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DfAM Strategic Design Considerations
Abstract
Design for additive manufacturing (DfAM) is when designers seek to create a product design that takes advantage of the unique capabilities of AM. DfAM also respects the specific process constraints of the AM technology that will be used to produce the product. This goes beyond merely re-designing existing parts for AM. Re-design for AM is useful because it can yield benefits such as a reduction in the use of material or the consolidation of several parts into one. However, what it fails to do is to consider the added benefits that AM can bring to an entire product through improvements in form, fit, and function. This book seeks to encourage engineers and designers to consider the strategic benefits of AM before concentrating on detailed design. Design for AM is definitely more of a thought process in which conscious decisions are made (often compromises) rather than just blindly following a set of design rules.
... Honeycomb support Cellular support Figure 2. Main support methods [13] ▪ Be vigilant about the minimum feature size for a given AM system or material and the clearances between moving parts. Diegel et al. [15] mentioned that the minimum hole (or slot size) is related to the thickness of the part, the print orientation, the layer thickness, as well as the used AM machine. Similarly, for the clearances between moving parts; the bigger the surface area of the components that are in close contact, the bigger the gap between the moving parts should be. ...
... ▪ The decision to manufacture a part by AM technologies should depend on its complexity. From a cost point of view, it would nearly frequently be more economical to produce geometrically simple parts using conventional technologies if they are quicker than AM [15]. Therefore, it could be wise to consider CNC machines and hybrid machines as alternatives during the manufacturing machine selection. ...
... Diegel et al. [15] have also identified general guidelines for designing AM parts. An additional guideline is, then, added to the previous ones: ...
Additive manufacturing (AM) technologies have seen fast growth in the last few decades. AM needs the implementation of new methods in design, fabrication, and delivery to end-users. Hence, AM techniques have given great flexibility to designers as the design of complex components and highly customized products are no longer binding from a manufacturability point of view. In addition to high material variety, this allows multi-material and variable mechanical characteristics of product manufacturing. This review paper addresses the design for additive manufacturing (DfAM) rules, guidelines, and tools to guide the designer to take advantage of the opportunities provided by AM whether in the early design stages (EDS) or in the later phase using computer-aided design (CAD) tools. It discusses issues related to the design for AM and proposes a DfAM framework applied in the design for the additive manufacturing process.
... Thus, experimental validation and testing, is usually required . Design for Additive Manufacturing (DfAM) was introduced to bridge design with the realized properties of a part considering the specific process potentials and constraints in the manufacturing of additive manufacturing (AM) components (cf. Figure 1) (Diegel et al., 2019). This can be done by design guidelines (Lachmayer and Lippert, 2020;Diegel et al., 2019) or algorithms (e.g. ...
... Design for Additive Manufacturing (DfAM) was introduced to bridge design with the realized properties of a part considering the specific process potentials and constraints in the manufacturing of additive manufacturing (AM) components (cf. Figure 1) (Diegel et al., 2019). This can be done by design guidelines (Lachmayer and Lippert, 2020;Diegel et al., 2019) or algorithms (e.g. overhang constraints or ...
Purpose
Metal laser-powder-bed-fusion using laser-beam parts are particularly susceptible to contamination due to particles attached to the surface. This may compromise so-called technical cleanliness (e.g. in NASA RPTSTD-8070, ASTM G93, ISO 14952 or ISO 16232), which is important for many 3D-printed components, such as implants or liquid rocket engines. The purpose of the presented comparative study is to show how cleanliness is improved by design and different surface treatment methods.
Design/methodology/approach
Convex and concave test parts were designed, built and surface-treated by combinations of media blasting, electroless nickel plating and electrochemical polishing. After cleaning and analysing the technical cleanliness according to ASTM and ISO standards, effects on particle contamination, appearance, mass and dimensional accuracy are presented.
Findings
Contamination reduction factors are introduced for different particle sizes and surface treatment methods. Surface treatments were more effective for concave design features, however, the initial and resulting absolute particle contamination was higher. Results further indicate that there are trade-offs between cleanliness and other objectives in design. Design guidelines are introduced to solve conflicts in design when requirements for cleanliness exist.
Originality/value
This paper recommends designing parts and corresponding process chains for manufacturing simultaneously. Incorporating post-processing characteristics into the design phase is both feasible and essential. In the experimental study, electroless nickel plating in combination with prior glass bead blasting resulted in the lowest total remaining particle contamination. This process applied for cleanliness is a novelty, as well as a comparison between the different surface treatment methods.
... The theoretical framework is underpinned by the Technological Pedagogical Content Knowledge (TPACK) and implemented through the Community of Inquiry (COI) models, which promote the development of a DfAM curriculum [7]. When superimposed and combined with ETaSTs' a more accurate design process can emerge to develop such a DfAM curricular product [16][17][18][19]. TPACK focuses on the integration of technology into teaching effectively by combining technological knowledge, pedagogical knowledge, and content knowledge ( Figure 1a). ...
... Literature and practice indicate that developers choose industry endorsement over qualifying and accreditation for DfAM skills development. [16,17]. ...
This study investigated the affordances (hindrances and opportunities) of developing a comprehensive Design for Additive Manufacturing (DfAM) curricular product in the South African higher education sector. The methodology consisted of an initial literature review illustrating the use of DfAM in higher education and the existence of formal DfAM curricula. Through the literature, the researchers sought these hindrances and opportunities to guide the development of a curriculum sample product. In addition, appropriate theoretical frameworks were investigated and then combined with pedagogical aids in the form of Embedded Tactile and Sensory Technology (ETaST). The overall theoretical findings indicate that a formally structured DfAM curricular product will benefit not just AM-related subjects, but education fields beyond STEM. This research indicates that a DfAM curricular product may lead to an expansion of AM utilisation beyond mere production initiatives for industry but also as a pedagogical aid product for higher education. Furthermore, the use of such DfAM curricular products can infiltrate broader sectors which will increase the time and uptake of AM. The study recommends the implementation of the DfAM curricular product in the undergraduate sector of various subjects to corroborate the findings.
... At order to optimize the topology [20], generate lattice, create the support structure and simulate the AM process. This is to allow lightweight and robust designs [21]. ...
In the current context promoting sustainable development, eco-design and eco-manufacturing concepts are being developed in research laboratories and being integrated gradually into manufacturing industries. Hence, the needed information to eco-design is scattered throughout the product life cycle and is not centralized; especially when designing for additive manufacturing. Contributing to tackle this issue, this paper aims to develop a collaborative eco-design methodology using eco-design tools in the different design stages. Either in the early design stage or in the detailed one, the designer will be supported to make sustainable conscious decisions. Actually, the proposed methodology based on the sustainable-failure modes, effects and criticality analysis (S-FMECA) eco-designing tool, would allow the communication with computer-aided design (CAD), computer-aided manufacturing (CAM), life cycle assessment (LCA), topology optimization (TO) and product life cycle management (PLM) software in order to assist the designer to make green conscious decisions.
... Accordingly, the fabrication of the PSMRP during the SLM process should start from the chin end and finish at the ramus end with support structures generated on the entire bottom surface of the PSMRP. A general rule of thumb is that angles greater than 45 °from the horizontal require support material [37] . Because of the personalization of the PSMRP, its profile is highly irregular, and many angles exist and require support structures. ...
Patient-specific mandibular reconstruction plates (PSMRPs) are being widely used to bridge segmental defects of the mandible after tumor resection or trauma as a result of their superior performance in mandibular reconstruction. Two structural optimized PSMRPs were created to boost the biomechanical behavior in patient-specific mandibular reconstruction by responding to the original design's unexpected in vivo fatigue fracture. Sequentially, through finite element analysis, the biomechanical benefit of the structural optimized PAMRPs was verified, and the biomechanical performances were compared between generally designed PSMRP1 with the customization and mandibular angle region optimized PSMRP2 with a tangent arc upper margin. Consequently, it was validated that the structural optimized PSMRPs reveal their better biomechanical performance, and the PSMRP1 presents better biomechanical performance to the patient-specific mandibular reconstruction than PSMRP2 as a result of its superior safety, preferable flexibility, and equivalent stability.
Background and Objective
: Owing to the unexpected in vivo fracture failure of the original design, structural optimized patient-specific mandibular reconstruction plates (PSMRPs) were created to boost the biomechanical performance of bridging segmental bony defect in the mandibular reconstruction after tumor resection. This work aimed to validate the biomechanical benefit of the structural optimized PAMRPs than the original design and compare the biomechanical performance between PSMRP1 with generic contour customization and PSMRP2 with a tangent arc upper margin in mandibular angle region.
Methods
: Finite Element Analysis (FEA) was used to evaluate the biomechanical behavior of mandibular reconstruction assemblies (MRAs) concerning these two structural optimized PSMRPs by simulating momentary left group clenching and incisal clenching tasks. Bonded contact was set between mandibular bone and fixation screws and between PSMRP and fixation screws in the MRA, while the frictionless connection was allocated between mandibular bone and PSMRP. The loads were applied on four principal muscles, including masseter, temporalis, lateral and medial pterygoid, whose magnitudes along the three orthogonal directions. The mandibular condyles were retrained in all three directions, and either the left molars or incisors area were restrained from moving vertically.
Results
: The peak von Mises stresses of structural optimized PSMRPs (264MPa, 296MPa) were way lower than that of the initial PSMRP design (393MPa), with 33% and 25% reduction during left group clenching. The peak magnitude of von Mises stress, minimum principal stress, and maximum principal strain of PSMRP1 (264MPa, 254MPa; -297MPa, -285MPa; 0.0020, 0.0020) was lower than that of PSMRP2 (296MPa, 286MPa; -319MPa, -306MPa; 0.0022, 0.0020), while the peak maximum principal stress of PSMRP1 (275MPa, 257MPa) was higher than that of PSMRP2 (254MPa, 235MPa) during both left group clenching and incisal clenching tasks.
Conclusions
: The structural optimized PSMRPs reveal their biomechanical advantage compared with the original design. The PSMRP1 presents better biomechanical performance to the patient-specific mandibular reconstruction than PSMRP2 as a result of its superior safety, preferable flexibility, and comparable stability. The PSMRP2 provides biomechanical benefit in reducing the maximum tension than PSMRP1, indicated by lower peak maximum principal stress, through tangent arc upper margin in mandibular angle region.
In response to Covid-19, the South African Higher Education Sector was forced to switch to remote learning and teaching practices. In this chapter, affordable digital communication tools are explored, including Additive Manufacturing, the Technology Pedagogy and Content Knowledge Model and the Community of Inquiry Model, to enhance distance learning experiences. A pragmatic and constructivist student-centred approach, with mixed methods, was adopted. Primary data were collected through mobile teaching documentation, assessment-by-survey, and analysis-by-attention cascade. The results showed effective communication and multi-media integration. However, financial constraints and network connection issues were highlighted. Based on the study, the use of the Technology Pedagogy and Content Knowledge Model and additive manufacturing with digital devices is recommended to promote effective remote learning and teaching, especially during crises. Lastly, investigating the social aspect of blended learning and developing adjusted pedagogical practices are suggested.
The manufacturing industry has been revolutionized by additive manufacturing (AM) by allowing the creation of complex geometries that were once impossible to manufacture using traditional methods. However, the layer-by-layer approach of additive manufacturing can result in dimensional and geometric errors due to the staircase effect, particularly in parts with complex shapes. Hence, achieving a balance between the quality and the cost is one of the most AM challenges. In this context, Design for Additive Manufacturing (DFAM) and adaptive slicing have emerged as promising approaches to reduce these errors while establishing a balance between the AM quality and cost. This work focuses on the importance of the adaptive slicing in minimizing the AM time and cost during the DFAM phase. A method for adaptive slicing is proposed based on minimizing errors due to the staircase effect caused by shape curvatures in the part. The results demonstrate that the proposed method can in some cases significantly save more than 80% of building time and cost in order to obtain the same surface quality comparing to the standard slicing method. Moreover, this slicing technique also improves the parts dimensional and geometrical tolerances, hence, reduces errors and improves the overall quality. The presented approach has the potential to enhance the capabilities of additive manufacturing, allowing the creation of parts with higher accuracy and precision, and reducing the need for post-processing.
Additive manufacturing creates objects from digital files and this layer by layer. Nowadays, additive manufacturing technologies are in full development, and are used in several industrial fields. It has a significant number of benefits, including mass reduction, design freedom, waste reduction, with a wide selection of possible material. As efforts to effectively apply additive manufacturing, design for additive manufacturing (DfAM) has increased to provide several recommendations and guidelines to designers, but knowledge, tools, rules, and methodologies related to DfAM, has not received much attention, and few works have addressed the development of this subject. This paper explores trends, issues, and challenges in design for AM, and previous Design for Additive Manufacturing (DfAM) methodologies are analysed widely and classified into distinct categories based on existing research works, however, it has been found that existing methodologies do not take full advantage of the additive manufacturing process capabilities. For that, we propose a frame for a methodology that takes advantages of additive manufacturing technologies capabilities and involve factors influencing the design, with a discussion of the additional value compared to the existent methodologies.KeywordsAdditive manufacturingDesign for additive manufacturing (DfAM)Methodology
Additive manufacturing continues to see increased growth, with adoption in many industrial sectors and increased commercial market value. Market growth is attributed to continued technology and software improvements, growing availability of material types and the ability to produce functional parts with complex geometries. The technology also provides the freedom to optimise the design of both the internal structure and external contours of a component. Additive Manufacturing in South Africa has been driven by the biotechnical/medical, aerospace and automotive industries due to a focus on research and high-value components. To date, there has been limited research involvement from the railway sector. Within the railway environment, the rolling stock and rail infrastructure consists of numerous systems and components which may benefit from the technology in creating replacement spare parts, lightweight structures, improved jigs and fixtures, and new designs of consolidated part-assemblies. This paper presents an industrial view on the use of additive manufacturing and design optimisation techniques for the production of railway related components, together with requirements and challenges. It provides examples that illustrate existing and potential applications of the technology for the design, manufacture and repair of various railway related assets in South Africa.
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