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  • 201.
    Ekström, Johanna
    et al.
    University West, Department of Engineering Science.
    Emanuelsson, Stefan
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Förstudie till implementering av papperslös verkstad2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Under sommaren 2012 genomfördes ett examensarbete på Siemens Industrial Turbo­mach­inery AB i Trollhättan gällande möjligheterna att införa pappers­lös verkstad. Syftet med examensarbetet var att kartlägga möjligheterna att minska administrativ hant­ering av produktions­orderkort och öka realtidsuppdatering. För att av­gränsa studien avsåg examens­arbetet endast flödet av produk­tions­­­order­kort ifrån plan­er­ings­avdelningen genom två pro­duk­tions­grupper och vidare in på gods­­­­avdel­ningen.

    För att kartlägga flödet för den manuella hanteringen av produktionsorderkort upprättades värdeflödesanalyser. Dessutom genomfördes ett studiebesök på Volvo Aero Corporation för att se hur ett annat företag har gjort för att eliminera elektronisk produk­tionsorder. Utifrån värdeflödesanalyserna och studiebesöket identifierades tre frågeställ­ningar vilka an­sågs vara betydelsefulla för att kunna införa elektronisk produk­tions­order. Dessa var huru­vida affärssystemet klarar av att hantera införande av elektronisk produk­tions­order, hur spårbarheten av material skall bibehållas samt hur godsavdelningen skall få information om var detaljer skall förflyttas. För att besvara dessa frågor genomfördes 15 inter­vjuer med per­sonal från Siemens Industrial Turbo­machinery i Trollhättan, med per­sonal från huvud­kontoret i Finspång samt med personal från systemutvecklingsföretaget Else AB.

    Informationen från alla intervjuer samt studiebesöket på Volvo Aero Corporation belyser möjligheterna och problemen med att eliminera produktionsorderkorten och samman­ställ­des i en utvärdering. Denna utvärdering ligger till grund för kartläggningen av det fram­tida tillståndet, vilken visar ett tänkbart arbetssätt när produktions­order­korten tagits bort och ersatts med elek­tronisk produktions­order. Det som huvud­sakligen belyses i det framtida tillståndet är att affärssystemet är förberett för elek­tronisk produk­tions­order, dock rekom­men­deras införande av Warehouse Management System samt ett transportssystem. För att under­­lätta implementering av elektronisk produktionsorder skulle införande av ett web­baserat användargränssnitt vara lämpligt.

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    Förstudie till implementering av papperslös verkstad - Siemens Industrial Turbomachinery AB i Trollhättan
  • 202.
    El Aoud, James-Dean
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Melin, Josef
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Affärsmodell för Fyrstads flygplats vid omställning till elflyg2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the study was to identify parts and lessons learned through a survey of the automotive industry, which can form part of a development of a business model for Fyrstad Airport. The problem that is intended to be investigated is based on the fact that the airport does not have a business model for charging electric aircrafts. A qualitative method has been used for the work, where a literature study has been carried out. For the study, literature and articles have been examined with a focus on businessmodels, electrification, electricity networks and infrastructure. To supplement the data obtained from the literature study, semi-structured interviews were conducted. Respondents have consisted of airport managements at regional airports in Sweden together with other professionals with knowledge in electricity networks and infrastructure. To produce a final business model, primary and secondary data together with tools for external analysis, SWOT analysis and a business model canvas have been used. The study has resulted in a business model where Fyrstad Airport will act as an intermediary for the electricity used by airlines when charging electric aircraft. The big difference arises around the aircraft-related revenues where commission per refueled liter of aviation fuel is instead exchanged for a commission per charged kWh. The business model is expected to be implemented during 2025-2026, when electric aircraft probably will be used at a commercial level. Fyrstad Airport should review collaboration opportunities with Trollhättan Energy as an expansion of electricity network capacity and power will probably be required. Furthermore, collaborations with municipalities and organizations should be strengthened, as a standard for charging infrastructure may soon be forthcoming, for which Fyrstad Airport will probably need financial assistance. 

  • 203.
    Elbing, Tommy
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Parametriserad stötfångarmodell av öppen profiltyp2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis has been performed at Benteler Aluminium System Norway in Raufoss in co-operation with Benteler Engineering Service. Since the automotive industry require lighter and safer vehicles, more and more car manufactures change to a bumper beam in alumi-num instead of the traditional one in steel. A lighter vehicle can directly be linked to lower fuel consumption and therefore also a reduced environmental impact.

    The bumper beam that BASN manufactures today is based on extruded aluminum profiles which are bend and formed into desired geometry. The uniqueness of BASN is that the whole value chain is available within the same area, from casting of aluminum alloys to extrusion, forming and finishing.

    To make changes in CAD models is time consuming and costly. To achieve a more time efficient process was the goal to create a simple and accurate parametric CAD model of a bumper. Changes can then be performed in a fast and simple way and lead times of devel-opment can be reduced.

    A CAD-model has been developed that uses parameters to control the geometry of the bumper. The bumper is of open profile type. The CAD-program calculates simple collision parameters such as the maximum bending moment in pure bending and maximum force. Further has a tool been implemented that characterizes the bumpers middle section to in-crease rigidity.

    The goal of creating a parameterized CAD model is satisfied. It is also possible to create parameterized models for other types of profile like closed profiles or multi-chamber pro-files.

  • 204.
    Elfwing, Jonny
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Thersthol, Alexander
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Konceptutveckling av provriggsutrustning för framdrivningssystem2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To carry out different tests on an electric car’s driveline, it often necessary to produce different unique test rigs, which may become costly in terms of both time and money. Thus, in the development of vehicle propulsion systems, there is a need for new modular rigging equipment that can allow shorter set times for switching between different test missions and more tests could be performed at the same time. The purpose of the thesis work is to produce one or more theoretical concepts of a test rig module. In the method section, a theoretical frame of reference is presented, describing the theories and assumptions that were considered relevant for solving the task. The approach to achieving the results includes, among other things, the tools TRIZ, idea generation, literature study and concept screening and weighting matrices. The result includes a proposal for a module-based concept and its characteristics and possibilities are described. The concept consists of three different types of functional elements which are objects that are used to hold and linearize the different components of an electric cars driveline, a module used to position and stabilize the objects and fasteners to attach components to each other and to the T-slots. The final part discusses the implementation and outcome of the thesis work, but there are also suggestions for further studies. The conclusion is that it seems possible to carry out tests with different drivelines using the module-based concept.

  • 205.
    Eliasson, Richard
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Development of new concepts for a blow moulded gymshaker2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project report covers how to perform a structured product development process. The process involves several steps in which different methods and tools are used.

    The purpose of the project is to develop a gymshaker in order to make the company, Emballator Mellerud Plast AB, competitive on the gymshaker market. The main goal of this project has been to present a viable proposal for a physical prototype of the product.

    The product development process starts, in this report, with opportunity identification and ends with a prototype of the product. Methods that are used throughout the process are for example; structured requirement lists with metrics and values, concept generation by exploring different sources, concept selection through different selection tools and computer-aided design modelling.

    A final model of the gymshaker was not officially made, but a preliminary model and drawing were made.

    In conclusion, structured documentation was important throughout the whole process to ensure that every solution was preserved and to be able to reflect thoroughly. The product development process resulted in a prototype of a gymshaker with only three components, the cap (two-parted) and the body. The shaker will be a low cost product considering the few components and the material cost

  • 206.
    Ellers, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Knutsson, Stefan
    University West, Department of Engineering Science, Division of Automation Systems.
    Utveckling, konstruktion och CE-märkning av robotcell för utbildningssyfte2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis work has focused on the efforts to CE-mark a robot cell that has been developed by us to be used for educational purposes. A significant part of the thesis work was to gather the necessary information regarding the CE-marking, robot safety and risk assessments. Security measures have been taken to achieve the requirements concerning the standards, and the conditions concerning both the limited surface and the environment the robot cell is to be used in. This thesis work has developed a large amount of technical documentation. This will be the basis for the final CE-marking of the robot cell. The CE-marking is not completed because the robot cell is not fully developed yet. This leads to that the CE marking cannot be completed until the final tests have been performed on the completed cell, regarding the construction and safety integrity of the structure

  • 207.
    Emanuelsson, Viktor
    et al.
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Wahlberg, Christoffer
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Omkonstruktion av fixtur avsedd för manuell svetskontroll av turbinmotorstativ2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor's thesis treats the production of a fixture for manual physical and visual weld inspection of an aircraft engine stand, 30k TEC (Turbine Exhaust Case), for GKN Aerospace in Trollhättan. The main problem is that the inspection of 30k TEC had not previously occurred to the extent that is current today. The purpose was to facilitate the inspection staff's work situation and to determine whether it is possible to use parts of a fixture adapted to a different aircraft engine stand.The work is based, for the project, on relevant methods that includes data collection, inter¬pretation of collected data, concept generation and concept selection. Interested parties were identified with their respective demands on the fixture and the environment. Concept proposals were generated along with interviews and observations of similar fixtures. The concept proposals went through a concept selection process, which resulted in a final concept.The final concept allows motorized rotation of the aircraft engine stand and it is equipped with supports which prevents the aircraft engine stand to fall off the fixture. The support prevents the turbine exhaust case from falling off during the inspection, which could result in both material damage to the aircraft engine stand and equipment as well as physical damage to the inspection staff. Due to the possibility to rotate the aircraft engine stand with a motor the fixture is classified as a machine and must therefore be CE marked by the manufacturer. The work therefore includes in-depth knowledge in the Machinery Directive and the requirements for CE marking of machines. To meet the ergonomic aspects for the inspection staff, guidelines for ergonomic work.The report presents the final concept and its included components. The employer's work deliverables consists of order documents ready to be sent to the manufacturer of the fix-ture containing drawings and parts lists. Both manufacturers and inspection staff have shown a positive attitude towards the outcome.

  • 208.
    Enberg, Joel
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Johansson, Alvin
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Utförande av aktiviteter inom fastighetsunderhåll2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The client Company X makes many purchases each year with several different decisionmakers, where there is a great variation in both price from different suppliers and execution of the purchasing process. This case study has been conducted with the aim of identifying and presenting guidelines for purchasing services that Company X can use in its procurement process. These guidelines can also be applied to other real estate companies' purchasing processes.

    The work has been limited to dealing only with the procurement of services and therefore presented guidelines cannot be implemented when purchasing goods. The work is a case study with a qualitative survey method where information gathering has taken place through literature studies, interviews and information gathering via the company's financial system and intranet. Due to the prevailing situation regarding Covid-19, the case study has been carried out remotely, and no observations have therefore been made.

    The company's purchasing process has been analyzed and compared with presented theory. Several interview objects with different positions within the company have presented their picture of the purchasing process as well as how the actual work on the purchasing process works. An entrepreneur has been interviewed to gather information from both sides of a purchase.

    The main discussion deals with how a service should be purchased or performed under its own auspices. Company X has an ingrained mentality within the organization to carry out activities internally to the greatest extent possible but is aware that in many cases purchasing is advantageous and sometimes even necessary. In addition, the discussion section addresses the issue of whether a centrally procured contract should be used or whether a service should be purchased individually. Several factors that influence these decisions are presented in the discussion section.

    The conclusion of the work done is that there are several factors that influence the outcome of the execution of activities. Based on these factors, several guidelines have been developed, which are then presented in a practical decision tree. The decision tree aims to help different decision makers through the purchasing process.

  • 209.
    Engman, Linus
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Stanisic, Oliver
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Kravspecifikation som förbättrar förpackningslogistik och arbetsmiljö: En problemlösande studie hos smaksättningsföretaget Santa Maria2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The study presented in the report is a qualitative study conducted by two students at Högskolan Väst. It includes a logistics and a working environment problem at the spice company Santa Maria. The report writers have been told by Santa Maria to review a certain number of articles/commodities that are delivered from different suppliers in a way that makes it unfavorable for employees when they handle the raw materials. The problem can be anything from high pallets, to pallets packed in a way that makes it difficult for employees to handle in certain parts of Santa Maria's production process. To try to fix this, a requirement specification must be prepared which is also the goal of the study. The idea is that Santa Maria will have the opportunity to demonstrate to its suppliers how the raw materials should be packaged and dispatched, and using a requirement specification as a source for decision making. The procedure in the study is based on the steps that follows in a product development process, which means that several different methods have been used to obtain useful information. Such as a current situation analysis, stakeholder analysis, benchmarking and SWOT analysis. Using these methods, we received the necessary information about Santa Maria, such as the current situation, the stakeholders included in the study, and the strengths and threats that the study and requirement specification causes. By carrying out a variety of interviews with Santa Maria, the report writers have gained a good picture and understanding of the problem that the employees experienced.

    The preparation of the requirement specification was based primarily on two aspects, such as economic and work environment aspects. This resulted in a requirement specification that covered both the working environment of Santa Maria employees and the economic aspects, such as how the raw materials should be loaded to optimize loading in a container. With the recommendations made by the report writers, Santa Maria should now have a good awareness of what things that should be improved and how to proceed to get a successful modification.

    The result in the form of the specification was analyzed in the discussion to determine its relevance. This led to the theory and previous research being rooted in the requirements specification. Both theory and previous research were in line with the requirements of stakeholders for the design of pallet goods. The conclusion drawn is that the study is relevant and the problem is appropriate for Santa Maria to consider. By demonstrating that employees' needs are considered, it can gain commitment and motivation can be generated by employees.

  • 210.
    Erichsen, Mathias
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Hallgren, Peter
    University West, Department of Engineering Science, Division of Production Systems.
    Automatiserat produktionsupplägg för fönstermoduler i trä2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor's thesis has been carried out at PTC in Trollhättan. The work has been a part of the larger project "Trämanufaktur – Tillverka i trä" where a potential product for manufacturing in a test & demo environment has been explored.

    The purpose of the thesis was to investigate how window modules are produced, but also to visualize and to evaluate a concept for manufacturing the window module. This manufacturing is planned to be carried out with the flexible robot cell, which is available at PTC in Trollhättan. The goal of the thesis was to find out if the window module is a suitable manufacturing product for the test & demo environment for the project "Trämanufaktur – Tillverka i trä".

    The development of manufacturing concepts required a definition of the window module, this was to clarify what its components are and what steps are made in the production. A definition of the module and an in-depth study of the woodworking industry was made through case studies on manufacturing companies and through a literature study.

    To visualize manufacturing concepts in RobotStudio, 3D models were produced of the manufacturing environment and the window module. With the help of visualizations, the concept that was best suited for the test & demo environment could be developed. This was done by evaluating different concepts regarding the project's limitations. The concept chosen was further evaluated, the result included a scope study and a time study for workflow in the current range of the robot.

    A discussion is made in the report on development potential for further studies, the result and concepts for manufacturing the window module outside the project's limitations.

    The conclusion that was established was that the product, window module is not suitable for being manufactured in existing robot cell as a part of the test & demo environment. This is because it will require either major reconstructions, a complicated fixture or a less than full reachability around the window module.

  • 211.
    Ericson Öberg, Anna
    et al.
    Chalmers Tekniska Högskola.
    Hammersberg, Peter
    Chalmers Tekniska Högskola.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    The right evaluation method - an enabler for process improvement2013Conference paper (Other academic)
    Abstract [en]

    This paper aims at describing the procedure where an alternative evaluation process was developed to support the improvement of both welding and weld quality evaluation. Welded structures are important when striving for reduced fuel consumption due to vehicle weight. Hence good control of the fabrication process is critical to keep welding performance on target, avoiding waste in terms of added weight and overproduction. The resulting distribution of weld weight has shown to be an important control parameter in the sense of keeping cost down.

    To identify the causes for deviations between actual and theoretical weld weight, information about the weld was needed. The currently used evaluation method showed not to be capable of giving the information needed. It was necessary to know the throat size as well as weld geometry. The current evaluation method introduced more variation due to the measurement than the actual fabrication process itself, leading to drift of process target and overproduction.

    To fulfil the need of information, that different functions within the company had, a PULL-approach was used. The information need, information presentation and sequence were outlined for each information receiver individually. An alternative measurement method was developed and named WIA – Weld Impression Analysis. The method consists of two parts; creating the replica and analysing the shape in an image analysis program.

    The method was tested to see if it was capable of delivering accurate and precise measurements, satisfying repeatability and reproducibility requirements for this particular situation. A thorough measurement system analysis was carried out. The measurement system assigned 98.98% of the total variation to part-to-part variation corresponding to long-term process variation. The variation that stems from taking the impressions and preparing them was as well investigated, also showing satisfying results. Finally it was investigated if the impressions reflect the true shape of the welds accurately. The results showed a tendency of slightly higher cross sectional areas in the range of 0-3 %. This however indicated that the accuracy of the measurement system was sufficient for its purpose.

    The PULL-approach generated a sufficient method which enabled the possibility to perform process improvement and gain large production cost savings.

  • 212.
    Ericsson, Mikael
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Johansson, Dahniel
    University West, Department of Engineering Science, Division of Production Systems.
    Stjern, David
    AI-Based Quality Control of Wood Surfaces with Autonomous Material Handling2021In: Applied Sciences, E-ISSN 2076-3417, Vol. 11, no 21, p. 9965-9965Article in journal (Refereed)
    Abstract [en]

    The theory and applications of Smart Factories and Industry 4.0 are increasing the entry into the industry. It is common in industry to start converting exclusive parts, of their production, into this new paradigm rather than converting whole production lines all at once. In Europe and Sweden, recent political decisions are taken to reach the target of greenhouse gas emission reduction. One possible solution is to replace concrete in buildings with Cross Laminated Timber. In the last years, equipment and software that have been custom made for a certain task, are now cheaper and can be adapted to fit more processes than earlier possible. This in combination, with lessons learned from the automotive industry, makes it possible to take the necessary steps and start redesigning and building tomorrows automated and flexible production systems in the wood industry. This paper presents a proof of concept of an automated inspection system, for wood surfaces, where concepts found in Industry 4.0, such as industrial Internet of things (IIoT), smart factory, flexible automation, artificial intelligence (AI), and cyber physical systems, are utilized. The inspection system encompasses, among other things, of the shelf software and hardware, open source software, and standardized, modular, and mobile process modules. The design of the system is conducted with future expansion in mind, where new parts and functions can be added as well as removed.

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  • 213.
    Eriksson, Amanda
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Westman, Anna
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Uppgiftsväxling: identifikation av motstånd och förslag tillförbättringar vid NU-sjukvården2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The lack of nurses is becoming a national problem in Sweden as well in NU-Hospital Group, region Trollhättan and Uddevalla. In 2016 NU-Hospital Group area I of III started a program for switching duties performed by nurses with focus on optimizing the resources. During the winter of the same year as the project started the leaders of the clinics began to resist the change. This year in autumn of 2017, NU-Hospital Group will launch a new program to switch nurses’ duties throughout the organization. This report addresses why the project “task switching” stagnated and what could be done differently in the upcoming program. The purpose of this report is to help NU-Hospital Group to achieve an improvement, avoid resistance from the co-workers and thereby implement a successful program. The authors have completed their work through performing an organizational charting, studying status reports, and applying the methods of literature reviews, interviews, surveys and a compilation of other hospitals achievements and what they have accomplished. These selected methods are chosen to ensure the result is valid and reliable. The healthcare needs to constantly improve their organization. The program “task switching” stagnated because the management perceived the resistance, which was of importance. The change made the leaders of the clinics feel lack of treatment, participation and trust. The purpose and goal of the project was unclear and changed during time. NU-Hospital Group still understand that this change is necessary for the healthcare and therefore they are planning to start the new program of switching duties, which concerns the entire organization. Ahead of the upcoming program the authors have identified a number of suggestions to improve the program. The suggestions are: focus on the project management, focus on the existing processes before switching duties, involvement from the employees and apply a Lean-philosophy. The result of this thesis is considered reliable because several methods have been used and the result have been analyzed from different perspectives. Therefore, we assert the validity and reliability of the study.   

  • 214.
    Eriksson, Kristina. M.
    University West, Department of Technology, Mathematics and Computer Science, Division for Mechanical Engineering.
    A comparison of changeover time reduction through design changes and changeover sensitive heuristics2007In: PLANs forsknings- och tillämpningskonferens 2007: kundfokuserade varor och tjänster : artiklar från konferensen på Tekniska högskolan i Jönköping 5-6 september 2007, PLAN - Logistikföreningen , 2007, p. 51-66Conference paper (Refereed)
  • 215.
    Eriksson, Kristina M.
    University West, Department of Engineering Science, Division of Production Systems.
    An investigation of change over sensitive heuristics in an industrial job shop environment2006Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The research in this thesis has investigated scheduling and Changeover Sensitive Heuristics (CSHs). The overall aim was to investigate the relationship between scheduling and changeovers and to develop and examine new scheduling heuristics that are intelligent enough to optimise both due dates and changeover requirements. Two new heuristics that incorporated the sequencing of jobs both according to product families and sub-product families were introduced. The new heuristics are named CSH12 and CSH12-K. A body of case studies have been undertaken. These are based on extensive data collected from the key collaborating company. In order to create generic data sets for a job shop environment, the case studies were extended to incorporate a range of parameters, such as several levels of processing times and job grouping strategies. Through discrete event simulation studies, the performance of the new heuristics has been compared to simple heuristics, semi-heuristics and existing changeover sensitive heuristics. In total, ten heuristics and two semi-heuristics were investigated. Scheduling according to product family (CSH1) compared to subproduct family (CSH2) was also studied and it is concluded that sub-product family sequencing performance better. Overall the new heuristics CSH12 and CSH12-Kshow a worthy performance and can reduce the changeover time the most through effective sequencing in a job shop environment with longer and shorter processing times. The research has also concluded that exhaustive heuristics perform better than non-exhaustive heuristics. Furthermore, CSHs are particularly effective for shorter processing times. This suggests that the choice of heuristic is more important for amix of jobs with shorter processing times. Or the reverse, a mix of jobs with comparatively long processing times is less sensitive to the choice of heuristic.

    Additionally, the research revealed that product families with overall longer processing times result in higher percentage of tardy jobs. Thus, suggesting that dissimilar due date setting is beneficial for different product families. The research has determined the importance of considering appropriate scheduling and sequencing approaches, especially when changeovers have been addressed through design and organisational changes. The application of CSHs has demonstrated that an increase of jobs into the shop is possible. Hence, applying CSHs will achieve a strong competitive advantage.

  • 216.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Alsaleh, Abdlkarim
    University West, Department of Engineering Science, Division of Production Systems.
    Behzad Far, Shervin
    Northvolt, .
    Stjern, David
    University West, Department of Engineering Science, Division of Production Systems.
    Applying Digital Twin Technology in Higher Education: An Automation Line Case Study2022In: Advances in Transdisciplinary Engineering, ISSN 2352-751X, Vol. 21, p. 461-472Article in journal (Refereed)
    Abstract [en]

    Abstract. Production systems are being expanded to include Digital Twins (DTs)

    as part of increased industrial digitalization. DTs can bring benefits e.g., increase

    visibility, safety, and accessibility of the system. Further, digital experimentation

    can reduce time and cost. Though, application of DT technologies involves

    challenges i.e., model accuracy or errors in transferring data or codes between the

    DT and the physical twin. Many studies on DTs focus on industrial applications.

    However, DT technology has potential for implementation of digital labs in

    education. This aspect of DTs is of rising importance as distance education has

    increased over the last decade and access to physical laboratories can be restricted

    due to factors such as the Covid-19 pandemic. Thus, there is a need to study the use

    of DT technology in higher education. To address this, we investigate possibilities

    and challenges of applying DT technology in education to conduct industrial-like

    labs virtually. A case of an automation line, with full scale industrial equipment,

    based at a research center, is focused. Results emphasize that the application of DT

    technologies require multi-domain expertise to understand the consequences of

    every single decision in the design process on every piece of equipment involved,

    making the modelling process complex and time consuming. Thus, when applied in

    education, test procedures need to be designed to focus on students’ motivation,

    improved learning and understanding of production systems. DTs are considered

    enabling technologies supporting the concept of Industry 5.0, thus stressing the

    human-centric aspects of advancing Industry 4.0. The predicted application of DTs

    emphasizes the need for educational curricula that include laboratory applications

    and theoretic understanding of DT technologies. This study focusses the application

    of DT technologies in higher education curricula, but the result of the study can

    contribute to other areas such as automation and virtual commissioning towards

    smarter manufacturing

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  • 217.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Bränneby, Eva
    University West, Department of Engineering Science, Division of Welding Technology.
    Hagelin, Monika
    University West, Grants and Innovation Office (GIO).
    An educational model for competence development within simulation and technologies for industry 4.02021In: Proceedings of the 2021 Winter Simulation Conference / [ed] S. Kim, B. Feng, K. Smith, S. Masoud, Z. Zheng, C. Szabo and M. Loper, 2021, p. 1-12, article id 177415Conference paper (Refereed)
    Abstract [en]

    In the era of industry 4.0 businesses are pursuing applications of technological developments towards increased digitization. This in turn necessitates continuous and increasing demand for competence development of professionals. This paper reports a study of the design of university courses targeted towards professionals and investigate how such an educational incentive can act as a catalyst for application of technologies for industry 4.0, including simulation. Quantitative data is collected from fifteen courses addressing the competence need in manufacturing industry, and the qualitative data includes ten focus groups with course participants from companies. The results highlight that the course design enables knowledge exchange between university and industry and between participants. Moreover the pedagogy of working on real cases can facilitate opportunities for introducing new technologies to management. The study shows that the educational incentive explored can act as a catalyst for application of simulation and technologies within industry 4.0 in manufacturing industry.

  • 218.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Carlsson, Linnea
    University West, School of Business, Economics and IT, Divison of Informatics.
    Olsson, Anna Karin
    University West, School of Business, Economics and IT, Division of Business Administration.
    Exploring Socially Sustainable, Smart Manufacturing: Building Bridges Over Troubled Waters2024In: Flexible Automation and Intelligent Manufacturing: Establishing Bridges for More Sustainable Manufacturing Systems Proceedings of FAIM 2023, June 18–22, 2023, Porto, Portugal, Volume 2: Industrial Management / [ed] Francisco J. G. Silva, Luís Pinto Ferreira, José Carlos Sá, Maria Teresa Pereira, Carla M. A. Pinto, Springer, 2024, Vol. 2Conference paper (Refereed)
    Abstract [en]

    Contemporary manufacturing organizations formulate strategies towards smart manufacturing. However, strategies often merely regard technological improvements of working processes and activities and pay limited attention to human-centric perspectives. This study addresses the complex phenomenon of reaching socially sustainable smart manufacturing by exploring the human-centric perspectives in the eras of Industry 4.0 and Industry 5.0. Data were collected through an explorative qualitative case study with focus groups applying the history wall approach to document informants’ choices of activities that impact digitalization. To investigate informants’ interpretations and experiences of digital initiatives and prospects, the history wall approach was coupled with the analytical lens of the co-workership wheel, with its four conceptual pairs: trust and openness, community spirit and cooperation, engagement and meaningfulness, responsibility, and initiative. A total of 17 informants from different organizational levels at a case company participated. Activities, impacting digitalization, brought forward were grouped into technology, organization, and external impact. Results showed that human-centric and intangible perspectives surfaced as prerequisites when navigating industrial digitalization. Further, digital initiatives and prospects risk drowning in re-occurring organizational changes making successful implementation difficult. Thus, organizations cannot rely solely on technology, but must consider activities related to organizational aspects and impacts from the external environment, when introducing digital initiatives. Intrinsically, recognition of the co-workership concept, emphasizing human-centricity, can support the foundation necessary for bridging the gap towards socially sustainable smart manufacturing and strengthening the emerging I5.0 research.

  • 219.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Chirumalla, Koteshwar
    Mälardalens högskola, Akademin för innovation, design och teknik, Innovation och produktrealisering, (SWE).
    Ericsson, Mikael
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Håkansson, Lars
    Linnéuniversitetet, Växjö, (SWE).
    Developing a professional course on digitalized production for Swedish manufacturing industry: An inter-university collaboration, its challenges, and opportunities2020Conference paper (Refereed)
  • 220.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Chirumalla, Koteshwar
    Mälardalen University, Eskilstuna, (SWE).
    Myrelid, Paulina
    Mälardalen University, Eskilstuna, (SWE).
    Ericsson, Mikael
    University West, Department of Engineering Science, Division of Production Systems.
    Granlund, Anna
    Mälardalen University, Eskilstuna, (SWE).
    Håkansson, Lars
    Linnaeus University, Växjö, (SWE).
    Johansson, Dahniel
    University West, Department of Engineering Science, Division of Production Systems.
    Experiences in Running a Professional Course on Digitally-Enabled Production in Collaboration Between Three Swedish Universities2022In: Advances in Transdisciplinary Engineering, ISSN 2352-751X, Vol. 21, p. 653-664Article in journal (Refereed)
    Abstract [en]

    Abstract. Needs for new competences and knowledge arise as industry 4.0 evolves

    in increasingly digitalized production. This development entails that job

    transformations and future skills need attention from the perspective of industry 5.0,

    where human and machine find ways of working together to improve production

    performance. Facing this perspective, one challenge is a growing need for novel

    lifelong learning initiatives, to meet emerging and altering occupations for the

    fulfilment of future skill requirements. This challenge is addressed here by

    portraying a case where three Swedish universities have formed a distinctive

    collaboration to develop a flexible (i.e. blended) course for professionals, in the

    subject of Digitally-enabled production. The purpose is to develop a sustainable

    collaboration between the universities and create a course format on master level

    addressing lifelong learning for the increasingly digitalized production. The

    ambition is to increase the impact of the universities respective efforts by sharing

    resources and utilizing individual specialized expertise to develop a practical and

    relevant course that can reach a larger target group. The course encompasses

    industry 4.0 readiness on three levels of production systems; plant-, production cell-,

    and component level; to adopt a holistic view of digitalization in production. We

    followed an action research approach for continuously collecting and documenting

    our experiences during the course development, implementation, and dissemination

    of the course. Within the frame of action research, an explorative case study

    describes and analyzes the initiative. The results highlight challenges and

    opportunities for succeeding with this form of co-produced course. The joint course

    gives professionals possibilities to work on cases from their own companies with

    expert supervision from three manufacturing levels to address complex challenges

    in industry 4.0 implementation. To conclude, the importance of lifelong learning in

    relation to the human-centric approach of industry 5.0 is emphasized as a future

    direction.

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  • 221.
    Eriksson, Kristina M
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Hanson, R.
    Chalmers University of Technology.
    Performance impact of options for routing and delivery initiation in tugger train delivery systems2008In: Proceedings of SPS08, Swedish Production Symposium, 18th – 20th November 2008, Stockholm, Sweden, 2008Conference paper (Refereed)
  • 222.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Hendberg, Ted
    Siemens Energy AB, Trollhättan, (Swe).
    A Case Study Initiating Discrete Event Simulation as a Tool for Decision Making in I4.0 Manufacturing2021In: Lecture Notes in Business Information Processing, ISSN 1865-1348, E-ISSN 1865-1356, Vol. 414 LNBIP, p. 84-96Article in journal (Refereed)
    Abstract [en]

    Smart manufacturing needs to handle increased uncertainty by becoming more responsive and more flexible to reconfigure. Advances in technology within industry 4.0 can provide acquisition of large amounts of data, to support decision making in manufacturing. Those possibilities have brought anew attention to the applicability of discrete event simulation for production flow modelling when moving towards design of logistics systems 4.0. This paper reports a study investigating challenges and opportunities for initiation of discrete event simulation, as a tool for decision making in the era of industry 4.0 manufacturing. The research has been approached through action research in combination with a real case study at a manufacturing company in the energy sector. The Covid-19 pandemic fated that adjusted and new ways of communication, collaboration, and data collection, in relation to the methods, had to be explored and tried. Throughout the study, production data, such as processing times, have been collected and analyzed for discrete event simulation modelling. The complexity of introducing discrete event simulation as a new tool for decision making is highlighted, where we emphasize the human knowledge and involvement yet necessary to understand and to draw conclusions from the data. The results also demonstrate that the data analysis has given valuable insights into production characteristics, that need addressing. Thus, revealing opportunities for how the initiative of introducing discrete event simulation as an anew tool in the wake of industry 4.0, can act as a catalyst for improved decision making in future manufacturing. © 2021, Springer Nature Switzerland AG.

  • 223.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Jellbo, Oskar
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Manufacturing logistics courses aimed at competence development: Perspectives of coproduction between university and industry2021In: Plans Forsknings- och tillämpningskonferens 2021: Logistik Möter Praktik, Plan - Logistikföreningen för effektiva flöden , 2021, p. 349-363Conference paper (Refereed)
    Abstract [en]

    New and elevated competences and knowledge needs arise as industry evolves and manufacturing is increasingly focusing digitalisation and sustainability. Facing those aspects of transformation one of the challenges is the continuous and growing need for competence development of professionals. In a work practice of constant implementation of new manufacturing processes, competence development becomes crucial for professionals within engineering fields such as production systems, product development and logistics. This paper reports a study of the design of courses within manufacturing logistics aimed at competence development for industrial professionals. We investigate how such courses can be designed to enable improved logistics practices in manufacturing industry. The course mode and its development are outlined, explaining the university and industry co-production of the incentive. The courses and their specified content are developed jointly with collaborating companies, and the courses are given free of charge as regular university courses advertised as free-standing courses. Data is collected between the period of spring semester 2019 – to spring semester 2021 from five completed courses of 2.5 ECTS on master level within manufacturing logistics. The data comprise quantitative data, such as throughput rate for course participants and qualitative data from focus groups. The focus groups emphasis the perspectives of the course participants and take place at the end of a completed course. Those focus groups serve as course evaluation coupled with highlighting themes of co-production and knowledge exchange between university and industry. The course concept of 2.5 ECTS credits on master level given during a period of five weeks has proven successful as regards meeting competence development need for professionals that are required to study in parallel with full time work. The results highlight participant’s perspectives, revealing that they value the potential of knowledge exchange enabled through the pedagogy of the course concept. Further, we emphasize that co-production between university and industry is beneficial to successfully design education aiming to meet real competence needs and challenges faced by manufacturing companies. To conclude, the results accentuate how the presented course concept can create and encourage conditions that lay the foundation for increased application of, at the companies, previously untried manufacturing logistic methods and new practices within logistics. 

  • 224.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Juste, A.
    Junefjäll, J.
    Reducing energy consumption through production flow simulation: A case study at a car engine manufacturer2021In: 8th International EurOMA Sustainable Operations and Supply Chain Forum La Rochelle Business School - Excelia Group. 22nd and 23rd March 2021, 2021Conference paper (Other academic)
  • 225.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Mileham, A. R.
    Newnes, L.B.
    A survey investigating current industrial scheduling practice among a cross-section of UK companies2003In: Proceedings of the International Conference on Manufacturing Research (ICMR03), 9th – 11th September, Glasgow, United Kingdom, 2003, p. 409-414Conference paper (Other academic)
  • 226.
    Eriksson, Kristina M.
    et al.
    University West, Department of Technology, Mathematics and Computer Science, Division for Mechanical Engineering.
    Mileham, A.R.
    Newnes, L.B
    A novel scheduling performance comparison tool: scheduling performance profile (SPP) graph2006In: Proceedings of IDMME06, International conference on integrated Design and Manufacturing in Mechanical Engineering: Grenoble, France. May 17-19, Grenoble, 2006Conference paper (Other academic)
  • 227.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Mileham, A.R.
    Newnes, L.B.
    A study of short- medium- and long horizon final production scheduling, applying priority rules and using a discrete event simulation approach2005In: Proceedings of the International Conference on Manufacturing Research (ICMR05), 6th – 8th September, Cranfield, United Kingdom., 2005Conference paper (Other academic)
  • 228.
    Eriksson, Kristina M.
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Ramasamy, Sudha
    University West, Department of Engineering Science, Division of Production Systems.
    Zhang, Xiaoxiao
    University West, Department of Engineering Science, Division of Production Systems.
    Wang, Zhiping
    Research and Technology Development, Volvo Group Trucks Operations, Gothenburg (SWE).
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Conceptual framework of scheduling applying discrete event simulation as an environment for deep reinforcement learning2022In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 107, p. 955-960Article in journal (Refereed)
    Abstract [en]

    Increased environmental awareness is driving the manufacturing industry towards novel ways of energy reduction to become sustainable yet stay competitive. Climate and enviromental challenges put high priority on incorporating aspects of sustainability into both strategic and operational levels, such as production scheduling, in the manufacturing industry. Considering energy as a parameter when planning makes an already existing highly complex task of production scheduling even more multifaceted. The focus in this study is on inverse scheduling, defined as the problem of finding the number of jobs and duration times to meet a fixed input capacity. The purpose of this study was to investigate how scheduling can be formulated, within the environment of discrete event simulation coupled with reinforcement learning, to meet production demands while simultaneously minimize makespan and reduce energy. The study applied the method of modeling a production robot cell with its uncertainties, using discrete event simulation combined with deep reinforcement learning and trained agents. The researched scheduling approach derived solutions that take into consideration the performance measures of energy use. The method was applied and tested in a simulation environment with data from a real robot production cell. The study revealed opportunities for novel approaches of studying and reducing energy in the manufacturing industry. Results demonstrated a move towards a more holistic approach for production scheduling, which includes energy usage, that can aid decision-making and facilitate increased sustainability in production. We propose a conceptual framework for scheduling for minimizing energy use applying discrete event simulation as an environment for deep reinforcement learning.

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  • 229.
    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  

  • 230.
    Eriksson, Oscar
    et al.
    University West, Department of Engineering Science.
    Synnerdahl, Daniel
    University West, Department of Engineering Science.
    Effektivisering av översyn på civila flygplansmotorer genom en värdeflödesanalys2023Independent thesis Advanced level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The thesis is performed at GKN Aerospace Sweden AB in Trollhättan. During the thesis a value stream mapping is performed at a value stream performing maintenance of engine components in the flight industry. After the value stream mapping several suggestions were presented to streamline the value stream. The thesis is also meant to be a starting point for future evaluations when working with improvements for flexible value streams.

    The component whose value stream has been evaluated is called 30k Compressor Intermediate Case. The value stream varies and different operations can be performed depending on what the customer orders. Due to the variation the lead time can be different from components in the value stream. The thesis focused on evaluating processes that occur regularly when 30k Compressor Intermediate Case components arrive at GKN. Other components that use the same processes have not been evaluated.

    A value stream mapping is a tool to visualize a value stream. A visualization of the stream will show how the value stream is built and the lead time can clearly be shown for the component. Deviant key figures can be evaluated to gather an understanding of where focus should be placed when working with improvements.

    Information has been gathered through interviews, observation and collected data from the company's databases. This was compiled to a description of the current value stream which was visualized. The gathered information was used to create a picture of the value stream to examine what processes that's regularly performed. The observations were performed to evaluate how the operators work within the processes which created an understanding of what happens. The information was concluded in a current state analysis which shows how the value stream is built. The suggestions of improvement were presented in a bulleted list after an evaluation of the current value stream.

    The result from the value stream mapping shows that there is a variety in queue time in the range of low to high ahead of the processes. The capacity of the blaster, varnishing and the arrival control is one at the time. An increased capacity would enable more details to undergo the processes at the same time. Waste has also been identified in the arrival inspection where operators move unnecessary distances to collect documents from a printer and to throw away debris arriving with the components packaging. Within the value stream the components are transported with a manually pushed cart that is rebuilt for other components from other value streams. This brings an adjustment time to the arrival inspection. In the analysis the authors suggest using component specific carts. During the blaster an observation was made of more masking than necessary which should be minimized. The result also shows that a standard should be set of how time reporting should be made by the company's guidelines.

    The report shows how a value stream mapping created a clear overview of value streams where bottlenecks can be identified. When eliminating bottlenecks it's important to not create another bottleneck in another process but to eliminate it entirely from the value stream. A value stream mapping is an efficient tool to map processes and their times which in the conclusion is described as a good methodology to streamline value streams.

  • 231.
    Eriksson, Rasmus
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Ohlsson, David
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Eliminering av finplaning vid tillverkning av axiallager2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today's striving manufacturing business leads to higher demands concerning tolerances, cost reduction and lead time for all processes. The demands must be fulfilled without any negative influence on the product quality. The most common manufacturing methods are categorised under machining in the form of material removal. To fulfil the demands, producers implement higher material removal rates (MRR) which is controlled by the cutting data cutting speed, feed rate and depth of cut. The implementation of higher MRR result in higher risks for issues concerning quality due to the increased cutting forces.

    This study focuses on the deformations that occur during the production of outer rings for spherical thrust bearings in a hard-turning process. The deformations are believed to be caused by cutting forces that can be altered by the programmed cutting data such as cutting speed, feed rate and depth of cut. The purpose of the study was to define the behaviour and pattern of the deformations and if they could be controlled by a change of cutting data. The results would act as a mapping of problem and give a clue of the influence that the cutting data have on the magnitude of the deformations. The results would also benefit future projects where the programming of turning process can be optimized to minimize the deformations. The long-term goal is to eliminate the secondary face grinding process that is currently necessary to ensure that the demands concerning tolerances are fulfilled.

    The study was performed by mapping the behaviour and pattern of the deformations using measurement data before and after the turning process. The deformations were studied by measuring the straightness and skewness of the widest plane on the outer rings. A reference group was created by performing measurements without the implementation of any changes concerning cutting data. Testing was accomplished by implementing changes to three different cutting data in the programming. The changes that were made was adjustment of cutting speed, feed rate and depth of cut.

    The analysis of the results does not show any certain connection between the cutting data and the magnitude of the deformation that occurs. The manufacturing process uses cutting tools recommended for the specific material and operation. The manufacturing process uses a relatively high feed rate considering the specific material type. Further studies concerning cutting data should be completed to improve the statistical credibility.

  • 232.
    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.

  • 233.
    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.

  • 234.
    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.

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  • 235.
    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.

  • 236.
    Eynian, Mahdi
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Magnevall, Martin
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing. Sandvik Coromant AB, Sandviken (SWE).
    Cedergren, Stefan
    GKN Aerospace Sweden AB, Trollhättan (SWE).
    Wretland, Anders
    GKN Aerospace Sweden AB, Trollhättan (SWE).
    Lundblad, Mikael
    Sandvik Coromant AB, Sandviken (SWE).
    New methods for in-process identification of modal parameters in milling2018In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 77, p. 469-472Article in journal (Refereed)
    Abstract [en]

    Chatter vibrations encountered in machining can degrade surface finish and damage the machining hardware. Since chatter originates from unstable interaction of the machining process and the machining structure, information about vibration parameters of the machining structure should be used to predict combinations of cutting parameters that allow stable machining. While modal test methods, for example those with impact hammers, are widely used to identify structural parameters; the need for sophisticated test equipment is prohibitive in their use. Furthermore, dynamic properties of critical components of a machine tool may change as they get affected by cutting loads, material removal and spindle rotation. Recently few algorithms have been proposed that identify the in-process dynamic parameters by frequency measurements, thus avoiding these problems. In this paper, some of these algorithms are reviewed and their capabilities and limitations in processing am experimental data set are compared and discussed. © 2018 The Authors. Published by Elsevier Ltd.

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  • 237.
    Fagefors, Carina
    et al.
    Sahlgrenska University Hospital, Department of Pediatric Anesthesiology, Intensive Care and Neonatology, Gothenburg ; Chalmers University of Technology, Technology Management and Economics, Gothenburg.
    Lantz, Björn
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering. Chalmers University of Technology, Technology Management and Economics, Gothenburg.
    Application of Portfolio Theory to Healthcare Capacity Management2021In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 18, no 2, p. 1-9, article id 659Article in journal (Refereed)
    Abstract [en]

    Healthcare systems worldwide are faced with continuously increasing demand for care, while simultaneously experiencing insufficient capacity and unacceptably long patient waiting times. To improve healthcare access and availability, it is thus necessary to improve capacity utilization and increase the efficiency of existing resource usage. For this, variations in healthcare systems must be managed judiciously, and one solution is to apply a capacity pooling approach. A capacity pool is a general, collaborative capacity that can be allocated to parts of the system where the existing workload and demand for capacity are unusually high. In this study, we investigate how basic mean-variance methodology from portfolio theory can be applied as a capacity pooling approach to healthcare systems. A numerical example based on fictitious data is used to illustrate the theoretical value of using a portfolio approach in a capacity pooling context. The example shows that there are opportunities to use capacity more efficiently and increase service levels, given the same capacity, and that a mean-variance analysis could be performed to theoretically dimension the most efficient pooling organization. The study concludes with a discussion regarding the practical usefulness of this methodology in the healthcare context.

  • 238.
    Fagefors, Carina
    et al.
    Sahlgrenska University Hospital, Department of Pediatric Anesthesiology, Intensive Care and Neonatology, Gothenburg; Chalmers University of Technology, Technology Management and Economics, Gothenburg.
    Lantz, Björn
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Rosén, Peter
    University of Gothenburg, Department of Business Administration, Gothenburg.
    Creating Short-Term Volume Flexibility in Healthcare Capacity Management2020In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 17, no 22, article id 8514Article in journal (Refereed)
    Abstract [en]

    It is well-known that unpredictable variations in supply and demand of capacity inhealthcare systems create the need for flexibility. The main tools used to create short-term volume flexibility in the healthcare system include overtime, temporary staff from internal calling lists, moving staff across units, internal staffing pools, external staffing agencies, queuing patients, and purchasing care from external providers. We study the creation of short-term volume flexibility in healthcare systems to manage short-term capacity losses and demand fluctuations. A questionnaire was developed and distributed among healthcare managers in the Region Västra Götaland healthcare system. Respondents were asked to what extent they used each tool to create short-term flexibility in capacity. Data were analyzed using multiple regression analysis. Several significant tendencies were found, including that acute units use overtime and internal staffing pools to a larger extent, and queuing patients and external providers to a lesser extent than planned units. The prerequisites and required managerial approaches used to efficiently manage aggregate capacity in the system differ substantially between different parts of the system. These differences must be addressed when, for example, capacity pools are considered. These results serve as a stepping stone towards a more thorough understanding of efficient capacity management in healthcare systems.

  • 239.
    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.

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  • 240.
    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.

  • 241.
    Fakhri, Ali
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Ramic, Erna
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Livscykelanalys och cirkulär ekonomi för ombeläggningsbar stekpanna2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The investigated case company manufactures kitchen products for both companies and retail clients. This study examines a recoatable frying pan. That is, the frying pan is recoated after it has worn out. The recoating process can be done eight times before the properties of the material deteriorate and must be recycled. Recycled aluminum is used in the manufacture of the frying pan and is therefore a part of a circular return system. The life span of the recoatable frying pan is calculated to be approximately 16 years and a coating is estimated to last two years.

    A life cycle analysis is performed on the frying pan, using the software EduPack, which is then compared with LCA for a cast iron and a cast aluminum frying pan. This in order to determine the estimated environmental impact of the frying pans. The results indicate that the cast iron frying pan has a relatively low environmental impact regarding the energy consumption and carbon dioxide emissions. While the recoatable frying pan has the second lowest environmental impact and the cast aluminum frying pan has the largest carbon dioxide emission and energy consumption.

    It is also analyzed from a circular economic perspective, which differences there are between recoating and manufacturing from scratch. The principle of dematerialization is applied to both production from scratch and recoating, since recycling and reuse of the frying pan occurs. These are part of the technical cycles of the processes as well. The product design is a central part of the circular economy, which was considered in the design stage of the recoatable frying pan. The frying pan does not comply with all five characteristics of CE. However, it is on the right path. 

  • 242.
    Falkenberg Hansen, Kjertil
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Ljungdahl Eriksson, Martin
    University West, School of Business, Economics and IT, Division of Media and Design. Edsbyn.
    Atienza, Ricardo
    University College of Arts, Crafts and Design, Stockholm, Sweden.
    Sound design through large audience interaction2019In: Proceedings of the Sound and Music Computing Conferences / [ed] Barbancho I.,Tardon L.J.,Peinado A.,Barbancho A.M., CERN , 2019, p. 119-126Conference paper (Refereed)
    Abstract [en]

    In collaboration with Volvo Cars, we presented a novel design tool to a large public of approximately three million people at the three leading motor shows in 2017 in Geneva, Shanghai and New York. The purpose of the tool was to explore the relevance of interactive audio-visual strategies for supporting the development of sound environments in future silent cars, i.e., a customised sonic identity that would alter the sonic ambience for the driver and by-passers. This new tool should be able to efficiently collect non-experts’ sonic preferences for different given contexts. The design process should allow for a high-level control of complex synthesised sounds. The audience interacted individually using a single-touch selection of colour from five palettes and applying it by pointing to areas in a colour-book painting showing a road scene. Each palette corresponded to a sound, and the colour nuance in the palette corresponded to certain tweaking of the sound. In effect, the user selected and altered each sound, added it to the composition, and finally would hear a mix of layered sounds based on the colouring of the scene. The installation involved large touch screens with high quality headphones. In the study presented here, we examine differences in sound preferences between two audiences and a control group, and evaluate the feasibility of the tool based on the sound designs that emerged. Copyright: © 2019 Kjetil Falkenberg Hansen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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  • 243.
    Faraji, Mahmoud
    University West, Department of Engineering Science.
    Process parameters optimization on laser welding of new Ni-based superalloy VDM Alloy 7802022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 244.
    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)
  • 245.
    Fefekos, Alexandros G.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Effect of spray angle and coating/substrate materials on formation and properties of High Velocity Air Fuel coatings2021Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Thermally sprayed coatings are often used to enhance the surface properties (wear resistance, corrosion resistance, etc.) of engineering components in order to extend their performance and service lifetime. Typically, the industrial components to be coated possess complex geometries and are fabricated using different materials with varied mechanical properties such as hardness, which can influence the deposited coating’s microstructure and its subsequent performance. High-velocity air fuel (HVAF) process is a relatively new thermal spray processing technique that has shown tremendous potential to deposit high performance coatings for durable industrial components. However, so far, no studies have been reported on HVAF sprayed coating formation mechanisms in relation to the spray angle, substrate properties (hardness) and coating material composition. Therefore, this work aims to plug the above knowledge gap by systematically examining the influence of spray angle, substrate properties (hardness) and coating material composition (cermet and metallic) on coating formation. For a given coating material, the effect of spray angle and substrate material on coating properties is also investigated.

    In this study, one cermet (WC-Co) and one metallic (Inconel 625) feedstock were deposited onto three different substrates (Aluminum, Steel and Hastelloy) utilizing different spray angles (40º, 50º, 60º, 70º, 80º and 90º). The preliminary effort at understanding the coating evolution involved splat characteristics analysis as well as careful examination of microstructures of coatings deposited with increasing number of passes. The coating evolution was analysed utilizing SEM/EDS, image analysis (porosity, surface coverage etc.), white light interferometry and micro-indentation technique. The deposited coating’s microstructure, porosity content, hardness, and surface roughness for Inco 625 and WC-CoCr coatings were correlated to the HVAF pro-cessing conditions (spray angle, substrate hardness). Furthermore, to determine the tribological performance, coatings were subjected to dry sliding wear test and the coefficient of friction and specific wear rates were obtained.

    It was shown that, substrate material affects splat formation but not the final coating properties. Spray angle, on the other hand, displayed a strong effect on coating formationand on some of the final coating properties such as micro-hardness and coating roughness.To the author’s knowledge, this study demonstrates the first approach to investigate deposition behaviour of different HVAF coating materials.

  • 246.
    Filipiak, David
    University West, Department of Engineering Science, Division of Production Systems.
    Deposition of Alloy 718 using robotized laser metal wire deposition2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aerospace industry wishes to investigate the possibilities of additive manufacturing (AM) processes to produce parts with improved design flexibility in cost-effective and environmentally friendly ways, serving as a complement to today's conventional manufacturing methods. MERLIN is an EU-funded research project constituting of University West and GKN Aerospace Sweden AB among others, with focus on developing AM for productivity improvements, monitoring and control techniques as well as thermal management strategies.

    The aim of this thesis work was to investigate the possibilities to build up a defined deposit geometry of Alloy 718 filler material onto flat Alloy 718 substrate plates by using the robotized laser metal wire deposition (rLMD-w) process. Alloy 718 belongs to the superalloys, a metal group that have been commonly used in aircraft engine and gas turbine applications due to their excellent material properties at elevated temperatures. The focus of the thesis was directed towards investigating the process stability and deposited material quality. A set of iterative experimental process trials combined with metallographic evaluations were conducted at the facilities of Production Technology Centre (PTC), in close collaboration with GKN Aerospace Sweden AB.

    The results revealed that both the deposition process and the microstructure are favored by maintaining a low delta-temperature throughout the welding build-up. Two thermal management strategies were applied, with their combined use showing to have the most beneficial outcome to the deposit quality. The delta-temperature effect is believed to have connections to hot cracking mechanisms and the relative cracking susceptibility of superalloys.

    The work conducted within this thesis was not able to succeed in building a deposit completely free from material defects. The final experiment geometry was however greatly improved regarding smooth and repeatable material transfer, with only minor online adjustments being necessary by the operator. The material defects in the form of lack of fusion and cracks were also immensely decreased in both size and quantity, compared to initial trials. The last deposit built, incorporating both thermal management strategies, resulted in no lack of fusion defects and only one micro-sized crack of 363 μm found between the top two layers of the geometry (layer 9 and 10).

  • 247.
    Flink, Erik
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Yassin, Mohamed
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Customer value analysis on case packer/palletizer machines in pharmaceutical industry2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The study was conducted with company X, which works with supplying machine solutions for pharmaceutical companies. They wanted to know the potential of case packer/palletizer machines that produce tape-sealed boxes, the customer value for the case packer/palletizer, which customer segments can be identified for the machine and to identify if the machine fits in today’s pharmaceutical market. From the background, a purpose was established that was to explore the customer value and customer segmentation for case packer/palletizer machines producing tape-sealed boxes. To achieve this purpose, the authors interviewed pharmaceutical companies to gather the information needed. Therefore, it was necessary to pick a method for interviews, interviews analysis, and benchmarking.

    Theories that were used in the study are business model canvas and value proposition canvas to gather information for the current situation analysis. The value proposition canvas is also used to help and identify the customer value with the help of other models like the Kano model and marketing mix. For the current situation analysis, a business model canvas and value proposition canvas were made for a general case packer/palletizer supplier. Important information about serialization and aggregation was gathered. Benchmarking was done to help to make questions for the interviews with pharmaceutical companies.

    The result of the interview analysis was that customer basic needs are elevated for the case packer/palletizer in the kano model. The reason being the products and packaging are heavily regulated by governments and customers because of their importance to patient’s health. It was also gathered that flexibility and package safety are important for the customer value on case packer/palletizer machines. From the interview’s analysis, the customer segment was divided into four categories which are case packer/palletizer in one, case packer individual as a machine, palletizer individual as a machine, and unknown solutions. Customers find the case packer/palletizer to be expensive compared to the machine being a small part of the production line, but they also know that the machine is essential for the safety of the products. When it comes to the future work of this thesis it is recommended to furthermore interview relevant and knowledgeable people in the pharmaceutical industry about case packer/palletizer. This includes interviewing and gather data from the suppliers of the case packer/palletizer. 

  • 248.
    Florent, Manon
    University West, Department of Engineering Science.
    Thermal Barrier Coatings on Electron Beam – Powder Bed Fusion additive manufactured substrates: coatings deposition and investigation2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aerospace industry is increasingly using the Additive Manufacturing (AM) to produce Nickel-based superalloy components with complex geometries. The use of this manufacturing technology is particularly focused on the development of hot-section components for gas turbine engines, which require increased efficiency. An increase in their operating temperatures could be achieved by developing cooling channels components using AM processes such as Electron Beam – Powder Bed Fusion (EB-PBF) and protecting them with Thermal Barrier Coatings (TBCs). Thermal Barrier Coatings have been used for several decades in the gas turbine industry to protect conventionally manufactured components from the high-temperature environment. The objective of this work is to evaluate the surface, the microstructure, and the functional properties of TBCs deposited on EB-PBF additive manufactured substrates.

    In this study, Thermal Barrier Coatings were sprayed onto HAYNES®282® superalloy AM substrates manufactured by the EB-PBF process. For reference, Thermal Barrier Coatings sprayed onto HAYNES®282® forged substrates have also been prepared. The TBC bondcoats were sprayed by the High Velocity Air-Fuel (HVAF) process using NiCoCrAlY powder feedstock. Seven different spray runs were performed to deposit the TBC top-coats by the Suspension Plasma Spraying (SPS) process using different parameters and two different suspensions of 8wt.% Yttria-Stabilized Zirconia (8YSZ). Characterizations were then carried out on the samples.

    The results obtained showed that the deposition of the bond-coats reduces the roughness and asperities of the AM substrates caused by the EB-PBF manufacturing method. The Thermal Barrier Coatings exhibit vertically cracked and columnar microstructures depending on the suspensions and spray parameters used. The TCF lifetimes obtained for the Thermal Barrier Coatings on the AM substrates were not lower than those achieved for the Thermal Barrier Coatings on the standard substrates. The deposition of Thermal Barrier Coatings on substrates made by Additive Manufacturing process results in microstructures similar to what could be obtained on conventional substrates. 

  • 249.
    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.

  • 250.
    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.

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