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Design for Additive Manufacturing
Abstract
Design for manufacture and assembly (DFM) has typically meant that designers should tailor their designs to eliminate manufacturing difficulties and minimize manufacturing, assembly, and logistics costs. However, the capabilities of additive manufacturing technologies provide an opportunity to rethink DFM to take advantage of the unique capabilities of these technologies. As we will cover in Chap. 14, several companies are now using AM technologies for production manufacturing. For example, Siemens, Phonak, Widex, and the other hearing aid manufacturers use selective laser sintering and stereolithography machines to produce hearing aid shells, Align Technology uses stereolithography to fabricate molds for producing clear dental braces (“aligners”), and Boeing and its suppliers use selective laser sintering to produce ducts and similar parts for F-18 fighter jets. For hearing aids and dental aligners, AM machines enable manufacturing of tens to hundreds of thousands of parts; where each part is uniquely customized based upon person-specific geometric data. In the case of aircraft components, AM technology enables low volume manufacturing, easy integration of design changes and, at least as importantly, piece part reductions to greatly simplify product assembly.
... The design freedom, material opportunities, design implementation are suggested. Gibson et al. [8] ascertained the capabilities of AM to rethink DFM for the improvement of end user product performance, functionality and cost. Gibson et al. [8] is the first research article published in the name of DfAM to the best of the authors' knowledge. ...
... Gibson et al. [8] ascertained the capabilities of AM to rethink DFM for the improvement of end user product performance, functionality and cost. Gibson et al. [8] is the first research article published in the name of DfAM to the best of the authors' knowledge. After this seed, several researches emerged in 2010s and still emerging. ...
Additive manufacturing (AM) developments over the past three decades have led to the emergence of design for additive manufacturing (DfAM) in the mid-2000s. DfAM focuses on optimizing product designs to leverage AM capabilities and considers AM manufacturability. The purpose of this paper is to review and summarize various literature studies using a systematic approach. The review explores DfAM potential, tools, standards, and applications and key insights/inferences are presented. The review presented 14 major DfAM insights and suggested areas for further development. Additionally, the article examines 14 significant DfAM challenges and research gaps, addressing key issues and outlining future research directions. This comprehensive review is confined to DfAM scope, guidelines, principles, and rules, with the aim of aiding designers, researchers, students, and AM machine operators in understanding DfAM potential, scope, and tools.
... With the mass development of proofs-of-concept to illustrate stimulus-responsive behaviors in objects and structures, it becomes important to think about a general design for 4D printing framework that promotes an inverse problem way to build innovative solutions. Compared to well-adopted design for AM, manufacturing, and assembly methods [28][29][30][233][234][235][236][237], the complexity level induced by the multiple involved stakeholders (i.e. product architect, product designer, material expert, AM process planner, mechanical engineer, etc.) and the inherent spatiotemporal behaviors of active materials require a progressive integration of the 4D printing constraints, whether at the functional, logical/behavioral, structure, and geometric levels, and also the introduction of usercentered design innovation mechanisms. ...
... composing transformation functions with multiple basic functions (for instance, a bending can be decomposed into several expansion/contraction functions); consolidating technical functions with multi-material and multi-functional objects; integrating technical and multi-material functionality with user-centric, user-interface, user-experience, and systems functions; advancing design for AM and design innovation with AM approaches for transformation, multi-material, and multifunctional capabilities through 4D printing [22,233,234]; elaborating bio-inspired AM, creative, and technical design principles that match shape/behavior/structure with SM/stimulus distribution patterns [62,[249][250][251][252][253][254][255][256][257][258]; setting up mechanisms for design principles recommendation. ...
The combination of scientific advances in additive manufacturing (AM) and smart materials (SMs) has enabled the development of a new interdisciplinary research area: 4D printing. This technology offers – via stimuli-responsive materials – promising transformation capabilities to objects whether at the functional, shape, or property levels. By considering such capabilities, researchers from multiple disciplines have investigated a large spectrum of stimuli-SMs associations with proofs-of-concept built from either commercial or custom 3D printers. Despite the abundant initiatives, 4D printing requires additional developments to meet robust system applications for the industry. The paper aims to highlight the status, inherent barriers, and challenges of 4D printing to be addressed from a product-systems design perspective. It firstly reminds the fundamentals of SMs, processes, stimulus, and AM to which a synthesis of significant research works related to 4D printing highlighting the current status as well as scientific, technical, and organizational limitations is provided. Beyond this comprehensive study, the paper emphasizes opportunities and challenges from multiple perspectives and draws a research roadmap for engineering design and cross-disciplinary design. The outcome of the work tends to structure research efforts for the next decade towards the development of smart products that meet use for humans and the industry.
... The fundamental standard that drives almost all AM technologies is forming a virtual solid design, then breaking down the design data into two-dimensional sectors and transferring these broken data to an AM system (Leary et al., 2019). The physical part is developed layer by layer (Gibson, Rosen and Stucker, 2010). AM techniques are generally categorized as (Li et al., 2018) vat polymerization, binder jetting, sheet lamination selected laser machining and directed energy deposition techniques. ...
... Table 12 lists the top 15 cited authors by the citation counts of their published articles in descending order to understand Figure 15. As shown in Table 12, the most cited author is SOOD AK (81) (Sood et al., 2010), the other top 14 cited authors are AHN SH (80) (Ahn et al., 2002), GIBSON I (64) (Gibson et al., 2010), MOHAMED OA (62) (Mohamed et al., 2016a(Mohamed et al., , 2016b, BOSCHETTO A (45) (Boschetto and Bottini, 2016), TURNER BN (43) (N. Turner et al., 2014), PANDEY PM (40) (Kumar et al., 2018), SUN Q (39) (Gao et al., 2019), SINGH R (38) (Singh et al., 2016) and BELLINI A (36) (Bellini et al., 2005), NING FD (36) (Ning et al., 2016), DAWOUD M (33) (Dawoud et al., 2016), GALANTUCCI LM (30) (Lavecchia et al., 2018), TYMRAK BM (30) (Tymrak et al., 2014) and AHN D (29) (Ahn et al., 2002). ...
Purpose
Additive manufacturing (AM) technology has a huge influence on the real world because of its ability to manufacture massively complicated geometrics. The purpose of this study is to use CiteSpace (CS) visual analysis to identify fused deposition modeling (FDM) research and development patterns to guide researchers to decide future research and provide a framework for corporations and organizations to prepare for the development in the rapid prototyping industry. Three-dimensional printing (3DP) is defined to budget minimize manufactured input and output for aviation and the medical product industrial sectors. 3DP has implemented its potential in the Coronavirus Disease of 2019 (COVID-19) reaction.
Design/methodology/approach
First, 396 original publications were extracted from the web of science (WOS) with the comprehensive list and did scientometrics analysis in CS software. The parameters are specified in CS including the span (from 2011 to 2019, one year slice for the co-authorship and the co-accordance analysis), visualization (show the merged networks), specific criteria for selection (top 20%), node form (author, organization, region, reference cited; cited author, journal and keywords) and pruning (pathfinder and slicing network). Finally, correlating data was studied and showed the results of the visualization study of FDM research were shown.
Findings
The framework of FDM information is beginning to take shape. About hot research topics, there are “Morphology,” “Tensile Property by making Blends,” “Use of Carbon nanotube in 3DP” and “Topology optimization.” Regarding the latest research frontiers of FDM printing, there are “Fused Filament Fabrication,” “AM,” in FDM printing. Where “Post-processing” and “environmental impact” are the research hotspots in FDM printing. These research results can provide insight into FDM printing and useful information to consider the existing studies and developments in FDM researchers’ analysis.
Research limitations/implications
Despite some important obtained results through FDM-related publications’ visualization, some deficiencies remain in this research. With >99% of articles written in English, the input data for CS was all downloaded from WOS databases, resulting in a language bias of papers in other languages and neglecting other data sources. Although, there are several challenges being faced by the FDM that limit its wide variety of applications. However, the significance of the current work concerning the technical and engineering prospects is discussed herein.
Originality/value
First, the novelty of this work lies in describing the FDM approach in a Scientometric way. In Scientometric investigation, leading writers, organizations, keywords, hot research and emerging knowledge points were explained. Second, this research has thoroughly and comprehensively examined the useful sustainability effects, i.e. economic sustainability, energy-based sustainability, environmental sustainability, of 3DP in industrial development in qualitative and quantitative aspects by 2025 from a global viewpoint. Third, this work also described the practical significance of FDM based on 3DP since COVID-19. 3DP has stepped up as a vital technology to support improved healthcare and other general response to emergency situations.
... However, the link between recipes and ingredient control has not been built in the current research status. A synergistic approach of componentwise printed recipe and traditional recipe printing would enable users near future to customize shape and ingredient and support a food design workflow to experiment diversified recipe options (Gibson et al., 2010). It can easily substitute ingredients based on nutritional contents as well as personal and social preferences. ...
Multidimensional Nanomaterials for Supercapacitors: Next Generation Energy Storage explores the cutting-edge advancements in multidimensional nanomaterials for supercapacitor applications, addressing key techniques, challenges, and future prospects in the field. The book offers a comprehensive overview of the fundamentals of supercapacitors, including electrode materials, electrolytes, charge storage mechanisms, and performance metrics. Key Features Comprehensive Coverage: 15 referenced chapters cover a wide range of topics, including graphene derivatives, quantum dots, MOFs, MXenes, and fiber-shaped supercapacitors, providing a holistic view of the field. Cutting-Edge Techniques: Covers the latest advancements in multidimensional nanomaterials for supercapacitors, providing insights into their synthesis, properties, and applications. Future Applications: Chapters explore the potential future applications of nanomaterials in energy storage devices, offering valuable insights for researchers and practitioners. Real-World Case Studies: Practical examples and case studies illustrate the application of nanomaterials in supercapacitors, enhancing understanding and applicability. Challenges and Opportunities: Highlights the challenges and limitations associated with nanomaterial-based supercapacitors, offering information into overcoming barriers and expanding possibilities for future research.
... This process results in the melting of the material above the substrate, which cools and solidifies into the desired shape. According to research conducted by the British Welding Institute [1], the DED process is ten times faster than the PBF process in terms of manufacturing speed and has a cost that is five times lower than that of the PBF process. Its advantages include the ability to repair workpieces, manufacture products with mixed material structures, and create large workpieces. ...
The purpose of this study is to optimize the critical parameters of the directed energy deposition (DED) process using the response surface methodology (RSM) and central composite design (CCD). The experiments investigate the influence of three key process factors, namely laser power, powder feed rate, and scanning speed, on deposition efficiency, deposition rate (DR), and porosity. Additionally, through analysis of variance (ANOVA), the significant factors and interaction effects are identified, and predictive models are developed for quality prediction. The research successfully optimizes the process parameters, which are validated through the fabrication of geometric components, specifically thin-walled nozzles. The study introduces innovative approaches such as “plunge-cutting toolpath” and “hybrid laser head lift height (Z-offset) method” to address the challenges associated with complex geometries. Additionally, the reliability and practicality of the optimized process parameters are confirmed.
... It enhances the therapeutic outcome and decreases the duration [146]. PBF technology can be used to produce complex orthodontic brackets [147]. Titanium is both biocompatible and lightweight, making it well suited for orthodontic purposes [148]. ...
Precision manufacturing requirements are the key to ensuring the quality and reliability of biomedical implants. The powder bed fusion (PBF) technique offers a promising solution, enabling the creation of complex, patient-specific implants with a high degree of precision. This technology is revolutionizing the biomedical industry, paving the way for a new era of personalized medicine. This review explores and details powder bed fusion 3D printing and its application in the biomedical field. It begins with an introduction to the powder bed fusion 3D-printing technology and its various classifications. Later, it analyzes the numerous fields in which powder bed fusion 3D printing has been successfully deployed where precision components are required, including the fabrication of personalized implants and scaffolds for tissue engineering. This review also discusses the potential advantages and limitations for using the powder bed fusion 3D-printing technology in terms of precision, customization, and cost effectiveness. In addition, it highlights the current challenges and prospects of the powder bed fusion 3D-printing technology. This work offers valuable insights for researchers engaged in the field, aiming to contribute to the advancement of the powder bed fusion 3D-printing technology in the context of precision manufacturing for biomedical applications.
... However, due to further advantages [4], AM captured a yet small but steadily growing share in industrial serial production. These assets involve the unprecedented design freedom associated with AM, which enables structural part optimization, function integration, the reduction of the total part number, and the implementation of new concepts like "mass customization" [5][6][7][8]. Furthermore, AM allows near net shape manufacturing, making part production more resource-efficient than full subtractive fabrication routes [9]. ...
Electron beam powder bed fusion (PBF-EB) is a high-power additive manufacturing technology for the efficient processing of complex metallic materials. The process characteristics like high-temperature and high-vacuum conditions render it suitable for the production of parts in highly demanding industries, e.g., aerospace or the medical technology sector. These application fields are linked to high requirements considering the quality of the manufactured parts. The current PBF-EB process technology cannot ensure full compliance with these requirements. One main reason for this circumstance is the lack of reliable tools for process monitoring due to the harsh conditions inside the PBF-EB build chamber. To overcome this limitation, the current thesis investigates how the in-situ acquisition of electron-optical (ELO) images of the build area may be used to monitor the build process and predict the quality of the manufactured parts. By measuring electrons emitted from the beam-material interaction, spatial information on the status of the build area is gathered, while drawbacks associated with alternative approaches are circumvented. For this purpose, an electron detector was integrated into the PBF-EB build cycle for the layer-wise acquisition of ELO images. The data is analyzed and optimized with respect to imaging accuracy and signal strength. Features of the molten slices are extracted and compared to reference data acquired by post-process X-ray computed tomography (XCT). The investigation reveals that in-situ ELO imaging provides high-quality information about the status of the molten slices, which strongly correlates to the quality of the as-built part. On the one hand, this is shown for surface defects leading to internal porosity, which can be reliably predicted for defects larger than 0.2 mm. On the other hand, also the dimensional accuracy of the manufactured parts is determined with an accuracy of up to 0.1 mm. Stronger deviations and uncertainties of the approach are related to processing parameters and the target geometry and traced back to the spatiotemporal limitations of the imaging principle. The demonstrated prediction capabilities exceed those of any other approach reported so far in metal additive manufacturing. Thus, the investigation provides a solid basis for using ELO imaging as a high-performance tool for effective monitoring of PBF-EB processes.
... The principle of DfAM comes from design for X (DfX), especially the design for manufacturing (DfM) approach, which typically means that designers must adapt their designs to address manufacturing concerns. Although the methods and tools of DfM will focus on manufacturing in general, DfAM will focus on the constraints and opportunities that AM offers since this new manufacturing technique opens new vistas for rethinking DfM (Gibson et al., 2010). The DfAM tools concentrate on defining design theories, processes, methods, tools, and techniques developed to address the inherent coupling between material, geometry, and quality (Thompson et al., 2016). ...
... 3D printing, on the other hand, is a new deposition process that turns a computer model into a three-dimensional item. In recent years, 3D printing technology has advanced at a breakneck pace, gaining new uses outside of its usual sectors [14][15][16]. It is the direct manufacture of components via layer-by-layer deposition guided by digital information from a computer-aided design file. ...
This study is focused on the investigation of three-dimensional (3D) printed SnS thin film and the optimisation of SnS thin film thickness by additive layer deposition of the film using three-dimensional printing system based on liquid deposition modelling (LDM). Voids in separate island-like state and traps associated with certain film thickness affect charge carriers due to the presence of large grain boundaries associated with small grains which acts as electron trap thus affecting SnS thin film's optical band gap energy and electrical conductivity among others. SnS thin films were printed on glass substrate using LDM-3D printing. Surface Profilometer, Energy dispersive X-ray spectroscopy, X-ray diffractometer, Scanning electron microscope, Uv-vis spectrophotometer, Hall effect measurement and four point probe were used to characterise the SnS thin films. A p type conductivity of 0.002987 (Ωm) −1 and optical energy band gap of 1.37 eV of 0.6 µm 3D printed SnS thin film was optimum and favours the attainment of the threshold voltage for optoelectronic and electronic application. The results demonstrate the potential of the LDM-3D printing of thin film for materials deposition and application which provides a new way of layer thickness variation and levelling of semiconductor thin film.
... The minimization of fixed prosthodontics restoration marginal gap is an imperative point within the field of prosthodontics. The quintessence of concern is the space existing between the tooth ar- Holmes., et al. characterized the inner gap as the estimation between the axial wall of the arranged tooth and the inner surface of the casting, whereas the same measurement at the edge is called "marginal gap" (22). It is considered the finest elective estimation since it continuously be the largest error at the edge and reflects the whole crown misfit at that point, both vertically and evenly [23]. ...
... Several researchers have reviewed and categorized DfAM techniques in an attempt to systematically integrate them into engineering design. Gibson et al. (2010) and Rosen (2014) review the various DfAM techniques that help leverage the unique capabilities of AM. A similar review is presented by Yang and Zhao (2015) with a focus on improving design functionality. ...
As additive manufacturing (AM) processes become ubiquitous in engineering and design, there has emerged the need for a workforce skilled in designing for AM (DfAM). Researchers have proposed educational interventions to train students in DfAM; however, few measures with sufficient validity evidence have been proposed to assess the effects of these educational interventions on student designers’ learning. In this paper, we present the development of a ten-item DfAM self-efficacy scale spanning the opportunistic and restrictive DfAM domains, as they relate to conceptual design (i.e., preliminary concept generation and selection). We tested the criterion-related validity of the scale by comparing students’ self-efficacy to their prior AM and DfAM experience. Additionally, we tested the construct validity of the scale through exploratory and confirmatory factor analyses. Students’ responses to the scale positively correlated with their prior experience in AM and DfAM, thereby lending criterion-related validity. Additionally, factor analyses reveal that students’ responses are composed of two dimensions: (1) opportunistic DfAM and (2) restrictive DfAM, reflecting the categorization observed in the literature. This finding lends construct validity evidence and demonstrates that the scale captures students’ self-efficacies in the two DfAM domains with sufficient separation. This work supports the use of the DfAM self-efficacy scale for assessing the effects of DfAM education on students’ DfAM learning in conceptual design. Moreover, the DfAM self-efficacy scale can support future research attempting to enhance the effectiveness of AM and DfAM educational interventions by measuring their effects on students’ self-perceived abilities.
... With the increasing adoption of modern manufacturing technologies (and of AM in particular), recent years have seen a drastic increase in the number of products coming to market that have shape complexity that has not previously been achievable [102]. While other technologies also provide parts with complex shape, this issue is most prominent within AM, so this subsection is focussed primarily on parts produced using that technology. ...
With the increasing adoption of Industry 4.0, optical metrology has experienced a significant boom in its implementation, as an ever-increasing number of manufacturing processes are overhauled for in-process measurement and control. As such, optical metrology for digital manufacturing is currently a hot topic in manufacturing research. Whilst contact coordinate measurement solutions have been adopted for many years, the current trend is to increasingly exploit the advantages given by optical measurement technologies. Smart automated non-contact inspection devices allow for faster cycle times, reducing the inspection time and having a continuous monitoring of process quality. In this paper a review for the state of the art in optical metrology is presented, highlighting the advantages and impacts of the integration of optical coordinate and surface texture measurement technologies in digital manufacturing processes. Also, the range of current software and hardware technologies for digital manufacturing metrology is discussed, as well as strategies for zero-defect manufacturing for greater sustainability, including examples and in-depth discussions of additive manufacturing applications. Finally, key current challenges are identified relating to measurement speed and data-processing bottlenecks; geometric complexity, part size and surface texture; user-dependent constraints, harsh environments and uncertainty evaluation.
... Developed by Charles Hull in the 1980's, SLA employs a liquid photopolymer resin which is cured layer-by-layer by a laser to prepare a finished part. SLA-printed products exhibit smooth surface finish [24] and high resolution at 20 microns or less [43], which is largely utilized for rapid prototyping in medicine [42], aerospace [44] and electronics [36]. Moreover, SLA resins can be modified to tailor its properties for specific applications such as those that require electrical conductivity, flame retardancy and chemical resistance. ...
(Journal of Micromechanics and Molecular Physics)
We have developed a novel, facile and architecturally versatile fabrication method for specially designed cellular graphene lattices using additively manufactured polymer-based gyroidal triply periodic minimal surface (TPMS) as the initial sacrificial scaffold. Three-dimensional (3D)-printed templates of the polymeric gyroid lattices were coated with a mixture of graphene oxide (GO) and hydrazine solution via the hydrothermal process, followed by drying and thermal etching of the polymer scaffold, which resulted in a neat reduced GO (rGO) lattice of the gyroidal TPMS structure. Scanning electron microscopy and micro-computed tomography were used to evaluate the morphology and size of the 3D rGO architectures, while a Raman response at 1360/cm (D peak), 1589/cm (G peak) and 2696/cm (2D peak) verified the presence of rGO. Thermo-electro-mechanical properties of rGO gyroid lattices of different densities were characterized where the highest Young's modulus recorded was 351 kPa for a sample with a density of 45.9 mg/ccm. The rGO gyroid lattice exhibits an electrical conductivity of 1.07 S/m and high thermal insulation property with a thermal conductivity of 0.102 W/m.K. It is demonstrated that the hydrothermal-assisted fabrication process is adaptable for different lattice architectures based on 3D-printed scaffolds and thus has wide functional applications.
... Comprehensive summaries on topology optimization can be found in Bendsøe and Sigmund (2004) and in dedicated review articles (Rozvany 2009;Sigmund and Maute 2013;Deaton and Grandhi 2014). The increased availability of additive manufacturing processes and materials has provided new possibilities compared to traditional methods, including design freedom and manufacturing of intricate shapes predicted by topology optimization (Gibson, Rosen, and Stucker 2010). ...
This article presents an infill topology optimization procedure to generate lightweight porous structures. The proposed method is based on discrete variables and builds upon the sequential element rejection and admission method, extending previous work on topology optimization for infill structures. Local volume constraints are introduced in the conventional formulation of the topology optimization problem for maximum stiffness design instead of the global volume constraint. The local constraints are applied, dividing the interior of a given design shape into quadrangular subdomains with variable aspect ratios. The localized material within these subordinate cells is allowed to flow between two discrete material models, ‘real’ and ‘virtual’, where two separate criteria are considered for the rejection and admission of elements. The results demonstrate the effectiveness of the method, showing that detailed porous designs are efficiently achieved with the proposed strategy. Numerical examples demonstrate the effects of the different design parameters.
... Additive manufacturing (AM) is an emerging manufacturing process applied both in research and industrial fields such as aerospace, biomedical, space, defense, naval, energy sectors, automotive, oil and gas industries, and others [1][2][3]. This process can be used for the production of parts with complex geometries that are otherwise difficult to produce using conventional manufacturing processes [4][5][6]. The complex, lightweight, and customized parts manufactured by the AM process can significantly minimize the consumption of raw materials and improve the competence in real field application. ...
In additive manufacturing (AM), the surface roughness of the deposited parts remains significantly higher than the admissible range for most applications. Additionally, the surface topography of AM parts exhibits waviness profiles between tracks and layers. Therefore, post-processing is indispensable to improve surface quality. Laser-aided machining and polishing can be effective surface improvement processes that can be used due to their availability as the primary energy sources in many metal AM processes. While the initial roughness and waviness of the surface of most AM parts are very high, to achieve dimensional accuracy and minimize roughness, a high input energy density is required during machining and polishing processes although such high energy density may induce process defects and escalate the phenomenon of wavelength asperities. In this paper, we propose a systematic approach to eliminate waviness and reduce surface roughness with the combination of laser-aided machining, macro-polishing, and micro-polishing processes. While machining reduces the initial waviness, low energy density during polishing can minimize this further. The average roughness (Ra=1.11μm) achieved in this study with optimized process parameters for both machining and polishing demonstrates a greater than 97% reduction in roughness when compared to the as-built part.
The additive manufacturing industry has witnessed rapid growth and has applications across various sectors such as aerospace, automotive, healthcare, and consumer goods. Both Thermoplastic Elastomer (TPE) and Polylactic Acid (PLA) hold significant relevance in these industries because of their unique properties and environmental sustainability, thus driving the demand for research aimed at improving their compatibility and performance in multi-material printing processes. This study delves into the interlayer adhesion aspects of multi-material filament fabrication, particularly focusing on the incorporation of TPE and PLA. TPEs offer elasticity and flexibility, while PLA provides rigidity and biodegradability, making them an intriguing combination for a wide range of applications. Experimental investigations of mechanical properties, specifically tensile, compression, and Charpy impact tests, are conducted to evaluate the interlayer adhesion between TPE and PLA. This study aims to contribute to the understanding of interlayer adhesion in multi-material filament fabrication, focusing on the integration of TPE and PLA. Through experimental analysis and exploration of industrial applications, we seek to shed light on the potential of these materials in additive manufacturing and outline future directions for research and development in this field.
Nickel silicides are crucial in advanced technology applications ranging from semiconductor devices to high-temperature materials. Gas atomization is a process that involves the formation of fine liquid droplets and their rapid cooling and solidification to make powder particles. The final microstructure and the properties of the particles are highly sensitive to the gas atomization process parameters. In the present study, gas atomization of NiSi12-wt% was performed at three different pressures (35, 40, and 45 bars) to optimize the particle size distribution for additive manufacturing applications. A comprehensive range of characterization techniques, including scanning electron microscopy, X-ray diffraction, particle size distribution measurements, light optical microscopy, and density measurements, was used to evaluate the microstructural features, phase composition, and density of the produced NiSi12-wt% powders. Higher atomizing gas pressures resulted in a finer particle size distribution due to improved molten droplet breakup, increased satellite formation, and a well-suited particle size distribution for additive manufacturing applications.
Understanding design complexity for additive manufacturing (AM) is essential in AM production planning since conventional make-to-order production for individual AM orders of complex designs can amplify operational uncertainty in an entire AM production system. As a response, this study aims not only to demonstrate the impact of design complexity on AM production but also to propose a novel order dispatching approach based on design complexity that mitigates operational uncertainty in an AM production system. First, a design complexity measure was developed using an information theoretic approach. Next, a discrete-event simulation model to represent an AM production system consisting of parallel AM machines for jet-engine bracket designs was built to identify the impact of design complexity on average order lead time and total production cost through regressions. Finally, a flexible order dispatching rule that reflects operational attitudes toward design complexity was proposed to determine part-processing priorities by tracking both part- and system-level design complexity states in a centralized queue for AM production. The proposed dispatching rule was compared with relevant static dispatching rules to assess its performance in operational efficiency under varied attitudes toward design complexity. The findings from this study clearly showed the negative impact of design complexity on operational performance for AM production. Moreover, the proposed dispatching rule resulted in lead time reduction and balanced lead time performance in AM production against alternative static dispatching strategies. This study demonstrates the importance of design complexity-based flexible operations to properly handle latent uncertainties in an AM production system.
This study introduces a post-treatment process, the subpressure-driven soft deformation method, to reduce inherent voids in Material Extrusion (MEX) components. By subjecting printed green components to heat treatment under subpressure, the process enhances viscosity, effectively filling voids formed between deposited tracks. The average porosities of the samples sintered from the green components without and with soft deformation are calculated to be 3.55% and 2.36%, respectively. A comparison of the tensile strengths and fracture surfaces of the sintered samples with and without soft deformation treatment indicated that the sintered samples with soft deformation treatment exhibited narrower standard deviation for the various mechanical properties. Capillary rheometer calculations indicate feedstock viscosity to be between 450.34 and 1018.31 Pa s under subpressure, diminishing inter-track voids without sizeable dimensional changes. Molecular dynamics simulation demonstrates a 3.7-fold increase in bond strength, indicating intertrack voids effectively eliminated. Reduced inter-particle distances facilitate necking, grain growth, and improved sintered density.
In this study, a hybrid MMC-AABH plus approach is developed for the fast optimal design of shell-graded-infill structures. The key idea is to use a proper description about the graded microstructural infill and the coating shell. To this end, a set of moving morphable components is adopted to represent the boundary of the coating shell, while the graded-infill is embodied by spatially varying orthotropic porous configurations. Under such a treatment, with a small number of design variables, both the boundary of the coating shell and the graded microstructure infill can be optimized simultaneously. Other attractive features of the present study are summarized as follows. First, the smooth variation across the microstructural infill can be automatically satisfied based on the proposed approach compared with other similar methods. Second, with the use of the extreme value principle of Laplace equation, the minimum feature size can be explicitly controlled during the optimization. Finally, compared with other methods in the frontier, the approach proposed in the present study enjoys a considerable reduction in the computation cost and can obtain a near-optimal design of the coating structures. The effectiveness of the proposed approach is further demonstrated with numerical examples.
Metal Additive Manufacturing is quite expensive and very different from traditional schemes. The possibility of realizing lightweight products with free-form shapes increases the interest in this technology in the industry. The main limitations of the widespread of Metal Additive Manufacturing concern the high cost of materials and 3D printers, and the necessity of post-processing activities. Additive Manufacturing generally claims different design constraints if compared to traditional manufacturing technologies. The improvements in 3D Metal Printing are increasing the design practices in Additive Manufacturing. The design workflow for Additive Manufacturing includes different tools and methods to manage the design complexity. These tools are CAD/CAE software, numerical simulations, database, etc. They mostly are the updated versions of already existing tools. Therefore, these tools are not directly developed to support the phases of Additive Manufacturing. The paper analyzes the main functionalities of Design for Metal Additive Manufacturing tools. The critical analysis suggests the necessity to improve the interactive practices between users and tools along the design workflow. A more interactive approach to design could reduce the gap between the definition of the part geometry and the parameter settings for the additive process.
This paper presents a state of the art review for 3D printed facades. In the review, three main topics are identified: (i) computational design strategies for 3D printed facades, (ii) fabrication processes and materials, and (iii) performance assessment. The design section displays computational tools and methods for design to production of 3D printed facades. The chapter fabrication processes, materials, and applications illustrates the technology potential for facade application sorted by material groups. The performance assessment section presents current approaches to evaluating and validating the performance of 3DP facades. Finally, knowledge gaps, challenges, and future trends are discussed to offer insights into leading-edge solutions for facade design and fabrication.
Design for Manufacture and Assembly (DfMA) in architectural, engineering, and construction (AEC) industry is attracting the attention of designers, practitioners, and construction project stakeholders. Digital fabrication (Dfab) and design for additive manufacturing (DfAM) practices are found in current needs for further research and development. The DfMA's conceptual function is to maximize the process efficiency of Dfab and AM building projects. This work reviewed 171 relevant research articles over the past few decades. The concept of DfMA and the fundamentals of DfMA in building and construction were explored. In addition, DfMA procedures associated with Dfab and DfAM, as well as its AM assembly process, were discussed. Lastly, the current machine learning research on DfMA in construction was also highlighted. Large research gaps in the DfMA for Dfab and DfAM can be filled to increase operational efficiency and sustainable practices.
A Design for Manufacture and Assembly (DfMA) in architectural, engineering, and construction (AEC) industry is attracting the attention of designers, practitioners, and construction project stakeholders. Digital fabrication (Dfab) and design for additive manufacturing (DfAM) practices are found apparent needs for development. The DfMA's conceptual function is to maximize the process efficiency of Dfab and AM building projects. This work reviewed 153 relevant research articles over the past few decades. The concept of DfMA and the fundamentals of DfMA in building and construction were explored. In addition, DfMA procedures associated with Dfab and DfAM, as well as its AM assembly process, were discussed. Lastly, the current machine learning research on DfMA in construction were also highlighted. Large research gaps in the DfMA for Dfab and DfAM can be filled to significantly increase operational efficiency and sustainable practices.
Additive manufacturing (AM), also referred to as 3D printing, emerged as a disruptive technology for producing customized objects or parts, and has attracted extensive attention for a wide range of application fields. Electrochemical energy storage is an ever-growing industry that exists everywhere in people’s daily life, and AM brings new opportunities and challenges for advanced energy storage. To date, for energy storage, enormous efforts have been devoted to exploring the pros and cons of AM compared to conventional methods, and significant progress has been made. In this chapter, the topic of AM of energy storage devices is comprehensively reviewed. A brief introduction to AM and a summary of basic AM categories are provided in the beginning. The diverse additively manufactured materials for energy storage are emphasized and discussed. The advancement of AM of rechargeable batteries and electrochemical capacitors is also given. Lastly, a summary and outlook of the future AM development for next-generation energy storage materials and devices are presented at the end of this chapter.
Direct Digital Manufacturing (DDM) is considered by many as one of the most promising approaches towards cost- and time-efficient mass customization. Compared to conventional manufacturing systems, DDM systems are not as common and incorporate several distinctive features, such as higher flexibility in product form and structure, lower economies of scale and higher potential for decentralized production network. The initial design phase of a DDM production system, where very important in term of efficiency and quality, decisions are made, is a relatively unexplored topic in the relevant literature. In the present study, the corresponding issues are investigated through a case study involving the direct digital production of a customized reusable face mask (respirator) for medical use. Investigated system design aspects include product, process, and facility design. Based on data generated through manufacturing tests, a preliminary cost analysis is performed and several scenarios regarding production throughput and facility planning are examined. According to the results, DDM of custom-made face masks is, to a large extent, technically and economically feasible. Interestingly, considering the whole process, a large part of production cost is associated with labor and materials. Finally, evidence for a fundamental trade-off between manufacturing cost and speed/flexibility is identified, implying that different implementations of DDM systems can be realized depending on strategic operational objectives.
This paper aims to develop a method for optimizing the geometry of complex-shaped additive manufacturing (AM) parts to minimize the need for assembly. The proposal relies on functional analysis and machine learning. The CA-3 automatic coupling mechanism for railway carriages was chosen as a design prototype. The proposed approach makes it possible to move from conventional to non-assembly AM designs with movable parts that require less material to be fabricated. The results can be used to develop new software solutions, technologies, and design strategies for fabricating complex AM mechanisms.
The practice of design in manufacturing is evolving. With the emergence of additive manufacturing (AM) technologies in recent years, design methodologies need to evolve beyond the conventional Design for Manufacturing and Assembly (DFMA) methodology. As manufacturing companies progressively adopt AM and realize a need to design with AM, new guidelines and a shift in the design mindset must be considered with respect to specific AM processes, machines, and materials.
This chapter begins by introducing a historical account of design methodologies for conventional manufacturing from DFMA and Design for X/Excellence to Design for Additive Manufacturing. The extensive impact of DFMA on different industries is illustrated through various successful case studies, followed by a paradigm shift in design methodologies. Finally, a list of key design considerations is proposed to facilitate the realization of optimal design with AM in our current and future manufacturing landscape.
Metals play a paramount role in modern industries and attract considerable interest in the field of additive manufacturing (AM) due to their enormous potential for diverse applications, especially in the aerospace, automotive, and health-care sectors. Stimulated by the rapid development of technologies regarding lasers, software control systems, and powder preparation over decades, metal AM has evolved from rapid prototyping to a mature processing technology for the manufacture of high-end products applied in various advanced industrial fields.
This chapter serves to provide a comprehensive review of the fundamentals of metal AM technology. It begins with the classification and principles of different metal AM techniques, followed by highlighting the feedstock preparation and characterization techniques. After that the standardized mechanical property testing methods, inherent printing defects, common postprocessing, and representative applications of metallic AM components are presented in detail. Finally, a brief perspective on the challenges and potential solutions for metal AM is provided to guide future research. It is anticipated that the chapter will help readers establish a fundamental understanding of metal AM and to exert the knowledge into their research work readily.
Researchers and industries rely heavily on standardized testing methods to ensure products are designed and manufactured with high quality. With increasing use of additive manufacturing processes, such as material extrusion (MEX), there is a significant gap in material testing standards tailored for such components, and a lack of guidance on preparing appropriate test specimens with mesostructures that best represent the final part being analyzed. This paper aims to support the standardization of MEX material testing by reviewing the current methods used for preparing test specimens for tensile testing and proposing guidelines for implementation in a new standard. The need for standardization of MEX specimen preparation is addressed by analyzing the effects of slicing parameters on resulting tensile properties of the specimen. It is suggested that a standard should acknowledge these parameters, in addition to specimen geometry, toolpath optimization, printer and material specifications, so that they are appropriately selected for the test specimen by regarding the final part structure. Consideration of the proposed guidelines in a standardized method may enable comparisons between published results and support the development of MEX technology for use in advanced applications.
The current limitations of design for additive manufacturing (DfAM) are the state of knowledge on materials and the effects of production parameters. As more engineering-grade polymers become available for fused filament fabrication (FFF), the designs and processes must be adapted to fully utilize the structural properties of such materials. By studying and comparing the production parameters of a material test specimen and a component, the effects of layer temperature on the strength, surface roughness, and dimensional accuracy of PA6-CF were found. As the cross-section increases in component manufacturing, maintaining the layer temperature becomes a major challenge. From the findings, the concept of thermal layer design (TLD) was introduced as a way of increasing strength via temperature in selected regions after presenting the effect of layer temperature. TLD proved to have a major effect on layer temperature and heat distribution. Depending on the investigated layer temperature, from 147 °C to 193 °C the UTS of PA6-CF increased from 42 MPa to 73 MPa. Implementing TLD in DfAM represents a big leap for designing high-performance polymer components.
Product Design based Knowledge graphs (KG) aid the representation of product assemblies through heterogeneous relationships that link entities obtained from multiple structured and unstructured sources. This study describes an approach to constructing a multi-relational and multi-hierarchical knowledge graph that extracts information contained within the 3D product model data to construct Assembly-Subassembly-Part and Shape Similarity relationships. This approach builds on a combination of utilizing 3D model meta-data and structuring the graph using the Assembly-Part hierarchy alongside 3D Shape-based Clustering. To demonstrate our approach, from a dataset consisting of 110,770 CAD models, 92,715 models were organized into 7,651 groups of varying sizes containing highly similar shapes, demonstrating the varied nature of design repositories, but inevitably also containing a significant number of repetitive and unique designs. Using the Product Design Knowledge Graph, we demonstrate the effectiveness of 3D shape retrieval using Approximate Nearest Neighbor search. Finally, we illustrate the use of the KG for Design Reuse of co-occurring components, Rule-Based Inference for Assembly Similarity and Collaborative Filtering for Multi-Modal Search of manufacturing process conditions. Future work aims to expand the KG to include downstream data within product manufacturing and towards improved reasoning methods to provide actionable suggestions for design bot assistants and manufacturing automation.
Advanced design is guided by requirements and relationships between manufacturing, material, and functions. This research aims to evaluate the dimensional integrity and the design rules for developing an aircraft bracket by atomic diffusion additive manufacturing (ADAM). The key manufacturing considerations are introduced in the design guide to achieve an integrated design approach. This project aims to compare the initial shape of an integrated aircraft engine bracket design and its shape after manufacturing. Mapping of surface deviations was set up to compare the two 3D models, the first one is from CAD and the second model was obtained via 3D scanning.
Additive Manufacturing is a key enabling technology for Industry 4.0 and the Green Deal, allowing more efficient resources exploitation while providing innovative design to critical components. Electron Beam Powder Bed Fusion (EB-PBF) is an edge technology for many sectors, i.e. aerospace, medical, and automotive. The control of the surface finish by surface topography measurements is essential to engineer surface functional properties, whose specifications are application specific. This works investigates the effect of thin-wall orientation and surface inclination on the topography, described by areal field and feature parameters, to provide designers with a useful tool in the early stage of product development and tolerance specification and verification.
While many studies for material extrusion–based additive manufacturing (AM) of polymers focus on experimental approaches to evaluate relevant performance measures from process parameters, there is a lack of discussion to connect experimental results with useful applications. Also, one of the major deficiencies in the application literature is a trade-off analysis between energy costs and cycle time (time to produce an item from the beginning to the end) since improving these two measures simultaneously is challenging. Thus, this paper proposes an energy simulation method for performing a trade-off analysis between energy costs and cycle time using combinations of major AM process parameters for material extrusion. We conduct experiments using carbon fiber–reinforced poly-ether-ether-ketone (CFR-PEEK), which is increasingly used in material extrusion. From experimental results, we build a power model in which power (kW) is derived as a linear function of material addition rates (MAR). This MAR regression model is then used in a proposed simulation model that integrates discrete event simulation and numerical simulation. In our simulation case study of 50 machines and 40 scenarios, we investigate trade-offs between energy costs and cycle time with three control policies (P1, P25, and P50) that allow 1, 25, or 50 machines to start heating, respectively. The trade-off analysis results show that P25 can be preferred when a balance between cycle time and energy costs is pursued, while P1 or P50 can be chosen if either energy cost (with P1) or cycle time (with P50) is more important than the other measure. Moreover, we find that the machine utilization, variability, and product volume have significant effects on energy costs and cycle time.
DESCRIPTION
This chapter deals with the latest manufacturing process, especially laser-based manufacturing of polymers with/without surface texturing, for their use in various fields of interest. Lasers have diverse applications in the fabrication of polymers. Lasers can be used from dry etching to soft lithography. This chapter is limited to exploration up to the fabrication of 3D micro/nanostructures in polymers using lasers. The wettability and optical response of these micro-textured polymers can easily be tuned through exposure to a laser of suitable wavelengths. Moreover, laser-assisted manufacturing can help produce extremely complex shapes. It is an excellent choice for functional prototypes, thermal applications, and end-use parts. Although laser-based manufacturing has many advantages that no other manufacturing process possesses, this process is not widely used or recommended. This chapter also extends the discussion to the issues/limitations with laser-based manufacturing and the type of materials being used. At the end, there shall be a discussion on the applications and scope of laser-assisted fabrication of polymers.
The emergence and rapid evolution of additive manufacturing have led to disruptive changes in the business landscape. However, empirical research on how additive manufacturing creates value for firms is still limited. This study, therefore, examines the relationships between additive manufacturing, new product development performance, and competitive advantage with moderating role of environmental dynamism. The sample consists of 226 manufacturing firms in Turkey. The results indicate that additive manufacturing is positively related to new product development performance and competitive advantage. For these relationships, a positive moderating effect of environmental dynamism is found. It is further demonstrated that new product development performance fully mediates the association between additive manufacturing and competitive advantage.
Often, simple questions do not have obvious answers and require an experiment that yields an unexpected answer. Have you ever wondered what will happen if you turn 180 degrees to the commonly accepted FDM printing convention? The paper presents the verification of the possibility of using the reverse orientation of the print head in traditionally used 3D printers of FFF/FDM systems. It has been shown that the mechanical parameters of the printed object can be even higher when reverse printing is used. The presented concept opens up new possibilities of designing printers in FFF/FDM systems, which use changed heat convection and the reverse effect of gravity on the printed object. This work was carried out using the TRIZ methodology.
High-resolution laser additive manufacturing (LAM) significantly releases design freedom, promoting the development of topology optimization (TO) and advancing structural design methods. In order to fully take advantage of voxelated forming methods and establish the quantitative relationship between the mechanical properties of printing components and multiple process factors (laser- and process- parameters), the concurrent optimization design method based on LAM should cover the process-performance relationship. This study proposes a novel artificial intelligence-facilitated TO method for LAM to concurrently design microscale material property and macroscale structural topology of 3D components by adopting heuristic and gradient-based algorithms. The process–structure–property relationship of selective laser sintering is established by the back propagation neural network, and it is integrated into the TO algorithm for providing a systematic design scheme of structural topology and process parameter. Compared with the classical optimization method, numerical examples show that this method is able to improve the mechanical performance of the macrostructure significantly. In addition, the collaborative design method is able to be widely applied for complex functional part design and optimization, as well as case studies on artificial intelligence-facilitated product evaluation.
Vat photopolymerization (VP) has been adopted rapidly and widely due to its ability to print 3D objects with high resolution and accuracy, and its high speed of fabrication over a wide range of materials. However, commercial VP printers have limited functionality and are designed primarily for local use. In this research, a generic web-based VP (WBVP) platform was built to provide enhanced functionality and remote access. A novel adaptive controller for printer parameters was developed to reduce the impact of pulling force problem in bottom-up VP 3D printing as well as speed up the manufacturing problem, new geometric and energy calibration algorithms were developed to alleviate shape distortion and uneven heating problems due to curvature of the lens, and a novel web interface was created to allow either one user to control multiple machines and or multiple users to control a single machine to make parts in real-time. The developed platform produced 3D parts with higher resolution and quality in less processing time as compared with a commercially available VP machine.
This paper presents a parametric modeling method to create truss structures to enhance a part’s mechanical and/or dynamic properties. The main idea behind this method is to replace thick part sections with thinner sections that are reinforced by truss structure. Computational methods are presented to create truss structures that conform to a part’s shape. The methods utilize Bezier surfaces to approximate the part surface and to create the truss structure. Truss topologies can be created for a two-dimensional truss, a three-dimensional truss for single volume and a three-dimensional truss for multiple volumes. The decomposition of the part surfaces, the construction of approximating Bezier surfaces, and solid modeling of the truss structures are also shown. An example is presented to demonstrate the utility of conformal truss structures for a large part from the aerospace industry.
Stereolithography apparatus (SLA) is capable of in situ fabrication of complex parts, as well as mechanisms and complex devices with embedded components. In this paper, a series of example devices are presented to illustrate the power of building around embedded components (inserts). The problem formulation, solution approach, and specific rules and procedures are presented using these examples and experimental results. A case study approach is used for presentation. These procedures and results lend insight into promising new applications of SLA technology, as well as novel methods of implementing additional functionality into SLA and other rapid prototyping technologies.
A new design-for-manufacturing method, called the geometric tailoring (GT), and the associated digital interface concept have been developed that enable the design activities to be separated from the manufacturing activities. Conditions for the successful application of this method are investigated. The GT method is demonstrated for rapid prototyping and rapid tooling technologies, where prototype parts are required to match the production properties as closely as possible. This method is embodied in a system called the rapid tooling testbed (RTTB). Research work is presented on GT and the distributed computing environment underlying the RTTB. Examples are summarized from the usage of this method and testbed.
This report is a review of additive/subtractive manufacturing techniques in Europe. Otherwise known as Solid Freeform Fabrication (SFF), this approach has resided largely in the prototyping realm, where the methods of producing complex freeform solid objects directly from a computer model without part-specific tooling or knowledge started. But these technologies are evolving steadily and are beginning now to encompass related systems of material addition, subtraction, assembly, and insertion of components made by other processes. Furthermore, these various additive/subtractive processes are starting to evolve into rapid manufacturing techniques for mass-customized products, away from narrowly defined rapid prototyping. Taking this idea far enough down the line, and several years hence, a radical restructuring of manufacturing as we know it could take place. Not only would the time to market be slashed, manufacturing itself would move from a resource base to a knowledge base and from mass production of single use products to mass customized, high value, life cycle products. At the time of the panel's visit, the majority of SFF research and development in Europe was focused on advanced development of existing SFF technologies by improving processing performance, materials, modeling and simulation tools, and design tools to enable the transition from prototyping to manufacturing of end use parts. Specific examples include: laser sintering of powders, direct metal deposition and laser fusion of powders, and ink jet printing techniques. Truly integrated layer-by-layer additive/subtractive processes under development are limited; European emphasis was on creating an entire process chain to create new business models.
Purpose
The purpose of this paper is to investigate design synthesis methods for designing lattice cellular structures to achieve desired stiffnesses. More generally, to find appropriate design problem formulations and solution algorithms for searching the large, complex design spaces associated with cellular structures.
Design/methodology/approach
Two optimization algorithms were tested: particle swarm optimization (PSO) and Levenburg‐Marquardt (LM), based on a least‐squares minimization formulation. Two example problems of limited complexity, specifically a two‐dimensional cantilever beam and a two‐dimensional simply‐supported plate, were investigated. Computational characteristics of the algorithms were reported for design problems with hundreds of variables. Constraints from additive manufacturing processes were incorporated to ensure that resulting designs are realizable.
Findings
Both PSO and LM succeeded in searching the design spaces and finding good designs. LM is one to two orders of magnitude more efficient for this class of problems.
Research limitations/implications
Three‐dimensional problems are not investigated in this paper.
Practical implications
LM appears to be a viable algorithm for optimizing structures of complex geometry for minimum weight and desired stiffness.
Originality/value
The testing of design synthesis methods (problem formulations and algorithms) for lattice cellular structures, and the testing of PSO and LM algorithms, are of particular value.
The paper presents a compact Matlab implementation of a topology optimization code for compliance minimization of statically
loaded structures. The total number of Matlab input lines is 99 including optimizer and Finite Element subroutine. The 99
lines are divided into 36 lines for the main program, 12 lines for the Optimality Criteria based optimizer, 16 lines for a
mesh-independency filter and 35 lines for the finite element code. In fact, excluding comment lines and lines associated with
output and finite element analysis, it is shown that only 49 Matlab input lines are required for solving a well-posed topology
optimization problem. By adding three additional lines, the program can solve problems with multiple load cases. The code
is intended for educational purposes. The complete Matlab code is given in the Appendix and can be down-loaded from the web-site
http://www.topopt.dtu.dk.
Shape and size optimization problems instructural design are addressed using the particle swarm optimization algorithm (PSOA).
In our implementation of the PSOA, the social behaviour of birds is mimicked. Individual birds exchange information about
their position, velocity and fitness, and the behaviour of the flock is then influenced to increase the probability of migration
to regions of high fitness. New operators in the PSOA, namely the elite velocity and the elite particle, are introduced.
Standard size and shape design problems selected from literature are used to evaluate the performance of the PSOA. The
performance of the PSOA is compared with that of three gradient based methods, as well as the genetic algorithm (GA). In attaining
the approximate region of the optimum, our implementation suggests that the PSOA is superior to the GA, and comparable to
gradient based algorithms.
With more emphasis being placed on the cost and quality of new products and on reducing the lead time to develop them, attention is turning to the increasingly important topic of design for manufacturing (DFM). This involves the collaboration among research and development, manufacturing, and other company functions and is aimed at accelerating the new product development process from product conception to market introduction. A company can create a competitive advantage for itself by managing the process and its related organizational dynamics effectively. This collection of essays focuses on the development of strategic capabilities through use of DFM tools and practices, the role of DFM in specific product development phases, and the social, political, and cultural context within which DFM is introduced.
Solid modeling of objects forms an important task in design and manufacturing. Recent developments in the field of layered manufacturing have shown potential for the physical realization of heterogeneous (multi-material) objects. Thus, there is a need to represent material information as an integral part of the CAD model data. Information models for the representation of product data are being developed as an international standard called STEP (ISO 10303). However, the current application protocols focus on the representation of homogeneous objects only. This paper proposes an information model to represent heterogeneous objects using the information modeling methodology developed for ISO 10303. This will help in providing a uniform base in the development of heterogeneous solid modeling systems. It will also equip the solid modeler with the ability to integrate with other applications and process planning in the domain of layered manufacturing.
Additive manufacturing is coming into its third decade of commercial technological development. During that period, we have experienced a number of significant changes that has led to improvements in accuracy, better mechanical properties, a broader range of applications, and reductions in costs of machines and the parts made by them. In this chapter we explore the evolution of the field and how these developments have impacted a variety of applications over time. We note also that different applications benefit from different aspects of AM, highlighting the versatility of this technology.
This paper discusses the relationship between modular products and manufacturing. The relationship is based on an expanded definition of modularity which incorporates the potential of modularity based not only on end uses of a product but also on the manufacturing processes. By incorporating this expanded definition of modularity, called manufacturing modularity, into product development, a more robust product modularity can be achieved. Modularization, due to the functional independence it creates, has been called the goal of good design. Industry has made an effort to modularize products to be flexible to the needs of end users and marketing. This effort has led to the creation of product families. Occasionally, modules are created with some aspects of production in mind. However, this modularization is done without fully understanding the implications of the design. Although often yielding highly functional products, once the entire manufacturing process is accounted for, this unstructured modularization often leads to costly redesigns or expensive products. In addition, the unstructured modularization makes the process difficult to repeat if it is successful and difficult to avoid if it is unsuccessful. Modularity requires maintaining independence between components and processes in different modules, encouraging similarity in all components and processes in a module, and maintaining interchangeability between modules. Modularity with respect to manufacturing necessitates understanding the various manufacturing processes undergone by each attribute of each component. This paper presents a basic methodology for creating manufacturing modules. These modules decrease manufacturing costs, decrease lead time, and strengthen product families. A design methodology is developed which prevents a cascade of product design changes due to changes in manufacturing processes and supports agility in the face of changes in manufacturing processes. The methodology and its elements are highlighted in the redesign of an electric coffee maker.
This paper details how Rapid Manufacturing (RM) can overcome the restrictions imposed by the inherent process limitations of conventional manufacturing techniques and become the enabling technology in fabricating optimal products. A new design methodology capable of exploiting RM's increased design freedom is therefore needed. Inspired by natural world structures of trees and bones, a multi-objective, genetic algorithm based topology optimisation approach is presented. This combines multiple unit cell structures and varying volume fractions to create a heterogeneous part structure which exhibits a uniform stress distribution.
The starting point in the formulation of any numerical problem is to take an intuitive idea about the problem in question and to translate it into precise mathematical language. This book provides step-by-step descriptions of how to formulate numerical problems so that they can be solved by existing software. It examines various types of numerical problems and develops techniques for solving them. A number of engineering case studies are used to illustrate in detail the formulation process. The case studies motivate the development of efficient algorithms that involve, in some cases, transformation of the problem from its initial formulation into a more tractable form.
Introduction Making Metal Foams Characterization Methods Properties of Metal Foams Design Analysis for Material Selection Design Formulae for Simple Structures A Constitutive Model for Metal Foams Design for Creep with Metal Foams Sandwich Structures Energy Management: Packaging and Blast Protection Sound Absorption and Vibration Suppression Thermal Management and Heat Transfer Electrical Properties of Metal Foams Cutting, Finishing and Joining Cost Estimation and Viability Case Studies Suppliers of Metal Foams Web Sites Index .
Three dimensional Rapid Prototyping processes, also called Layered Manufacturing or Solid Freeform Fabrication (SFF), promise designers the ability to automatically fabricate complex shapes. SFF processes were invented with the assumption that designers would submit complete part models for automated planning and manufacturing. This planning process is normally based on some form of "decomposition," for example slicing into layers. Especially for newer, more complex SFF processes, there are several disadvantages to this approach, primarily that decomposition is difficult and doesn't reliably produce good process plans. Furthermore, it is hard for the designer to get feedback on the manufacturability of his design, and today's decomposition systems are not fully automated. This dissertation presents an alternative approach, "design by composition," where users build designs from "primitives" that include high-level manufacturing plans. When the user combines two primitives with a Boolean operation, software will automatically generate a manufacturing plan for the new design from the plans for the source primitives. In contrast to the decomposition method, design by composition offers several benefits to designers, primarily access to manufacturability feedback during design-time, a greater degree of automation, the ability to create designs with embedded components (such as sensors, electronic circuits, bearings, and shafts), and enhanced control over manufacturing plans. These advantages make design by composition a more attractive approach to SFF processing, especially for designers who are new to these techniques. This dissertation presents scalable, robust algorithms for the implementation of design by composition, and describes a prototype implementation and sample parts which were designed with it.
Cellular solids include engineering honeycombs and foams (which can now be made from polymers, metals, ceramics, and composites) as well as natural materials, such as wood, cork, and cancellous bone. This new edition of a classic work details current understanding of the structure and mechanical behavior of cellular materials, and the ways in which they can be exploited in engineering design. Gibson and Ashby have brought the book completely up to date, including new work on processing of metallic and ceramic foams and on the mechanical, electrical and acoustic properties of cellular solids. Data for commercially available foams are presented on material property charts; two new case studies show how the charts are used for selection of foams in engineering design. Over 150 references appearing in the literature since the publication of the first edition are cited. It will be of interest to graduate students and researchers in materials science and engineering. © Lorna J. Gibson and Michael F. Ashby, 1988 and Lorna J. Gibson and Michael F. Ashby, 1997.
A cylindrically symmetric layout of two opposite families of logarithmic spirals is shown to define the layout of minimum-weight, symmetrically loaded wheel structures, where different materials are used for the tension and compression members, respectively; referred to here as dual-material structures. Analytical solutions are obtained for both structure weight and deflection. The symmetric solutions are shown to form the basis for torsion arm structures, which when designed to accept the same total load, have identical weight and are subjected to identical deflections. The theoretical predictions of structure weight, deflection, and support reactions are shown to be in close agreement to the values obtained with truss designs, whose nodes are spaced along the theoretical spiral layout lines. The original Michell solution based on 45 deg equiangular spirals is shown to be in very close agreement with layout solutions designed to be kinematically compatible with the strain field required for an optimal dual-material design.
In this paper, a piecewise constant level set (PCLS) method is implemented to solve a structural shape and topology optimization problem. In the classical level set method, the geometrical boundary of the structure under optimization is represented by the zero level set of a continuous level set function, e.g. the signed distance function. Instead, in the PCLS approach the boundary is described by discontinuities of PCLS functions. The PCLS method is related to the phase-field methods, and the topology optimization problem is defined as a minimization problem with piecewise constant constraints, without the need of solving the Hamilton–Jacobi equation. The result is not moving the boundaries during the iterative procedure. Thus, it offers some advantages in treating geometries, eliminating the reinitialization and naturally nucleating holes when needed. In the paper, the PCLS method is implemented with the additive operator splitting numerical scheme, and several numerical and procedural issues of the implementation are discussed. Examples of 2D structural topology optimization problem of minimum compliance design are presented, illustrating the effectiveness of the proposed method. Copyright © 2008 John Wiley & Sons, Ltd.
The aim of this article is to evaluate and compare established numerical methods of structural topology optimization that
have reached the stage of application in industrial software. It is hoped that our text will spark off a fruitful and constructive
debate on this important topic.
In this paper, we analyze a metal honeycomb sandwich beam/torsion bar subjected to combined loading conditions. The cell wall arrangement of the honeycomb core is addressed in the context of maximizing resistance to either bending, torsion, or combined bending and torsion for given dimensions, face sheet thicknesses and core relative density. It is found that the relative contributions of the honeycomb core to torsion and bending resistances are sensitive to the configuration of cell walls and the optimal properties significantly exceed those of stochastic metallic foams as sandwich beam core materials for this configuration.
The performance characteristics of a truss core sandwich panel design based on the 3D Kagome has been measured and compared with earlier simulations. Panels have been fabricated by investment casting and tested in compression, shear and bending. The isotropic nature of this core design has been confirmed. The superior performance relative to truss designs based on the tetrahedron has been demonstrated and attributed to the greater resistance to plastic buckling at the equivalent core density. (C) 2003 Published by Elsevier Ltd.
The effective mechanical properties of the octet-truss lattice structured material have been investigated both experimentally and theoretically. Analytical and FE calculations of the elastic properties and plastic yielding collapse surfaces are reported. The intervention of elastic buckling of the struts is also analysed in an approximate manner. Good agreement is found between the predictions of the strength and experimental observations from tests on the octet-truss material made from a casting aluminium alloy. Moreover, the strength and stiffness of the octet-truss material are stretching-dominated and compare favourably with the corresponding properties of metallic foams. Thus, the octet-truss lattice material can be considered as a promising alternative to metallic foams in lightweight structures.
Spatial discretization of the domain and/or boundary conditions prevents application of many numerical techniques to physical problems with time-varying geometry and boundary conditions. By contrast, the R-functions method (RFM) for solving boundary and initial value problems discretizes not the domain but the underlying functional space, while the prescribed boundary conditions are satisfied exactly. The clean and modular separation of geometric information from the numerical procedures results in a solution technique that is essentially meshfree and allows an almost effortless modification of geometrical shapes, boundary conditions, and the governing equations. We show that these properties of the RFM make it highly suitable for automated modeling and simulation of non-stationary physical problems with time-varying geometries and boundary conditions.
In this paper, we briefly review the existing direct implicit geometry generation methods, which include creation of blending surfaces, a limited family of sweeps, and reconstruction of solid geometry from a sample set of surface data points. A broader approach is presented, utilizing the properties of the graph of the implicit defining function, to systematically construct swept solids and perform morphing between sections by implicit methods.
In a general setting, the transfinite interpolation problem requires constructing a single function f(x) that takes on the prescribed values and/or derivatives on some collection of point sets. The sets of points may contain isolated points, bounded or unbounded curves, as well as surfaces and regions of arbitrary topology. All such closed semi-analytic sets may be represented implicitly by real valued functions with guaranteed differential properties. Furthermore, such functions may be constructed automatically using the theory of R-functions. We show that such implicit representations may be used to solve the general transfinite interpolation problem using a generalization of the classical inverse distance weighting interpolation for scattered data. The constructed interpolants may be used to approximate boundary value and smoothing problems in a meshfree manner.
Rapid prototyping (RP) can be used to make complex shapes with very little or even no constraint on the form of the parts. New design methods are needed for parts that can take advantage of the unique capabilities of RP. Although current synthesis methods can successfully solve simple design problems, practical applications with thousands to millions elements are prohibitive to generate solution for. Two factors are considered. One is the number of design variables; the other is the optimization method. To reduce the number of design variables, parametric approach is introduced. Control diameters are used to control all strut size across the entire structure by utilizing a concept similar to control vertices and Bezier surface. This operation allows the number of design variables to change from the number of elements to a small set of coefficients. In lattice structure design, global optimization methods are popular and widely used. These methods use heuristic strategies to search the design space and thus perform, as oppose to traditional mathematical programming (MP) methods, a better global search. This work propose that although traditional MP methods find local optimum near starting point, given a quick convergence rate, it will be more efficient to perform such method multiple times to integrate global search than using a global optimization method. Particle Swarm Optimization and Levenburg-Marquardt are chosen to perform the experiments.
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The advent of rapid manufacturing has enabled the realization of countless products that have heretofore been infeasible. From customized clear braces to jet fighter ducts and one-off dental implants, rapid manufacturing allows for increased design complexity and decreased manufacturing costs. The manufacturing capabilities of this process have evolved to the point that they have surpassed current design capabilities. Meso-scale lattice structures can now be built that contain more lattice struts than it is reasonable to efficiently define. This work has attempted to create a method for designing such lattice structures that is efficient enough to allow for the design of large or complex problems. The main hindrance to the design of complex meso-scale lattice problems is essentially the need to define the strut diameters. While it is obvious that a large design would contain more struts than can be specified by hand, designs also quickly surpass the current capabilities of computational optimization routines. To overcome this problem, a design method has been developed that uses a unit-cell library correlated to finite element analysis of the bounding geometry to tailor the structure to the anticipated loading conditions. The unit-cell library is a collection of base lattice primitives, or unit-cells, that have been specialized for certain applications. In this case, primitives have been created that perform best under the types of stress analyzed by finite element analysis. The effectiveness of this process has been demonstrated through several example problems. In all cases, the unit-cell library approach was able to create structures in less time than current methods. The resulting structures had structural performance slightly lower than similar models created through optimization methods, although the extent of this degradation was slight. The method developed in this work performs extremely well, and is able to create designs for even the most complex lattice structures. There is room for future development, however, in the streamlining of the design process and consideration of higher-order affects within unit-cells. M.S. Committee Chair: David, Rosen; Committee Member: Chris, Paredis; Committee Member: Seung-Kyum, Choi
eberhart @ engr.iupui.edu A concept for the optimization of nonlinear functions using particle swarm methodology is introduced. The evolution of several paradigms is outlined, and an implementation of one of the paradigms is discussed. Benchmark testing of the paradigm is described, and applications, including nonlinear function optimization and neural network training, are proposed. The relationships between particle swarm optimization and both artificial life and genetic algorithms are described, 1
: In this paper, the application of Rapid Prototyping in fabricating non-assembly robotic systems and mechanisms is presented. Using the Stereolithography Apparatus SLA 190 of the Department of Mechanical and Aerospace Engineering of Rutgers University, and the Selective Laser Sintering Sinterstation 2000 of DTM Corporation of Austin, TX, prototypes of mechanical joints were fabricated experimentally. The designs of these component joints were then used to fabricate the articulated structure of experimental prototypes for two robotic systems: 1) a threelegged parallel manipulator; 2) a four degreeof -freedom finger of a five-fingered robotic hand. These complex multi-articulated, multilink, multi-loop systems have been fabricated in one step, without requiring assembly while maintaining their desired mobility. Introduction: It is always desirable to evaluate a proposed robot design prior to full prototyping to ensure the swiftest and most cost effective design changes. Even though pow...
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