Browsing by Author "Partanen, Jouni, Prof., Aalto University, Department of Mechanical Engineering, Finland"

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Assessment of additively manufactured end-use components - Current state and incremental improvements in design, materials, and decision making
(2020) Kretzschmar, Niklas
School of Engineering | Doctoral dissertation (article-based)
Increasingly integrated into various fields of industries as rapid prototyping, rapid tooling and rapid manufacturing applications, since first commercialized in 1987, are layer-wise additive manufacturing (AM) techniques. Among those, end-use AM applications are particularly challenged, however, by economic and technological obstacles including slow production speeds, high material cost, insufficient part quality repeatability and (bio)material unavailability. This thesis aims at both exploring the economic and technological current state of AM end-use components, and providing incremental development steps in design, material, and decision-making.To assess the current state of end-use AM, a computer-driven decision support system (DSS) for rapid economic assessments of uploaded components supported by a case study is developed and an industry-related survey is conducted to match the demands for AM with the existing capabilities of AM. The current situation can be further improved by introducing new incremental developments concerning experimental material development, AM process-configurations, (re)design, and component classifica-tion based on case studies. These enhancements aim at developing new biocomposite materials for AM, implementing the axiomatic design meth-odology to design for AM (DfAM), and classifying end-use AM components according to the level of DfAM. The final version of the DSS provides rapid online quotations of uploaded digitized components to obtain insights into costs and production times for varying machine, material, and distribution scenarios (conventional manufacturing versus AM, make-or-buy decisions). In this context, the tool was used to demonstrate the trade-off between feature-resolution and production speed on cost, which constitutes the importance of production speeds as a cost-driver in AM part production. However, further increases alone have no significant cost-saving potential for the already existing high-end metal powder bed fusion machines considering high production throughput scenarios. Thus, expenses on materials need lowering to increase cost efficiency. The underlying technological state of end-use AM components involved comparing size-, material-, and surface roughness demands with best-in-class and locally installed AM system capabilities. The incremental developments imply that traditional design methodologies are applicable for AM and can potentially assist designers in DfAM. Components designed for the use of AM techniques can be logically classified according to their level of DfAM exploitation. Furthermore, the newly developed biocomposite material and its inherent process variations lead to new opportunities in environmental sustainability and design freedom, opening up new possibilities for AM part production.
From rapid prototyping to digitalization: Steps on industrializing additive manufacturing
(2017) Flores Ituarte, Inigo
School of Engineering | Doctoral dissertation (article-based)
Additive manufacturing (AM) systems have evolved drastically bringing the technology to the spotlight of manufacturing digitalization. Incremental technology improvements allow new possibilities in manufacturing, unlocking a number of serious applications. However, there are still gaps between the technological projections and the practical constrains of the technology. In this regard, research based on case studies is helping firms to evaluate factors for technology adoption. With this in mind, the purpose in this research is to advance on AM direct digital applications and its integration with secondary processes in order to drive the technology to industrialization. This dissertation is built upon four interrelated case studies. The scientific contribution is grounded on cross case analysis and mixed methods for research. This aided to link industry relevant applications with academic research methods to finally construct new knowledge on strategic, operational, technical and environmental factors for AM implementation. Results show that direct digital manufacturing of low volume plastic structural components are feasible, when geometrical and mechanical requirement are meet. Especially in pre-series production and highly customizable components. Nevertheless, parts will often require secondary manufacturing operations. Besides, the need for removal of support structures, secondary operations are implemented to obtain engineering specifications. Results in this regard show that hybrid processes can be combined and automated to create parts with tight geometrical and dimensional requirements. However, its environmental feasibility is dependent on the material volume removal ratio subtracted from the initial stock. AM systems are not always intrinsically at disadvantage in medium and high volume production industries. Factors such as geometry variability and the elimination of tooling reduces upfront cost prevalent on conventional methods manuafcturing. Nevertheless, AM systems are still in the industrialization process that require integration with conventional manufacturing methods for secondary operations. To this end, future research and development activities should take a holistic perspective considering multiple factor for technology transfer. During the coming years firms will need to look at their legacy products to identify potential benefits of AM implementation with a life cycle perspective. However, the big opportunities are yet to come when technology improves and additive methods are taken into consideration early in the design stages as a manufacturing solution.
Imaging and digital design for medical applications of additive manufacturing
(2019) Huotilainen, Eero
School of Science | Doctoral dissertation (article-based)
Since their inception in the late 80s, additive manufacturing (AM) technologies have contributed largely in the paradigm change of production engineering. A focal area where these processes offer exceptional contemporary applications and future potential is the medical milieu; low production volumes, high degree of customization, and complexity of required shapes are strong drivers leading towards digital fabrication. Medical applications of additive manufacturing are classified to span five distinct categories: medical models, external prostheses and guides, surgical tools, inert implants, and biomanufacturing. The primary aim for this dissertation is to develop the five-step process for medical applications of AM: medical imaging, digital design, fabrication, post-processing, and clinical application. In the center of a successful clinical AM application lies the digital design phase. The results of this dissertation present optimization framework for medical imaging in order to ensure quality of source material for the designs. Subsequently, the design step is enhanced by developing and presenting practical and computational methods for design automation and conversion techniques into efficient clinical applications. The research focusing on the critical steps of the process is complemented with a holistic view on the complete process. Apart from the technical solutions offered, the collaborative needs, and information and communication flows within the process are essential for successful medical application of additive manufacturing. Critical future research topics required in the research area include novel material and software development as well as more efficient utilization of existing technologies.
Industrial Opportunities of Additive Manufacturing - Workflow planning and decision making of additively manufactured end-use components
(2019) Chekurov, Sergei
School of Engineering | Doctoral dissertation (article-based)
The progression of additive manufacturing—from being limited to producing prototypes to being a valuable technology in producing end-use components—has been noted by many researchers and companies. Nevertheless, the industrial opportunities of this progress are not clear to new users of the technology because the number of end-use applications for additive manufacturing is vast and growing rapidly. The major advantages of using additive manufacturing lie in the increased freedom of design and the possibility to produce components that have previously been impractical. On the other hand, additive manufacturing can also be used in situations where the component does not benefit from the additional design freedom. In such cases, the advantage of using additive manufacturing must come from operational benefits, such as improved delivery speed or cheaper manufacturing cost. To clarify the opportunities, the thesis proposes categorizing the end-use applications from the point of view of design into "components designed for additive manufacturing", "components redesigned for additive manufacturing", and "components not designed for additive manufacturing". Each of these categories has their use in industrial applications and can help achieve specific technical and operational benefits. In the thesis, the categories are provided with design workflows that draw from the design process of Pahl & Beitz and are augmented with relevant previous research from the field of design for additive manufacturing. To investigate the industrial opportunities in the form of technical and operational advantages of the categories, the thesis demonstrates the use of the categories and their workflows by providing a case study for each. In the case studies, the design process of the components is demonstrated with the help of the developed design workflows, and the technical and operational benefits of each component are evaluated. The case studies of the categories involve the design of a novel high-performance heat exchanger, the redesign of a digital hydraulic valve manifold, and the production of a memory cover for use in the repair of a portable computer. In addition, the thesis contains a focus group study in the category "components not designed for additive manufacturing" to discover in which scenarios it could be employed. In the final section of the thesis, the technical and operational advantages of using additive manufacturing in each of the categories are collected and presented. The main technical advantages discovered in the investigations were the creation of new functionalities and improvement of performance, and the main operational benefits were the simplification of supply chains and shorter repairs. The thesis gives researchers in the field of design for additive manufacturing a framework to communicate their findings in a way that can be understood easily by practitioners not previously intimately familiar with designing for additive manufacturing.
Medical Applications of Additive Manufacturing – Application-Oriented Classification for Case Design and Documentation
(2018) Tuomi, Jukka
School of Engineering | Doctoral dissertation (article-based)
Rapid development has recently occurred in Additive Manufacturing (AM) technologies, some of which are called 3D Printing. One of driving force behind the development of AM is variation in both industrial and medical applications. Certain applications occur in clinical practice, with others under research or in a developmental phase. The application of these new technologies in medical settings has raised concerns among specialists regarding quality control of the manufacturing process, case documentation and patient safety. This thesis presents a novel classification system for medical applications of AM; the system is based on both own research cases and patient cases presented in the literature. Combining application classes and procedural phases of clinical patient cases into one representation was an objective of this work. The solution concerned the development of a medical application of additive manufacturing (MAAM) matrix case presentation. One research goal involved developing a model to support patient-case design, documentation, and learning. According to cognitive psychologists, knowledge is clustered into packets that enable knowledge to be organised, stored and contextually placed. Matrix-based representation aims to help stakeholders understand MAAM cases as packets. The presented concept uses matrix cells to store actual case data. Such data presentation technology has potential to serve as the basis for further developments related to feature-based product modelling and expert system technologies in medical applications of AM. This thesis presents a MAAM matrix system with potential application as a qualified standard platform for medical-case design and documentation. The MAAM matrix system supports learning and is an established operational platform for computerised systems. This thesis demonstrates the validation of the MAAM matrix system in an orbital wall implant clinical case. The second validation case was a research case studying the effects of both applied AM system technology and finishing technology to part cytotoxicity. Both cases involved storing materials and methods data in MAAM matrix cells.
Perspectives on ecodesign implementation with quantitative analysis
(2019) Sihvonen, Siru
School of Engineering | Doctoral dissertation (article-based)
Degradation and scarcity of natural resources at the planetary scale have triggered a context in which circular economy has emerged as a concept framing the discussion on these challenges. Companies are the critical stakeholders that should embrace circular economy thinking in order to take these discussions into practice. More specifically, such thinking should be explicated in product development where many of circular economy related aspirations are realized. This is examined in this dissertation from the perspective of the ecodesign domain. This dissertation consists of three published scientific articles, and a summary combining the results from these articles. This research provides new insights particularly from the soft-side of ecodesign which emphasizes the role of human factors influencing the uptake of environmental considerations in product development practices. It deepens the understanding of context for an enhanced ecodesign implementation by answering three research questions: Are there significant associations between ecodesign practices? To what extent circular economy considerations are associated with other ecodesign practices? And, how human factors, such as ecological concern, are related to ecodesign practices? Answers to these research questions are based on quantitative data using a descriptive research approach. The survey was conducted among people working with product development and representing various industries in Finland. The content analysis was based on data obtained from sustainability reports within one sector. Using content analysis allowed to extend understanding on the applicability of this research method within the ecodesign domain. These quantitative results contribute to the knowledge base by deepening the understanding of the current state of ecodesign practices. Results indicate that implementing ecodesign has progressed within proactive companies' product development. However, it is not yet a mainstream activity in the analyzed data. Established product development processes are associated with more formal management processes for environmental considerations within them. The results show the ways in which quantitative environmental targets for products are associated with circular economy related activities, and environmental performance within one sector. However, the awareness of circular economy is just emerging. These findings further indicate that the role of durability, and the way durability considerations enter the product development context should be further examined, as such considerations were not found to correlate with ecodesign practices apart from the earliest product development phase, nor with lifecycle thinking. Novel contributions were also achieved by using a scarcely applied unit of analysis within the field: the micro-level. This allowed a deepening in the understanding of human factors, such as ecological concern, and their associations with ecodesign practices. This dissertation provides new insights for companies struggling to implement ecodesign practices beyond their documentation.