Stoneridge, Inc. is an independent designer and manufacturer of highly engineered electrical and electronic components, modules and systems principally for the automotive, commercial vehicle, motorcycle, agricultural and off-highway vehicle markets. A subsidiary of Stoneridge, Inc. is the company Stoneridge Electronics. They specialise in instrument clusters and tachographs which are manufactured in high quantityin their production plant in Örebro, Sweden. This master thesis focuses on the production line of an instrument cluster called Angela. In close collaboration with Stoneridge Electronics, the goal was to find ways to improve the output of the Angela line by at least 10% compared to the three best months in terms of output from the year before. The Angela line was analyzed thoroughly and from different perspectives using lean tools such as value stream mapping, spaghetti diagram and continuous improvement. Finally, the simulation software ExtendSim was used in order to simulate and analyse different suggestions. The results show that various steps can be taken to improve the efficiency and output of the manufacturing line by as much as 16.3%. Due to the fact that other production lines within the production are similar to the one that the project was carried out on, the project results could be applicable for the other lines as well. / Stoneridge, Inc. är en oberoende designer och tillverkare av högteknologiska elektriska och elektroniska komponenter, moduler och system huvudsakligen för fordonsmarknaderna. Ett dotterbolag till Stoneridge, Inc. är företaget Stoneridge Electronics. De är specialiserade på instrument kluster och färdskrivare som tillverkas i produktionsanläggning i Örebro. Denna examensarbete fokuserar på produktionslinje av ett instrumentkluster som heter Angela. I nära samarbete med Stoneridge Electronics,målet var att hitta sätt att förbättra produktionen av Angela linje med minst 10 % jämförtmed de tre bästa månaderna när det gäller produktion från året innan. Angela-linjen analyserades grundligt och från olika perspektiv med lean verktyg som värdeflödesanalys, spaghetti diagram och kontinuerlig förbättring. Slutligen användes simuleringsprogrammet ExtendSim för att simulera och analysera olika förslag. Resultaten visar att olika steg kan vidtas för att förbättra effektiviteten och produktionen av produktionslinjen med så mycket som 16.3%. På grund av att andra produktionslinjer inom produktionen liknar den som projektet genomfördes på, kan projektresultaten vara tillämpliga för andra linjer också.

The research aims to investigate the lack of cohesive workflow of production lines within a company, exploring the factors and dynamics at play. It also seeks to analyze the identified issues, focusing on their root causes and potential impacts on operational efficiency. An important aspect of the research is the consideration of value stream mapping (VSM). The methodology is based on a literature review and a single-case study. The literature review, including a systematic review, was conducted to identify existing practices. To explore the research objectives, a case study was performed, examining the industrial implementation and challenges of using the VSM tool. The current state VSM was designed and analyzed, identifying various types of waste within the workflow. Based on this analysis, a future state VSM was recommended to address the inefficiencies. The field of study is well-researched but has a notable gap regarding the application of VSM in complex industrial settings. The research identified inadequacies for using and implementing VSM in organizations, aiming to fill this gap. The research concluded that while there are several benefits to using VSM, there are also challenges that need to be addressed. To bridge these challenges and support decision-making in the improvement process, the study proposes specific recommendations. The study faced limitations, particularly in data collection due to time constraints and validity concerns. The data collection period was limited to less than two months. Additionally, the complexity of the data led to generalizations in the creation of the VSM. This "good enough" approach, however, is not deemed to significantly affect the study's overall validity or reliability. By providing a systematic way of mapping, the research enhances operational efficiency by more efficient use of resources, reduced cycle times, improving process flow, and facilitating better decision-making. These efforts lead to improved overall performance within the company.

Thesis (PhD (Industrial Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Injection moulding of polymer components is subject to ever increasing demands for improved part quality and production rate. It is widely recognised that the mould cooling strategy employed is crucial to achieving these goals. A brief overview of injection moulding units and different types of injection moulds is given. The modern Additive Manufacturing (AM) technology for processing metal powders such as Direct Metal Laser Sintering (DMLS) and Selective Laser Melting (SLM) offers almost full freedom to the mould designer. Some of these modern manufacturing methods based on metal powders, which are able to produce complex cooling channels are analysed. A drastic change has entered the mould design domain - shifting the paradigm from design for manufacture to manufacture for design. In combination with suitable AM methods the concept of surface cooling moulds can now be efficiently implemented. This study presents a new approach of predicting the minimum cooling time required for the produced part. Different cooling layouts are analysed taking the heat transfer into consideration. The lumped heat capacity method is implemented in this research in order to determine the minimum cooling cycle time required. A new approach was developed to determine the most suitable cooling layout configuration, such as conventional cooling, conformal cooling or surface cooling, required for a moulded part based on its characteristics such as shape complexity, space available for the cooling layout, part quality requirements, production volume, and product life cycle. A mould cooling design process including simulation, reverse engineering and manufacturing of the mould insert was implemented in this study. In order to validate the generic model developed during the course of this research comparative experiments were carried out to determine the difference in performance of injection moulding using conventional or surface cooling methods. The experimental results showed a significant improvement in part quality produced with reduced cycle times using the surface cooling method. / AFRIKAANSE OPSOMMING: ‘Injection Moulding’ van polimeer komponente word al meer gedruk vir verbeterde kwaliteit en vinniger produksie tyd. Dit is orals bekend dat die gietvorm afkoeling strategie ‘n groot rol speel om hierdie twee doelwitte te bereik. Eers word ‘n kort oorslag gegee van ‘Injection Moulding’ eenhede en van verskillende ‘Injection Moulding’ vorms. Die moderne Aditatiewe Vervaardigingstegnologie vir die prosessering van metaal poeiers soos bv. Direkte Metaal Laser Sintering (DMLS) en Selektiewe Laser Smelting (SLM) bied basies volle vryheid ten opsigte van gietvorm ontwerp. Party van die moderne vervaadigings metodes, wat op metaal poeiers gebaseer is, wat komplekse koelings kanale kan produseer word geanaliseer. Die ontwerpers arena het ‘n groot verandering ondergaan deurdat die fokus van ontwerp vir vervaardiging verskuif het na vervaardiging vir ontwerp. In kombinasie met toepaslike aditatiewe vervaardigings metodes kan oppervlak verkoeling nou effektief geïmplementeer word. Hierdie studie bied a nuwe manier om die minimum verkoelings tyd benodig vir ‘n part te voorspel. Verskeie verkoelings uitlegte word geanaliseer waar hitte oordrag in ag geneem word. Die “lumped heat capacity” metode word gebruik om die minimum siklus tyd te bepaal. ‘n Nuwe benadering is ontwikkel om die mees geskikste verkoelings uitleg soos bv. konvensionele verkoeling, konvorme verkoeling of oppervlak verkoeling te bepaal vir ‘n spesifieke part gebaseer op die part se vorm kompleksiteit, spasie beskikbaar vir verkoelings kanale, kwaliteit vereistes en produk lewensiklus. Die volgende is in die studie geïmplementeer: ‘n vorm verkoelings ontwerp proses met simulasie, ‘reverse engineering’ en vervaardiging van die vorm insetsel. Om die generiese model te verifieer gedurende die studie is vergelykende eksperimente uitgevoer om die verskil in prestasie te bepaal tussen die gebruik van konvensionele en oppervlak verkoelings metodes. Die eksperimentele resultate het ‘n beduidende verbetering in part kwaliteit getoon met ‘n verkorte siklus tyd tydens die gebruik van die oppervlag verkoelings metode.

This dissertation is concerned with the tail asymptotics of queueing networks with subexponential service time distributions. Our objective is to investigate the tail characteristics of key performance measures such as cycle times and waiting times on a variety of queueing models which may arise in many applications such as communication and manufacturing systems. First, we focus on a general class of closed feedforward fork and join queueing networks under the assumption that the service time distribution of at least one station is subexponential. Our goal is to derive the tail asymptotics of transient cycle times and waiting times. Furthermore, we argue that under certain conditions the asymptotic tail distributions remain the same for stationary cycle times and waiting times. Finally, we provide numerical experiments in order to understand how fast the convergence of tail probabilities of cycle times and waiting times is to their asymptotic counter parts. Next, we consider closed tandem queues with finite buffers between stations. We assume that at least one station has a subexponential service time distribution. We analyze this system under communication blocking and manufacturing blocking rules. We are interested in the tail asymptotics of transient cycle times and waiting times. Furthermore, we study under which conditions on system parameters a stationary regime exists and the transient results can be generalized to stationary counter parts. Finally, we provide numerical examples to understand the convergence behavior of the tail asymptotics of transient cycle times and waiting times. Finally, we study open tandem queueing networks with subexponential service time distributions. We assume that number of customers in front of the first station is infinite and there is infinite room for finished customers after the last station but the size of the buffer between two consecutive stations is finite. Using (max,+) linear recursions, we investigate the tail asymptotics of transient response times and waiting times under both communication blocking and manufacturing blocking schemes. We also discuss under which conditions these results can be generalized to the tail asymptotics of stationary response times and waiting times. Finally, we provide numerical examples to investigate the convergence of the tail probabilities of transient response times and waiting times to their asymptotic counter parts.

Dans le processus de fabrication en fraisage à grande vitesse ‘FGV’, l’étude de la réaction de la machine au cours de l’usinage est une tâche très délicate et importante. En effet, l’identification du comportement de la machine nécessite la modélisation de la loi de mouvement des axes et de la trajectoire réelle aux niveaux des discontinuités. Le nombre important de discontinuités engendrent une instabilité de la vitesse de déplacement des axes, ce qui implique une augmentation du temps d’usinage et un non-respect de la vitesse d’avance programmée, se traduisant par des problèmes de productivité et une sous-estimation du coût de l’usinage pour l’industriel. L’objectif de cette thèse est de développer un outil informatique qui permet de calculer la vitesse d’avance et de faire une estimation précise du temps de cycle pour n’importe quelle trajectoire générée par un logiciel de FAO. Pour ce faire, nous avons déterminé un modèle qui permet d’identifier le comportement cinématique des axes d’un centre d’usinage en FGV pour toute forme de trajectoire. À partir de la modélisation de la variation de la vitesse d’avance, nous avons déterminé le temps réel selon les trajectoires et l’erreur imposée par le bureau des méthodes. Enfin, nous utilisons ces résultats pour mettre en place une méthodologie pour l’aide au choix du diamètre de l’outil et de la stratégie d’usinage. Afin de valider les modèles et les méthodologies développés, une étude expérimentale a été réalisée sur des applications didactiques et industrielles. / In the context of high speed milling ‘‘HSM’’, the feed rate does not always reach the programmed value during the machining process which implies an increase of machining time and non-compliance with the programmed feed rate. This phenomenon leads to productivity issues and an underestimation of the cost of machining for the industry.The aim of this study is to develop a computerised tool in order to automate the determination process of the evolution of the feed rate for an imposed error and the estimation of cycle time and production cost. To begin with,a modeling approach in order to evaluate feed rate during any type of discontinuity between linear and circular contours in different combination by taking into account the specific machining tolerances.is presented. Then, the cycle time will be estimated with a maximum error of 7% between the actual and the prediction cycle time. The proposed method permits to develop a methodology to determine the optimal diameter of the tool and the optimal strategy. Finally, an industrial application was carried out in order to validate models and to determine the influence of feed rate evolution on the cycle time.

This thesis deals with the optimisation of the selected manufacturing process. The aim is to analyse the effectiveness of the selected welding and assembly lines. Another objective is to do a detailed analysis for the line with the lowest efficiency in terms of cycle time and the Overall Equipment Effectiveness and calculate the lost production time due to availability, performance and defects. The third objective is to identify possible measures leading to higher utilization of manufacturing line and to propose a possible implementation. The theoretical part is based on the literature examining the term standardization, the norms of labour intensity, the cycle time, the Total Productive Maintenance and the calculation of the Overall Equipment Effectiveness. In the practical part the profile of Car manufacturing is being presented, the analysis of secondary data to calculate the Overall Equipment Effectiveness is being done and the appropriate manufacturing line for the innovative plan is being selected. Furthermore, the analysis of secondary data regarding the effectiveness of the using time of the manufacturing line is being done, the calculation of the Overall Equipment Effectiveness and the collection of primary data is being carried out. Subsequently, the problematic spots of the manufacturing line are being found and the possible measures leading to higher efficiency of manufacturing line are being proposed.

The constant needs for the reduction of companies operational costs has transformed Inventory into a targeted source for this end by upper management. The high investment value that it represents for organizations, aside from the immediate contribution to cash flow, when it is reduced, allows inventory to be a source of strategic advantage. The objective of this study is to understand the behavior of independent variables such as production cycletime or lead-time, daily demand rate of finished product and the interval between production orders and their effects on the determination of an inventory policy. The study is performed in a manufacturing company that produces intermittent, repetitive small batches and a large variety of products. Cash flow techniques are applied to detail the production processes and respective planning. The historical data of mentioned variables refer to the period from January 2000 to February 2002. These data are used to develop the calculations of safety stock and average and maximum stock from the viewpoint of the management approach in Replenishment Point and Periodically Review. The real application of the data available from the company is studied to calculate the inventory policy. It is concluded that, in spite of the adoption of a sophisticated mechanism of production planning and a strong culture of measurements by the company, the statistical data of fundamental variables are not utilized systematically to determine the inventory policy. This fact confirms the thesis that inventory reductions, in general, are circumstantial and is not supported by fundamental techniques. / A constante necessidade de redução dos custos operacionais das empresas tem transformado o Inventário em fonte preferencial, para este fim, pela alta administração. O alto valor de investimento que ele representa para as organizações, além da contribuição imediata no fluxo de caixa, quando da sua redução, faz com que o inventário seja uma fonte de vantagem competitiva.O objetivo deste estudo é compreender o comportamento das variáveis independentes como tempo de ciclo da produção ou lead-time, taxa diária de demanda do item de produto acabado e tempo de intervalo entre ordens de produção, e os seus efeitos no cálculo de uma política de inventário.O estudo é realizado em uma empresa de manufatura de produção intermitente repetitiva em lotes de pequenas quantidades e grande variedade de produtos.Técnicas de fluxo de valor são aplicadas para detalhamento dos processos de produção e do seu respectivo planejamento. Os dados históricos das variáveis mencionadas referem-se ao período de janeiro de 2000 a fevereiro de 2002. Com estes dados, desenvolvem-se os cálculos de estoque de segurança, estoque médio e máximo,sob a óptica das abordagens de gerenciamento por Ponto de Reposição e Revisão Periódica. Analisa-se a real aplicação dos dados disponíveis na empresa, para o cálculo da política de inventário. Conclui-se que apesar de ser adotado mecanismo sofisticado de planejamento de produção e haver uma forte cultura de medições por parte da empresa, os dados estatísticos das variáveis fundamentais não são utilizados de forma sistemática para o cálculo da política de inventário. Este fato confirma a tese de que as reduções de inventário, de uma maneira geral, são circunstanciais e não sustentadas por fundamentos técnicos.

Lean production is one of the proven approaches for identifying and eliminating the activities that do not add value to the customers and delivering and provide the best possible quality service to customers. Implementation of lean is deemed to be feasible in any organization regardless of its size or industry background. For initiating lean in an organization there are many tools, techniques and approaches that are available. Value Stream Mapping (VSM) is one such tool that is touted as cost-effective and easy to be implemented. This thesis proposes to conduct Value Stream Analysis (VSA) at at e-commerce (online) department at the case company to understand their material and information flows by analyzing the current state and develop implementable solutions to improve the overall productivity of the online deliveries. The tasks to perform are: · To map the current state value stream. · To identify wastages and propose solutions to eliminate them. · To provide productivity improvement proposals. A mix of quantitative and qualitative methods were used in this study for data collection and data analysis. This project, which is designed as a longitudinal case study that pri-marily focuses on gathering accurate, real-time data related to the product family, and on drawing a visual representation of the current materials and information flow. VSM has been implemented and the data were analysed. The results obtained from this study concludes that, VSM is an appropriate technique to initiate lean ways of work in larger firms that lacks sufficient knowledge and experience on lean. In addition to it, produc-tivity improvement proposals provided in this study are considered to be key factors in initiating lean transformation in an organization from a technical point of view while, management support and acceptance of change is necessary from an organizational point of view. This thesis will be useful to researchers, professionals and others con-cerned subject to understand the significance of value stream mapping in larger e-com-merce logistic firms.

This thesis deals with the analysis of data obtained by observing and measuring workplaces of assembly lines with a focus on the efficiency of their utilization, through selected elements of industrial engineering, which the reader can get acquainted with in the theoretical part of the thesis. In this thesis the line productivity during the shifts is analyzed, an ideal line balancing condition is defined and suggestion for changing the time of line consumption norm according to the measured line cycle time is made. According to the complex analyzes of the workplaces, suggestions are concluded and an economic appreciation of these proposals is also elaborated. The author of this thesis finds the main benefit of this work in increasing of the productivity of the analyzed line in the case of implementation of solution designs.

Despite decades of automation initiatives, manual assembly still represents one of the most cost-effective approaches in scenarios with high product variety and complex geometry. It represents 50% of total production time and 20% of total production cost. Understanding human performance and its impact in the assembly line is key in order to improve the overall performance of an assembly line. Along this thesis work, by studying the deviations occurring in the line, it is aimed to understand how human workers are affected by certain functioning aspects of the assembly line. To do so, three different influence factors have been chosen, and then observed its impact in human performance: i. How past events occurring in the line affect the current action of the worker. ii. How do scheduled stops affect the current action of the worker. iii. How does theoretical cycle time affect the performance of the worker. In order to observe these influence relationships, it has been used data gathered in the shop floor from SCANIA's Manufacturing Execution System (MES). By applying methods of Knowledge Discovery in Database (KDD) data has been indexed and the analyzed providing the necessary results for the study. Finally, from the results shown, it can be inferred that variability on the functioning of the line does have an impact on human performance overall. However, due the complexity of the manufacturing system, impact in human performance might not be as regular as initially thought. / Trots decennier av automatiseringsinitiativ utgör manuell montering fortfarande en av de mest kostnadseffektiva metoderna i scenarier med hög produktsortiment och komplex geometri. Den representerar 50% av den totala produktionstiden och 20% av den totala produktionskostnaden. Att förstå mänsklig prestanda och dess inverkan i monteringsledningen är nyckeln för att förbättra den totala prestandan hos en monteringslinje. Utöver detta avhandlingsarbete, genom att studera avvikelserna som uppstår i linjen, syftar det till att förstå hur mänskliga arbetstagare påverkas av vissa fungerande aspekter av monteringslinjen. För att göra det har tre olika inflytningsfaktorer valts och sedan observerat dess inverkan i mänsklig prestation: i. Hur tidigare händelser som uppstår i linjen påverkar arbetarens nuvarande åtgärder. ii. Hur påverkar planerade stopp arbetstagarens nuvarande åtgärder. iii. Hur påverkar teoretisk cykeltid arbetarens prestation. För att observera dessa inflytningsrelationer har det använts data som samlats in i butiksgolvetfrån SCANIAs Manufacturing Execution System (MES). Genom att tillämpa metoder för Knowledge Discovery i Database (KDD) har data indexerats och analyseras vilket ger de nödvändiga resultaten för studien. Slutligen kan det framgå av de visade resultaten att variationen i linjens funktion har en inverkan på den mänskliga prestationen övergripande. På grund av tillverkningssystemets komplexitet kan emellertid effekten i mänsklig prestanda inte vara så regelbunden som ursprungligen tänkt.