Examensarbeten för masterexamen

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    Expanding the Circular Life of a Garment Proposing a Circular Concept for the Clothing Company EmmaMalena
    (2023) Minborg, Elis; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Rexfelt, Oskar; Heinerud, Johan
    Summary Textiles are an environmental problem causing water use, pollution, greenhouse emissions and great landfills. One way to reduce global textile impact is through increased circularity, meaning that the textile is used as much as possible through methods such as passing it on to several people or re-making the material into new items before disposal. Although many people are willing to participate in a circular economy by donating used clothes, these garments can still face disposal instead of being re-used. Improvements in production standards, infrastructure, and user motivation is required for a successful re-utilization of the products. This thesis was done in cooperation with EmmaMalena, a clothing company from Käringön Sweden, and representatives from the Chalmers Department of Industrial & Material Science. The purpose was to find a solution where the clothing company can increase circularity of their garments in a way that is attractive for their customers and helps strengthen their brand. Field studies, data collection from existing personas, and in-depth interviews were conducted to explore existing user needs and requirements. A new concept was created by ideation and workshops together with EmmaMalena. The design Toolkit, Use2Use, supported and structured the development process. Furthermore, the motivational design tool Octalysis was utilized to increase the likelihood of users successfully performing the required actions. The final concept consisted of a pilot project designed to collect disused EmmaMalena clothing and resell them in-store. It further included a branding concept called “Tångcirkeln” to be implemented in-store, on garments, and online to symbolize and highlight EmmaMalena's sustainability efforts. Moreover, Tångcirkeln is also a name of a loyalty program where people provide action in a group for a higher cause. One specific common-cause solution is to participate in replanting eelgrass. Eelgrass acts as a carbon sink, and keeps the local shores clear and diverse, making participation in replanting initiatives a suitable cause for all EmmaMalenas customer segments.This report's design process has further yielded a great number of concepts that can be implemented in Tångcirkeln in a long-term perspective.
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    Manufacturability assessment of an additively manufactured heat exchanger
    (2024) Perbo, Frej; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Panarotto, Massimo; Hajali, Tina
    Abstract Texel Energy Storage, a start-up based in Gothenburg, is collaborating with the US Department of Energy, Savannah River National Laboratory, and Curtin University in Australia to develop a revolutionary energy storage technology that competes directly with fossil fuels when combined with renewable energy sources. The goal of this thesis is to evaluate the feasibility of manufacturing Texel’s future system’s heat exchanger, while also enhancing our understanding of design for AM and the associated costs and time requirements. This master thesis aims to explore the process of assessing the time and cost involved in designing and manufacturing the heat exchanger. However, it solely focuses on the redesign and assessment of one part of Texel’s system and does not consider the entire product development process. The final model design will incorporate Design for Additive Manufacturing, and manufacturability assessment based on time & cost estimation for the newly designed heat exchanger in the case study, along with the base methods described in the theory chapter. This thesis will evaluate the degree of manufacturability based on the time and cost required for designing and manufacturing the heat exchanger in Texel’s system, considering the economic aspects of AM. The theory for the method for the manufacturability assessment of the heat exchanger component will be described separately. As per the thesis, the majority of costs associated with producing a metal additive manufacturing heat exchanger occur during the processing phase, which is consistent with previous research on metal AM part production.
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    Binder jetting of aluminum alloys: Design for Additive Manufacturing and Material Characterization
    (2024) Alam, Didarul; Dessai, Omkar Rajan; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Hryha, Eduard; Babu Nagaram, Anok; Hryha, Eduard
    Binder jetting technology (BJT) is an additive manufacturing (AM) process wherein a liquid binder is deposited on the power bed to join the particles together layer by layer, thus creating the desired geometry. This process can print various metals and polymers with higher productivity. Even so, among other metals, aluminum alloys are not commercially available to be produced by BJT. However, due to aluminum’s intrinsic characteristics and properties, the passenger and commercial vehicle industries extensively utilize this metal. For this reason, it is a highly desired material for BJT/M in the automotive industry due to the possibility of printing complex shapes and having higher productivity than other metal additive manufacturing technologies. A Japanese company, RICOH Company Ltd, is currently working on developing technology for printing aluminum alloys in BJT. In this master thesis, design for AM and material characterization studies were conducted in collaboration with Volvo Car Corporation (VCC) and RICOH to study a heat sink for the headlamp for the XC90 production series car against two different aluminum alloys. As-produced aluminum alloy was 4000 series aluminum alloy, which had a Si content of less than 10 wt.%, and high pressure die casted aluminum alloy had a Si content of 12 wt.%. A study of design guidelines was carried out by printing design artefacts, and the geometry evaluation was done using scanning and superimposing CAD data. This provided knowledge about critical design features that can be produced using the technology and the limit. 10mm3 produced cubes were analyzed for porosity using Light Optical Microscopy (LOM). Density verification on the cubes using LOM, Geometrical, and Archimedes showed a relatively high density of 98% with a standard deviation of 0.91. The primary function of the heatsink studied here is dissipating heat away from other components. Thus, thermal conductivity and convection performance were measured. Thermal conductivity for as-sintered material was found to be 154.41 W/mK at room temperature (20 °C), and it was increased to 166.68 W/mK after Hot Isostatic pressing (HIP), compared to 97.94 W/mK for as-casted aluminum alloy which is currently being used. To improve the thermal convection, the new design features, namely Gyroid with varying wall thicknesses, were produced as test pieces and tested in the experimental setup to determine the design with the best performance. Heat dissipation increased by 99% in free convection and 82% in forced convection compared to the as-casted heatsink; this was demonstrated during the experiment. A new heatsink design produced using BJT Al alloys also resulted in a weight reduction of 42% to the existing design. Regarding the mechanical properties, HV5 was found to be 51.91% less for as-sintered aluminum alloy compared to as-casted aluminum alloy and 48.98% less for as-sintered aluminum alloy when HK1 was considered. The microstructure analysis showed that the reason for the thermal conductivity increase and hardness decrease in the aluminum alloy produced by BJT/M is connected to the lower Si content. Hence, the lower fraction of AlSi-precipitates was produced.
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    Implementing ISO 26262-5: A guide to Functional Safety for Product Development at Hardware Level
    (2023) Dahl, Sofia; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Bergsjö, Dag; Pierrau, Stefan
    Abstract The increasing use of electrical and electronics in road vehicles increases the risk for failures caused by malfunctioning electronic systems. The demand for regulations to ensure functional safety is therefore a fact. The standard ISO 26262 is produced specifically for the automotive industry and presents procedures and requirements for manufacturers to follow. This report focuses on ISO 26262-5 which is product development on hardware level. Before starting with the ISO 26262-5, the prerequisites need to be defined. The prerequisites are procedures as Hazard Analysis and Risk Assessment, Fault Tree Analysis and safety goal. The safety goals are assigned an ASIL-classification depending on the outcome in case of failure. The ASIL decides the requirements for each safety goal when implementing ISO 26262-5. A method describing the procedures for implementing ISO 26262-5 is developed. The method guides the developer through the steps presented in ISO 26262-5 and provides the requirement to each procedure. For clarity, an example for following the method is provided to show the context within the procedures. The example verified that a result can be reached by following the method. The reliability of the result could not be verified and needs to be compared to a result produced by another method. Depending on the outcome of the comparison, improvements may be necessary to ensure the reliability of the method. The main task for manufacturers or developers regarding the implementation of ISO 26262-5 in the development system is providing the necessary documentation to follow the method.
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    Improving Business Excellence Culture
    (2023) Dorner, Kevin; Gustafsson, Fredrik; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Hammersberg, Peter; Hammersberg, Peter
    With the increasing popularity of Business Excellence (BE) and Lean, many companies have engaged in implementing one or several of these concepts. SKF Gothenburg is one such company that aims to achieve a Lean transformation in the context of a long journey with BE efforts. This history provides the company with both advantages and challenges in its journey towards excellence, hereby creating a unique context for BE. In this qualitative research, a case study of SKF Gothenburg was conducted with an inductive approach. Data was collected through semi-structured interviews with 22 employees, unstructured and semi-structured observations, and review of company documents. Company interviewees spanned a wide range of functions, most of them being functional managers related to the factory management. For improved contextual understanding, interviewees also included some central roles in the SKF Group organization, as well as factory employees with supportive, and more operational roles. Based on the company’s needs, and the identified gaps in literature, two research questions were formulated. Through these questions, the challenges with the current Business Excellence culture have been identified, and improvements have been suggested. Problematic areas were linked to four topics. The first improvement area was the implementation approach and organizational context of the company’s Lean implementation through the SKF Production System. Related to this was also the company’s approach towards strategy creation and deployment. Furthermore, people related aspects were found to be in need of improvement regarding the state and management of knowledge, motivation, culture, and collaboration. Leadership was the last identified improvement area, where issues with prioritization, leadership style, and ownership were described. For these areas, improvement suggestions were derived from the current literature in related scientific fields. Suggestions regarding the SPS implementation were related to increasing the understanding, ownership, and improving the clarity of the vision. Hoshin Kanri implementation, as well as improved communication and visibility of the strategy were suggested to improve strategy aspects. To improve people related aspects, better training, increased cross-functional collaboration and knowledge sharing, and improved HR approaches were suggested. Lastly, to address leadership improvements, it was suggested to increase knowledge and use of transformational and lean leadership, to improve focus on proactiveness and continuous improvement, and to increase the time spent with strategic matters. Through this report, SKF Gothenburg can reach a better understanding regarding issues with its BE culture. These issues, as well as their implications, were well-described based on the collected data. The high variety of the potential areas for improvements identified were addressed with a multifaceted literature review, whereby appropriate solutions or approaches towards developing solutions have been suggested.