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  • 1.
    Al Choueyri, Yousef
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Fayazi, Mojtaba
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Digital models of manufacturing: with emphasis on titanium welding for early product development2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis work is part of the BTH research lab, focusing on developing the early product development, by analyzing how to integrate the manufacturing process with the early design process. A known problem in the manufacturing industry is the knowledge gap between the designers and the manufacturing process. Where in the early stages of the product development a knowledge regarding the manufacture process is needed. This is in many cases ignored by the designers because it is commonly thought that the responsibility of selecting the manufacturing processes for a product falls upon the manufacturers, despite the fact that the manufacturing processes in reality is highly dependent upon the design choses such as materials, size, shape, finishing and tolerances of the product. To mitigate this problem a variations of product ‘team’ approaches have been used where the idea is to involve a multitude of people with the necessary experience to produce a ‘production friendly product’. Those approaches have a few drawbacks mainly the problem of finding people with the relevant experiences or that the expertise only covers the manufacturing processes already used in the organization, losing the opportunity to benefit from any alternative manufacturing process.

    This thesis focuses on how the welding manufacturing technic, analysis can be integrated into the design process with the help of a digital model?

    To improve the communications between the manufacturers and designers, two excel files were developed. The first excel file aimed at the manufacturers where they can present the specific machines used in the workshop. Focusing on specific machine and workshops instead of on the general welding method will give the designers a better understanding of the feasibility of producing their design in a specific workshop instead of focusing on a specific manufacturing method.

    The second excel file is aimed at calculating and comparing the weld methods where the cost and requirements are derived for general welding methods and compared with the machine specifications gathered from the manufacturers using the first excel file. To assess the excel files, a parametrized CAD model of the rear engine turbine structure was developed, and three different cases were used to evaluate the developed excel files.

    The values used are presented in Appendix A: Table 11–15, and were gathered from public sources. Values were also approximated using regression analysis.

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  • 2.
    Andraéy, Erik
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Development of verified FE simulation method on crimp joint with gasket: A combined experimental and numerical study2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When developing drivetrain cooling modules for commercial vehicles, the top priority is the strength of the products. The reason lays within the structural change that companies are undergoing where the warehouses are minimized and the companies are relying on the transportation of commercial vehicles. If a drivetrain cooling module would fail to maintain a targeted temperature range of the drivetrain, there is not long until the vehicle is forced to a stop. At worst, the downtime of commercial vehicles can cause companies to come to a halt as well. Therefore, developing verified FE simulation methods together with strength verification tests, are some of the core activities to ensure the strength of the cooling modules before implementation in vehicles.

    One of the methods that have not been sufficiently verified regards how to perform structural FEA on a crimp joint with a gasket. A crimp joint is established through a hemming process, where the aluminium header tabs are crimped over the polyamide tank, creating a watertight seal together with a gasket. The objective of this master’s thesis is to verify the existing simulation methods of the crimp joint and determine the margin of error with respect to strains. The objective of this thesis is also to develop a verified FE simulation method with a lower margin of error compared to the existing methods. The verification of the methods has been conducted through a comparison between numerical results and an experimental stress analysis, where the strain located on the header is measured with strain gauges in a pressure pulsation rig.

    The average margin of error found on the three existing methods of simulating the crimp joint was 39,7%, 13,4%, and 11,5% located on the outer bottom dimensioning radius of the crimp joint at a pressure of 100 kPa. However, the method used to determine the margin of error was found to be invalid, but the margin of error is only slightly affected by the verification method where the existing methods still are insufficiently representing the crimp joint. The method of determining the margin of error was then corrected for the development of the new method to represent the crimp joint in the FE model. The developed method in this thesis has an average margin of error of 6,9% at 100, 160, 220, and 260 kPa.

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  • 3.
    Erbil, Karaca-Rojan
    Blekinge Institute of Technology, Faculty of Engineering, Department of Industrial Economics.
    Customer perceived value and the importance of information visualization in a B2B context: Case study of a Swedish low-volume, process-oriented manufacturing company2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It was Thomas Babington Macaulay who once stated that “… logicians may reason about abstractions. But the great mass of men must have images”. Recent research on visualization within the manufacturing industry has been focusing around the notion of how to improve performance measures, such as the effectiveness and efficiency of completing a task. Consequently, this led to the dimension of user experience in regard to a visualization becoming relatively neglected. Furthermore, it is mentioned that concepts which are created based on how they are perceived by the customer, have shown to be of significance when creating customer value. Consequently, the purpose of this thesis was to shine light on both of the dimensions of visualization, user performance and user experience, and to study their influence on customer perceived value (CPV) in a business-to-business (B2B) relationship.This thesis was designed as a single case study of a Swedish low-volume, process oriented manufacturing company. Moreover, the case study included two units of analysis, representing current clients involved in two different projects with the company at which the case study was conducted. It is stated that one of the application areas of visualization lies in communication and it can be utilized in order to effectively convey certain information. The information which was in focus in the focal study was the information which is collected during quality control activities performed during the manufacturing process.The findings of the thesis suggest that certain aspects of visualization can have an influence on the functional and emotional dimensions of CPV in a B2B relationship. The conceptually proposed model provides an expanded view on the dimensions of visualization and helps to demonstrate how they stand in relation to the dimensions of CPV, as well as the dimensions used to measure relationship strength in a B2B context. Hereby, the evidence collected during the case study demonstrates that certain relationships between visualization and CPV are suggested to be eminent empirically as well. Thus, suggesting that visualization is an important factor to consider for practitioners in their communication with the customer.

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  • 4.
    Falk, Johannes
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Fracture prediction of stretched shear cut edges in sheets made of Dual-Phase steel2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Dual-Phase (DP) steels, part of the group of Advanced High Strength Steels (AHSS), are used by car manufactures due to its large strength to weight ratio. The high strength of the DP steel does have a negative impact on the formability during sheet metal forming and stretch forming, e.g. fractures often appear in shear cut edges during forming of blanks made of DP steel.

     

    The main objective with this thesis is to develop a new punch for Volvo Cars that concentrates the strain to the sheared edges of a test specimen made from different types of DP steel. This is done to be able to measure and obtain maximum fracture strain during stretch forming tests in a press. The newly developed test method is called CTEST (Concentrated Trim Edge Strain Test).

     

    The tests are performed with DP steel specimens with three different qualities of the shear cut edges; fine cut, medium cut and worn cut. DP steels tested are DP600GI, DP600UC and DP800GI from three different suppliers. 10 different types of DP steels are tested in this study with different thickness. Thickness of specimens tested are 1 mm, 1.1 mm, 1.5 mm and 2 mm and all specimens tested have a lengthwise (RD) rolling direction.

     

    The quality of the sheared cut edge has a great impact to the formability and maximum fracture strain of the specimen. A specimen with a fine cut endures higher fracture strain than medium cut and a worn cut for all types of DP steel with different thickness. A 1 mm thick specimen endures a lower fracture strain than 1.5 mm and 2 mm specimen for all cut qualities.

     

    Further, the impact of the orientation of the burr zone of a shear cut edge is studied. With the burr zone facing upwards from the CTEST punch the formability of the specimens is decreased compared to a burr zone facing downwards, especially for a worn cut specimen with micro cracks and imperfections in the edge surface.

     

    ARAMIS Digital Image Correlation (DIC) system is used to analyze the specimen edges during press experiments. The ARAMIS results unveil that several small fractures appear in the sheared edges of a specimen just before the specimens split into two pieces. This phenomenon was seen for specimen with worn and medium shear cut qualities.

     

    Finite Element (FE) simulations of the CTEST is performed in AutoForm to determine maximum values of the true strain for the three different cut qualities. The simulation in AutoForm does show a slightly higher value of the force and press depth than the value from the press test before maximum fracture strain in reached. The small fractures seen in ARAMIS just before the specimen split into two pieces cannot be seen in the simulation in AutoForm.

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  • 5.
    Karlsson, Emmy
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Industrial Economics.
    Suljeva, Arijeta
    Blekinge Institute of Technology, Faculty of Engineering, Department of Industrial Economics.
    Hur en ökad kunskap om kabelns mätmetoder kan leda till materialbesparing och därigenom kostnadsoptimering samt ökad produktivitet: En fallstudie inom NKT High Voltage Cables2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today's manufacturing industry places increasingly high demands on high quality products with the lowest possible production cost. To be able to meet these requirements in production, it is necessary to optimize the production process and thereby lowering the costs. At the same time, increasing demands are being made on the manufacturing industry from the community, a minimal material consumption versus the consumption demands leads to sustainable development.

    In order to achieve the vision of an optimized production process, quality control today becomes increasingly important for the industries. The goal is to achieve a high-quality product, free from significant variations, and thereby meeting the customer needs or even exceeding the customer´s expectations of the product, while at the same time optimizing the manufacturing process to small margins.

    The purpose of this work is therefore to contribute to increased knowledge of quality control in the production process and some of the most common measurement methods used today. As well as investigating whether increased knowledge can enable an optimization of the production process through production with reduced margins. The work is carried out with the hope that this optimization can lead to several advantages for both the manufacturing industry but also for society, partly through reduced material usage and thus cost optimization, but also a product with optimized dimensions that can thereby be made more efficient and increase the productivity of the process.

    The Master thesis is done as a case study in cooperation with NKT HVC. Measurement data from the manufacturing process have been studied to detect variations and relationships between the different measurement methods. Two production lines have been considered in the study. All measurement data from the two lines treats an equivalent product.

    The result of the empirical study indicates that there are opportunities for optimization in the production process as there are differences between quality control performed with different measuring instruments. An increased knowledge is therefore essential in order to ensure which measurement method that fits best with reality, and thus be able to optimize the process with a reduced material consumption and thereby a cost optimization and increased productivity as a result.

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  • 6.
    Karlsson, Hampus
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Karlsson, Anton
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Konceptutveckling av en caterpillar med inriktning på kvalitet: En utvecklingsprocess2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When transporting a sea cable, what is commonly called a caterpillar is used, but the most common said is a cable tensioner. These machines can be found in a flurry of different variants, where there are a multitude of competitors, which applies demands to having an extremely distinctive machine. Therefore  from  a  market  analysis  it  have  been  identified  that  a  lack  of  quality  regarding  the machines are a factor. A poor quality shortage that usually occurs in hard weather conditions, but this is something that should not happen as it may lead to machine breakdown.

    Semcon AB in Karlskrona constructs and then collaborates with Ronneby Svets & Smide, who manufacture cable carousels, armrests and other equipment for the cable industry but not the cable tensioner that are ordered separately by external companies. This is the background to why the project is created because Semcon sees a need to eliminate this bottleneck and also expand their product portfolio for customer recovery. The aim it therefore, together with Semcon, develop a new concept for a completely  new cable tensioner with given preferences, rough drawing and selection of qualitative features for the machine in order to be competitive with its future overall solution for the cable industry.   

    To find a solution to the described problem, a product development process has been followed to establish  structure.  The  process  include  a  planning,  concept  development,  design  and  detailed development phase. From the first phase, a wide understanding of how the complex machine works and where its deficiencies may be. Even hidden customer needs in form of interviews with cable manufacturers in Karlskrona and with industries that handle sea cable were conducted to get a broader spectrum. The needs are transformed into specifications to generate concepts based on the rankings of the measurably formulated specifications. Followed up by an evaluation where the best concepts were taken to the design phase and detailed development. All design calculations have been made, either by hand or with computer-based programs.  

    The work has resulted in an innovative concept of a whole cable tensioner with all key components, rough drawing, together with a new thinking solution regarding the contact face between the cable and the machine, developed through experiments and theory studies. As this project is very broad, the overall project has been divided into two master thesis works and all electronics are handles by  an  electrical/automation  company.  Therefore,  for  a  broader  understanding  and  information about functionality, reference is made to the second project “Konceptutveckling kring funktionerna hos en kabeldragare” authored by Anton Hansson.  

    It is extremely important to mention that the outcome of this project is intended to be a concept for a new innovative cable tensioner. This means that with future work on the concept, which includes  continued  depth  of  calculation  and  further  contact  with  suppliers,  can  provide  an opportunity  to  manufacture  the  generated  concept.  Another  development  area  Semcon  must proceed with is to review the safety routines of the machine. The authors of this report believe that a highly competitive solution has been presented, and that work contributes to a strong foundation for  the  development  of  transporting  sea  cable  technology  in  the  future  with  the  help  of  this innovative concept.

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  • 7.
    Moberg, Pontus
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Industrial Economics.
    Svensson, Filip
    Blekinge Institute of Technology, Faculty of Engineering, Department of Industrial Economics.
    Cost Optimisation through Statistical Quality Control: A case study on the plastic industry2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background. Shewhart was the first to describe the possibilities that come with having a statistically robust process in 1924. Since his discovery, the importance of a robust process became more apparent and together with the consequences of an unstable process. A firm with a manufacturing process that is out of statistical control tends to waste money, increase risks, and provide an uncertain quality to its customers. The framework of Statistical Quality Control has been developed since its founding, and today it is a well-established tool used in several industries with successful results. When it was first thought of, complicated calculations had to be performed and was performed manually. With digitalisation, the quality tools can be used in real-time, providing high-precision accuracy on the quality of the product. Despite this, not all firms nor industries have started using these tools as of today. 

     

    The costs that occur in relation to the quality, either as a consequence of maintaining good quality or that arises from poor quality, are called Cost of Quality. These are often displayed through one of several available cost models. In this thesis, we have created a cost model that was heavily inspired by the P-A-F model. Several earlier studies have shown noticeable results by using SPC, COQ or a combination of them both.  

     

    Objectives. The objective of this study is to determine if cost optimisation could be utilised through SQC implementation. The cost optimisation is a consequence of an unstable process and the new way of thinking that comes with SQC. Further, it aims to explore the relationship between cost optimisation and SQC. Adding a layer of complexity and understanding to the spread of Statistical Quality Tools and their importance for several industries. This will contribute to tightening the bonds of production economics, statistical tools and quality management even further.

     

    Methods. This study made use of two closely related methodologies, combining SPC with Cost of Quality. The combination of these two hoped to demonstrate a possible cost reduction through stabilising the process. The cost reduction was displayed using an optimisation model based on the P-A-F (Prevention, Appraisal, External Failure and Internal Failure) and further developed by adding a fifth parameter for optimising materials (OM). Regarding whether the process was in control or not, we focused on the thickness of the PVC floor, 1008 data points over three weeks were retrieved from the production line, and by analysing these, a conclusion on whether the process was in control could be drawn. 

     

    Results. Firstly, none of the three examined weeks were found to be in statistical control, and therefore, nor were the total sample. Through the assumption of the firm achieving 100% statistical control over their production process, a possible cost reduction of 874 416 SEK yearly was found. 

     

    Conclusions. This study has proven that through focusing on stabilising the production process and achieving control over their costs related to quality, possible significant yearly savings can be achieved. Furthermore, an annual cost reduction was found by optimising the usage of materials by relocating the ensuring of thickness variation from post-production to during the production.

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  • 8.
    Schulte, Jesko
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Strategic Sustainable Development.
    Hallstedt, Sophie
    Blekinge Institute of Technology, Faculty of Engineering, Department of Strategic Sustainable Development.
    Risk Management Practices in Product Development Companies2018In: Proceedings of Norddesign 2018, The Design Society, 2018Conference paper (Refereed)
    Abstract [en]

    Product development (PD) is inherently linked to taking and managing risks. For risk management (RM) to be truly effective, it cannot be treated in product development in isolation. Instead, a holistic perspective is required that recognizes and leverages the communication and connections between RM sub-disciplines across the organizational hierarchy, including e.g. enterprise-, portfolio-, project-, and product RM. Therefore, the purpose of this study is (i) to investigate current RM practices on the strategic, tactical, and operational levels, and (ii) to increase the understanding of how RM sub-disciplines are connected and interact. To answer these questions, semi-structured interviews were conducted at two large multinational PD and manufacturing companies in Sweden. Also, based on previous research, a novel self-assessment tool was developed and tested to map areas of strength and identify improvement potential. The results show that RM processes are mostly formalized and systematic, but there is variation in the quality of performed RM activities. Qualitative support tools are dominating. The tools themselves are considered to be helpful, however, the challenge is to make people use them in value-adding ways. Other challenges and success factors include competence and awareness, culture, top-down demand for high quality RM activities and deliverables, a dedicated role with clear responsibility, and working early and continuously with RM. The importance of experience is stressed, however, no systematic way to work with lessons learned and knowledge sharing is in place at the companies. Risks are found to be primarily escalated bottom-up. The corresponding top-down flow constitutes of objectives, which ideally are cascaded all the way from company vision and strategy into product requirements. Through these findings, the contribution of this study is (i) providing detailed insight into current RM practices, not limited to the PD function, but considering a broader organizational context; and (ii) clarifying the role of goals and objectives for connecting RM on different levels.

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  • 9.
    Sigvant, M.
    et al.
    Volvo Cars, SWE.
    Pilthammar, Johan
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Hol, J.
    TriboForm Engn, NLD.
    Wiebenga, J. H.
    TriboForm Engn, NLD.
    Chezan, T.
    Tata Steel, NLD.
    Carleer, B.
    AutoForm Engn, DEU.
    van den Boogaard, A. H.
    Univ Twente, NLD.
    Friction and lubrication modelling in sheet metal forming simulations of the Volvo XC90 inner door2016In: NUMISHEET 2016: 10TH INTERNATIONAL CONFERENCE AND WORKSHOP ON NUMERICAL SIMULATION OF 3D SHEET METAL FORMING PROCESSES, PTS A AND B / [ed] Cardoso, RPR Yoon, JW Dick, RE Neto, ES DeSa, JMAC Adetoro, OB, IOP PUBLISHING LTD , 2016, article id UNSP 032090Conference paper (Refereed)
    Abstract [en]

    The quality of sheet metal formed parts is strongly dependent on the friction and lubrication conditions that are acting in the actual production process. Although friction is of key importance, it is currently not considered in detail in stamping simulations. This paper presents project results considering friction and lubrication modelling in stamping simulations of the Volvo XC90 inner door. For this purpose, the TriboForm software is used in combination with the AutoForm software. Validation of the simulation results is performed based on door-inner parts taken from the press line in a full-scale production run. The project results demonstrate the improved prediction accuracy of stamping simulations.

  • 10.
    Zavadil, Jaromir
    et al.
    VSB Tech Univ Ostrava, CZE.
    Ström Bartunek, Josef
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mathematics and Natural Sciences.
    Fojtik, David
    VSB Tech Univ Ostrava,CZE.
    Analysis of Periodicities in Surface Topography of Cold rolled sheets Using Data Captured by Camera System2020In: Measurement Science Review, ISSN 1335-8871, Vol. 20, no 3, p. 145-149Article in journal (Refereed)
    Abstract [en]

    A method for surface analysis of cold rolled sheets is proposed in this paper. The approach is based on a low-cost specially built camera system followed by spectral analysis of the data captured from metal surfaces. The focus is on the changes in the surface topography caused by cold rolling with emphasis towards periodicities in the processed surface. Angular profile of the spectrum is calculated and used to display periodicities in surface topography and show their direction. The results obtained by using the proposed system were compared with results obtained from the optical profilometer MicroProf FRT. The experiments show that cold rolling creates marks on the surface of the material, which represent periodicities that can be effectively detected by the proposed method and camera system. Even though the camera system is not able to measure precise surface roughness, it is able to detect periodicities and the results of spectral analysis are comparable with the results from the optical profilometer.

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