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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Kritikalitetsanalys på virapressar / Criticality analysis of belt filterpresses

Ahlinder, Anton January 2019 (has links)
Föreliggande arbete utfördes på Ortvikens pappersbruk i Sundsvall som tillverkar pappersmassa och papper. Inom pappersmasseproduktionen finns flera virapressar, vilket är en sorts torkmaskin som pressar vattnet ur pappersmassan. För att kunna hålla en hög tillgänglighet på maskinutrustningen har det 2010 genomförts en kritikalitetsanalys, där pressarna klassades utefter deras egenskaper, speciellt hur viktiga de är för resten av processen. Baserad på denna klassning fördes de in i en underhållsplan, som säkerställer effektivt underhåll och ett långsiktigt förbättringsarbete på utrustningen. För att se om klassningen fortfarande håller utförs i detta arbete en ny utredning och klassning på tre av dessa virapressar. Som del i analysen undersöks de vanligaste och kostsammaste felen under de senaste 13 åren. Den nya kritikalitetsklassningen skiljer sig från den tidigare på några punkter, främst angående underhållsmässighet och felfrekvens. Detta har ingen påverkan på slutklassningen, men det är värt att notera om man vill använda klassningen som underlag för andra ändamål. Den historiska utredningen visar att de vanligaste felet är virahaveri och att en av pressarna som ansetts vara trasig oftast faktiskt också har varit det. Slutbetyget av nya klassningen blir samma som den förra, dock ändras några av delkriterierna. / This work was carried out at Ortvikens paper mill in Sundsvall, which produces pulp and paper. Inpulp production, there are several belt filter presses, which is a kind of dryer that squeezes thewater out of the pulp. In order to maintain a high level of availability of the machine equipment,all equipment is classified according to their properties, especially how important they are for therest of the process. This is to include them in a maintenance plan to be able to plan and performefficient maintenance and long-term improvement work on the equipment. In order to be able tocarry out more correct preventive maintenance and continued improvement work, a newinvestigation and classification of three of these belt filter presses is needed. As a part of thisinvestigation, the most common and costly technical faults in the last 13 years are examined. Thenew criticality classification differs from the previous one in a few points, mainly maintenanceand failure rate, which have been overlooked during the prior classification. This has no effect onthe final classification, but it is worth noting in case the classification is used as a basis for otherpurposes. The historical investigation shows that the most common fault is a wire breakdownand that one of the presses that was considered to be broken most often, has actually been justthat. The investigation shows that the new criticality classification gives the same result as theprevious one, but that there are changes in some of the individual criteria.

Kundorderstyrd tillverkning och kontinuerliga flöden : En fallstudie utförd på Mercado Medic AB, Lidingö Stockholm / Customer based production planning, and continuous production flow

Larsson, Christoffer January 2020 (has links)
The study was conducted at the organisation Mercado Medic AB, whohad problems regarding production planning in one of their assemblysections. The assembly section that was studied produces componentsthat are later to be used in the assembly of medically customizedchairs. The study examines both how work is conducted in thesection, and how orders are communicated to and within said section.Data was collected by observing the assembly section, and byinterviewing both the personnel and planning manager. Cycle-timeswere also measured for the activities that are carried out withinthe section. The data was then analysed with theories originatingfrom the sphere of quality management and Toyota Production Systems.The analysis shows that the current state of communications to, andwithin the section, is vertical. Orders are communicated frommanagement top – down, thus having the section produce componentswithout an actual need from downstream sections. This way ofproducing is more commonly known as a "push-system".The study presents, based on the analysis, a future state for howthe use of a kanban system and a simplified and balanced workflowwould solve the problem currently had with production planning. Thisway of producing is more commonly known as a "pull-system". Thefuture state is recommended to be implemented by the personnel inthe form of "experiments" (PDSA/PDCA-cycles), thus allowing thepersonnel to learn more about their process while experimenting.Lastly, it is important to note that the future state that thisstudy presents is not necessarily the best state that can be. Oncethe future state presented in this study is achieved, a new andimproved future state should be made. It is the endeavour ofstriving towards a continuously evolving future state that ensurescontinuous improvements.

Development of a process for environmental life cycle investigations

Berntsson, Erik, Dimgård, Albin January 2022 (has links)
As a result of increasing interest in sustainable development, the subject of this report is the exploration of methods to analyse the environmental impact of car components. The project is conducted as a case study, and the theory section is a literature study where several scientific articles about life cycle assessment (LCA) and environmental analysis are examined alongside previously performed LCAs, books about the subject, and ISO standards. The ISO14040-series provides a structure for the basic methodology used in this report, both to organise the theory section as well as the resulting process. The theory concludes with a 7-step process for conducting life cycle investigations, primarily for car components. The first step contains the ISO standard’s requirements of defining goal and scope. Steps 2-6 then process the data collection of different phases during the life cycle and the 7th and final step is a compilation and calculation of the data. The developed process aims to provide a fast and simple way of analysing the environmental impact for a product as the development work is progressing. To validate the functionality of the process and to further refine the process, it is used to perform an analysis of energy use and CO2 emissions during the life cycle of an active car bonnet device. This validation includes definitions of goal, scope, functional unit, and a Process Flow Chart in the first step.Steps 2-6 includes the data collection for raw materials, additional processes, use phase, end-of-life, and the transports related to the manufacturing of the investigated product. The last step of the validation is to compile the product’s energy use and CO2 emissions. The study also provides a suggestion for a table, called Life Cycle Eco Data Table, to use when conducting a life cycle investigation using the process, to get an overview of the environmental data. The conclusion is that the developed process is easy to use and aspires to high quality as it is based on scientific research.

From reactive maintenance towards increased proactiveness through digitalisation : Vital factors to achieve momentum towards preventive maintenance using digital tools

Liedberg, Jesper January 2021 (has links)
At today's manufacturers, reactive maintenance mostly takes place instead of prevention. At the same time, maintenance is seen as a necessary evil and many companies have no direct strategies or goals for maintenance. In today's maintenance, Industry 4.0 with digitalisation has begun research in and new methods and ideas are produced for more efficient maintenance. The purpose of this study is: To increase the knowledge of how manufacturers can understand and develop a strategy to achieve preventive maintenance and at the same time find essential elements for maintenance digitalisation.   Through a literature study, the existing research in prevention and digitalisation in maintenance was studied. To supplement, a single-case study was also conducted that included interviews from a manufacturing company that has reactive maintenance. Two focus groups were also conducted, one on the case company but also on another manufacturing company to compare the answers to the theory.   The study shows that there are several root causes that cause manufacturers to remain in reactive efforts in maintenance and it can be difficult to get out. This creates expensive costs for the manufacturer and stress for the maintenance operators. To get out and move towards more prevention, it is important to start with the basics, which is to have a strategy that has been jointly agreed within the organisation. Therefore, it is also important with training and choosing the right kind of maintenance depending on the machine and complexity. The last research question is more complex and it turned out that there are factors in digitalisation where manufacturing companies with reactive maintenance develop and use.   By understanding the causes and seeing elements to deal with preventive maintenance, manufacturers can practically use the study to achieve their maintenance goals. Regarding digitization, it is a step further and try to see if it is practical to implement at a company with reactive maintenance.   The study only covered information about a specific machine that is the base for generalisation within the case company factory plant. At the same time, the study focused only on the step between reactive and preventive maintenance in order to delimit the theoretical part.

Uppbyggnad av kvalitetsledningssystem enligt ISO 9001 : En analysstudie för förberedelse inför certifiering av ISO 9001:2015

Garbac, Michelle, Hedberg, Oscar January 2021 (has links)
This report presents the performance and results of an analysis study conducted at a small company in the foundry business. The purpose of the study has been to prepare the company for a certification of the quality standard ISO 9001: 2015. The reason for the study is to create a foundation for a future quality management certification for a small company that wants to develop its business and expand its customer base. The study begins with a description of the problem, which involves an examination of the gap that exists between the company's current quality management system and the requirements of ISO 9001. The collection of all essential information in the form of relevant theories and data has taken place through theory research and informative meetings with the company's management. The workflow is described to clarify what the process looked like. A description of the current situation is given to gain understanding of the starting point and to have as a basis for analysis of deficient functions and processes within the business. In the analysis a comparison is made of the current situation with the requirements set in the ISO 9001 standard, and then proposals for measures to cover the analyzed gaps are presented. The results of the study give the company a thorough description of what measures are required to be able to accomplish an approved certification. The study provides suggestions for concrete measures such as which platform can be used to create a quality management system, which managing documents should be included, suggestions for quality goals and how these should be measured regularly. Descriptions of important core processes in the form of routines with associated templates have been produced to create continuity. With the help of these measures, a suggestion of a functioning management system was presented that is suitable for the smaller business.

Hur ledare kan påverka delaktighet hos medarbetare

Kamal Ali, Alex, Lindblom, Patrik January 2020 (has links)
Forskning har visat att ledarskap har en betydande roll för att påverka delaktighet hos medarbetarna och för att nå framgång. De två hörnstenarna engagerat ledarskap och att skapa förutsättningar för delaktighet valdes från Bergman och Klefsjös (2012) hörnstensmodell. Syftet var att skapa en ökad förståelse för hur ledare kan påverka delaktighet hos medarbetare genom att inse sambandet mellan ledarens betende och medarbetarnas grad av delaktighet.Studien utfördes på två kommunala avdelningar i Norge. Resultaten kommer från en enkätundersökning med 30 respondenter och intervjuer genomförda med tre ledare från arbetsplatserna. En mixad forskningsmetod tillämpades och från enkätens resultat har författarna sett samband mellan enkätens olika faktorer. Resultatet från enkäten har tillsammans med citat från intervjuer med ledarna bidragit till studiens resultat.Resultaten visade att en ledare som ger möjlighet till medarbetarna att vara delaktiga vid besluttagande tillfällen bidrar till motivation och arbetstillfredsställelse hos medarbetarna. Vidare visar studien att en faktor som påverkar delaktighet är en ledare som har tillit till sina medarbetare och ger stöd samt delegerar ansvar och befogenheter. Studiens resultat visar betydelsen av hur en ledare kommunicerar och ger stöd till medarbetarna. Stöd och kommunikation har en avgörande betydelse för att positivt kunna påverka medarbetarnas delaktighet. / Research has shown that leadership plays a significant role in influencing employee participation and achieving success. The two cornerstones involved leadership and creating the conditions for participation were chosen from Bergman and Klefsjö's (2012) cornerstone model. The aim was to create a better understanding of how leaders can influence employee participation by realizing the relationship between the manager's behavior and the employees' level of participation.The study was conducted at two municipal departments in Norway. The results come from a survey with 30 respondents and interviews conducted with three leaders from these departments. A mixed research method was applied, and from the results of the survey the authors have seen the connection between the different factors of the survey. The results show that the survey, together with citations from interviews with the leaders, have contributed to the study's results.The results show that a leader who gives the employees the opportunity to participate in decision making creates motivation and job satisfaction among the employees. Furthermore, the study shows that a factor that influences participation is a leader who has confidence in his or her employees and provides support and delegates both responsibility and authority. The results of the study also show that how a leader communicates and gives support to employees is of crucial importance in influencing employee participation / <p>2020-06-26</p>

Fallstudie om hantering av transportrelaterade kvalitetsbrister : En fallstudie på ett möbeltillverkande företag / Case study on managing transportrelated quality defects

Fredén, Adam, Svanström, Marcus January 2023 (has links)
Företag X är en organisation som värderar kvalitet högt. Detta företag tillverkar möbler med sin utgångspunkt i Sverige. Inom svensk industri uppskattas kvalitetsbristkostnader stå för 10–30 % av omsättningen. Företaget är bekymrade över de stora antalet reklamationer som uppstår, anledningar till detta kan vara konstruktionsfel, leverantörsfel och transportskador. Transportskadorna som företag X har står för ca 20 % gentemot alla de andra reklamationstyper företaget har identifierat. Syftet med detta arbete är att bidra till utveckling av kvalitetsarbetet på företag X och minska de kvalitetsbristkostnaderna som uppstår vid transportrelaterade reklamationer. För att kunna besvara syftet ställs frågorna:  Vad är rotorsakerna till reklamationer i samband med transport?  Vilka åtgärder kan vara lämpliga för företaget att implementera för att minska transportrelaterade reklamationer?  Hörnstensmodellen som tillhör offensiv kvalitetsutveckling används för att besvara frågeställningarna. Utöver teorin som presenteras används metoden fallstudie för att besvara frågeställningarna.   Resultatet pekar mot att det befintliga transportkonceptet för utleverans till kund anses vara ett bra koncept. Däremot så avviker de förutsättningar som finns för konceptet. Avvikelser leder till att chaufför och montörer tvingas till extra hantering av produkter, exempelvis omplacering av produkter i lastbil. Varje omplacering skapar en extra hantering som anses öka risken för skada på produkten. Extra hantering blir en huvudorsak till att reklamationer uppstår. Den andra huvudorsaken som identifieras är att ett stort antal defekta produkter från produktion når kund, vilket i affärssystemet är en transportskada.  Utifrån dessa huvudorsaker bedrivs två workshops med mål att identifiera flertalet avvikande förutsättningar, orsaker till att de avviker och till slut åtgärderna för avvikelserna. Resultatet av frågeställningarna är att det presenteras 36 rotorsaker med tillhörande åtgärdsförslag. Åtgärdsförslagens lämplighet verifieras av experter på företaget och en åtgärdslista tas fram utifrån en prioriteringsmatris.  Sammanfattningsvis konstateras arbetet uppfylla dess syfte. Om företaget följer den åtgärdslista som presenterats så förväntas transportskadorna minska och arbetssättet går senare att ta med sig i framtida förändringsarbeten samt även inom andra organisationer som upplever liknande problematik. / Company X is an organization that values quality highly. This company manufactures furniture with its base in Sweden. Within the Swedish industry, quality-related costs are estimated to account for 10-30 % of the turnover. The company is concerned about the high number of complaints that arise, which may be due to design flaws, supplier errors, and transportation damages. Among the types of complaints identified, the transportation damages account for approximately 20 % for company X. The purpose of this work is to contribute to the development of quality work at company X and reduce the quality-related costs associated with transportation-related complaints. To answer the purpose, the following questions are posed:  What are the root causes of complaints related to transportation?  What actions may be appropriate for the company to implement in order to reduce transportation-related complaints?  The cornerstone model, belonging to offensive quality development, is used to address these questions. In addition to the presented theory, the case study method is used to answer the questions.  The results indicate that the existing delivery concept to customers is considered a good concept. However, there are deviations from the conditions of the concept. Deviations lead to additional handling of products by drivers and assemblers, such as product rearrangement in the truck. Each rearrangement creates additional handling, which is deemed to increase the risk of product damage. Extra handling becomes a major cause of complaints. The second major cause identified is that a large number of defective products from production reach the customer, which is classified as transportation damage in the business system.  Based on these root causes, two workshops are conducted with the aim of identifying multiple deviating conditions, reasons for the deviations, and eventually, the actions to address the deviations. The result of the research questions is the presentation of 36 root causes with associated action proposals. The suitability of the action proposals is verified by experts within the company, and an action list is developed based on a prioritization matrix.  In conclusion, the work is found to fulfill its purpose. If the company follows the presented action list, it is expected that transportation damages will decrease, and the approach can be applied in future change efforts and even within other organizations experiencing similar issues.


El Masry, Sheila January 2022 (has links)
Logistics is a talked about but also difficult to define concept as this concept has several different interpretations. Actually, logistics is primarily about more efficient material flows, which in turn should create more efficient work processes in production. In literature research, knowledge has been sought about efficient logistics and lean, which in turn led to investigating the various areas and factors that lead to waste. Logistics within the construction industry, and not least production, is today an area that is well debated and is one of the more important aspects to achieve more efficient production. Based on the knowledge gathered, a measurement tool has since been developed which is intended to be used within construction production to measure the actual efficiency of logistics. This means that the tool can, if desired, be used in more projects than those processed and treated in this scientific report. This scientific report will answer the following questions: 1. What shortcomings are found in logistics in the construction industry 2. Are there one or more widespread deficiencies? 3. Develop a measurement tool that should be able to measure the efficiency of logistics in projects within construction production. The result shows that with well-planned logistics, more efficient logistics can be achieved and thus profit can be achieved in the form of both time and money. This scientific report will provide an insight into the field of logistics during construction production. Furthermore, the work will highlight the shortcomings that appear in the efficiency of logistics within the investigated projects and give suggestions on how this can be remedied.

Towards a learning organization for product development

Cronemyr, Peter January 2000 (has links)
The costs of late changes due to earlier misunderstandings in product development are very high, even though no company wants to admit how high they really are. From experience in Swedish industry and based on results from previous research found in the literature, the conclusion is drawn that people need to talk to one another to be able to understand one another and thereby avoid misunderstandings. Information technology can be used to increase the frequency and amount of information communicated within a product development organization but it cannot replace talking. This project aims at delivering methods that are intended to improve effectiveness of product development, i.e. fewer misunderstandings will contribute to improved quality and, as a consequence, lowered costs and shortened lead-times. The project also aims at delivering a method that is intended to improve organizational learning, which would in turn improve a company’s ability to adapt more easily to a changing environment. The ultimate goal and vision is more competitive companies. The following contributions to the theory of Engineering Management are presented in this thesis: (i) ‘An Engineering Management Model for Improvement of Organizational Learning’ is a theoretical model of how three management disciplines can be used together to improve organizational learning within a product development organization, based on the framework of Senge’s five disciplines. (ii) ‘Phantom Turbine Development’ is a presentation of how people engaged in development of technology and processes for product development can share goals and visions based on future customer needs. (iii) ‘Process Improvement Simulations’ are a method for simulating and comparing improvements to the development process before they actually take place. (iv) ‘Knowledge Overlapping Seminars (KOS)’ are a communication method for engineers in a product development team with the purpose of eliminating misunderstandings. Obstacles that occur in ‘ordinary meetings’ are avoided in a KOS. Action research has been used as research method. It has been performed at ABB STAL, a company developing gas and steam turbines, where the researcher of this project is employed. The approach used, collaborative action inquiry, is characterized by the researcher having an almost total identification with the activities and direction of change of the company, which is the case since the research is to a great extent based on the researcher’s own experience. / Kostnaderna för ändringar sent i produktutvecklingsprojekt på grund av missförstånd tidigare i projektet är mycket höga, även om inget företag vill erkänna hur höga de verkligen är. Baserat på erfarenheter från svensk industri och på resultat från tidigare forskning inom området drasslutsatsen att människor måste tala med varandra för att kunna förstå varandra och därmed undvika missförstånd. Informationsteknik kan användas för att öka frekvensen och mängden information som kommuniseras inom en produktutvecklingsorganisation men den kan inte ersätta samtal mellan människor. Detta forskningsprojekt har som mål att presentera metoder som ska kunna användas för att förbättra måluppfyllelsen vid utveckling av nya produkter, det vill säga färre missförstånd ska ge en förbättrad produkt- och processkvalitet, vilket i sin tur medför sänkta kostnader och förkortade ledtider. Ytterligare ett mål är att presentera en metod för att öka det organisatoriska lärandet, vilket skulle förbättra en organisations förmåga att anpassa sig till förändringar i dess omvärld. Det övergripande målet är mer konkurrenskraftiga företag. Följande bidrag till forskningsområdet Metoder och organisation för ledning av ingenjörsarbete (Engineering Management på engelska) lämnas i denna avhandling: (i) En modell för ledning av ingenjörsarbete är en teoretisk modell av hur tre olika ledningsfilosofier kan användas tillsammans för att förbättra det organisatoriska lärandet inom en produktutvecklingsorganisation baserat på Senges ramverk ‘De fem disciplinerna’. (ii) Fantomturbinutveckling är en presentation av hur ingenjörer som arbetar med utveckling av teknik och process för produktutveckling kan dela mål och visioner baserade på framtida kundbehov. (iii) Simulering av processförbättringar är en metod för att simulera och jämföra förbättringar av en utvecklingsprocess innan de införs. (iv) Kunskapsöverlappningsseminarium (KOS) är en kommunikationsmetod som ingenjörer i ett produktutvecklingsteam kan använda för att eliminera missförstånd. Hinder som uppträder i vanliga möten undviks i KOS. Aktionsforskning har använts som forskningsmetod. Forskningen har utförts på ABB STAL, ett företag som tillverkar gasturbiner och ångturbiner, där författaren till denna avhandling är anställd. Det använda angreppssättet, samverkande aktionsforskning, karaktäriseras av att forskaren i stort sett totalt identifierar sig med företagets aktiviteter och förändringsriktning, vilket väl överensstämmer med forskningen inom detta projekt som till stor del är baserat på författarens egna erfarenheter.

Stratégie de maintenance centrée sur la fiabilité dans les réseaux électriques haute tension

Fouathia, Ouahab 22 September 2005 (has links)
Aujourd’hui les réseaux électriques sont exploités dans un marché dérégulé. Les gestionnaires des réseaux électriques sont tenus d’assurer un certain nombre de critères de fiabilité et de continuité du service, tout en minimisant le coût total consacré aux efforts effectués pour maintenir la fiabilité des installations. Il s’agit de trouver une stratégie, qui répond à plusieurs exigences, comme : le coût, les performances, la législation, les exigences du régulateur, etc. Cependant, le processus de prise de décision est subjectif, car chaque participant ramène sa contribution sur base de sa propre expérience. Bien que ce processus permette de trouver la « meilleure » stratégie, cette dernière n’est pas forcément la stratégie « optimale ». Ce compromis technico-économique a sensibilisé les gestionnaires des réseaux électriques à la nécessité d’un recours à des outils d’aide à la décision, qui doivent se baser sur des nouvelles approches quantitatives et une modélisation plus proches de la réalité physique. Cette thèse rentre dans le cadre d’un projet de recherche lancé par ELIA, et dénommé COMPRIMa (Cost-Optimization Models for the Planning of the Renewal, Inspection, and Maintenance of Belgian power system facilities). Ce projet vise à développer une méthodologie qui permet de modéliser une partie du réseau électrique de transport (par les réseaux de Petri stochastiques) et de simuler son comportement dynamique sur un horizon donné (simulation de Monte Carlo). L’évaluation des indices de fiabilité permet de comparer les différents scénarios qui tentent d’améliorer les performances de l’installation. L’approche proposée est basée sur la stratégie RCM (Reliability-Centered Maintenance). La méthodologie développée dans cette thèse permet une modélisation plus réaliste du réseau qui tient compte, entre autres, des aspects suivants : - La corrélation quantitative entre le processus de maintenance et le processus de vieillissement des composants (par un modèle d’âge virtuel) ; - Les dépendances liées à l’aspect multi-composant du système, qui tient compte des modes de défaillance spécifiques des systèmes de protection ; - L’aspect économique lié à la stratégie de maintenance (inspection, entretien, réparation, remplacement), aux coupures (programmées et forcées) et aux événements à risque (refus disjoncteur, perte d’un client, perte d’un jeu de barres, perte d’une sous-station, etc.).

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