Christoph Schmutzler, Tobias H. Stiehl and Michael F. Zaeh
The purpose of this work is to explain the emergence of warpage due to a locally and temporally inhomogeneous shrinkage in 3D printing (Binder-Jetting) of polymers.
Abstract
Purpose
The purpose of this work is to explain the emergence of warpage due to a locally and temporally inhomogeneous shrinkage in 3D printing (Binder-Jetting) of polymers.
Design/methodology/approach
An analysis of shrinkage yields parameters for a one-dimensional layer model of the binding process. Based on this, residual stresses and deformation are calculated by means of a numerical simulation model.
Findings
The simulation supports the assumption that the curling of specimens is created by a force transmission between layers due to inhomogeneous shrinkage. Furthermore, the layered production process might contribute to nonlinear deformations of not horizontally orientated surfaces.
Research limitations/implications
The simulation allows imitating the warping during the manufacturing process qualitatively. Exact values of deformations cannot be predicted, yet.
Practical implications
The results expand the knowledge about warpage effects in 3D printing caused by the layer-wise building process.
Originality/value
The developed model imitates the mechanisms leading to deformations during the 3D printing process, focusing on the physical interaction of layers with each other.
Details
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Xiao Fan Zhao, Andreas Wimmer and Michael F. Zaeh
The purpose of this paper is to demonstrate the impact of the welding sequence on the substrate plate distortion during the wire and arc additive manufacturing (WAAM) process…
Abstract
Purpose
The purpose of this paper is to demonstrate the impact of the welding sequence on the substrate plate distortion during the wire and arc additive manufacturing (WAAM) process. This paper also aims to show the capability of finite element simulations in the prediction of those thermally induced distortions.
Design/methodology/approach
An experiment was conducted in which solid aluminum blocks were manufactured using two different welding sequences. The distortion of the substrates was measured at predefined positions and converted into bending and torsion values. Subsequently, a weakly coupled thermo-mechanical finite element model was created using the Abaqus simulation software. The model was calibrated and validated with data gathered from the experiments.
Findings
The results of this paper showed that the welding sequence of a part significantly affects the formation of thermally induced distortions of the final part. The calibrated simulation model was able to capture the different distortion behavior attributed to the welding sequences.
Originality/value
Within this work, a simulation model was developed capable of predicting the distortion of WAAM parts in advance. The findings of this paper can be used to improve the design of WAAM welding sequences while avoiding high experimental efforts.
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Johannes Glasschroeder, Emanuel Prager and Michael F. Zaeh
The purpose of this paper is to show a possibility of how new functions can be integrated in parts, created by the powder-bed-based 3D-printing technology. One big advantage of…
Abstract
Purpose
The purpose of this paper is to show a possibility of how new functions can be integrated in parts, created by the powder-bed-based 3D-printing technology. One big advantage of additive manufacturing technologies is the possibility to create function-integrated parts during the manufacturing process. This applies to mechanical functions like movable elements, thermodynamic functions like contour near cooling channels in a part as well as electrical functions like conductive lines and electrical components.
Design/methodology/approach
A powder-bed-based 3D-printer is utilized to process polymethyl methacrylate (PMMA) as base material. To enable new functionalities, an automated exhausting mechanism was implemented into the test system. The created cavities can be filled with new components or rather new materials.
Findings
Three different approaches are shown in this paper. The first one was the integration of screw nuts to enhance bolted joints compared to threads, directly created in the part. The average tensile strength could be raised from 200 to 430 N/mm. The second approach was the integration of different reinforcement elements like carbon or metallic fibers. Here again a reinforcement of the tensile strength of approximately 27 per cent could be reached. The last approach shows a method to integrate conductive material as well as electrical components in a part to create simple electrical circuits.
Originality/value
The paper demonstrates how to extend an additive powder-bed-based technology with a powder-exhausting mechanism. The possibilities of this technology are illustrated by three examples, integrating mechanical as well as electrical functions in a part.
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Cara Greta Kolb, Maja Lehmann, Johannes Kriegler, Jana-Lorena Lindemann, Andreas Bachmann and Michael Friedrich Zaeh
This paper aims to present a requirements analysis for the processing of water-based electrode dispersions in inkjet printing.
Abstract
Purpose
This paper aims to present a requirements analysis for the processing of water-based electrode dispersions in inkjet printing.
Design/methodology/approach
A detailed examination of the components and the associated properties of the electrode dispersions has been carried out. The requirements of the printing process and the resulting performance characteristics of the electrode dispersions were analyzed in a top–down approach. The product and process side were compared, and the target specifications of the dispersion components were derived.
Findings
Target ranges have been identified for the main component properties, balancing the partly conflicting goals between the product and the process requirements.
Practical implications
The findings are expected to assist with the formulation of electrode dispersions as printing inks.
Originality/value
Little knowledge is available regarding the particular requirements arising from the systematic qualification of aqueous electrode dispersions for inkjet printing. This paper addresses these requirements, covering both product and process specifications.
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Jingfu Liu, Behrooz Jalalahmadi, Y.B. Guo, Michael P. Sealy and Nathan Bolander
Additive manufacturing (AM) is revolutionizing the manufacturing industry due to several advantages and capabilities, including use of rapid prototyping, fabrication of complex…
Abstract
Purpose
Additive manufacturing (AM) is revolutionizing the manufacturing industry due to several advantages and capabilities, including use of rapid prototyping, fabrication of complex geometries, reduction of product development cycles and minimization of material waste. As metal AM becomes increasingly popular for aerospace and defense original equipment manufacturers (OEMs), a major barrier that remains is rapid qualification of components. Several potential defects (such as porosity, residual stress and microstructural inhomogeneity) occur during layer-by-layer processing. Current methods to qualify AM parts heavily rely on experimental testing, which is economically inefficient and technically insufficient to comprehensively evaluate components. Approaches for high fidelity qualification of AM parts are necessary.
Design/methodology/approach
This review summarizes the existing powder-based fusion computational models and their feasibility in AM processes through discrete aspects, including process and microstructure modeling.
Findings
Current progresses and challenges in high fidelity modeling of AM processes are presented.
Originality/value
Potential opportunities are discussed toward high-level assurance of AM component quality through a comprehensive computational tool.
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Keywords
Michael Cloots, Livia Zumofen, Adriaan Bernardus Spierings, Andreas Kirchheim and Konrad Wegener
For geometries exhibiting overhanging surfaces, support structures are needed to dissipate process heat and to minimize geometrical distortions attributed to internal stresses…
Abstract
Purpose
For geometries exhibiting overhanging surfaces, support structures are needed to dissipate process heat and to minimize geometrical distortions attributed to internal stresses. The use of support structures is often time- and cost-consuming. For this reason, this study aims to propose an approach which minimizes the use of such structures.
Design/methodology/approach
For minimizing the use of support structures, process parameters in combination with a contour-like exposure strategy are developed to realize support-less overhanging structures of less than 35°. These parameters are implemented in a shell-core strategy, which follows the idea of applying different processing strategies to the critical (overhanging) shell and the uncritical core of the part. Thereby, the core is processed with standard parameters, aiming a dense material. On the critical shell, optimized processing parameters are applied, reaching good results in terms of surface quality, especially at extreme overhang situations.
Findings
The results show that the selective laser melting (SLM) technology is able to realize support-less overhanging surfaces by choosing suitable scan strategies and process parameters. Particularly good results are always obtained when the exposure direction of the shell is parallel to the contour of the sample.
Originality/value
The validity of the results is demonstrated through the successful reproduction of the build strategy on two commercial SLM machines, reaching support-free builds of surfaces with an angle to the horizontal of less than or equal to 30°.
Details
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Bing Zhang, Raiyan Seede, Austin Whitt, David Shoukr, Xueqin Huang, Ibrahim Karaman, Raymundo Arroyave and Alaa Elwany
There is recent emphasis on designing new materials and alloys specifically for metal additive manufacturing (AM) processes, in contrast to AM of existing alloys that were…
Abstract
Purpose
There is recent emphasis on designing new materials and alloys specifically for metal additive manufacturing (AM) processes, in contrast to AM of existing alloys that were developed for other traditional manufacturing methods involving considerably different physics. Process optimization to determine processing recipes for newly developed materials is expensive and time-consuming. The purpose of the current work is to use a systematic printability assessment framework developed by the co-authors to determine windows of processing parameters to print defect-free parts from a binary nickel-niobium alloy (NiNb5) using laser powder bed fusion (LPBF) metal AM.
Design/methodology/approach
The printability assessment framework integrates analytical thermal modeling, uncertainty quantification and experimental characterization to determine processing windows for NiNb5 in an accelerated fashion. Test coupons and mechanical test samples were fabricated on a ProX 200 commercial LPBF system. A series of density, microstructure and mechanical property characterization was conducted to validate the proposed framework.
Findings
Near fully-dense parts with more than 99% density were successfully printed using the proposed framework. Furthermore, the mechanical properties of as-printed parts showed low variability, good tensile strength of up to 662 MPa and tensile ductility 51% higher than what has been reported in the literature.
Originality/value
Although many literature studies investigate process optimization for metal AM, there is a lack of a systematic printability assessment framework to determine manufacturing process parameters for newly designed AM materials in an accelerated fashion. Moreover, the majority of existing process optimization approaches involve either time- and cost-intensive experimental campaigns or require the use of proprietary computational materials codes. Through the use of a readily accessible analytical thermal model coupled with statistical calibration and uncertainty quantification techniques, the proposed framework achieves both efficiency and accessibility to the user. Furthermore, this study demonstrates that following this framework results in printed parts with low degrees of variability in their mechanical properties.
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Michael Hülsmann, Bernd Scholz-Reiter, Philip Cordes, Linda Austerschulte, Christoph de Beer and Christine Wycisk
The intention of this article is to show possible contributions of the concept of autonomous cooperation to enable complex adaptive logistics systems (CALS) to cope with…
Abstract
The intention of this article is to show possible contributions of the concept of autonomous cooperation to enable complex adaptive logistics systems (CALS) to cope with increasing complexity and dynamics and therefore to increase the systems' information-processing capacity by implementing autopoietic characteristics. In order to reach this target, the concepts of CALS and autopoietic systems will be introduced and connected. The underlying aim is to use the concept of self-organization as one of their essential similarities to lead over to the concept of autonomous cooperation as the most narrow view on self-organizing systems, which is discussed as a possible approach to enable systems to handle an increasing quantity of information. This will be analyzed from both a theoretical and an empirical point of view.
Usman Tariq, Ranjit Joy, Sung-Heng Wu, Muhammad Arif Mahmood, Asad Waqar Malik and Frank Liou
This study aims to discuss the state-of-the-art digital factory (DF) development combining digital twins (DTs), sensing devices, laser additive manufacturing (LAM) and subtractive…
Abstract
Purpose
This study aims to discuss the state-of-the-art digital factory (DF) development combining digital twins (DTs), sensing devices, laser additive manufacturing (LAM) and subtractive manufacturing (SM) processes. The current shortcomings and outlook of the DF also have been highlighted. A DF is a state-of-the-art manufacturing facility that uses innovative technologies, including automation, artificial intelligence (AI), the Internet of Things, additive manufacturing (AM), SM, hybrid manufacturing (HM), sensors for real-time feedback and control, and a DT, to streamline and improve manufacturing operations.
Design/methodology/approach
This study presents a novel perspective on DF development using laser-based AM, SM, sensors and DTs. Recent developments in laser-based AM, SM, sensors and DTs have been compiled. This study has been developed using systematic reviews and meta-analyses (PRISMA) guidelines, discussing literature on the DTs for laser-based AM, particularly laser powder bed fusion and direct energy deposition, in-situ monitoring and control equipment, SM and HM. The principal goal of this study is to highlight the aspects of DF and its development using existing techniques.
Findings
A comprehensive literature review finds a substantial lack of complete techniques that incorporate cyber-physical systems, advanced data analytics, AI, standardized interoperability, human–machine cooperation and scalable adaptability. The suggested DF effectively fills this void by integrating cyber-physical system components, including DT, AM, SM and sensors into the manufacturing process. Using sophisticated data analytics and AI algorithms, the DF facilitates real-time data analysis, predictive maintenance, quality control and optimal resource allocation. In addition, the suggested DF ensures interoperability between diverse devices and systems by emphasizing standardized communication protocols and interfaces. The modular and adaptable architecture of the DF enables scalability and adaptation, allowing for rapid reaction to market conditions.
Originality/value
Based on the need of DF, this review presents a comprehensive approach to DF development using DTs, sensing devices, LAM and SM processes and provides current progress in this domain.
Details
Keywords
Katrin Oettmeier and Erik Hofmann
The purpose of this paper is to provide a systematic analysis about the effects of additive manufacturing (AM) technology adoption on supply chain management (SCM) processes and…
Abstract
Purpose
The purpose of this paper is to provide a systematic analysis about the effects of additive manufacturing (AM) technology adoption on supply chain management (SCM) processes and SCM components in an engineer-to-order environment.
Design/methodology/approach
Based on two explorative case studies from the hearing systems industry, the impact of AM technology adoption on SCM processes and SCM components is investigated. General systems theory and the contingency approach serve as theoretical underpinning.
Findings
Not only the internal processes and management activities, e.g. in manufacturing and order fulfillment, of producers are affected by a changeover to AM, but also the SCM processes and components relating to the supply and demand side of a firm’s supply chain. Endogenous and AM technology-related factors are contingency factors that help to explain differing effects of AM technology adoption on SCM processes and SCM components.
Research limitations/implications
It is proposed that AM’s ability to economically build custom products provides the potential to alleviate the common dilemma between product variety and scale economies.
Practical implications
Manufacturing firms are encouraged to consider the potential effects of AM on SCM processes and SCM components when deciding whether to adopt AM technologies in the production of industrial parts.
Originality/value
The research adds to the widely unexplored effects that AM technology usage in customized parts production has on SCM processes and components. Moreover, the general lack of case studies analyzing the implications of AM technology adoption from a supply chain perspective is addressed. The resulting propositions may serve as a starting point for further research on the impact of AM in engineer-to-order supply chains.