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3D printed heterogeneous lattice structures are beam-and-node based structures characterised by a variable geometry. This variability is obtained starting from a periodic structure and modifying the relative density of the unit cells or by combining unit cells having different shapes. While several consolidated design approaches are described to implement the first approach, there are still computational issues to be addressed to combine different cells properly. In this paper, we describe a preliminary experimental study focused on exploring the design issues to be addressed as well as the advantages that this second type of heterogeneous structures could provide. The Three-Point-Bending test was used to compare the behaviour of different types of heterogeneous structures printed using the Fused Deposition Modeling (FDM) technology. Results demonstrated that the possibility of combining multiple unit cells represents a valid strategy for performing a more effective tuning of the material distribution within the design space. However, further studies are necessary to explore the behaviour of these structures and develop guidelines for helping designers in exploiting their potential.
As additive manufacturing (AM) continues to grow in its abilities, so does the need for a quick and effective method of determining how it should be applied. Over time, these methods are naturally developed and passed on as tacit knowledge. However, with the rapid advancement of AM technologies, identifying parts which are eligible for AM as well as gaining insight on what value it may add to a product needs to be modelled in an objective and transferrable way. This paper presents a framework for determining the candidacy of a part or assembly for AM, represented by its economic feasibility and potential for AM-specific benefits. A set of selection criteria is developed with the goal of fast-screening in mind; that is specific data which can be automatically extracted from CAD models and resource planning databases. A case study is performed to validate the criteria and decision model chosen, as well as gain insight to the potential for a more widespread application. The decision model successfully identified economic feasibility and AM potentials, which suggests the results of the case study show promise for a semi-automatic decision support system for identifying AM candidates.
Additive Manufacturing (AM) brought new design freedom and possibilities that enable design and manufacturing of products with new forms and functionalities. To utilise these possibilities a new design approach emerged, Design for Additive Manufacturing (DfAM), that contains methods and tools for supporting AM oriented design process. Designers working with AM are aware of the need to apply DfAM and AM possibilities in conceptual design phase where they have the most significant influence on product architecture and form but are facing a lack of suitable DfAM approaches for early design phases. Therefore, the presented research is investigating possibilities of storing and representing AM knowledge in the form of design principles to be used in the conceptual design phase. The paper proposes conceiving of Design Principles for Additive Manufacturing repository where formalised AM knowledge is stored in the form of design principles and structured based on function criteria. In the paper, various elements of design principle representation are discussed, as well as their role in the conceptual design process.
Additive Manufacturing (AM) offers the potential to increase the ability to customise large-scale plastic components. However, a substantial amount of manual work is still required during the customisation process, both in design and manufacturing.
This paper looks into how the additive manufacturing of mass customised large-scale products can be supported. Data was collected through interaction with industrial partners and potential customers in a case study regarding the customisation of kayaks.
As a result, the paper proposes a model-based methodology which combines design automation with a user interface.
The results point to the benefit of the proposed methodology in terms of design efficiency, as well as in terms of displaying results to the end user in an understandable format.
The rapid development of 3D printing technology has an impact on all aspects of modern manufacturing, design and society. However, the home use of 3D printers is still limited by the difficulty in deploying the software and the technology which both need professional understanding and training. How to enable non-technical home users to use 3D printers without the need for training, becomes an urgent problem for both academics and the industry. This paper is concerned in an investigation into home use of 3D printers, their needs and preferences, their impacts on the interaction design of 3D printing. First, a questionnaire survey supported by 127 non-technical users is conducted to understand their preferences on several key steps of the 3D printing procedure. Then, we integrate the survey results into the interaction design process to improve the usability of the 3D printing software. Finally, the advantage of our implementation is tested via the user satisfaction and feedback towards the post-use period. Our design project shows a simple method to extend 3D printing interactive software to non-technical users, and pushes forward the landscape of the home use of 3D printers.
This study defines a methodological procedure for the design and manufacturing of a prosthetic implant for the reconstruction of a midsagittal bony-deficiency of the skull due to the Apert congenital disorder. Conventional techniques for craniofacial defects reconstruction rely on the mirrored-image technique. When the cranial lesion extends over the midline or in case of bilateral defects, other approaches based on thin plate spline interpolation or constrained anatomical deformation are applied.
The proposed method uses the anthropometric theory of cranial landmarks identification for the retrieval of a template healthy skull, useful as a guide in the successive implant design. Then, anatomical deformation of the region of interest and free-form modelling allow to get the customized shape of the implant. A full bulk and a porous implant have been provided according to the surgeon advises.
The models have been 3D printed for a pre-surgical analysis and further treatment plan. They fulfilled the expectancies of the surgeon thus positive results are predictable.
This methodology results to be reproducible to any other craniofacial defect spanning over the entire skull.
Additive manufacturing (AM) has enabled great application potential in several major industries. The footwear industry can customize shoe soles fabricated by AM. In this paper, lattice structures are discussed. They are used to design functional shoe soles that can have controllable stiffness. Different topologies such as Diamond, Grid, X shape, and Vintiles are used to generate conformal lattice structures that can fit the curved surface of the shoe sole. Finite element analysis is conducted to investigate stress distribution in different designs. The fused deposition modeling process is used to fabricate the designed shoe soles. Finally, compression tests compare the stiffness of shoe soles with different lattice topologies. It is found that the plantar stress is highly influenced by the lattice topology. From preliminary calculations, it has been found that the shoe sole designed with the Diamond topology can reduce the maximum stress on the foot. The Vintiles lattice structure and the X shape lattice structure are stiffer than the Diamond lattice. The Grid lattice structure buckles in the experiment and is not suitable for the design.
In recent years, reducing cost and lead time in product development and qualification has become decisive to stay competitive in the space industry. Introducing Additive Manufacturing (AM) could potentially be beneficial from this perspective, but high demands on product reliability and lack of knowledge about AM processes make implementation challenging. Traditional approaches to qualification are too expensive if AM is to be used for critical applications in the near future. One alternative approach is to consider qualification as a design factor in the early phases of product development, potentially reducing cost and lead time for development and qualification as products are designed to be qualified. The presented study has identified factors that drive qualification activities in the space industry and these “qualification drivers” serve as a baseline for a set of proposed strategies for developing “Design for Qualification” guidelines for AM components. The explicit aim of these guidelines is to develop products that can be qualified, as well as appropriate qualification logics. The presented results provide a knowledge-base for the future development of such guidelines.
Additive Manufacturing (AM) processes had an extensively and substantially technological growth over the past years that directly influences the continuously increased and manifold possibilities for processing new and innovative products. However, additively manufactured products mostly are still fabricated with only small adaptions compared to conventional parts, and thus waste many design potentials although specific design guidelines have been widely developed to restrict geometrical deficiencies or suggest improvements in component design.
As a result, this contribution furtherly aims to systematically consider AM potentials already on the functional level of product development offering significant but until now still not or just insufficiently exploited potentials. Therefore, the presented approach uses the already proven Design Pattern Matrix (DPM) approach for conventional technologies extended by a concurrent selection of materials and processes specifically for AM. Here, the DPM derives information about the manufacturing process in form of design elements and links them to the function carriers of the product including a methodological determination of requirements.
Additive Manufacturing (AM) offers a new degree in design freedom. However, in order to exploit AM's potentials in end-use products a methodical approach and suitable tools especially during conceptual design are needed. This paper presents a methodology for application in industrial practice, which should support the component conception for additively manufactured products. The approach focuses on a benefit-oriented preparation and provision of knowledge. In addition to general design methods for abstraction and promotion of creativity, AM-specific tools are introduced which support the provision of solution principles and process-specific restrictions. A broad applicability of the solution principles is ensured by an expansion of the solution space through abstraction. Consequently, product developers are sensitised to the new design possibilities of AM, on the one hand. On the other hand, they are supported in a holistic exploitation of design potentials in ideation in order to foster innovative solution ideas. Finally, the methodological procedure and the developed tools will be demonstrated in a workshop by using an example from industrial practice of the automotive sector.
Physical prototyping is critical activity in the produce development process, but the cost and time required to produce prototypes hinders it use in the design process. Hybrid prototyping through coupling LEGO and FDM printing is presented as an approach to address these issues. After establishing the separate design rules for FDM printing and LEGO, this paper created new set of rules called Design for Fabrication (DfF) for hybrid prototyping. These cover the three main considerations (Technical, Process, and Design) that the designer and process planning must include to practically implement LEGO and FDM hybrid prototyping. The DfF rules were considered in a prototype of a computer mouse. While the fabrication time was not reduced as expected, it showed that the rules could be practically implemented in a real-world example. Additional considerations were identified that are to be included in the DfF rules.
Further work is required to realise the predicted step-change reduction in fabrication time. The first approach is to leverage multiple printers to parallelise the printing. The second is to reduce fidelity while maintaining high fidelity in key regions of interest.
New advances in both neurosciences and computational approaches have changed the landscapes for smart devices design serving mobility-related disabilities. In this paper we present the integration of affordable robotics and wearable sensors through our mechatronic product platform, Sparthan, to enable accessibility of the technology in both the power prosthesis and neurorehabilitation space. Sparthan leverages 3rd party EMG sensors, Myo armband, to process muscles sensor data and translate user intention into hand movements. Key innovation includes the modularity, scalability and high degree of customization the solution affords to the target users. User-centered design approaches and mechatronic system design are detailed to demonstrate the versatility of integrative systems and design. What started off as an engineering research endeavor is also positioned to be deployed to deliver real-world impact, especially for prosthesis users in developing countries.
When using additive manufacturing processes, the choice of the numerous settings for the process and design parameters significantly influences the build and production time. To reduce the required build time, it is useful to adapt the parameters with the greatest influence. However, since the contribution of the individual parameters is not readily apparent, a sensible choice of process and design parameters can become a challenging task.
Thus, the following article presents a method, that enables the product developer to determine the main contributors to the required build time of additively manufactured products. By using this sensitivity analysis method, the contributors of the individual parameters can be analyzed for a given parametrized CAD model with the help of an analysis-based build time estimation approach. The novelty of the contribution can be found in providing a method that allows studying both design and process parameters simultaneously, taking the machine to be used into account. The exemplary application of the presented method to a sample part manufactured by Fused Deposition Modeling demonstrates its benefits and applicability.
In recent years, rapid technical progress has led to additive manufacturing achieving a high degree of technological maturity that enables a broad range of applications. This is reinforced in particular by the advantages of the technology, such as the production of complex components, smaller quantities and fast reaction times. However, a lack of knowledge of the various process techniques, such as insufficient potential assessment, specific design guidelines or even of process restrictions, often lead to different errors.
This paper presents a methodological approach to support designers in the manufacturing process selection of specific parts at an early stage of product development. In a four-stage procedure, potential part candidates are first identified and part classes formed on the basis of characteristics. Building on this, AM thinking is to be stimulated, for example, with the aid of design guidelines. A comparison between conventionally and additively manufactured parts can be made using a simplified cost model. The results are incorporated into a process model that supports companies in the systematic selection of manufacturing processes.
Additive manufacturing (AM) opens new possibilities for innovative product designs. However, due to a lack of knowledge and restrained creativity because of design fixations, design engineers do not take advantage of AM's design freedom. Especially multi-material AM provides new opportunities for functional integration that hardly considered in ideation. To overcome barriers in the development of solution ideas and utilizing such new design potentials, new design methods and tools are needed. Therefore, in this contribution, a methodological approach for a function-oriented provision of solution principles specific to material extrusion is presented. A tool is developed to facilitate effective guidance in developing solution ideas and to foster a realistic concretization by providing a combination of opportunistic and restrictive AM knowledge. Besides general levers of AM, process-specific design opportunities support the design engineers in exploiting AM's potentials, especially those who are not familiar with Design for AM. Finally, the applicability of the methodological approach is evaluated in an academic study by means of redesigning a hand prosthesis with a grab function.
Technology of 3D printing is opening the possibility for small-scale production in quantities between ten and several hundred pieces. The technology of adding material enables the production of complex and integrated functional concepts in a single-pass process, which consequently potentially reduces the need for assembly operations. Design approaches and manufacturing processing are not mastered well because of a constant stream of new materials and manufacturing options. Well-designed products need to consider attributes of 3D printing as early as the conceptual phase. The cost of the product can be reduced with a systematic research and considering principles for small-scale production. In a cheaper, alternative production process the quality range of products is often lower. It has to be compensated with appropriate construction solutions which are less tolerance-sensitive. Therefore, in order to support the designer, to reduce the costs and design time of the product, a computer program was created to provide the user with an insight into the appropriate 3D printing technology. For simplifying the use, the program is also integrated into the product development process.
In practical design work, a designer needs to consider the feasibility of a part for a manufacturing using additive manufacturing (AM) instead of conventional manufacturing (CM) technology. Traditionally and by default parts are assumed to be manufactured using CM and using AM as an alternative need to be justified. AM is currently often a more expensive manufacturing method than CM, but its employment can be justified due to number of reasons: improved part features, faster manufacturing time and lower cost. Improved part features means usually reduced mass or complex shape. However, in low volume production lower manufacturing time and lower part cost may rise to the most important characteristics.
In this paper, we present a practical feasibility model, which analyses the added value of using AM for manufacturing. The approach is demonstrated in the paper on four specific parts. They represent real industrial design tasks that are ordered from an engineering office company. These parts were manufactured by Selective Laser Meting (SLM) technology and the original design done for conventional manufacturing is also presented and used for comparison purpose.
Nowadays, topology optimization and lattice structures are being re-discovered thanks to Additive Manufacturing technologies, that allow to easily produce parts with complex geometries.
The primary aim of this work is to provide an original contribution for geometric modeling of conformal lattice structures for both wireframe and mesh models, improving previously presented methods. The secondary aim is to compare the proposed approaches with commercial software solutions on a piston rod as a case study.
The central part of the rod undergoes size optimization of conformal lattice structure beams diameters using the proposed methods, and topology optimization using commercial software tool. The optimized lattice is modeled with a NURBS approach and with the novel mesh approach, while the topologically optimized part is manually remodeled to obtain a proper geometry. Results show that the lattice mesh modelling approach has the best performance, resulting in a lightweight structure with smooth surfaces and without sharp edges at nodes, enhancing mechanical properties and fatigue life.
The biggest advantage of Additive Manufacturing is the individualization of products. Mass Customization is well known as a promising future application. The use of Additive Manufacturing for assembly groups is mostly not reasonable, however combining it with conventional manufacturing processes can lead to new opportunities.
This paper works out concepts to join, by using similar material combinations, an injection molded part with an additive deposited geometry by the Fused-Deposition-Modeling (FDM) process. Therefore, two of the main industrially used polymers, acrylonitrile butadiene styrene (ABS) and polypropylene (PP), are selected for further study. In particular, this investigation focuses on the procedural potentials and surface preparation of the injection molded part. By the variation of adhesive bonding, the fusion of similar materials can be identified and tested in several series of testing.
First in general a direct joining function by the FLM process will be tested. After proving this hypothesis, the results will be summarised in a recommendation of joining similar materials, which are manufactured in different ways.
One of the foundations of product design is the division between production and design. This division manifests as designers aspiring to create fixed iconic archetypes and production replicates endlessly in thousands or millions. Today innovation and technological change are challenging this idea of product design and manufacturing. The evolution of Rapid Prototyping into Additive Manufacturing (AM), is challenging the notion of mass manufacture and consumer value. As AM advances in capability and capacity, the ability to economically manufacture products in low numbers with high degrees of personalisation poses questions of the accepted product development process. Removing the need for dedicated expensive tooling also eliminates the cyclical timescales and commitment to fixed designs that investment in tooling demands. The ability to alter designs arbitrarily, frequently and responsively means that the traditional design process need not be applied and because of this, design processes and practice might be radically different in the future. In this paper, we explore this possible evolution by drawing parallels with principles and development models found in software development.