A bibliometric analysis of research in design for additive manufacturing

Purpose The purpose of this paper is to understand how Design for Additive manufacturing Knowledge has been developing and its significance to both academia and industry. Design/methodology/approach In this paper, the authors use a bibliometric approach to analyse publications from January 2010 to December 2020 to explore the subject areas, publication outlets, most active authors, geographical distribution of scholarly outputs, collaboration and co-citations at both institutional and geographical levels and outcomes from keywords analysis. Findings The findings reveal that most knowledge has been developed in DfAM methods, rules and guidelines. This may suggest that designers are trying to learn new ways of harnessing the freedom offered by AM. Furthermore, more knowledge is needed to understand how to tackle the inherent limitations of AM processes. Moreover, DfAM knowledge has thus far been developed mostly by authors in a small number of institutional and geographical clusters, potentially limiting diverse perspectives and synergies from international collaboration which are essential for global knowledge development, for improvement of the quality of DfAM research and for its wider dissemination. Originality/value A concise structure of DfAM knowledge areas upon which the bibliometric analysis was conducted has been developed. Furthermore, areas where research is concentrated and those that require further knowledge development are revealed.

A Smart Wing Rib Structure Suitable for Design for Additive Manufacturing (DfAM) Process

Additive manufacturing has been adopted widely across various industries for producing parts mainly due to their ability to create complex geometries, eliminate material wastage and enable faster production rate, among others. Additive manufacturing has also increased design solution space by enabling exploration of mechatronic solutions for mechanical structures. This includes the integration of smart devices into wing structures to achieve a datadriven predictive maintenance-based system. For this, there is still the need to continuously explore various ways of integrating sensory capability into a mechanical structure during the manufacturing processes to ensure improvement and reliability of aircraft components. The scope of this paper was to analyse different wing rib geometries and the influence of embedding sensory capability via design for additive manufacturing process. In this work, three wing rib geometries with cut-outs and for sensory placement were designed and analysed to estimate their equivalent stress and deformation when such sensory locations are introduced. The results confirm the idea that it is feasible to introduce holding cavities for structural performance monitoring sensors without compromising the structural design requirements. The results also show that deformation and stress are highly dependent on the rib thickness and the insertion of sensory locations

Impact of Timing in the Design Process on Students' Application of Design for Additive Manufacturing Heuristics

The goal of this work is to study the way student designers use design for additive manufacturing (DfAM) rules, or heuristics. It can be challenging for novice designers to succeed at creating successful designs for additive manufacturing (AM), given its differences from traditional manufacturing methods. A study was carried out to investigate the way novices apply DfAM heuristics when they receive them at different points in the design process. A design problem was presented to students, and three different groups of student participants were given a lecture on DfAM heuristics at three different points in the design process. The novelty and quality of each of the resulting designs was evaluated. Results indicate that although the DfAM heuristics lecture had no impact on the overall quality of the designs generated, participants who were given the heuristics lecture after the initial design session produced designs that were better suited for 3D printing in the second phase of the design activity. However, receiving this additional information appears to prevent students from creatively iterating upon their initial designs, as participants in this group did not experience an increase in novelty between the two sessions. Additionally, receiving the heuristics lecture increased all students' perceptions of their ability to perform DfAM-related tasks. These results validate the practicality of design heuristics as AM training tools while also emphasizing the importance of iteration in the design process.

Development of Technical Creativity Featuring Modified TRIZ-AM Inventive Principle to Support Additive Manufacturing

The design for additive manufacturing (DFAM) processing was introduced to fully utilise the design freedom provided by additive manufacturing (AM). Consequently, appropriate design methodologies have become essential for this technology. Recently, many studies have identified the importance of DFAM method utilisation to produce AM parts, and TRIZ is a strategy used to formalise design methodologies. TRIZ is a problem-solving tool developed to assist designers to find innovative and creative solutions. However, the pathway for synergising TRIZ and DFAM is not clearly explained with respect to AM capabilities and complexities. This is mainly because most methods continue to involve use of the classical TRIZ principle, which was developed early in 1946, 40 years before AM technologies were introduced in the mid-1980s. Therefore, to tackle this issue, this study aims to enhance the 40 principles of classical TRIZ to accommodate AM design principles. A modified TRIZ-AM principle has been developed to define the pathway to AM solutions. TRIZ-AM cards are tools that assist designers to select inventive principles (IPs) in the early phases of product design and development. The case study illustrates that even inexperienced AM users can creatively design innovative AM parts.

An optimisation framework for designs for additive manufacturing combining design, manufacturing and post-processing

Purpose The purpose of this paper is to present a Design for Additive Manufacturing (DfAM) methodology that connects several methods, from geometrical design to post-process selection, into a common optimisation framework. Design/methodology/approach A design methodology is formulated and tested in a case study. The outcome of the case study is analysed by comparing the obtained results with alternative designs achieved by using other design methods. The design process in the case study and the potential of the method to be used in different settings are also discussed. Finally, the work is concluded by stating the main contribution of the paper and highlighting where further research is needed. Findings The proposed method is implemented in a novel framework which is applied to a physical component in the case study. The component is a structural aircraft part that was designed to minimise weight while respecting several static and fatigue structural load cases. An addition goal is to minimise the manufacturing cost. Designs optimised for manufacturing by two different AM machines (EOS M400 and Arcam Q20+), with and without post-processing (centrifugal finishing) are considered. The designs achieved in this study show a significant reduction in both weight and cost compared to one AM manufactured geometry designed using more conventional methods and one design milled in aluminium. Originality/value The method in this paper allows for the holistic design and optimisation of components while considering manufacturability, cost and component functionality. Within the same framework, designs optimised for different setups of AM machines and post-processing can be automatically evaluated without any additional manual work.

Design for Additive Manufacturing and for Machining in the Automotive Field

High cost, unpredictable defects and out-of-tolerance rejections in final parts are preventing the complete deployment of Laser-based Powder Bed Fusion (LPBF) on an industrial scale. Repeatability, speed and right-first-time manufacturing require synergistic design approaches. In addition, post-build finishing operations of LPBF parts are the object of increasing attention to avoid the risk of bottlenecks in the machining step. An aluminum component for automotive application was redesigned through topology optimization and Design for Additive Manufacturing. Simulation of the build process allowed to choose the orientation and the support location for potential lowest deformation and residual stresses. Design for Finishing was adopted in order to facilitate the machining operations after additive construction. The optical dimensional check proved a good correspondence with the tolerances predicted by process simulation and confirmed part acceptability. A cost and time comparison versus CNC alone attested to the convenience of LPBF unless single parts had to be produced.

Development of a Design for Additive Manufacturing Worksheet for Medical Casts

Traditional plaster casts often cause dermatitis due to disadvantages in usability and wearability. Additive manufacturing (AM) can fabricate customized casts to have light-weight, high strength, and better air permeability. Although existing studies have provided design for additive manufacturing (DfAM) guidelines to facilitate design applications for AM, most relevant studies focused on the mechanical properties of outputs and too general/specific design guidelines; novice designers may still have difficulty understanding trade-offs between functional and operational performance of various DfAM aspects for medical casts. As a response, this study proposes a DfAM worksheet for medical casts to effectively guide novice designers. First, important DfAM criteria and their possible solutions for medical casts are examined through a literature review to construct a basic DfAM framework for medical casts. Next, a scoring system that considers relative criteria importance and criteria evaluation from both functional and operational perspectives is developed to identify the overall suitability of a medical cast design for AM. A case study of finger cast designs was performed to identify the DfAM performance of the sample designs along with redesign requirements suggested by the worksheet. The proposed worksheet would be used to achieve rapid medical cast design by objectively assessing its suitability for AM.

Local Redesign for Additive Manufacturability of Compliant Mechanisms Using Topology Optimization

Compliant mechanisms are crucial components in current and future high-precision applications. Topology optimization and additive manufacturing offer freedom to design complex compliant mechanisms that were impossible to realize using conventional manufacturing. Design for additive manufacturing constraints, such as the maximum overhang angle and minimum feature size, tend to drastically decrease the performance of topology optimized compliant mechanisms. It is observed that, among others, design for additive manufacturing constraints are only dominant in the flexure regions. Flexures are most sensitive to manufacturing errors, experience the highest stress levels and removal of support material carries the highest risk of failure. It is crucial to impose these constraints on the flexure regions, while in others part of the compliant mechanism design, these constraints can be relaxed. We propose to first design the global compliant mechanism layout in the full domain without imposing any design for additive manufacturing constraints. Subsequently we redesign selected refined local redesign domains with design for additive manufacturing constraints, whilst simultaneously considering the mechanism performance. The method is applied to a single-input-multi-output compliant mechanism case study, limiting the maximum overhang angle, introducing manufacturing robustness and limiting the maximum stress levels of a selected refined redesign domain. The high resolution local redesigns are detailed and accurate, without a large additional computational effort or decrease in mechanism performance. Thereto, the method proves widely applicable, computationally efficient and effective in its purpose.