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  • 101.
    Eriksson, Matilda
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Samuelsson, Andreas
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Framgångsfaktorer inom partneringanbud: en fallstudie utförd på Peab i Trollhättan2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Peab in Trollhättan have in recent years completed more and more constructions projects in the form of partnering. Partnering means that the buyer mutually plans and implements the project together with the builder. Procurement of partnering projects are done by evaluation of proposals and Peab feels that there are underlying factors for why the proposals win or lose. The aim for this thesis was to present a supportive basis for Peabs proposal process and to increase the possibility of influence the outcome. Method for the study was case study which gave opportunity for deeper knowledge within the area. Through interviews with six buyers and one educator qualitative data could be gathered. Qualitative data was also collected from analysis of former requests for proposals (RFP) from buyers. The current situation analysis was performed with an employee from Peab. During the interviews with buyers and the educator it was confirmed that partnering lacks a definition and a common meaning. There was, on the other hand, a common perception of what partnering is. The buyer’s interpretation and knowledge of partnering can affect the valuation of proposals. Buyers who have knowledge and competence of what partnering is ensures that the request for proposals is based on demanded needs and conditions. As per the buyers, the most difficult part of the evaluation was the interview, since it is subjective evaluation. A balance in knowledge and competence for partnering between the actors would contribute to a more stable process and minimize uncertainty. It is not only the builders proposals process that need to be improved, but also the buyer´s understanding for the evaluation model and demands. Peab ought to implement a process for evaluating contract award decisions. It will generate possibility to improve the proposal process and to develop its activities. The study has identified a number of factors for success to develop the proposal process and Peab should prioritize the following subjects: - Coordinate the knowledge and competence within the organization - Implement a process for evaluation of all contract award decisions - Prioritize the two initial parts of the proposal process  

  • 102.
    Eynian, Mahdi
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Analytical Stability Prediction in Five Axis Ball-End Milling2013In: Proceedings of the International Conference on Advanced Manufacturing Engineering and Technologies NEWTECH 2013 / [ed] Andreas Archenti and Antonio Maffei, Stockholm: KTH Royal Institute of Technology, 2013, p. 189-198Conference paper (Refereed)
    Abstract [en]

    In five axis ball-end milling, the cutting edge is a continuous curve and the engagement with workpiece changes as the cutting tool rotates. Therefore the sensitivity to vibration varies along the cutting edge and as the tool rotates. In this paper, the vibration-force relationship (VFR) is obtained for infinitesimal length of cutting edge as a function of tool’s rotation angle. Numerical integration results in the VFR of the whole cutting edge and the tool. VFR of the tool is coupled to the dynamic vibration model of the tool and the workpiece to predict the possibility of vibrational instability. This algorithm is then used to predict the effects of changing the lead angle in a test setup with a flexible depth of cut direction. The analytical results, along with experiments demonstrate that the large lead angles considerably improve the stability of the process.

  • 103.
    Eynian, Mahdi
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Effect of thin viscoelastic material treatments of the clamping region on dynamic stiffness of the cantilever beams2013In: Proceedings of the International Conference on Advanced Manufacturing Engineering and Technologies NEWTECH 2013: Volume 1 / [ed] Andreas Archenti and Antonio Maffei, Stockholm: KTH Royal Institute of Technology, 2013, p. 313-322Conference paper (Refereed)
    Abstract [en]

    Cantilever beams and similar structures are found in machining systems. Often a set of cantilever beams attached to each other on spindle-tool holder and tool holder-cutter interfaces position the cutting edge with respect to the workpiece. Small static stiffness leads to deformations and geometrical errors due to the process forces, while small dynamic stiffness initiates chatter vibrations. Dynamic stiffness of structures could be improved by passive or active damping methods. Passive damping methods are suitable design choices considering their low cost and ease of application. In this paper, the constrained layer damping (CLD) method is compared to the application of viscoelastic damper materials on the clamping region and the resulting improvements are compared in terms of enhancement of damping ratio and dynamic stiffness. The maximum enhancement of dynamic stiffness was 487% using a thick layer of viscoelastic material on the clamping region. The effect of the thickness of the viscoelastic material is also studied which shows a linear increase in dynamic stiffness as the thickness of the viscoelastic layer increases.

  • 104.
    Eynian, Mahdi
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Frequency Domain Study of Vibrations above and under Stability Lobes in Machining Systems2014In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 14, p. 164-169Article in journal (Refereed)
    Abstract [en]

    Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions.

  • 105.
    Eynian, Mahdi
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Selection of chatter-free milling conditions using vibration frequency measurements2016In: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings: 25th – 27th of October 2016, Lund: Swedish Production Academy , 2016, p. 1-6Conference paper (Refereed)
    Abstract [en]

    Unwanted vibration of the tool with respect to the workpiece, known as chatter, can damage machine tool, cutting tool, and the surface finish of the workpiece in a machining operation such a milling. These vibrations could be avoided by reducing the depth of cut, but this approach hurts the productivity and reduces material removal rate. Previous studies have established methods, known as stability prediction methods that provide that enable using large depth of cuts while avoiding chatter. The calculation of stability lobes commonly starts by measurement of dynamic properties of the machining structure. This paper investigates an alternative approach, in which vibration frequencies gathered during test cuts with the target machining system are used to identifying the modal parameters of the machining system in its operational condition. An earlier method that was based on a one dimensional dynamics model is modified to use relationships developed for a two dimensional model that describes the dynamics of spindles and tools with axisymmetric dynamics. This approach improves the stability lobe prediction considerably as shown in results.

  • 106.
    Fahlström, Karl
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Laser welding of boron steels for light-weight vehicle applications2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Laser beam welding has gained a significant interest during the last two decades. The suitability of the process for high volume production has the possibility to give a strong advantage compared to several other welding methods. However, it is important to have the process in full control since various quality issues may otherwise occur. During laser welding of boron steels quality issues such as imperfections, changes in local and global geometry as well as strength reduction can occur. The aspects that need to be considered are strongly depending on alloy content, process parameters etc. These problems that can occur could be fatal for the construction and the lowest level of occurrence is wanted, independent of industry.

    The focus of this study has been to investigate the properties of laser welded boron steel. The study includes laser welding of boron alloyed steels with strengths of 1500 MPa and a recently introduced 1900 MPa grade. Focus has been to investigate weldability and the occurrence of cracks, porosity and strength reducing microstructure that can occur during laser welding, as well as distortion studies for tolerances in geometry. The results show that both conventional and 1900 MPa boron alloyed steel are suitable for laser welding.

    Due to the martensitic structure of welds the material tends to behave brittle. Cracking and porosity do not seem to be an issue limiting the use of these steels. For tolerances in geometry for larger structures tests has been done simulating laser welding of A-pillars and B-pillars. Measurements have been done with Vernier caliper as well as a more advanced optical method capturing the movements during the welding sequence. Results from the tests done on Ushaped beams indicates that depending on the geometry of the structure and heat input distortions can be controlled to give distortions from 1 to 8 mm, at a welding length of 700 mm. This means that important geometry points can be distorted several millimeters if the laser welding process not is controlled.

  • 107.
    Fahlström, Karl
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West. Swerea KIMAB, Joining Technology, Kista, Sweden .
    Andersson, Oscar
    Volvo Cars, Torslanda; XPRES, KTH Royal Institute of Technology.
    Todal, Urban
    Volvo Cars, Torslanda.
    Melander, Arne
    Swerea KIMAB, Joining Technology, Kista; XPRES, KTH Royal Institute of Technology, Stockholm.
    Minimization of distortions during laser welding of ultra-high strength steel2014In: ICALEO 2014 Congress proceedings, 2014, p. 1-10Conference paper (Refereed)
    Abstract [en]

    Ultra high strength steels are frequently used within the automotive industry for several components. Welding of these components is traditionally done by resistance spot welding, but to get further productivity and increased strength, laser welding has been introduced in the past decades. Fusion welding is known to cause distortions due to built-in stresses in the material. The distortions result in geometrical issues during assembly which become the origin of low joint quality due to gaps and misfits.

    U-beam structures of boron steel simulating B-pillars have been welded with laser along the flanges. Welding parameters and clamping have been varied to create different welding sequences and heat input generating a range of distortion levels. The distortions have been recorded dynamically with an optical measurement system during welding. In addition, final distortions have been measured by a digital Vernier caliper. The combined measurements give the possibility to evaluate development, occurrence and magnitude of distortions with high accuracy. Furthermore, section cuts have been analyzed to assess joint geometry and metallurgy.

    The results shows that final distortions appear in the range of 0-8 mm. Distortions occur mainly transversely and vertically along the profile. Variations in heat input show clear correlation with the magnitude of distortions and level of joint quality. A higher heat input in general generates a higher level of distortion with the same clamping conditions. Section cuts show that weld width and penetration are significantly affected by welding heat input.

    The present study identifies parameters which significantly influence the magnitude and distribution of distortions. Also, effective measures to minimize distortions and maintain or improve joint quality have been proposed.

    Finally, transient FE simulations have been presented which show the behavior of the profiles during the welding and unclamping process.

  • 108.
    Fahlström, Karl
    et al.
    Swerea KIMAB.
    Andersson, Oscar
    KTH Royal Institute of Technology.
    Todal, Urban
    Volvo Car Corporation.
    Melander, Arne
    Swerea KIMAB.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Production Engineering.
    Karlsson, Leif
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Distortion Analysis in Laser Welding of Ultra High Strength Steel2014In: Proceedings of the 6th International Swedish Production Symposium 2014 / [ed] Stahre, Johan, Johansson, Björn & Björkman, Mats, 2014, p. 1-9Conference paper (Refereed)
    Abstract [en]

    Due to increased demands on reduced weight in automotive industries, the use of ultra high strength steels (UHSS) has increased. When laser welding UHSS sheets, heating and cooling of the material will cause geometrical distortions and may cause low joint quality. 700 mm long U-beam structures of 1 mm thick boron steel simulating structural pillars in body-in-white constructions have been welded along the flanges with different welding speeds to investigate distortions and weld quality. The results show that final distortions appear in the range of 0-8 mm. FE simulation methods have also been presented which generally predict the distribution of welding distortions.

  • 109.
    Fasth, Angelica
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Nylen, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Choi, B.
    Center for Theraml Spray Research, Stony Brook, New York.
    Klement, Uta
    Chalmers University.
    A Comparative studey of Mechanical Properties Between HVOF-spryed Maxphase Materials and Plasma Sprayed MCrAIY Coatings2009In: Surface Modification Technologies XXII: Proceedings of the Twenty Second International Conference on Surface Modification Technologies Held at University West, Trollhättan, Sweden September 22-24 2008 / [ed] T.S. Sudarshan & Per Nylen, VALAR Docs , 2009, p. 149-156Conference paper (Other academic)
  • 110.
    Fransson, William
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Svetsbarhetsutvärdering av ATI® 718Plus™: Inverkan av δ-fas2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    ATI® 718Plus™ is a newly developed nickel-based Superalloy. The predecessor, Alloy 718, have been used, among other things, in the turbine part of jet engines due to its ability to maintain its mechanical performance at high temperatures. As the temperature of the turbines is gradually raised to increase the combustion efficiency and reduce emissions, Alloy 718 have disclosed weaknesses. The alternative has been the more expensive alloy Waspaloy which unfortunately shown deficiencies when welded. Welding is a well-used method for this type of products. To replace the Alloy 718, ATI® 718Plus™ was developed as a more cost-effective alternative. Research on Superalloys is done continuously to see how these materials are affected by the extreme environments they are designed for.

    This work investigates how an increased amount of δ-phase affects the weldability of ATI® 718Plus™. δ-phase can transform from the strengthening phase γ" at prolonged exposure to high temperatures, when the alloy is solution heat treated repeatedly. This is expected to occur after repeated heat treatments, that is to say, when being repair welded. δ-phase positively affects the properties of alloys at small concentrations, but negative with more presence.

    The comparison is made between the ATI® 718Plus™ that has been solution heat treated in 954°C for 15 hours and 1 hour. Longer heat treatment results in an increased amount of δphase. Then a Varestraint weldability testing was carried out to compare the crack propagation at different strains. In order to increase the decision base, measurements of hardness and grain size are also implemented as this normally are important factors that affects the weldability. Investigation of microstructure and resulting cracks are carried out using microscopy.

    Weldability test shows an increased susceptibility to hot cracking with more presence of δ-phase. Because hardness and grain size differ minimally the δ-phase is assumed to negatively affect weldability. The hypothesis is that the δ-phase's ability to transform to Laves prompts the crack propagation in the heat-affected zone. The presence of Laves weakens the grain boundaries. This transformation is expected to take place at rapid heating during the welding process.

  • 111.
    Fredriksson, Fredric
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Optimering av skärande bearbetning för detalj tillverkad i höghållfast nickellegering2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The manufacturing industry is met today by increasing demands in regards to both efficient, economical methods for manufacture, as well as better precision. An effective means of meeting these demands is machining processes, such as turning and milling. However, in-creased demands for higher material removal rates (MRR) increase the risks that the ma-chining process is affected by problems as for instance vibrations, which have negative con-sequences on both quality and MRR. In addition, the use of difficult-to-machine materials, such as high-strength nickel-alloys, is increasing. A good knowledge-base of the properties of such materials is required to be able select the correct tools and cutting parameters in order to machine them effectively.

    In this report, the possibilities of reducing tool wear and generating optimized cutting pa-rameters for the processing of a part manufactured from high-strength nickel-alloy was explored. One specific milling operation was examined in regards to vibration problems, tools used and cutting parameters.

    The vibration analysis performed on the tool machine and part was based on the method for vibration prevention developed by prof. Altintas, in which areas of stable, vibration free ma-chining can be identified by performing modal analysis of the machining system.

    Additionally, the tool material and geometry was studied in order to determine suitable tools for the operation as well as determining sets of machining conditions where different tools could be used.

    Analysis of the results in this report shows that the machining operation currently takes place in vibration free conditions. The high rate of tool wear seems to be a result of the poor machinability of the part material. However, suggestions for changes to the cutting parame-ters has been generated that may have a positive impact on the cutting process.

  • 112.
    Fuente, Raquel
    et al.
    IK4-LORTEK, Ordizia, Spain.
    García de la Yedra, Aitor
    IK4-LORTEK, Ordizia, Spain.
    Beizama, Ane Miren
    IK4-LORTEK, Ordizia, Spain.
    Fernández, Erik
    IK4-LORTEK, Ordizia, Spain.
    Gorostegui Colinas, Eider
    IK4-LORTEK, Ordizia, Spain.
    Echeverria, Alberto
    IK4-LORTEK, Ordizia, Spain.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Thorpe, Nigel
    Tecnitest ingenieros, Madrid, Spain.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Automation Systems.
    Henrikson, Per
    GKN Aerospace Engine Systems Sweden, Trollhättan, Sweden.
    Development and demonstration of an automated system for limited access weld inspection by using infrared active thermography2015In: Proceedings 7th International Symposium on NDT in Aerospace, Berlin, 2015, p. 1-8Conference paper (Refereed)
    Abstract [en]

    Weld inspection for surface breaking defects detection has been traditionally performed by using NDT methods such as Fluorescent PenetrantInspection (FPI), Visual Inspection (VI) or Eddy Currents (EC). All those well known techniques have as common drawback the need of skilled operator intervention in order to analyse obtained results. In the specific case of inspection of welds with limited access, the application of those traditional methods is even more complex, thus increasing inspection time and reducing the defect detection capability. Therefore, the development of a fully automated non-contact method overcoming these limitations is desired. Active thermography (IRT) represents one of the most promising techniques for replacing traditional techniques for surface breaking defect detection in welds.This technique makes use of an excitation source in order to heat the sample undertest and an infrared camera for thermal evolution monitoring. With the combination of these excitation-monitoring techniques, heterogeneities in the heat flow caused bysurface breaking cracks can be detected. In this work, a robotic solution was developed and demonstrated for the inspection of welds with real cracks in a representative environment with limited access. The system consists of a continuous laser-line excitation source together with a FLIR SC 655 micro bolometer thermographic camera. In order to access limited areas, two different aluminium polished mirrors have been used for bothinfrared radiation monitoring and laser excitation respectively. The inspection results, analysis and comparison with traditional methods will be shown.

  • 113.
    Ganvir, Ashish
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Comparative analysis of Thermal Barrier Coatings produced using Suspension and Solution Precursor Feedstock2014Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The research work performed in this thesis has been carried out at the Production Tech-nology Centre where the Thermal Spray research group of University West has its work-shop and labs.

    This research work has been performed in collaboration with the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad, India.

    First of all, I would like to express my sincere thanks and gratitude to my supervisors Dr. Nicolaie Markocsan and Dr. Nicholas Curry for their guidance, great support and valuable suggestions without which this work could not have been possible. I would also like to thanks Prof. Per Nylén for keeping faith in me and providing me an opportunity to work at PTC, which is a great place to perform research. It is my pleasure being their student and I wish I would keep learning from all of them, both on academic and personal grounds. I would also like to thank my colleagues at PTC Mr. Mohit Gupta and Mr. Stefan Björklund, for their help and support during this work.

    I would like to acknowledge the H.C. Starck Company for its financial support for the pro-ject; Dr. Filofteia-Laura TOMA at Fraunhofer IWS, Dresden to help us in spraying suspen-sion sprayed YSZ top coats, G Shivkumar from ARCI to help us in spraying solution pre-cursor sprayed top coats and Toni Bogdanoff, Jönköping University to help us in conduct-ing the LFA experiment

  • 114.
    Gao, Jiaming
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Industrial robot motion control for joint tracking in laser welding2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Laser welding is used in modern industrial production due to its high welding speed and good welding performance comparing to more traditional arc welding. To improve the flex-ibility, robots can be used to mount the laser tool. However, laser welding has a high require-ment for the accuracy in positioning the laser tool. There are three main related variables which affect the laser welding accuracy: robot path accuracy, workpiece geometry and fixture repeatability. Thus, joint tracking is very important for laser welding to achieve high quality welds.

    There are many joint tracking systems which were proposed in recent years. After receiv-ing the joint information, a control system is necessary to control the robot motion in real-time. The open control system for the industrial robot is one trend for the future. A lot of methods and systems are proposed to control the robot motion. Some systems can achieve a high accuracy in the experiments. However, it is still hard to apply them in practical indus-trial production. Thus more commercial solutions appear to overcome the robot motion problem nowadays. They are very useful to realize practical applications.

    ABB EGM path correction module, a new function of Robotware, is one of the com-mercial solutions for robot motion control in real time. In the experiments presented in this work, a computer is used to simulate a sensor to create a path correction signal.

    To test its feasibility for the laser welding application, many experiments are conducted. One was to test the robot path repeatability when there is no correction message sent to the robot. Another was to test the level of accuracy EGM can achieve during the correction process. Different types of paths and three different speeds were separately carried out. The results showed that it is possible to use the EGM in the laser welding application. In the EGM feasibility test, there exists deviation in the z-direction. Since these deviations are less than 0.2mm, it will have a minor influence the laser welding performance, implying that the EGM path correction can be applied in practical production.

  • 115.
    Garcia de la Yedra, Aitor
    et al.
    Control and Evaluation, IK4-LORTEK; Arranomendia Kalea 4A, Ordizia, Spain.
    Fernandez, Erik
    Control and Evaluation, IK4-LORTEK; Arranomendia Kalea 4A, Ordizia, Spain.
    Beizama, Ane Miren
    Control and Evaluation, IK4-LORTEK; Arranomendia Kalea 4A, Ordizia, Spain.
    Fuente, R.
    Control and Evaluation, IK4-LORTEK; Arranomendia Kalea 4A, Ordizia, Spain.
    Echeverria, A.
    Control and Evaluation, IK4-LORTEK; Arranomendia Kalea 4A, Ordizia, Spain.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Automation Systems.
    Henrikson, Per
    GKN Aerospace Engine Systems.
    Defect strategies in Nickel Superalloys weld using active thermography2014In: 12th International Conference on Quantitative InfraRed Thermography, 7-11/7 Bordeaux, 2014, p. 1-9Conference paper (Refereed)
    Abstract [en]

    As a result of extreme operation conditions in gas turbines, high resistance materials with excellent behaviour at high temperature are required. Alloys, such as MarM-247 nickel based superalloy, with excellent mechanical properties at very high temperature (even at 85 % of their melting point) are being used in these applications. This extraordinary behaviour is mainly due to the presence of a strengthening phase (γ’) with the following chemical composition: Ni3(Al, Ti). However, during welding these materials are susceptible to cracking and this is why weld inspections become crucial. In this work different strategies for defect detection in welds are introduced, all of them based on active thermography. The work covers aspects such as different excitation and data evaluation strategies.

  • 116.
    Gislén, Linda
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Alternative design of robot cell concepts for flexible production2016Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Flexible manufacturing is something that most companies is aiming to accomplish due to the increased demand for variety and a competitive global market.

    This thesis report includes an introduction to the automation concept and the development towards flexible automation. A general flexible assembly cell is presented and its content and requirements are discussed. The work has been done with focus on an assembly process with dedicated fixtures at VCE (Volvo Construction Equipment).

    Based on the literature review and the general example, a list of actions to take while planning and implementing a process is developed. The actions roughly include: mapping of the process, defining goals, investigation of automation level, holistic view while planning, definition of the need for flexibility, investment plan, designing and comparing concepts, investigation of possible issues and implementation in small scale.

    The current manual process at VCE is presented and analysed. Three concepts are designed with product flexibility as an alternative to processes in which traditional dedicated fixtures are used. The designed concepts are a fully automated concept, a hybrid concept with separated workspace and a human-robot collaboration.

    Finally, the concepts are analysed and compared based on following parameters: productivity, product cost, investment, flexibility, space requirement and setup time. One final comparing summary of the concepts is done. The analysis shows that a fully automated concept is to prefer in this case. However, a human-robot collaboration could be appropriate to use if the process is expected to improve with the human workforce. Examples of when it could be reasonable to use human-robot collaboration despite this are: if the task provides better quality when conducted by human or if the task is complex to automate.

  • 117.
    Gislén, Linda
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Agell, Ulrica
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Flödesanalys av orderhantering vid SKF Logistics Services Sweden2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the thesis is to provide SKF Logistics Services Sweden, within Customer Services and Warehousing, with an analysis of the actual process and improvement suggestions to reduce late invoicing. The objective of the thesis contain a mapping of the process, identified parameters that affect late invoicing, reduce non-value added activities and improvement proposals to keep the internal invoice deadline.According to DMAIC, which was used as a method to analyse the qualitative and quantitative data, the most broken deadlines occur to the container traffic. That became the focus of the investigation. Further analysis led to the conclusion that the orders are not packed by Warehousing on time. It was decided to address that as a main problem to improve on.Quality tools were used to find root causes and improvements. The improvements were evaluated and two main improvements were chosen. Organisational improvements on how to work with process improvements are proposed. It contain working with PDCA, standardisation, decision making and measurements. A process improvement for Warehousing are proposed which contain segmentation of articles, letting the bottleneck limit the throughput and prioritisation of assignments.

  • 118.
    Glorieux, Emile
    University West, Department of Engineering Science, Division of Automation Systems.
    Constructive cooperative coevolution for optimising interacting production stations2015Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Engineering problems have characteristics such as a large number of variables, non-linear, computationally expensive, complex and black-box (i.e. unknown internal structure). These characteristics prompt difficulties for existing optimisation techniques. A consequence of this is that the required optimisation time rapidly increases beyond what is practical. There is a needfor dedicated techniques to exploit the power of mathematical optimisation tosolve engineering problems. The objective of this thesis is to investigate thisneed within the field of automation, specifically for control optimisation ofautomated systems.The thesis proposes an optimisation algorithm for optimising the controlof automated interacting production stations (i.e. independent stations thatinteract by for example material handling robots). The objective of the optimisation is to increase the production rate of such systems. The non-separable nature of these problems due to the interactions, makes them hard to optimise.The proposed algorithm is called the Constructive Cooperative CoevolutionAlgorithm (C3). The thesis presents the experimental evaluation of C3, bothon theoretical and real-world problems. For the theoretical problems, C3 istested on a set of standard benchmark functions. The performance, robustness and convergence speed of C3 is compared with the algorithms. This shows that C3 is a competitive optimisation algorithm for large-scale non-separable problems.C3 is also evaluated on real-world industrial problems, concerning thecontrol of interacting production stations, and compared with other optimisation algorithms on these problems. This shows that C3 is very well-suited for these problems. The importance of considering the energy consumption and equipment wear, next to the production rate, in the objective function is also investigated. This shows that it is crucial that these are considered to optimise the overall performance of interacting production stations.

  • 119.
    Glorieux, Emile
    University West, Department of Engineering Science, Division of Production System.
    Multi-Robot Motion Planning Optimisation for Handling Sheet Metal Parts2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Motion planning for robot operations is concerned with path planning and trajectory generation. In multi-robot systems, i.e. with multiple robots operating simultaneously in a shared workspace, the motion planning also needs to coordinate the robots' motions to avoid collisions between them. The multi-robot coordination decides the cycle-time for the planned paths and trajectories since it determines to which extend the operations can take place simultaneously without colliding. To obtain the quickest cycle-time, there needs to bean optimal balance between, on the one hand short paths and fast trajectories, and on the other hand possibly longer paths and slower trajectories to allow that the operations take place simultaneously in the shared workspace. Due to the inter-dependencies, it becomes necessary to consider the path planning, trajectory generation and multi-robot coordination together as one optimisation problem in order to find this optimal balance.This thesis focusses on optimising the motion planning for multi-robot material handling systems of sheet metal parts. A methodology to model the relevant aspects of this motion planning problem together as one multi-disciplinary optimisation problem for Simulation based Optimisation (SBO) is proposed. The identified relevant aspects include path planning,trajectory generation, multi-robot coordination, collision-avoidance, motion smoothness, end-effectors' holding force, cycle-time, robot wear, energy efficiency, part deformations, induced stresses in the part, and end-effectors' design. The cycle-time is not always the (only) objective since it is sometimes equally/more important to minimise robot wear, energy consumption, and/or part deformations. Different scenarios for these other objectives are therefore also investigated. Specialised single- and multi-objective algorithms are proposed for optimising the motion planning of these multi-robot systems. This thesis also investigates how to optimise the velocity and acceleration profiles of the coordinated trajectories for multi-robot material handling of sheet metal parts. Another modelling methodology is proposed that is based on a novel mathematical model that parametrises the velocity and acceleration profiles of the trajectories, while including the relevant aspects of the motion planning problem excluding the path planning since the paths are now predefined.This enables generating optimised trajectories that have tailored velocity and acceleration profiles for the specific material handling operations in order to minimise the cycle-time,energy consumption, or deformations of the handled parts.The proposed methodologies are evaluated in different scenarios. This is done for real world industrial case studies that consider the multi-robot material handling of a multi-stage tandem sheet metal press line, which is used in the automotive industry to produce the cars' body panels. The optimisation results show that significant improvements can be obtained compared to the current industrial practice.

  • 120.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Automation Systems.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Automation Systems. Chalmers University of Technology, Department of Signals and Systems, Gothenburg, Sweden.
    Constructive cooperative coevolutionary optimisation for interacting production stations2015In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 78, no 1-4, p. 673-688Article in journal (Refereed)
    Abstract [en]

    Optimisation of the control function for multiple automated interacting production stations is a complex problem, even for skilled and experienced operators or process planners. When using mathematical optimisation techniques, it often becomes necessary to use simulation models to represent the problem because of the high complexity (i.e. simulation-based optimisation). Standard optimisation techniques are likely to either exceed the practical time frame or under-perform compared to the manual tuning by the operators or process planners. This paper presents the Constructive cooperative coevolutionary (C3) algorithm, which objective is to enable effective simulation-based optimisation for the control of automated interacting production stations within a practical time frame. C3 is inspired by an existing cooperative coevolutionary algorithm. Thereby, it embeds an algorithm that optimises subproblems separately. C3 also incorporates a novel constructive heuristic to find good initial solutions and thereby expedite the optimisation. In this work, two industrial optimisation problems, involving interaction production stations, with different sizes are used to evaluate C3. The results illustrate that with C3, it is possible to optimise these problems within a practical time frame and obtain a better solution compared to manual tuning.

  • 121.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Franciosa, Pasquale
    University of Warwick, Warwick Manufacturing Group, CV4 7AL Coventry, UK.
    Ceglarek, Darek
    Warwick Manufacturing Group, University of Warwick, CV4 7AL Coventry, UK.
    End-effector design optimisation and multi-robot motion planning for handling compliant parts2018In: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 57, no 3, p. 1377-1390Article in journal (Refereed)
    Abstract [en]

    The deformation of compliant parts during material handling is a critical issue that can significantly affect the productivity and the parts' dimensional quality. There are multiple relevant aspects to consider when designing end-effectors to handle compliant parts, e.g. motion planning, holding force, part deformations, collisions, etc. This paper focuses on multi-robot material handling systems where the end-effector designs influence the coordination of the robots to prevent that these collide in the shared workspace. A multi-disciplinary methodology for end-effector design optimisation and multi-robot motion planning for material handling of compliant parts is proposed. The novelty is the co-adaptive optimisation of the end-effectors' structure with the robot motion planning to obtain the highest productivity and to avoid excessive part deformations. Based on FEA, the dynamic deformations of the parts are modelled in order to consider these during the collision avoidance between the handled parts and obstacles. The proposed methodology is evaluated for a case study that considers the multi-robot material handling of sheet metal parts in a multi-stage tandem press line. The results show that a substantial improvement in productivity can be achieved (up to 1.9%). These also demonstrate the need and contribution of the proposed methodology.

  • 122.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Automation Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Automation Systems. Department of Signals and systems, Chalmers University of Technology.
    Improved Constructive Cooperative Coevolutionary Differential Evolution for Large-Scale Optimisation2016In: Computational Intelligence, 2015 IEEE Symposium Series on, IEEE, 2016, p. 1703-1710, article id 7376815Conference paper (Refereed)
    Abstract [en]

    The Differential Evolution (DE) algorithm is widely used for real-world global optimisation problems in many different domains. To improve DE's performance on large-scale optimisation problems, it has been combined with the Cooperative Coevolution (CCDE) algorithm. CCDE adopts a divide-and-conquer strategy to optimise smaller subcomponents separately instead of tackling the large-scale problem at once. DE then evolves a separate subpopulation for each subcomponent but there is cooperation between the subpopulations to co-adapt the individuals of the subpopulations with each other. The Constructive Cooperative Coevolution (C3DE) algorithm, previously proposed by the authors, is an extended version of CCDE that has a better performance on large-scale problems, interestingly also on non-separable problems. This paper proposes a new version, called the Improved Constructive Cooperative Coevolutionary Differential Evolution (C3iDE), which removes several limitations with the previous version. A novel element of C3iDE is the advanced initialisation of the subpopulations. C3iDE initially optimises the subpopulations in a partially co-adaptive fashion. During the initial optimisation of a subpopulation, only a subset of the other subcomponents is considered for the co-adaptation. This subset increases stepwise until all subcomponents are considered. The experimental evaluation of C3iDE on 36 high-dimensional benchmark functions (up to 1000 dimensions) shows an improved solution quality on large-scale global optimisation problems compared to CCDE and DE. The greediness of the co-adaptation with C3iDE is also investigated in this paper.

  • 123.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production System.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production System.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production System. Department of Signals and Systems, Chalmers University of Technology,Gothenburg, Sweden.
    Multi-objective constructive cooperative coevolutionary optimization of robotic press-line tending2017In: Engineering optimization (Print), ISSN 0305-215X, E-ISSN 1029-0273, Vol. 49, no 10, p. 1685-1703Article in journal (Refereed)
    Abstract [en]

    This article investigates multi-objective optimization of the robot trajectories and position-based operation-coordination of complex multi-robot systems, such as press lines, to improve the production rate and obtaining smooth motions to avoid excessive wear of the robots’ components. Different functions for handling the multiple objectives are evaluated on realworld press lines, including both scalarizing single-objective functions and Pareto-based multi-objective functions. Additionally, the Multi-Objective Constructive Cooperative Coevolutionary (moC3) algorithm is proposed, for Pareto-based optimization, which uses a novel constructive initialization of the subpopulations in a co-adaptive fashion. It was found that Paretobased optimization performs better than the scalarizing single-objective functions. Furthermore, moC3 gives substantially better results compared to manual online tuning, as currently used in the industry. Optimizing robot trajectories and operation-coordination of complex multi-robot systems using the proposed method with moC3 significantly improves productivity and reduces maintenance. This article hereby addresses the lack of systematic methods for effectively improving the productivity of press lines.

  • 124.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Automation Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Manufacturing Processes. Chalmers.
    Optimised Control of Sheet Metal Press Lines2014In: Proceedings of the 6th International Swedish Production Symposium 2014 / [ed] Stahre, Johan, Johansson, Björn & Björkman, Mats, 2014, p. 1-9Conference paper (Refereed)
    Abstract [en]

    Determining the control parameters for sheet metal press lines is a large scale and complex optimisation problem. These control parameters determine velocities, time constants, and cam values of critical interactions between the equipment. The complexity of this problem is due to the nonlinearities and high dimensionality. Classical optimisation techniques often underperform in solving this kind of problems within a practical timeframe. Therefore, specialised techniques need to be developed for these problems. An existing approach is simulation-based optimisation, which is to use a simulation model to evaluate the trial solutions during the optimisation. In this paper, an efficient simulation-based optimisation algorithm for large scale and complex problems is proposed. The proposed algorithm extends the cooperative coevolutionary algorithm, which optimises subproblems separately. Hence, the optimisation problem must be decomposed into subproblems that can be evaluated separately. To optimise the subproblems, the proposed algorithm allows using embedded deterministic algorithms, next to stochastic genetic algorithms, getting the flexibility of using either type. It also includes a constructive heuristic that creates good initial feasible solutions to expedite the optimisation. The extension enables solving complex, computationally expensive problems efficiently. The proposed algorithm has been applied on an automated sheet metal press line from the automotive industry. The objective is to find control parameters that maximise the line’s production rate. The results show that the proposed algorithm manages to find optimal control parameters efficiently within the practical timeframe. This is a step forward in press line optimisation since to the authors’ knowledge this is the first time a press line has been optimised efficiently in this way.

  • 125.
    Goel, Sneha
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Hybrid powder-suspension plasma spraying for diverse function-dependent coating architectures2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Suspension Plasma Spraying (SPS) is an emerging plasma spray technique which overcomes the difficulties typically associated with feeding of fine powders (submicron or nano-sized) in conventional Atmospheric Plasma Spraying (APS) to develop interesting microstructural features for varied engineering applications, such as wear resistance, corrosion/oxidation protection, thermal barrier, etc. Another breakthrough in plasma spraying pertains to the advent of systems that allow axial injection of feedstock which considerably improves thermal exchange between the plasma plume and the injected feedstock, thereby enabling substantial enhancement in deposition rates/efficiency.

    The present study utilizes both the above advances in plasma spraying to demonstrate the ability to deposit various function-dependent coating architectures by sequential/simultaneous axial injection of both powder and a suspension feedstock, henceforth referred to as hybrid plasma spray. The results amply demonstrate the flexibility and versatility of the hybrid spray process for production of superior function dependent coating architectures. Sim-ultaneous injection of the two feedstocks to form composite coatings, which is the most challenging from a processing standpoint as it requires identification of a process window which is suitable for both powder and suspension, was investigated in particular detail using deposition of Al2O3-YSZ composites as a case study. Composite coating architectures produced by hybrid spraying showed good homogeneity and the microstructure of the coating was characterized by presence of multi-scale features attributable to co-deposition of powder (micron-sized Al2O3) and suspension (involving fine YSZ powder) feedstock.

    In order to better understand the role of particle size and the implications of a distributed second phase on the tribological behavior of coatings, properties of the above mentioned powder-suspension hybrid coatings were also comprehensively compared with (a) Al2O3 coatings deposited using powder (b) Al2O3 coatings deposited using suspension and (c) Al2O3-YSZ coatings deposited using both constituents as suspensions. It has been observed that fine particle size of the feedstock leads to improved tribological performance of the coating in comparison with micron-sized powder feed-stock. In addition, introduction of fine second phase into conventional coating using the hybrid approach has shown significant improvement in tribological response of the conventional coatings. However introduction of fine second phase in a fine structured coating matrix showed negligible effect on the tribological response of the coating.

  • 126.
    Gokavarapu, Naga Sai Pavan Rahul
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Termisk cyklisk utmattning studie av Gd2Zr2O7 / YSZ flerskikts termiska barriärbeläggningar2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    From many years YSZ is used as the top coat material for TBC's, as it has good phase stability up to 1200°C, higher fracture toughness, lower thermal conductivity, erosion resistance & higher coefficient of thermal expansion. But, it has a drawbacks at high temperature such as sintering and transformation of phases. For this reason new ceramic materials with pyrochlores crystal structure such as Gd2Zr2O7 are being considered as it has high melting points, phase stability, lower thermal conductivity and CMAS resistance. But it has low fracture toughness when compared to YSZ. In order to take advantage of low thermal conductivity and high thermal stability of gadolinium zirconate and avoiding the drawbacks of low coefficient of thermal expansion and low toughness using YSZ, a double/multi-layer coatings approach is being used. Therefore, multi-layer TBCs are sprayed and compared with single layer coating in this work. These coatings are processed by suspension plasma spraying. For single layer coating YSZ is used, for double layer coating YSZ as the intermediate coating and Gd2Zr2O7 as the top coat is used. Additionally, a triple layer coating system comprising YSZ, Gd2Zr2O7 and dense Gd2Zr2O7 as top coat is also sprayed. The as sprayed coatings are characterized for microstructure analysis using optical microscope and scanning electron microscope (SEM), elemental analysis of TGO using Energy-Dispersive Spectrometer (EDS). XRD analysis was done to identify various phases in the coating. Porosity analysis using Archimedes principle was carried out. Thermal cyclic fatigue (TCF) test of the sprayed coatings was carried out at 1100°C. Failure analysis of the TCF specimens was carried out using SEM/EDS. TCF results showed that the triple layer coatings (dense Gd2Zr2O7/Gd2Zr2O7/YSZ) had higher thermal cyclic fatigue life and lower TGO thickness when compared to single layer (YSZ) and double layer (Gd2Zr2O7/YSZ) TBCs.

  • 127.
    Granlund, Erik
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Framtagning av koncept för tryckindikator och informationsöverföring för luftaxel2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of the project has been to develop a concept for both indicating the pressure level in the rolling axle hoses and for transferring this information from the rotating shaft to non-rotating machine parts. The report's literature study describes sensor technology and information-transferring-techniques for non-stationary objects. Study visits and interviews have been made to pay attention to the demands and expectations of future stakeholders on the product. During the concept generation phase, several methods have been used, including function trees and investigations of patents. A total of 21 concepts were generated. During the concept screening and concept scoring phase, an independent engineering student has been used for feedback. A cost analysis based on estimates for the sub-concepts has been carried out before the concept selection. The work resulted in a total of four subconcepts. Two sub-concepts for pressure indication and two sub-concepts for information transfer. Prior to final conceptual selection, more assessment steps should be performed, for example, subcontractors should be contacted regarding quotation requests and a FMEA should be created.

  • 128.
    Gråsjö, Urban
    University West, Department of Economics and IT, Division of Law, Politics and Economics.
    Accessibility to R&D and Patent Production2005Report (Other academic)
    Abstract [en]

    The main purpose in this paper is to study to what extent accessibility to R&D can explain patent production. Therefore a knowledge production function is estimated both on aggregated level and for different industrial sectors. The output of the knowledge production is the number patent applications in Swedish municipalities from 1994 to 1999. In order to account for the importance of proximity, the explanatory variables are expressed as accessibilities to university and company R&D. The total accessibility is then decomposed into local, intra-regional and inter-regional accessibility to R&D. As often is the case with R&D outputs, the regional distribution of patents is highly skewed with influential outliers. The estimations are therefore conducted with quantile regressions. The main results on aggregated level indicate that high accessibility (local) to company R&D has the greatest positive effects on patent production. The effects are statistically significant for municipalities with a patent production corresponding to the median and to quantiles above the median. Local accessibility to university R&D is only of importance for certain industrial sectors and not on aggregated level. There is also evidence that intra-regional accessibility to company R&D affects patent production positively. A conclusion is that concentrated R&D investments in companies situated in municipalities with a high patenting activity would not only gain the municipalities themselves, but also the patent production in other municipalities in the functional region.

  • 129.
    Grönberg, Christoffer
    University West, Department of Engineering Science.
    Simulering och cykeltidsberäkning av automatiserad produktionslina med hjälp av Process Simulate2010Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis has been carried out in collaboration with Löfqvist Engineering in Örebro. The task has been to perform a simulation of a large automation line, to be used in the manufacture of exhaust systems for trucks. Based on this simulation accurate cycle times for production are determined. These times can then be used by Löfqvist Engineering to verify the earlier estimated times.

    The work includes a literature review of Lean Production and how it works with automation. There is also some background information on Just In Time, different file formats and robot simulation in general for the reader to get a bit more background knowledge of the subject.

    The program that has been selected to perform the simulation is Tecnomatix Process Simulate and its built in Line Simulation module. The automation line consists of four handling robots, 13 operator stations and eight identical welding cells. Cycle times for the automation line have been determined and the result was 6 min 31s, for the automation line to complete one product. Cycle times were determined by calculating the average time to produce 10 pieces of products when the line was full of material.

    The report describes how the work for arriving at these cycle times have been performed and how simulation problems encountered during such operations have been resolved.

  • 130.
    Gunnarsson, Håkan
    et al.
    University West, Department of Engineering Science.
    Johansson, Filip
    University West, Department of Engineering Science.
    Framtagning av koncept för monteringsstation2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor's thesis has been carried out at Parker Hannifin Manufacturing Sweden AB in Trollhättan. This report presents the work for producing and evaluating concepts for an assembly station. The company assembles three models of hydraulic pumps named F1, F2 and F3 in the assembly station. In the assembly station there is a screwing station that enables assembly of the pumps. The screwing station is badly adjusted for assembly of F3 and the assembly personnel may suffer from damage due to lack of ergonomics in the form of manual lifting.

    The purpose of this bachelor's thesis was therefore to improve ergonomics for the personnel and increase the flexibility in the screwing station. The goal was to produce a concept of an assembly station adapted for assembly of F1, F2 and F3 with transport of pumps to and from the screwing station where manual lifting does not exceed seven kilograms.

    By collecting information on the current assembly station, a zero-position description and a list of interpreted needs and requirements were complied. The list included the needs and requirements of the assembly personnel, to achieve a working assembly station and from the organization. Based on collected information and identified improvement areas, solutions were generated and combined into concepts. Generated concepts included solutions for reducing ergonomic risk and the possibility to standardize the tools in the screwing station. The concepts were screened in a screening matrix where the concepts were evaluated against the current assembly station. The remaining concepts were graded in a selection matrix where a winning concept was selected. To identify and resolve any problem that may arise when the concept is realized, the concept was further evaluated by modelling and simulating in a computer program. 

    The result of the concept development process and the concept recommended to Parker was named “H+”. Concept H+ consists of a conveyor with an integrated screwing station and a lifting device between the conveyor and the next part of the assembly line. The screwing station has a rotating shaft where F1, F2 and F3 are fixed with a standardized tool. The rotating shaft allows torqueing of screws from the front of the screwing station. Assembly of F3 has been adapted in the concept through standardized tools. The concept also reduces ergonomic risks, as transport from the screwing station is made by a conveyor and a lifting device. Manual lifting over seven kilograms has thus been eliminated. If Parker chooses to develop and realize the concept they will, according to this report, be provided with an assembly station with increased flexibility and improved ergonomics for their employees.

  • 131.
    Gupta, Mohit Kumar
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Design of Microstructures in Thermal Barrier Coatings: A Modelling Approach2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Plasma sprayed Thermal Barrier Coating systems (TBCs) are commonly used for thermal protection of components in modern gas turbine application such as power generation, marine and aero engines. The material that is most commonly used in these applications is Yttria Stabilized Zirconia (YSZ) because of this ceramic’s favourable properties, such as low thermal conductivity, phase stability to high temperature, and good erosion resistance. The coating microstructures in YSZ coatings are highly heterogeneous, consisting of defects such as pores and cracks of different sizes which determine the coating’s final thermal and mechanical properties, and the service lives of the coatings. Determination of quantitative microstructure–property correlations is of great interest as experimental procedures are time consuming and expensive.

    This objective of this thesis work was to investigate the relationships between coating microstructure and thermal-mechanical properties of TBCs, and to utilise these relationships to design an optimised microstructure to be used for next generation TBCs. Simulation technique was used to achieve this goal. Important microstructural parameters influencing the performance of TBCs were identified and coatings with the identified microstructural parameters were designed, modelled and experimentally verified. TBCs comprising of large globular pores with connected cracks inherited within the coating microstructure were shown to have significantly enhanced performance. Low thermal conductivity, low Young‘s modulus and high lifetime were exhibited by these coatings. The modelling approach described in this work can be used as a powerful tool to design new coatings as well as to achieve optimised microstructures.

  • 132.
    Gupta, Mohit Kumar
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Dwivedi, Gopal
    Stony Brook University, USA.
    Nylén, Per
    University West, Department of Engineering Science, Research Environment Production Technology West.
    Vackel, Andrew
    Stony Brook University, USA.
    Sampath, Sanjay
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    An Experimental Study of Microstructure: Property Relationships in Thermal Barrier Coatings2013In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 22, no 5, p. 659-670Article in journal (Refereed)
    Abstract [en]

    The thermal-mechanical properties of thermal barrier coatings are highly influenced by the defects present in coating microstructure. The aim of this study was to meet the future needs of the gas turbine industry by further development of zirconia coatings through the assessment of microstructure-property relationships. A design of experiments was conducted for this purpose with current, spray distance, and powder feed rate as the varied parameters. Microstructure was assessed with SEM and image analysis was used to characterize porosity content. Evaluations were carried out using laser flash technique to measure thermal properties. A bi-layer beam curvature technique in conjunction with controlled thermal cycling was used to assess the mechanical properties, in particular their nonlinear elastic response. Coating lifetime was evaluated by thermo-cyclic fatigue testing. Relationships between microstructure and coating properties are discussed. Dense vertically cracked microstructure and highly porous microstructure with large globular pores were also fabricated. Correlations between parameters obtained from nonlinear measurements and lifetime based on a priori established microstructural analysis were attempted in an effort to develop and identify a simplified strategy to assess coating durability following sustained long-term exposure to high temperature thermal cycling.

  • 133.
    Gupta, Mohit Kumar
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Eriksson, Robert
    Linköping University, Linköping, Sweden.
    Sand, Ulf
    EDR Medeso, Västerås, Sweden.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    A Diffusion-based Oxide Layer Growth Model using Real Interface Roughness in Thermal Barrier Coatings for Lifetime Assessment2015In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 271, no June, p. 181-191Article in journal (Refereed)
    Abstract [en]

    The development of thermo-mechanical stresses during thermal cycling can lead to the formation of detrimental cracks in Atmospheric Plasma Sprayed (APS) Thermal Barrier Coatings systems (TBCs). These stresses are significantly increased by the formation of a Thermally Grown Oxide (TGO) layer that forms through the oxidation of mainly aluminium in the bondcoat layer of the TBC. As shown in previous work done by the authors, the topcoat-bondcoat interface roughness plays a major role in the development of the stress profile in the topcoat and significantly affects the lifetime of TBCs. This roughness profile varies as the TGO layer grows and changes the stress profile in the topcoat leading to crack propagation and thus failure.

    In this work, a two-dimensional TGO growth model is presented, based on oxygen and aluminium diffusion-reaction equations, using real interface profiles extracted from cross-section micrographs. The model was first validated by comparing the TGO profiles artificially created by the model to thermally cycled specimens with varying interface roughness. Thereafter, stress profiles in the TBC system, before and after the TGO layer growth, were estimated using a finite element modelling model described in previous work done by the authors. Three experimental specimens consisting of the same chemistry but with different topcoat-bondcoat interface roughness were studied by the models and the stress state was compared to the lifetimes measured experimentally. The combination of the two models described in this work was shown to be an effective approach to assess the stress behaviour and lifetime of TBCs in a comparative way.

  • 134.
    Gupta, Mohit Kumar
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    A modelling approach to design of microstructures in thermal barrier coatings2013In: Journal of Ceramic Science and Technology, ISSN 2190-9385, Vol. 4, no 2, p. 85-92Article in journal (Refereed)
    Abstract [en]

    Thermo-mechanical properties of TBCs are strongly influenced by coating defects, such as delaminations and pores, thus making it essential to have a fundamental understanding of microstructure-property relationships in TBCs to produce a desired coating. Object-Oriented Finite element analysis (OOF) has been shown previously as an effective tool for evaluating thermal and mechanical material behaviour, as this method is capable of incorporating the inherent material microstructure as an input to the model. In this work, OOF was used to predict the thermal conductivity and effective Young's modulus of TBC topcoats. A Design of Experiments (DoE) was conducted by varying selected spray parameters for spraying Yttria Stabilized Zirconia (YSZ) topcoat. Microstructure was assessed with SEM and image analysis was used to characterize porosity content. The relationships between microstructural features and properties predicted by modelling are discussed. The microstructural features having the most beneficial effect on properties were sprayed with another spray gun so as to verify the results obtained from modelling. Characterisation of the coatings included microstructure evaluation, thermal conductivity and lifetime measurements. The modelling approach in combination with experiments undertaken in this study was shown to be an effective way in achieving coatings with optimised thermo-mechanical properties.

  • 135.
    Gupta, Mohit Kumar
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Nylén, Per
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Design of Low Thermal Conductivity Thermal Barrier Coatings by Finite Element Modelling2011In: Surface Modification Technologies XXIV: SMT24, Dresden, September 7-9, 2010 / [ed] T. S. Sudarshan, Eckhard Beyer, and Lutz-Michael Berger, 2011, p. 353-365Conference paper (Refereed)
    Abstract [en]

    Fundamental understanding of relationships between coating microstructure and thermal conductivity is important to be able to understand the influence of coating defects, such as delaminations and pores, on heat insulation in thermal barrier coatings (TBC). Object Oriented Finite element analysis (OOF) has recently been shown as an effective tool for evaluating thermo-mechanical material behaviour as this method is capable of incorporating the inherent material microstructure as an input to the model. The objective of this work was to evaluate a procedure where this technique is combined with Tbctool, a plasma-sprayed TBC like morphology generator, thus enabling development of low thermal conductivity coatings by simulation. Input parameters for Tbctool were computed from SEM images of sprayed microstructures using the image analysis software, Aphelion. Microstructures for as-sprayed as well as heat treated samples were evaluated. The thermal conductivities of the artificially generated microstructures were determined using OOF. Verification of the modelling procedure was performed by comparing predicted values by OOF with corresponding measured values using the laser flash technique. The results, although tentative in nature, indicate that the proposed simulation approach can be a powerful tool in the development of new low conductivity coatings.

  • 136.
    Gupta, Mohit Kumar
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Nylén, Per
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Structure-property Relationships in Thermal Barrier Coatings by Finite Element Modelling2012In: Surface Modification Technologies XXV : proceedings of the Twenty Fifth International Conference on Surface Modification Technologies: SMT25, Trollhättan, June 20-22, 2011 / [ed] T. S. Sudarshan, and P. Nylén, [Chennai]: Valardocs , 2012, p. 175-184Conference paper (Refereed)
    Abstract [en]

    The thermal and mechanical properties of Thermal Barrier Coating systems (TBCs) are strongly influenced by coating defects, such as delaminations and pores, thus making it essential to have a fundamental understanding of microstructure-property relationships in TBCs, to produce a desired coating. Object-Oriented Finite element analysis (OOF) has been shown previously as an effective tool for evaluating thermal and mechanical material behaviour, as this method is capable of incorporating the inherent material microstructure as an input to the model. In this work, OOF was used to predict the thermal conductivity and effective Young’s modulus of TBC topcoats. A Design of Experiments (DoE) was conducted by varying selected spray parameters for spraying Yttria Partially Stabilized Zirconia (YPSZ) topcoat. Characterisation of the coatings included microstructure, porosity and crack content and thermal conductivity measurements. The relationships between microstructural features, thermal conductivity and Young’s modulus are discussed.

  • 137.
    Gupta, Mohit Kumar
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Skogsberg, Kristoffer
    University West, Department of Engineering Science.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Influence of Topcoat-Bondcoat Interface Roughness on Stresses and Lifetime inThermal Barrier Coatings2014In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 23, no 1-2, p. 170-181Article in journal (Refereed)
    Abstract [en]

    Failure in Atmospheric Plasma Sprayed (APS) Thermal Barrier Coatings (TBCs) is associated with the thermo-mechanical stresses developing due to the Thermally Grown Oxide (TGO) layer growth and thermal expansion mismatch during thermal cycling. The interface roughness has been shown to play a major role in the development of these induced stresses and lifetime of TBCs. Modeling has been shown as an effective tool to understand the effect of interface roughness on induced stresses. In previous work done by our research group, it was observed that APS bondcoats performed better than the bondcoats sprayed with High Velocity Oxy-Fuel (HVOF) process which is contrary to the present literature data. The objective of this work was to understand this observed difference in lifetime with the help of finite element modeling by using real surface topographies. Different TGO layer thicknesses were evaluated. The modeling results were also compared with existing theories established on simplified sinusoidal profiles published in earlier works. It was shown that modeling can be used as an effective tool to understand the stress behavior in TBCs with different roughness profiles.

  • 138.
    Gupta, Mohit Kumar
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Weber, André
    Karlsruhe Institute of Technology, Germany.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Gindrat, Malko
    Oerlikon Metco, Switzerland.
    Electrochemical Performance of Plasma Sprayed Metal Supported Planar Solid Oxide Fuel Cells2016In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 163, no 9, p. F1059-F1065Article in journal (Refereed)
    Abstract [en]

    High production cost is one of the major barriers to widespread commercialization of solid oxide fuel cells (SOFCs). Thermal spraytechniques are a low cost alternative for the production of SOFCs. The objective of this work was to evaluate the electrochemicalperformance of cells produced by plasma spraying. The anode was deposited on a porous metallic support by atmospheric plasmaspraying (APS) whereas the electrolyte was deposited by plasma spray-thin film (PS-TF) technique, which can produce thin anddense coatings at high deposition rates. The cathode was deposited by screen-printing and in-operando sintering. The electrochemicaltests were performed at 650–800◦C. Current-voltage characteristics and impedance spectra were measured and analyzed. The impactof electrolyte composition and layer thickness on the gas tightness of the electrolyte and the area specific resistance of the cell isdiscussed. The results show that the applied thermal spraying techniques are a potential alternative for producing SOFCs.

  • 139.
    Gupta, Mohit Kumar
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Weber, André
    Karlsruhe Institute of Technology, Germany.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Helden, Nadine
    Oerlikon Metco, Germany.
    Development of plasma sprayed Ni/YSZ anodes for metal supported solidoxide fuel cells2017In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 318, p. 178-189Article in journal (Refereed)
    Abstract [en]

    Solid oxide fuel cells (SOFCs) offer a promising technique for producing electricity by clean energy conversionthrough an electrochemical reaction of fuel and air. Plasma spraying could be a potential manufacturing routefor commercial SOFCs, as it provides a distinct advantage especially in case of metal supported cells (MSCs) byallowing rapid processing at relatively low processing temperatures preventing thus the degradation of themetallicsubstrate. The objective of this work was to develop nickel/yttria stabilised zirconia (Ni/YSZ) anodes withhigh porosity and homogeneous phase distribution by atmospheric plasma spraying forMSCs. Various feedstockmaterial approaches were explored in this study, both with single injection aswell as separate injection of differentfeedstock materials , and with and without the use of pore formers to create additional porosity. The advantagesand issues with each material route were investigated and discussed. It was shown that agglomerated Ni/YSZ/polyester feedstock material resulted in the best distribution of Ni and YSZ in the anodemicrostructurewithhomogeneous porosity. Subsequently, the Ni/YSZ/polyester material route with different amounts and size distributionsof polyester was chosen to develop anode symmetrical cells using a commercial zirconia sheet as supportfor electrochemical testing. The Ni/YSZ/polyester anode powder with 10 wt.% standard size polyesterexhibited the best electrochemical performance. The results show that plasma spraying of the agglomeratedNi/YSZ/polyester could be a promising route to achieve high performance and rapid production anodes withoutusing the carcinogenic nickel oxide.

  • 140.
    Gustafsson, Andreas
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Modalanalys av ett lågtrycksturbinhus till en jetmotor2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As flight travel has increased dramatically over the past 30 years and the fact that flight travel consumes a lot of energy in form of jet fuel has led to an intensified search for lighter and more fuel-efficient designs. Thereof, the aircraft engine area is strongly affected. This yields more thin-walled structures, which means that they show an increased tendency to vibrate, especially during manufacturing.

    In the area of chatter vibrations, there is a large extent of literature and research that describe and prevent vibrations during machining. One approach is to predict instability and chatter vibrations. The approach of predict instability have been implemented in this project, in order to generate optimal cutting parameters in the manufacturing of a low pressure turbine casing.

    A modal analysis has been performed on the machining system that is included in the manufacturing of the low pressure turbine casing. Here, modal analysis on each part of the machining system has generated modal parameters that indicate the structures dynamic stiffness.

    Based on the modal analysis and the specific cutting force for Inconel 718, the actual work material, stability lobe diagrams has been generated out of which the axial depth of cut and spindle speed that yields chatter free machining could be selected.

    In parallel with the modal analysis, a FEM-analysis made as a modal analysis has been performed in ANSYS Workbench. This has been executed to improve the machining system and the supports that are included in the tooling fixture to raise the stability frontier for this particular system.

    The results from this project show that it is not possible to achieve significantly increased depths of cut or spindle speeds in the machining of the low pressure turbine casing. However, Cutpro still shows the potential that exists in this software, which GKN Aerospace can benefit from, out of a quality perspective where GKN Aerospace has the chance to increase the control of their manufacturing processes.

  • 141.
    Gustafsson, Fredric
    et al.
    University West, Department of Engineering Science.
    Ulldal, Jonatan
    University West, Department of Engineering Science.
    Optimering av smidesgeometri för P-fläns på bakre turbinstativ (TEC)2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis work has been performed at Volvo Aero Corporation in Trollhättan, at the department of “hot structures” involving aircraft engine GP7000. The purpose with the study was to investigate the possibility to reduce size of the forging of flanges on the rear turbine frame when purchasing. Thereto examine the parameters that affect the flanges motion during the manufacturing process. The goal was to provide Volvo Aero with foundation to later bring in slimmed forgings. In order to supply the company with a concrete result the report was limited into studying the P-flange.

    During the manufacturing process the flanges moves. By measuring the deviation from calculated points on nominal geometry relative to scanned geometry after affecting operations, the motion could be mapped. From these studies two proposals for optimization was presented.

    The first proposal is based on evening out the tilt caused from the TIG-welding operation. Purchasing tilted forgings would compensate the angle and make room for further savings. If the introduction became a success it could eventually mean that a whole operation (roughing) might be removed. Due to insufficient knowledge about whether the tilt would change as expected after introduction, it requires another analyze after implemented before material can be reduced.

    The second proposal is based on reducing material solely on the point´s motion. Calculating with four sigma safety (99,379%) on the movements gave information about how much excess material that could be reduced on the forgings. Considerations about whether decreased material would modify the movement pattern have been taken into account. The result shows that 10 % from the bought in forgings can be removed directly.

    The authors suggest that Volvo Aero begin with the tilt-proposal as a first step in bringing in slimmed forgings. For future work the company could implement the approach taken on this report to the other flanges.

  • 142.
    Gustafsson, Pontus
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Larsson, Patrik
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Utkastbegränsning samt anpassning av krockgardiner vid sidorutor i bagageutrymme2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor’s thesis was performed as a concept development project at Autoliv Sverige AB, an automotive safety company located in Vårgårda, Sweden.

    US vehicle safety standards require countermeasures to prevent a vehicle occupant from ejection through side windows during a rollover crash. Autoliv is currently using a three-row inflatable curtain to fulfil these requirements but wish to evaluate possibilities for a different type of countermeasure for side windows in a vehicle’s cargo area. Main evaluation parameters were cost, weight, size, and ejection mitigation performance.

    To reach the purpose of the project, concept generation, evaluation and simulation has been performed prior to building a prototype. The prototype was built to test a function principle and not to be considered as a final concept. It was tested in a horizontal impactor to provide further evaluation data.

    By generating concepts, conducting simulations, construct a prototype and perform an impact test, an evaluation and comparison between new and old concepts can be performed. The impactor tests indicated that the identified function principle can provide performance necessary to prevent ejection.

    Conclusions was made that even if the physical prototype did not surpass the limits regarding cost, weight or size, the function has great opportunities for refinement, unless any existing patents would hinder further development. It performs best and show great potential in small windows and gives a minor increase in ejection mitigation performance in larger windows. Weight saving can be achieved if a refined prototype can be implemented

  • 143.
    Gustafsson, Rickard
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Lunde, Petronella
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Möjligheter i restmaterialet från stickindustrin: En konceptstudie2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Consumption of textiles, in the form of clothing and footwear, has increased by 40% in Sweden between 1999 and 2009. It is, in Sweden, annually bought 15 kg of textiles per person and picking-analyses shows that around 8 kg textiles are thrown away as sack-waste and domestic refuse. The increased consumption has led to increased negative environmental impact, as a large proportion of the products from the textile industry finally ends up in incineration facilities and landfill. Increased consumption has also resulted in increased production, which also increase the textile industry's negative environmental impact. Part of the increased environmental impacts can be directly traced to the combustion of waste materials from the production.

    This thesis treats the waste material from the Swedish garment manufacturer Ivanhoe AB and their cutting process in the form of pattern-trimming in felted wool fabric. Pattern-trimming is a process where the parts, which will be stitched into a garments, are cut out from one piece of fabric. The process generates waste material which the company don't take advantage of today.The objective of this project was to, through the identification of possible recycling methods for the waste material, produce concepts which will be feasible to the company. The product development process used in the project is based on a tiered approach described in Ulrich and Eppinger's book Product Development: construction and design. The project's product development process included the following steps; planning, identification of customer requirements, information gathering, concept generation and selection of concepts.

    The project resulted in three possible strategies that can be used for making the waste material useful. The strategies identified is Recycling, Patchwork Design and New Products. The latter two strategies was chosen to continue working with and develop concepts. The project finally resulted in six concepts, three concepts to each of the two chosen strategies. Before the company starts the production of one or more of the concepts, further evaluation should be carried out to ensure both economic and environmental sustainability.

  • 144.
    Gustafssson, Filip
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Mattsson, Idha
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Materialflödesoptimering: Siemens2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Siemens Industrial Turboamachinery AB stands before an expansion of the company caused by increased volumes of production and new articles to produce, which results in lack of space. The high demands on production contributes with large orders of details from the production to the logistics department, which cannot handle the variations.

    The purpose with this project is to get a better supply flow in the business whom supports the planning which is made for the production. This project also aims at creating a better understanding among the employees, how the supply chain affects the organization and an optimization of the milkround to decrease the variation of delivery time. The goals during this work is to determine and stabilize the demands and the delivery processes, visualize the need of transportation and secure the time of delivery. This study is partly qualitative and partly quantitative, with a base on interviews and collecting of data by measurements. The information/data is then used in the problem solving method of Six Sigma. Six Sigma is a systematic problem solving method which uses statistical quality tools. In this work a pres-tudy is included which also is performed at the company. The pre study contain the two first phases of the DMAIC method, define and measure.

    The result of the phases in the pre-study, define and measure, was that the group gained a greater understanding of the problem by identifying the stakeholders and costumers with their demands. After performing interviews with all the team leaders, the group realized that they had problem with the planning and many of them thought that the cause was because of the sudden appearance of material from other production groups. The measuring per-formed on the (by the group) identified problems showed the magnitude of the problem. This resulted in a cost–benefit analysis which shows the value of performing this project. The analysis phase consisted of analyzing the measurements that had been done and resulted in a focus area contained how the orders should be done and what the milkround frequency should be. During the improve phase a number if improvements was produced; priority lists, guides and a suggestion of a development of the business system.

    The conclusions from this project is that the company should start with simple solutions and create a well-structured flow and a standardized work which all employees follows. There is a lot of possible developments in the company but to reach world class the simple problems should be solved first. The future work laying a head of Siemens is among others to imple-ment the suggestions from the group of a system development to support the logistics in form of computers for the forklifts and ordering through SAP at decided times.

  • 145.
    Gustavsson Christiernin, Linn
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Augustsson, Svante
    University West, Department of Engineering Science, Division of Production System.
    Interacting with Industrial Robots: A Motion-based Interface2016In: AVI '16 Proceedings of the International Working Conference on Advanced Visual Interfaces / [ed] Paolo Buono, Rosa Lanzilotti, Maristella Matera, New York: ACM Digital Library, 2016, p. 310-311Conference paper (Refereed)
    Abstract [en]

    Collaborative industrial robot cells are becoming more and more interesting for industry through the new Industrie 4.0 initiative. In this paper we report early work on motion-based interaction with industrial robots. Human motion is tracked by a Kinect camera and translated into robot code. A group of tests subjects are asked to interact with the system and their activities are observed. Lessons learned on interaction challenges in a robot cell are reported.

  • 146.
    Göransson, Daniel
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Haaga, Jerry
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Framtagning av en mobilhållare för bilar2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this thesis has been to develop and design a mobile phone holder for cars. A mobile phone holder can fulfil many purposes, and with the legislation today stating that communication equipment should not interfere when driving a vehicle, this type of product becomes extra important. The holder has been developed to enable simple use through acombination of user friendly functions. A few examples of functions are; easy mounting and demounting of mobile phone, automatic connection to car and wireless charging. Through a structured product development process, where tested methods have been used to identify requirements, generate concepts and choosing concept, an amount of concepts have been created and finally narrowed down to one final winner. Examples of methods and tools that has been used is interviews and House of Quality for identifying requirements, TRIZ Effects Database and Merlin for generating concepts and finally Concept screening and Concept scoring for the selection. The chosen concept has thereafter gone through necessary construction work for creating CAD-models, performing FE-analysis and 3D-printing a prototype. The final concept meets the requirement of easy use through simple one-hand mounting and demounting of mobile phone. The solution also works with a wide variety of mobilephones without the need to make adjustments. The concept is designed and prepared for integrating techniques such as NFC and Qi-charging in future work. More work needs to be done regarding the constructions strength, choice of material and fulfilling of laws before proceeding any further.

  • 147.
    Hadzic, Mirella
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Stridsberg, Louise
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Tejp som kraftöverförande fogmetod: en kartläggning2018Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor’s thesis is a survey of adhesive tape as a force-transmitting bonding method in partnership with TechROi Engineering, Trollhättan, Sweden. TechROi Engineering is a consulting company that works with design solutions frequently for the automotive industry and the manufacturing industry. The company wishes to implement taping as a bonding method but wants to evaluate the strength of the adhesive joint. A matrix that consists of characteristics of the tapes and established requirements are conducted with the purpose to enable an obtainment of correlations. The identified requirements are of surface preparation prior application of adhesives and its effects on the durability and the strength of the joint. Two methods for surface preparation is degreasing and abrasion. Further, factors and thus requirements are identified that are necessary whilst conducting an analysis and experiments of the strength of the adhesive joints. The identification of requirements for strength tests are done so with the benefit of a number of selected standards as well as previously conducted tests by researchers. The test methods are primarily intended to evaluate the mechanical properties such as fracture toughness and are sorted in the report depending on the fracture modes. Mode I, mode II and mixed-mode are studied in this thesis. The standardized test methods contain guidelines regarding how the tests shall be conducted. There is an importance to execute the tests, preparations and calibration according to the same circumstances. There is a need to rank the requirements although this may prove difficult since it depends on the application in which the adhesive joint shall be. Additionally, the occurrence of conflicting requirements is dependent on the application. Difficulties with obtaining test methods for mixed-mode arise, particularly due to the absence of standardized tests.

  • 148.
    Hagqvist, Petter
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science, Division of Automation Systems.
    Heralic, Almir
    GKN Aerospace.
    Automation of a laser welding system for additive manufacturing2015In: Proceedings of the 2015 IEEE International Conference on Automation Science and Engineering / [ed] Kazuhiro Saitou, Univ. of Michigan, IEEE, 2015, p. 900-905Conference paper (Refereed)
    Abstract [en]

    This paper presents the benefits and challenges ofusing a standard robotised laser welding cell for additive manufacturing(AM). Additive manufacturing, sometimes denoted3D-printing or rapid prototyping, has lately met strong interestin several areas of society, and a variety of technologies andmaterials have been in focus. The current paper summarisesautomation efforts for AM of advanced aero engine componentsusing high power laser with welding optics as power source formelting metal wire and using an industrial robot for obtaininga 3-dimensional feature shape. The challenges are related to theprocess itself encountering high and repeated temperatures withmelting and solidification of the metal as the main players. Themajor research solutions discussed in this paper are relatedto automation issues for obtaining a stable process and tohave control of the temperatures and temperature changes thatthe metals encounter during the process. The solutions aresuccessfully implemented in an industrial laser welding cell.

  • 149.
    Hall, Maria
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Henriksen, Sara
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Identifiering av mätetal för att öka effektiviteten inom inköp2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is performed at GKN Aerospace Sweden AB (GAS) in Trollhättan with purpose to map the purchasing process and find indicators to make the process more efficient. The target is that by the end of March 2016 to be able to determine if the efficiency of the purchasing process can be measured. The thesis has been limited to find metrics for the purchase of production materials and delimited to map the purchasing process from "purchase requisition" to stock. The thesis is a qualitative study and has been carried out through interviews, observations, benchmarking, concept screening and mapping in terms of a BPI-workshop. During the BPI-workshop a number of roles in the process participated to map the "current state", which contained 38 wastes. Based on the "current state" 15 improvement proposals was generated which GAS should implement to achieve "future state". If the proposed improvements are introduced the lead time for the process is expected to reduce from 96 to 42 days.Of the three companies that were visited during the study none of them had metrics for how efficient their process is. The companies including GAS only had measures for how well the suppliers are performing and other measurements for the internal process. The conclusion is that it is difficult to find a single metric that can represent the efficiency of the entire purchasing process, because of its complexity that is influenced by many factors. The only metrics the students suggests GAS to measure for the defined process is: Number of incorrect purchase requisitions The metric does not measure how efficient the process is, the metric will only measure how often errors occur which creates an inefficient process. In order for the metric to be relevant GAS need to implement the proposed improvements that were generated during the BPI workshop.The metric should be measured before and after the implementation of the improvement proposals to achieve the desired effect. Besides this metric, the students suggest GAS to measure the following metrics to eventually get an efficient process: Continuous improvement purchase Finally GAS is urged to continue to implement BPI-workshops for other parts of the purchasing process to identify wastes that are not discussed in this thesis.

  • 150.
    Hallqvist, Alexandra
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Effektivisering av genomloppstid inom termisk sprutning2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the thesis was to investigate possible ways to increase the throughput efficiency for a part that is thermally sprayed at GKN Aerospace in Trollhättan.

    The goal of the project was to identify technical solutions that can reduce the lead time for the part by at least 40 % and to investigate improvements that could increase the efficiency for all the products that are coated at the department. The project was carried out because the part had one of the longest process times at the department due to a lot of handwork, masking, low-power spray gun and multiple machine stops during the spray operation. The process has been observed and employees have been interviewed to map the current state. Process documentation and part drawings have also been investigated to understand the requirements and ensure that the solutions are useful for the department. The time each activity took were mapped during the observations. Based on the recorded times histograms were made to investigate which moments are most time consuming and therefore needs to be improved. Through the interviews, observations and the benchmarking, solutions were found and further investigated and assessed to identify which ones are the most effective and implementable. Together with operators and technicians, the possible solutions were discussed for in terms of feasibility and improvements. The technicians also discussed the possible time reductions per activity that the proposed solutions are expected to entail when implemented. To achieve the goal, the masking needs to be changed as the masking tools cause the bouncing of coating on the tools and back on the gun, which makes necessary to stop the spraying process after each stroke. If the masking tools are redesigned, a five-hour deburring operation that is performed at another department can be eliminated.

    The conclusion from this work is that it is possible to increase the process efficiency by 49.5% if the existing spray gun is used. If a higher-powered gun can be employed, it enables further efficiency improvement. The increased efficiency of the process makes it possible that the lead time can be shortened from seven days to four days as the part can be completed in the department.

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