equipment costs, and good structural integrity make Wire+Arc Additive Manufacturing a suitable candidate for replacing the current method of manufacturing from solid billets or large forgings, especially with regards to low and medium complexity parts. A variety of components have been successfully manufactured with this process, including Ti-6Al-4V spars and landing gear assemblies, aluminium wing ribs, steel wind tunnel models and cones. Strategies on how to manage residual stress, improve mechanical properties and eliminate defects such as porosity are suggested. Finally, the benefits of non-destructive testing, online monitoring and in situ machining are discussed.
Additive manufacturing technologies based on melting and solidification have considerable similarities with fusion-based welding technologies, either by electric arc or high-power beams. However, ...several concepts are being introduced in additive manufacturing which have been extensively used in multipass arc welding with filler material. Therefore, clarification of fundamental definitions is important to establish a common background between welding and additive manufacturing research communities. This paper aims to review these concepts, highlighting the distinctive characteristics of fusion welding that can be embraced by additive manufacturing, namely the nature of rapid thermal cycles associated to small size and localized heat sources, the non-equilibrium nature of rapid solidification and its effects on: internal defects formation, phase transformations, residual stresses and distortions. Concerning process optimization, distinct criteria are proposed based on geometric, energetic and thermal considerations, allowing to determine an upper bound limit for the optimum hatch distance during additive manufacturing. Finally, a unified equation to compute the energy density is proposed. This equation enables to compare works performed with distinct equipment and experimental conditions, covering the major process parameters: power, travel speed, heat source dimension, hatch distance, deposited layer thickness and material grain size.
There has been significant development in metal additive manufacturing (MAM) technology over the past few decades, and considerable progress has been made in understanding how various processes and ...their parameters influence the properties of printed metallic parts. Despite this, the knowledge concerning its characteristics has been dispersed across a variety of publications and sources, making it difficult to gain a comprehensive understanding of the entire field, especially for businesses interested in additive manufacturing (AM). In order to bridge this gap, periodic reviews encompassing state-of-the-art as the whole are necessary. Therefore, this article provides a comprehensive overview of the essential features of MAM techniques based on the most recent scientific knowledge. It explores emerging research on four of the most significant technologies, including material extrusion (ME), binder jetting (BJ), powder bed fusion (PBF), and directed energy deposition (DED). As well as providing an outline of fundamental process characteristics, ongoing efforts to optimize them and current challenges, it also highlights gaps in understanding and future research and development needs. A significant feature of this review is the provision of substantial documentation regarding the mechanical properties of materials processed by a variety of commercial systems, including a variety of novel hybrid additive manufacturing (HAM) machines. This is accompanied by an investigation into the most recent works done to characterize the environmental impact along with a conceptual framework for improving the energy efficiency (EE) of the manufacturing process. As a result of reporting on both the characteristics of several MAM processes along with their sustainability features in one integrated article, it is anticipated that this information will serve as a valuable resource for both the academic and manufacturing communities to better appreciate and understand what differentiates MAM from traditional manufacturing (TM) processes, thus facilitating its future advancement and adoption.
Additive manufacturing (AM) technology, in other words “layered manufacturing” or “3D printer technology” has been developing rapidly in recent years. Unlike the traditional manufacturing method ...(TM), the working principle of AM technology is to create layer-based production by deposition the layers on top of each other. Owing to its advantages such as material saving, lower cost, the ability to produce parts without the need for molds and the design flexibility in complex shaped parts, it has brought a breath of fresh air to the areas where it is used primarily medical, aerospace and automotive. However, the parts produced by AM method have dimensional limitations. According to recent studies, in order to eliminate this problem, metal materials produced with AM can be combined with commonly used by different welding methods so that large parts can be obtained. In this study, these welding methods are explained and recent researches are examined. AM technology and methods are introduced. The usage areas of the method are described. In addition, the welding parameters and the effects of this new method on the mechanical properties and microstructures are investigated.
•FSAM is the new class of metal additive manufacturing (MAM) technique utilized for improved microstructural and mechanical properties.•Very limited articles are available in open literature on the ...research outcomes of FSAM.•Present work highlights the detailed background of the FSAM and reported the findings and results reported by previous authors.•It also discussed the futuristic approach of FSAM and its application in various fields of engineering and medical.
Friction stir additive manufacturing (FSAM) method is one of the growing techniques of additive manufacturing that utilizes the concept of solid state friction stir processing to develop multilayer components through layer by layer joining. The present work aims to highlight the working principle and the past research work carried out by the various authors that utilize FSAM as a fabrication process. Based on the available experimental data, the summary of additive based friction stir processes, type of machine for fabrication, materials, process parameters taken for the study is also discussed in detail. Mechanical properties such as grain refinement, microhardness variation, and tensile strength are also summarized, in comparison with their base materials. In addition, the current scenario and future scope of the FSAM process are also discussed in detail in terms of its utilization in various sectors of engineering along with estimated future trends.
Wire + arc additive manufacturing components contain significant residual stresses, which manifest in distortion. High-pressure rolling was applied to each layer of a linear Ti-6Al-4V wire + arc ...additive manufacturing component in between deposition passes. In rolled specimens, out-of-plane distortion was more than halved; a change in the deposits' geometry due to plastic deformation was observed and process repeatability was increased. The Contour method of residual stresses measurements showed that although the specimens still exhibited tensile stresses (up to 500 MPa), their magnitude was reduced by 60%, particularly at the interface between deposit and substrate. The results were validated with neutron diffraction measurements, which were in good agreement away from the baseplate.
This paper is part of a Themed Issue on Measurement, modelling and mitigation of residual stress.
•The initial cyclic softening followed by cyclic hardening behavior is observed.•The dislocation rearrangement process promotes initial cyclic softening behavior.•The martensite formation results in ...the cyclic hardening behavior of SLM 304L.
Considering the relationship between austenite stability and strain level, the cyclic response curves are obtained for SLM 304L under different strain amplitude at R = 0.3. The results indicate that since the microstructure characteristics shift from stacking faults (SFs) at low strain amplitude to martensite and twins at high strain amplitude, the cyclic softening behavior transitions to cyclic hardening behavior. Besides, it also indicates that high strain levels can overcome the influence of initial microstructure on fatigue performance, presenting a new sight to understand the relationship between cyclic hardening and martensite transformation.
•Gas protection improves the forming quality of deposited WE43-Mg by WAAM.•The cooling effect induced by gas protection enhances grain refinement.•Gas protection significantly reduces the content of ...oxides.•Eliminating oxide inclusions and refining grain enhances the mechanical properties.
In this study, WE43 magnesium alloy was successfully fabricated using wire arc additive manufacturing technology, focusing on reducing the common oxide inclusion defects. The implementation of a gas shielding hood significantly improved the grain morphology of the deposited samples and diminished both the quantity and size of oxides. In addition, the cooling effect induced by the shielding gas contributed to the refinement of grain size. The synergistic effect of oxide reduction and grain refinement significantly improves the mechanical properties of the deposited samples. For heat treatable magnesium alloys, minimizing the consumption of rare earth elements is beneficial for optimizing heat treatment mechanical properties.
As the application of additive manufacturing (AM) reaches an unprecedented scale in both academia and industry, a reflection upon the state-of-the-art developments in the design for additive ...manufacturing (DfAM) and structural optimisation, becomes vital for successfully shaping the future AM-landscape. A framework, highlighting both the interdependencies between these two central aspects in AM and the necessity for a holistic approach to structural optimization, using lightweight strategies such as topology optimization and/or latticing, was established to summarize the reviewed content. Primarily focusing on isotropic material considerations and basic stiffness-optimal problems, these concepts have already found wide application, bridging the gaps between design and manufacturing as well as academia and industry. In pursuit of streamlining the AM-workflow towards digitally print-ready designs, studies are increasingly investigating mathematically-based structural optimization approaches in conjunction with DfAM-specific constraints, providing a portfolio of solutions like generative design, which is gaining traction in industry. Besides an overview on economically-driven to performance-driven design optimizations, insight into commercial AM-specific software is provided, elucidating potentials and challenges for the community. Despite the abundance of AM design methods to-date, computationally inexpensive solutions for common engineering problems are still scarce, which is constituting one of many key challenges for the future.
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•Extensive review, providing a joint perspective on design and structural optimisation in additive manufacturing (AM).•Overview on the lightweighting approaches topology optimization and latticing, considering isotropic material assumptions.•Consolidated summary, elucidating the gaps between design and manufacturing as well as academia and industry.•Establishment of a design for AM framework, highlighting the interdependencies between state-of-the art research topics.•Identification of future trajectories beneficial to explore in pursuit of exploiting the potential AM has on offer.
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