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  • 1.
    Abu Baker Karim, Aria
    et al.
    Örebro University, School of Science and Technology.
    Schnelzer, Anna
    Örebro University, School of Science and Technology.
    Optimering av glidlager och utveckling av dess konstruktion2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    We have in this project become engrossed in a plain bearing design that is located in a screw press. The screw press compact an unknown mass that is confidential. Robustus have a suggestion to over dimensioning the present plain bearing. The aim of this project was to analyze and to do an optimization on some plain bearings and compare them to the present bearing and to take the choice of material and the environment where the bearing is located into account. The analysis and the optimizations showed that the current plain bearing had the best geometry but not the optimal material selection. The project is in an early state and it needs some geometrical changes. The most important of everything is that the problem has been identified with the help of the wrecked plain bearing and with an excel model.

  • 2.
    Alfredsson, Axel
    et al.
    Örebro University, School of Science and Technology.
    Knutson, Gustav
    Örebro University, School of Science and Technology.
    Analys av driftstopp i ett hyvleri2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Moelven is an industrial group that produces building materials and systems for the construction industry; with its 52 productions units in Norway, Sweden and Denmark, it is one of the biggest in Scandinavia. This study has been carried out in the planing mill at Moelven Valåsen Wood AB in Karlskoga.

    Because of the low utilization rate in the planing mill (65%), it constitutes a bottleneck, meaning it limits the capacity and flow of material, for most of the products. The purpose of the study was to analyze the stoppage in the planing mill in order to make recommendations on how the utilization rate can be increased.

    The study began with a wide perspective to identify the reasons behind this problem. A summary of all stops in the planing mill concluded that set ups of the planer made up for 30% of total stoppage. Because of this, the study was narrowed down to mainly analyze the different types of set ups, which was done through extensive observations and videotaping. The solutions and recommendations that were given are therefore almost entirely regarding set up-time reduction, and more specifically, milling set ups. The recommendations, based on the results of the study, includes:

    • Suggestions on how to separate internal and external set up.

    • Better order of tools through designing a check table.

    Standardizing the procedure by creating a routine and dividing the operators into different work roles.

    Involving everyone in the organization in order to work with continuous improvement.

    A simulation of milling set ups was done by implementing parts of the recommendations – this resulted in a setup up-time reduction of 13 minutes, which corresponds to 32.5%. Because of common denominators, such as movements, the recommendations given are likely generalizable for all set ups.

  • 3.
    Algesten, Johannes
    et al.
    Örebro University, School of Science and Technology.
    Svedberg, Sofie
    Örebro University, School of Science and Technology.
    KONSTRUKTION AV AUTOMATISK PÅHASPLINGSPROCESS VID TILLVERKNING AV BANDSTÅL2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The mission that we have received is to design a device that will automate the coiling processin the manufacture of steel strip. The goal of this project is to develop a production documentation that will form the basis for further development of the product. The production documentation shall include drawings, list of components and a cost estimate. A pilot study was conducted where we visited one of the largest strip steel manufacturer to investigate the solutions they had to our problem. Based on what we saw, a concept generation was made that led to the concept that we proceeded with. In the process, we have placed great emphasis on making the design as simple as possible to get a reasonable production cost. We have also taken into account that the design will be integrated with existing equipment. Regarding cost, we have as far as possible tried to use standard components and standard dimensions of the material in the construction. Parts of the structure exposed to high forces have been analyzed by using ANSYS. The result is a construction with two arms using a belt to envelope the coil. The arm is controlled using a hydraulic cylinder, while the other is positioned when the belt is stretched. The construction will be placed above the coil and lowered when it is used.

  • 4.
    Almerstedt, Matilda
    et al.
    Örebro University, School of Science and Technology.
    Lindhé, Johanna
    Örebro University, School of Science and Technology.
    Empirisk studie i form och geometrins upplevda inverkan på konsument produkter2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    It is unclear which mechanical properties that affect consumer products, it can be assumed that the shape and geometry affect the perceived feeling of consumer products. The aim of the project is to examine how the geometry and folding views affect the feeling in the use of consumer products.The study was performed on three consumer products of different dimensions where each product was produced in two different versions. The results showed that consumer product’s geometry is significant, while the folding views do not have a significant impact.

  • 5.
    Almér, Ida
    et al.
    Örebro University, School of Science and Technology.
    Hed, Johanna
    Örebro University, School of Science and Technology.
    Utveckling av delningsarm2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report describes a bachelor degree project conducted at the company EMBA Machinery AB. The company manufactures corrugated cardboard conversion machines. The machines convert cardboard sheets into folded corrugated boxes. EMBA´s machines are so-called internal machines that consist of several devices. The unit involved in the thesis work reported herein was the unit Counter Stacker. The Counter Stacker is the last unit in the EMBA machines, it counts and divides the finished cardboard boxes into bundles.

    EMBA wanted the authors to redesign the function that divides the sheets, the divider arm, in the affected unit. The divider arm should be controlled via electric servo operation and also act as a rebuild kit for previously sold machines.

    Calculations to investigate the stresses that arise at critical points in the design have been carried out. Motion profiles have been developed and motors and gearboxes have been dimensioned. Parallel to this a 3D-model was created in CAD. Based on the CAD-model, the company can proceed with creating complete drawing documents.

  • 6.
    Alzghoul, Ahmad
    et al.
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Löfstrand, Magnus
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Increasing availability of industrial systems through data stream mining2011In: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 60, no 2, 195-205 p.Article in journal (Refereed)
    Abstract [en]

    Improving industrial product reliability, maintainability and thus availability is a challenging task for many industrial companies. In industry, there is a growing need to process data in real time, since the generated data volume exceeds the available storage capacity. This paper consists of a review of data stream mining and data stream management systems aimed at improving product availability. Further, a newly developed and validated grid-based classifier method is presented and compared to one-class support vector machine (OCSVM) and a polygon-based classifier.

    The results showed that, using 10% of the total data set to train the algorithm, all three methods achieved good (>95% correct) overall classification accuracy. In addition, all three methods can be applied on both offline and online data.

    The speed of the resultant function from the OCSVM method was, not surprisingly, higher than the other two methods, but in industrial applications the OCSVMs' comparatively long time needed for training is a possible challenge. The main advantage of the grid-based classification method is that it allows for calculation of the probability (%) that a data point belongs to a specific class, and the method can be easily modified to be incremental.

    The high classification accuracy can be utilized to detect the failures at an early stage, thereby increasing the reliability and thus the availability of the product (since availability is a function of maintainability and reliability). In addition, the consequences of equipment failures in terms of time and cost can be mitigated.

  • 7.
    Alzghoul, Ahmad
    et al.
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Löfstrand, Magnus
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Backe, Björn
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Data stream forecasting for system fault prediction2012In: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 62, no 4, 972-978 p.Article in journal (Refereed)
    Abstract [en]

    Competition among today’s industrial companies is very high. Therefore, system availability plays an important role and is a critical point for most companies. Detecting failures at an early stage or foreseeing them before they occur is crucial for machinery availability. Data analysis is the most common method for machine health condition monitoring. In this paper we propose a fault-detection system based on data stream prediction, data stream mining, and data stream management system (DSMS). Companies that are able to predict and avoid the occurrence of failures have an advantage over their competitors. The literature has shown that data prediction can also reduce the consumption of communication resources in distributed data stream processing. In this paper different data-stream-based linear regression prediction methods have been tested and compared within a newly developed fault detection system. Based on the fault detection system, three DSM algorithms outputs are compared to each other and to real data. The three applied and evaluated data stream mining algorithms were: Grid-based classifier, polygon-based method, and one-class support vector machines (OCSVM). The results showed that the linear regression method generally achieved good performance in predicting short-term data. (The best achieved performance was with a Mean Absolute Error (MAE) around 0.4, representing prediction accuracy of 87.5%). Not surprisingly, results showed that the classification accuracy was reduced when using the predicted data. However, the fault-detection system was able to attain an acceptable performance of around 89% classification accuracy when using predicted data.

  • 8.
    Alzghoul, Ahmad
    et al.
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Löfstrand, Magnus
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Karlsson, Lennart
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Karlberg, Magnus
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Data stream mining for increased functional product availability awareness2011In: Functional Thinking for Value Creation: Proceedings of the 3rd CIRP International Conference on Industrial Product Service Systems, Technische Universität Braunschweig, Braunschweig, Germany, May 5th - 6th, 2011 / [ed] Hesselbach, J. & Herrmann, C., Springer Berlin/Heidelberg, 2011, 237-241 p.Conference paper (Refereed)
    Abstract [en]

    Functional Products (FP) and Product Service Systems (PSS) may be seen as integrated systems comprising hardware and support services. For such offerings, availability is key. Little research has been done on integrating Data Stream Management Systems (DSMS) for monitoring (parts of) a FP to improve system availability. This paper introduces an approach for how data stream mining may be applied to monitor hardware being part of a Functional Product. The result shows that DSMS have the potential to significantly support continuous availability awareness of industrial systems, especially important when the supplier is to supply a function with certain availability.

  • 9.
    Amouzgar, Kaveh
    et al.
    Department of Mechanical Engineering, School of Engineering, Jönköping University, Jönköping, Sweden.
    Rashid, Asim
    Department of Mechanical Engineering, School of Engineering, Jönköping University, Jönköping, Sweden.
    Strömberg, Niclas
    Department of Mechanical Engineering, School of Engineering, Jönköping University, Jönköping, Sweden.
    Multi-objective optimization of a disc brake system by using SPEA2 and RBFN2013In: ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference: Volume 3B: 39th Design Automation Conference, New York: ASME Press, 2013Conference paper (Other academic)
    Abstract [en]

    Many engineering design optimization problems involve multiple conflicting objectives, which today often are obtained by computational expensive finite element simulations. Evolutionary multi-objective optimization (EMO) methods based on surrogate modeling is one approach of solving this class of problems. In this paper, multi-objective optimization of a disc brake system to a heavy truck by using EMO and radial basis function networks (RBFN) is presented. Three conflicting objectives are considered. These are: 1) minimizing the maximum temperature of the disc brake, 2) maximizing the brake energy of the system and 3) minimizing the mass of the back plate of the brake pad. An iterative Latin hypercube sampling method is used to construct the design of experiments (DoE) for the design variables. Next, thermo-mechanical finite element analysis of the disc brake, including frictional heating between the pad and the disc, is performed in order to determine the values of the first two objectives for the DoE. Surrogate models for the maximum temperature and the brake energy are created using RBFN with polynomial biases. Different radial basis functions are compared using statistical errors and cross validation errors (PRESS) to evaluate the accuracy of the surrogate models and to select the most accurate radial basis function. The multi-objective optimization problem is then solved by employing EMO using the strength Pareto evolutionary algorithm (SPEA2). Finally, the Pareto fronts generated by the proposed methodology are presented and discussed.

  • 10.
    Amouzgar, Kaveh
    et al.
    Department of Mechanical Engineering, School of Engineering, Jönköping University Jönköping, Sweden .
    Strömberg, Niclas
    Department of Engineering Science, University West, Trollhättan, Sweden.
    An approach towards generating surrogate models by using RBFN with a priori bias2014In: Proceedings of the ASME International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, 2014, Vol. 2B, New York, USA: ASME Press, 2014, V02BT03A024Conference paper (Refereed)
    Abstract [en]

    In this paper, an approach to generate surrogate modelsconstructed by radial basis function networks (RBFN) with a prioribias is presented. RBFN as a weighted combination of radialbasis functions only, might become singular and no interpolationis found. The standard approach to avoid this is to add a polynomialbias, where the bias is defined by imposing orthogonalityconditions between the weights of the radial basis functionsand the polynomial basis functions. Here, in the proposed a prioriapproach, the regression coefficients of the polynomial biasare simply calculated by using the normal equation without anyneed of the extra orthogonality prerequisite. In addition to thesimplicity of this approach, the method has also proven to predictthe actual functions more accurately compared to the RBFNwith a posteriori bias. Several test functions, including Rosenbrock,Branin-Hoo, Goldstein-Price functions and two mathematicalfunctions (one large scale), are used to evaluate the performanceof the proposed method by conducting a comparisonstudy and error analysis between the RBFN with a priori and aposteriori known biases. Furthermore, the aforementioned approachesare applied to an engineering design problem, that ismodeling of the material properties of a three phase sphericalgraphite iron (SGI) . The corresponding surrogate models arepresented and compared

  • 11.
    Amouzgar, Kaveh
    et al.
    Product Development Department, School of Engineering, Jönköping University, Jönköping, Sweden; School of Engineering Science, University of Skövde, Skövde, Sweden.
    Strömberg, Niclas
    Örebro University, School of Science and Technology. Department of Mechanical Engineering.
    Radial Basis Functions as Surrogate Models with A Priori Bias in Comparison with a Posteriori Bias2017In: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 55, no 4, 1453-1469 p.Article in journal (Refereed)
    Abstract [en]

    In order to obtain a robust performance, the established approach when using radial basis function networks (RBF) as metamodels is to add a posteriori bias which is defined by extra orthogonality constraints. We mean that this is not needed, instead the bias can simply be set a priori by using the normal equation, i.e. the bias becomes the corresponding regression model. In this paper we demonstrate that the performance of our suggested approach with a priori bias is in general as good as, or even for many test examples better than, the performance of RBF with a posteriori bias. Using our approach, it is clear that the global response is modelled with the bias and that the details are captured with radial basis functions. The accuracy of the two approaches are investigated by using multiple test functions with different degrees of dimensionality. Furthermore, several modeling criteria, such as the type of radial basis functions used in the RBFs, dimension of the test functions, sampling techniques and size of samples, are considered to study their affect on the performance of the approaches. The power of RBF with a priori bias for surrogate based design optimization is also demonstrated by solving an established engineering benchmark of a welded beam and another benchmark for different sampling sets generated by successive screening, random, Latin hypercube and Hammersley sampling, respectively. The results obtained by evaluation of the performance metrics, the modeling criteria and the presented optimal solutions, demonstrate promising potentials of our RBF with a priori bias, in addition to the simplicity and straight-forward use of the approach.

  • 12.
    Ander, Rebecka
    Örebro University, School of Science and Technology.
    Effektivisering av materialflödet genom processkartläggning2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    How does the current process look like and how can it be improved? That was the two questions that the company posed. That was the beginning for this degree project. Through process mapping and analysis of today's process, a proposal for development of the internal material flow has been made.

  • 13.
    Andersson, Alexander
    et al.
    Örebro University, School of Science and Technology.
    Hjelmqvist, Rasmus
    Örebro University, School of Science and Technology.
    Värdeflödeskartläggning och slöserier2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Atria Scandinavia is a company belonging to the Atria Group which is one of the largest companies in the food industry in Finland. One of their factories is located in Sköllersta, Sweden, that produce sausages, burgers and whole-meat products.

    Two products of whole-meat department was in need of a value stream mapping because the current time studies of the processes were no longer relevant. One of the products are one of the most common and oldest in Atria, sliced whole-muscle and the other a poultry product that is one of the newest. In order to calculate the cost of the sold goods in a correct manner an updated time-study was required.

    Value Stream Mapping is a powerful tool from the Lean philosophy that gives the company a very good overview of the value stream and all processes. This provides good opportunity for a deep understanding of the processes and value-flows, something that is vital for further improvement. The work with value stream analysis generated following results:

    • Updated time studies

    • Process descriptions

    • Value Stream Maps

    • Presentation of the value-adding as well as non-value-adding time

    • A kinship chart with problem areas in the value flows of the products

    • Possible root causes of problems in the flows

    • Proposed measures to handle these problems

  • 14.
    Andersson, Henrik
    Örebro University, School of Science and Technology.
    Yt- och strukturpåverkan vid finfräsning av härdat verktygsstål2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis, investigations on hardened finish milled surfaces was done in collaboration with the tool steel manufacturer Uddeholms AB in Hagfors, Sweden. The steel material is affected by machining operations, sometimes in a negative destructive manner. An experimental test series containing a total of 90 surfaces in hot work steels Uddeholm Orvar Supreme and Uddeholm Dievar were milled, measured and evaluated to clarify the milling operations effect on the steels mechanical properties. It was found that the material is affected differently according to how the milling was preformed and with which type of milling tool. In this thesis, only solid carbide end-radius milling tools were used. The surface analysis were conducted with a range of measuring techniques including optical surface roughness measurements, hardness measurements in Vickers scale, residual stress measurements with X-ray diffraction (XRD) and microstructural analysis with optical light microscope. These measurements were conducted in order to determine the milling operations mechanical affects and grade of alteration of the tool steels surfaces. In the least favorable cases, the effect from machining are so profound, that degradation of produced components can be expected in terms of fatigue wear resistance. The goal of the thesis is to identify the most favorable process parameters, in order to minimize degradation of the tooling material in customer user cases, together with the opportunity to give fact based advice to Uddeholms AB customers on the most favorable process parameters in finish milling with radius-mills of hardened hot work tool steels. In this way the customer can utilize the tooling material at its full potential.  

  • 15.
    Andersson, Joakim
    et al.
    Örebro University, School of Science and Technology.
    Bertilsson, Jimmy
    Örebro University, School of Science and Technology.
    SETUP TIME OPTIMIZATION2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

     

    Emhart Glass Ltd is a world leader in glass bottle manufacturing. They design automated machines that shape glass bottles. In Sweden there are two factories, one in Örebro and one in Sundsvall. In Örebro they manufacture primarily spare parts and new parts for the machines while they in Sundsvall assemble the machines. There are a total of 15 factories and offices around the world with the headquarter located in Swiss Cham.Since Emhart Glass Örebro has long setup times on some of their machines. This is why we want to identify the current setup process and how the setup process differs between operators. We will also look at whether there are any opportunities for improvement to be made and if they have a standardized way to work. A document that describes how to setup work should be done will also be developed.An excellent tool to shorten the setup time in a production is the SMED method. The philosophy behind SMED is that you should analyze and separate the inner and outer activities. Inner and outer activities mean those activities which can only be performed when the machine is turned off, respectively those activities that can be performed when the machine is in operation.

    In order to standardize the adjustment process so that all operators are working in a similar way it's required that you make a documentation about how the work should be done. Therefore, checklists been developed to the operator. "Checklista - Omställning.xls" is a checklist with the purpose to be able to check which parts of the preparations they have made before the next setup work. It has been designed to be easy to keep track of what parts you have done if you had to work with the machine between the trial or if you quit your shift and leaving parts of the work to the next operator.

    If all of these improvements are implemented, we expect a set-up time reduction of 20.5% which corresponds to about 35min per set-up. By ignoring the running time and only check on the setup times, one can see an improvement of 36.4%.

  • 16.
    Andersson, Joakim
    et al.
    Örebro University, School of Science and Technology.
    Zurita, Arturo
    Örebro University, School of Science and Technology.
    Reducering av tidsslöseri med hjälp av 5S inom Umicore Autocat Sweden AB2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Umicore is a global company that works with materials. The group has some 80 production plants and around 14400 employees around the world. In Sweden they are at two places, one of which is in Karlskoga. Their name is Umicore Autocat Sweden AB. With their, at the present, 37 employees they manufacture catalysts.

     

    The mission was assigned to us by Umicore Autocat Sweden AB and the purpose of it was to suggest improvements that can be used to try to reduce or eliminate time-wasting that take its shape in the production department. At first it was meant that we would help them to introduce the first three steps of 5S. But because of that we miss estimated the time it would take to do this, we agreed with the company to leave it as suggestion for improvements.

     

    The width of the report consists of the current problems that exist in the company production department. Meanwhile there will be methods and recommendations that will enable improvements to these.

     

    In the implementation of this work interviews, literature studies and all files that the company contributed with from previous work with 5S were used. This is to try to find possible solutions. The result of this is presented as some proposed solutions that can help the company to continue with their quality work. The report also consists of a proposal, with analysis and calculations, of a new layout for the bellows, fixtures and Leister. Some of the information that was used in the calculations we received from the production manager in the company.

     

    We believe that our proposals will work as a tool for the company so they keep improving the quality in their production department by continuing to introduce and implement improvements within 5S. For this purpose it demands that the management ensures that the staff is committed, in this case in 5S.

  • 17.
    Andersson, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Berneke, Anders
    Örebro University, School of Science and Technology.
    Basis and a concept for a Paper machine in a laboratory scale2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis studies paper and what it is made of and different ways to manufacture it in a laboratory scale. It also contains a comparison of different ways to dry tissue and which method that suits a small laboratory tissue machine best.

     A small paper machine was found at Metso in Karlstad that was used as a basis for the concept machine. Since the machine at Karlstad used pressing and a cylinder drying method that involves pressing an alternative method to dry the paper had to be chosen.

    For drying tissue there are several methods like, infrared and through air drying. A comparison was made between those methods to find out which suited the specification best.

    The comparison shows that through air drying is the best drying method for the machine.

  • 18.
    Andersson, Per-Allan
    Örebro University, Department of Technology.
    Läggartemperaturens inverkan på glödskalet, samt dess inverkan på metoden för avlägsning av glödskalet: litteraturstudie2003Report (Other academic)
  • 19.
    Antegård, Kristian
    et al.
    Örebro University, School of Science and Technology.
    Mucic, Fuad
    Örebro University, School of Science and Technology.
    CE-märkning av lyftredskap. Processen, användningsområden och dokumentation.2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The report is a thesis carried out at BAE Systems Bofors AB in Karlskoga. This report is about exploring and to give suggestions for improvement of the production process and CE-marking of lifting tools. The report also discusses documentation management and documentation requirements for CE marking. What is true at the CE Marking of lifting tools designed for military purposes. The report provides a basic understanding of what purposes CE-marking has and why it is done. Through research and interviews conducted at the company a map of the process for creating and CE marking of lifting tools was created. Using the same method an investigation of the dossier was done. After an analysis of the problem and what emerged during the interviews, the results of the current situation were summarized. One proposed solution was developed that contains suggestions for improvement of the process, suggestions for documentation that should be available and suggestions where documentation should be stored.

  • 20.
    Arén, Björn
    Örebro University, Department of Technology.
    Die Stresses in the compaction of powders: experiments and analysis2004Conference paper (Refereed)
  • 21.
    Arén, Björn
    Örebro University, Department of Technology.
    Dimensioning of dies for the compaction of shaped PM-parts2003Conference paper (Refereed)
  • 22.
    Arén, Björn
    Örebro University, School of Science and Technology.
    Utveckling - är att se, söka och förverkliga: kursbok i produktutveckling2010 (ed. 1)Book (Other academic)
  • 23.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    3D Printing / Additative Manufacturing from Product Creator and Tool Maker Perspectives in the Automotive Industry2016Conference paper (Other academic)
  • 24.
    Asnafi, Nader
    VA Automotive AB, Hässleholm, Sweden .
    3D-printning från produktskapares och verktygsmakares perspektiv2015Conference paper (Other academic)
  • 25.
    Asnafi, Nader
    Volvo Car Components Corporation/Industrial Development Centre, Olofström, Sweden.
    Analytical modelling of tube hydroforming1999In: Thin-walled structures, ISSN 0263-8231, E-ISSN 1879-3223, Vol. 34, no 4, 295-330 p.Article in journal (Refereed)
    Abstract [en]

    The automotive industry has shown a growing interest in tube hydroforming during the past years. The advantages of hydroforming (less thinning, a more efficient manufacturing process etc.) can, for instance, be combined with the high strength of extra high strength steels, which are usually less formable, to produce structural automotive components which exhibit lower weight and improved service performance. Design and production of tubular components require knowledge about tube material behaviour and tribological effects during hydroforming and how the hydroforming operation itself should be controlled. These issues are studied analytically in the present paper. Hydroforming consists of free forming and calibration. Only the so-called free forming is treated here. The analytical models constructed in this paper are used to show what the limits are during the free forming, how different material and process parameters influence the loading path and the forming result, and what an experimental investigation into hydroforming should focus on. The present study was a part of a larger investigation, in which finite-element simulations and experiments were also conducted. The results of these simulations and experiments will be accounted for in coming papers.

  • 26.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden.
    Automotive Tools & Dies - Volvo Cars Perspective2007Conference paper (Other academic)
  • 27.
    Asnafi, Nader
    VA Automotive AB, Hässleholm, Sweden .
    Automotive/Car Body Stamping Tools & dies: 3D Printing Offers Shorter Lead Time and Reasonable Costs2016Conference paper (Other academic)
  • 28.
    Asnafi, Nader
    Jönköping University, Jönköping, Sweden .
    Development of Sustainable Products and Manufacturing/Production2014Conference paper (Other academic)
  • 29.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    Improved Lightweight Manufacturing Flexibility by Stamping of Selectively Laser Heat Treated Boron Steel Sheet2016Conference paper (Other academic)
  • 30.
    Asnafi, Nader
    Uddeholms AB, Hagfors, Sweden .
    Kunddriven produktutveckling på en varierad marknad för global framgång2012Conference paper (Other academic)
  • 31.
    Asnafi, Nader
    Industrial Development Center/Volvo Cars Body Components, Olofström, Sweden .
    On Springback of Double-Curved Autobody Panels1998In: Proceedings, working groups meeting - IDDRG, International Deep Drawing Research Group: Genval, Benelux, June 15 - 16, 1998, 1998Conference paper (Other academic)
  • 32.
    Asnafi, Nader
    Gränges Technology, Finspång, Sweden.
    On springback of double-curved autobody panels2001In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 43, no 1, 5-37 p.Article in journal (Refereed)
    Abstract [en]

    The springback of double curved autobody panels is studied theoretically and experimentally. Both steel and aluminum sheets are included in this investigation. The obtained results show that the springback is decreased with increasing binder force, increasing curvature, increasing sheet thickness and decreasing yield strength. This paper comprises also a discussion on the plastic strains and their influence on the springback.

  • 33.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    On Springback of Double-Curved Autobody Panels, Part I: Theoretical Treatment1996Report (Other academic)
  • 34.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    On Springback of Double-Curved Autobody Panels, Part II: Experimental Analysis1996Report (Other academic)
  • 35.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden .
    Proceedings of the IDDRG 2008 Conference: Best in class stamping, 16-18 June 2008, Olofström, Sweden2008Conference proceedings (editor) (Other academic)
  • 36.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden.
    Proceedings of the international conference on recent advances in manufacture & use of tools & dies and stamping of steel sheets: October 5-6, 2004, Olofström, Sweden2004Conference proceedings (editor) (Other academic)
  • 37.
    Asnafi, Nader
    VA Automotive AB, Hässleholm, Sweden .
    Sustainable Product and Production Development2015Conference paper (Other academic)
  • 38.
    Asnafi, Nader
    Uddeholms AB, Hagfors, Sweden .
    Tooling & Technologies for Processing Ultra High Strength Materials2011Conference paper (Other academic)
  • 39.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden .
    Tooling in manufacturing of car bodies: today & tomorrow2002Conference paper (Other academic)
  • 40.
    Asnafi, Nader
    Uddeholms AB, Hagfors, Sweden .
    Tools & Dies for Processing of Advanced High Strength Sheet Steels2011Conference paper (Other academic)
  • 41.
    Asnafi, Nader
    et al.
    Volvo Cars Body Components, Olofström, Sweden.
    Johansson, T.
    Volvo Cars Body Components, Olofström, Sweden.
    Miralles, M.
    Volvo Cars Body Components, Olofström, Sweden.
    Ullman, A.
    Volvo Cars Body Components, Olofström, Sweden.
    Laser surface-hardening of dies for cutting, blanking or trimming of uncoated DP6002004In: Proceedings of the International Conference on Recent Advances in Manufacture and Use of Tools and Dies and Stamping of Steel Sheets / [ed] Nader Asnafi, Olofström: Vovo Cars , 2004, 193-214 p.Conference paper (Refereed)
    Abstract [en]

    In this study, the methods used to harden trim dies were at the focus. Laser surface-hardening was compared to induction- and through-hardening for small and medium-size series production. The sheet materials used were 1.2 mm thick uncoated Docol 600DP and 1.95 mm thick uncoated Docol 600DL The die materials tested were Fermo, Canmo and Sleipner. This investigation showed that the optimum laser-hardening parameters must be established for each trim die material. The trim die in laser-hardened Sleipner exhibits the smallest wear, whilst the trim die in induction-hardened Fermo displays the largest wear in the semi-industrial phase of this study. The magnitude of this largest wear is, however, very small. The trim die in induction-hardened Fermo managed 100 000 strokes without any problem. The dimensional changes after laser hardening are very small. The burr height is very small, regardless of how the trim die is hardened. In this study, two sets of production trim dies were manufactured and set up. This production trim dies are used in the manufacture of V70 B-pillar Left and Right Laser hardening resulted in a lead time reduction by 5 labour days. However, the Tool & Die unit estimates that the lead time reduction obtained with laser hardening should be around 10 days under normal conditions. The cost analysis conducted by the Tool & Die unit shows that the manufacturing costs are reduced by 6%, if laser-hardening is selected. These production trim dies are and will be monitored continuously. As this paper is being written, these dies have been subject to 50 000 strokes.

  • 42.
    Asnafi, Nader
    et al.
    Sapa Profiles/Sapa Technology, Finspång, Sweden.
    Nilsson, T.
    Sapa Profiles/Sapa Technology, Finspång, Sweden.
    Lassl, G.
    Volvo Car Corp..
    Automotive tube bending and tubular hydroforming with extruded aluminium profiles2000In: SAE technical paper series, ISSN 0148-7191, 2670Article in journal (Refereed)
    Abstract [en]

    Side Member Left and Side Member Right, which go from bumper to bumper, were at the focus in the present study. These side members were produced using straight round (hollow with a circular cross-section) extruded aluminium profiles as tube material. The tubes were bent and hydroformed. Rotary-draw bending yielded the best result. A spread within 8 mm after bending was found to be acceptable provided that the bent tube was hydroformed with a high maximum internal pressure (1300 bars in this study). Pressure-assisted tool (hydroforming tool) closure should be preferred. Such a tool closure prevents formation of buckles, which may be difficult to straighten out completely during hydroforming. Planeness and parallelity of the press tables and adapters play a significant role, as far as the spread and inplaneness of hydroformed components are concerned. The hydroforming tool must be matched in the press that actually will be used. Proper evacuation (of particularly air) is essential, especially in long hydroforming tools. All cross sections must be deformed at least 2% (average perimeter enlargement), if the hydroformed components are to exhibit a reasonable spread. The critical (fracture) cross-sections predicted by finite-element simulation correspond to those found in practical tests. However, the finite-element simulation was not able to predict formation of wrinkles at the tube ends caused by excessively large strokes. Such wrinkles were obtained in practice.

  • 43.
    Atterling, Lise-Lotte
    Örebro University, School of Science and Technology.
    TAK-mätning slipmaskiner2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today's Suzuki Garphyttan AB (SG) part of the Suzuki Metal Industry Group. Which is a Japanese company. SG is a world leader in the manufacturing of advanced spring wire used for various automotive applications. The core business of SG is the manufacturing and sales of valve spring wire, flat wire and profiled wire, oil quenched wire, spring wire, and stainless steel spring wire.  SG has its own manufacturing of valve springs for trucks in the Springshop. It´s located within the SG factory area. Springshop implements an improvement with the intention to changes todays functional production to line production. The customers require quality certifications and some customers have themselves wound up its quality control on for spring. The quality control and quality guarantee is then responsible for spring production. This means even higher quality and reliability of the manufacturers. Springshop improvement work to restructure from even higher quality and reliability of the manufacturers.  From the OEE-analysis of grinders machine available data and information on the reasons for include machine downtime. Through the analysis of the measurement results are obtained for the continued improvement of the grinding machine increase utilization and thus secure future production volumes.  The project undertaken was OEE-analysis of grinding machines and it has worked out well. The results that come up have led to what has previously been indications to low utilization now has been measured and documented.  Recommendation to SG is to work with preventive maintenance to have a uneven get a smoother production, a custom orders to the grinders operator are allocated to plots the day before. Order shall be within a reasonable production capacity and with the utmost focus on quality.

  • 44.
    Babu Surreddi, Kumar
    et al.
    Dalarna University, Falun, Sweden.
    Oikonomou, Christos
    Uddeholms AB, Sweden.
    Karlsson, Patrik
    Örebro University, School of Science and Technology.
    Olsson, Mikael
    Dalarna University, Falun, Sweden.
    Pejryd, Lars
    Örebro University, School of Science and Technology.
    In-situ Micro-tensile Testing of Additive Manufactured Maraging Steels in the SEM: Influence of Build Orientation, Thickness and Roughness on the Resulting Mechanical Properties2017Conference paper (Refereed)
    Abstract [en]

    Selective laser melting (SLM) is frequently used additive manufacturing technique capable of producing various complex parts including thin-wall sections. However the surface roughness is a limiting factor in thin sections produced by SLM process when strength is the main criterion. In this study, the influence of build orientation, thickness and roughness on the resulting mechanical properties of as-built test samples was investigated. Various thin sheets of EN 1.2709 maraging steel built in horizontal and vertical orientations produced by SLM were investigated using in-situ micro-tensile testing in a scanning electron microscope. The mechanical strength and deformation mechanisms were analyzed and explained based on thickness and build orientation. Increased ductility was observed in thicker samples as well as in the horizontal build samples. The results illustrate the potential of the in-situ test technique and aspects important to consider in design guidelines for thin AM structures.

  • 45.
    Bark, Alexander
    et al.
    Örebro University, School of Science and Technology.
    Hygerth, Fredrik
    Örebro University, School of Science and Technology.
    Söka en signifikant skillnad huruvida skadeutvecklingen skiljer mellan punktlast och utbredd last inom pappersteknik2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Thesis work performed on behalf of BillerudKorsnäs AB, the project is part of a larger research project which the company works with. BillerudKorsnäs would like to provide the optimum material for the cartonboard that the customer seeks. This report deals with the problem of whether the fracture development differs between the point load and distributed load in paper technology. To limit the scope of the project, five spherical loads were chosen to attack a total of four selected panels. The four panels are specifically selected and divided into two geometrically distinct cartonboards but with the same quality. The project investigated parameters structural stiffness and structural strength from the unloaded condition to initial damage development in cartonboards. The results from the tests will be presented inaquantitative analysis of compiled charts, force-/extension charts and qualitative analysis of fracture development. The purpose of the project, the significant difference, was found in the result when the structural stiffness increased nonlinearly when tested with certain loads. The project presents a conclusion that the load 1-3 is point load and load 5 is distributed load on all panels. The project presents a basis for further development towards the final goal that BillerudKorsnäs is working toward.

  • 46.
    Basic, Mehmed
    Örebro University, School of Science and Technology.
    Specifikation av OP-tid (Operation Time)2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this technical thesis is to investigate different methods and tools to measure the OP time (operating time). Ericsson is headquartered in Stockholm,and is divided into different departments, these department’s together has approximately 10 000 employees who is specializedin their areas. The focus of this technical report has been to investigate the questions like, what is OP time, is there a way to measure the OP time.The Department that is the focus of this project produces filters for radio base stations. This should be viewed both from a financial and engineering perspective. This examine will give an explanation on what the OP time is in a test lab environment and to give suggestions on how to measure the OP time. Time is money which means that a separation between OP time and other time will lower the unnecessary costs. By establishing "clean" OP time apart from other time, obtains the actual cost of the product. In theory section Lean production and JIT (just in time) and its grounds will be described. The idea is to compare a volume business with a prototype business, and thereafter focus on the prototype business, specifically on its problem areas and solutions.

  • 47.
    Bengtsson, Per
    et al.
    Örebro University, School of Science and Technology.
    Fransson, Martin
    Örebro University, School of Science and Technology.
    Ställtidsreducering vid orderbyte: En fallstudie på Millcon AB2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Millcon AB is a company that performs a service which is roll converting of paper. The company has recently noticed that their production waste a lot of time between orders due to mandatory setup activities, when a change of order in their rolling machines needs to be done. This leads to reduced production, which consequently contributes to reduced profitability for the company. This thesis will generate comprehensive data consisting of suggestions for improvement for the company to reduce setup time at one of their machines, but the suggestions for improvement can be used on all the machines that the company possess if certain modifications are made. The SMED method has been the main basis of the literature study which have been required to accomplish this thesis. The thesis began with a survey of how the conversion work is carried out at the present time, the survey was done with the help of video filming and interviews. Then several improvements which consisted of various opportunities to improve efficiency of the conversion process was made. The thesis concludes with a discussion of whether the streamlining suggestions that emerged are credible to generate a more time efficient approach for the company’s setup activities. The discussion then results in a number of finding conclusions, the conclusions are expected to provide Millcon a basis for their further improvement of their setup activities between orders.

  • 48.
    Berg, Niklas
    et al.
    Örebro University, School of Science and Technology.
    Persson, Isac
    Örebro University, School of Science and Technology.
    Jämförelse mellan två metoder för mätning av kartongförpackningars greppstyvhet2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This Bachelor’s thesis is a collaborated work done between the paper manufacturer BillerudKorsnäs and Örebro University, within the research project "A New Model for Deformation of Carton Board Packages by Manual Handling". The aim of this work is to test and evaluate two methods regarding their ability to determine grip stiffness of cartonboard packages. This was achieved by analyzing how well each method was able to distinguish between various cartonboard qualities.

    The two methods that were compared were: box compression tests performed by a Lloyd Instrument LR5K tensile testing unit, and BioTac which is a finger-like tactile sensory device made by Syntouch LLC.

    About 120 box compression tests, with varying sphere sizes, were performed on cartonboard packages supplied by BillerudKorsnäs. Statistical methods were then applied to the data from these tests in order to see whether this method was able to distinguish between the different cartonboard materials.

    A member of the research project had previously performed experiments using the BioTac on the same types of packages. Data from those experiments underwent the same statistical tests. The results from the two methods could thus be compared.

    Albeit being able to distinguish maximum stiffnesses between the cartonboard materials for arbitrary forces, the box compression method failed at this endeavor for fixed low forces. The BioTac, however, showed better results in that regard.

  • 49.
    Bergendahl, Fredrik
    Örebro University, School of Science and Technology.
    RENODLA FLÖDET FÖR POWERTRONIC TRANSMISSIONENS ARTIKLAR2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Powertronic department at Volvo Powertrain, Köping manufactures and assembles automatic transmission called Powertronic and is primarily used in construction equipment. The manufacturing of parts for the gearbox has been the same in terms of layout and article flow point since the start of the department. The demand on the gearbox becomes more and more important due to price and quality, this results in the desire to be able to control and manage the time of how long the details are in manufacturing before assembly. It is difficult to achieve this because spare parts and prototypes are produced in the same machines and the workflow contains sections that are slow and difficult to assume the amount of time.

     

    The idea behind this study is to verify which of all the details that belong to the Powertronic gearbox and make a new flow of articles. The goal is to make it easier to manage and control the manufacturing time of articles and get exact value of this, resulting in reduced inventory and more profit. To achieve the desired results, analysis of flow and calculations of the differences between for and after a new flow and layout was implemented.

     

    The results show that improvements can be done for instance the production time of an article can be reduced by days. To get a new flow of articles requires some initial investments, most can be done with existing equipment.

     

    The recommendation is to place the new multi-tasking machine by following the proposal in this study and secondly to obtain a balancing equipment. 

  • 50.
    Bergman, Christian
    Örebro University, School of Science and Technology.
    How Lean is Swedish Product Development?: A study of Lean practices in large Swedish companies2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    This master’s thesis aims to capture the essence of Lean Product Development and to evaluate to what extent Swedish companies have implemented lean principles. Previous studies in this field exemplify how methods are used by already lean practitioners, and there is a lack ofknowledge about the extent to which lean in is used in product development in industry.

    A literature review reveals a number of principles and perspectives; 5 Lean principles, 13 Lean Product Development principles, 14 Lean Management principles and 4 critical factors for Lean (or Knowledge-based) Product Development. These principles and perspectives were the starting point in developing the survey questions.

    The survey of 26 questions was sent to 67 large Swedish companies (more than 249 employees) working with product development and design. The response rate of 39 per centwas unusually high for this type of internet survey.

    The main results of the survey are that Lean methods and tools are rather extensively used in product development, but the culturehas yet not permeated the entire company. The workload of the product developmentdepartment is too high and a structured method for organizational learning is lacking.

    Recommendations for the studied companies are to reduce the workload and increase thetime for reflection, learning and process improvement. Also, the capability to implement strategies can be improved.

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