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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.
31

Produktionsoptimering av Fladder-avgradningssystem : Framtagning av layout för materialhanteringen runt   Fladder-avgradningssystem

Sundelin, Niklas January 2019 (has links)
Detta examensarbete genomfördes för att undersöka hur   materialhanteringen runt avgradningssystemet Fladder kan utvecklas och   automatiseras. Behovet uppkom av dagens manuella hantering som är ineffektiv   och tidskrävande och behöver därmed optimeras. Arbetet genomfördes med metodik från   produktutvecklingsprocessen för att erbjuda layout-förslag på hur   materialhantering kan förbättras. Först gjordes en förstudie där en   datainsamling, litteraturstudie och nulägesanalys att identifiera behovet.   Koncept genererades baserat på kraven på systemet och genom olika   beslutsmatriser valdes två lösningar för vidareutveckling. Lösningarna   granskades och analyserades mer i detalj och beräkningar på deras   effektivitet och lönsamhet genomfördes. Lösningarna förfinades och mynnade ut i två layouter på   hur materialhanteringen kan förbättras. Där slutkoncept 1 är ett enkelt   system för situationen idag och slutkoncept 2 är en mer avancerad lösning för   framtida investeringar. / The bachelor   thesis was performed to investigate how material handling around the   deburring system Fladder can be developed and automated. The reason is due to   today's manual handling which is inefficient and time consuming and therefore   needs to be optimized. The work was   carried out with methodology from the product development process to offer   layout suggestions on how material handling can be improved. First, a   feasibility study was conducted in which a data collection, literature study   and current situation analysis were done to identify the needs. Concepts were   generated based on the requirements of the system and through various   decision matrices, two solutions were chosen for further development. The   solutions were reviewed and analyzed in more detail and calculations of their   efficiency and profitability were made. The solutions   were refined and resulted in two layouts on how the material handling can be   improved. The first concept is a simple system for the situation today and   the second concept is a more advanced solution for future investments. / <p>Betyg 2019-07-24</p>
32

Product Development of Material Supply : Implementation of Karakuri Kaizen

Porteiro Paraponiaris, Yanni, Mateos Rodríguez, Arturo January 2019 (has links)
The industry 4.0 is continuously aiming to produce faster, increasing quality, and strictly using what is necessary to achieve efficiency enhancement. Within the wide list of methods used to reach this target, robot automation is usually used, although is expensive and rigid. Alternatively, a Japanese cheap automation philosophy called "Karakuri", is being introduced by Volvo GTO to manage this goal. This thesis relies on this philosophy, which takes profit of the existing energy, like gravity, to put in motion mechanisms, in order to reduce costs and improve the production efficiency by developing a semi-automated material handling system. The design method followed, the Scrum, divides the thesis in several phases of development, presenting a fully developed solution at the end of each one and iteratively increasing the level of definition along the process, to finally provide a solution suitable to be implemented.
33

Load Carriers; Optimized Solution to Improve Performance of Roll containers : A Case Study at VGR-WESTMA Organization

Alimohamadi, Bardia January 2009 (has links)
Roll containers are widely used in transportation and delivery operations due to the high level of flexibility and agility they offer to supply chains. However, there is a negative side to the application of roll containers in industry which can be removed or minimized by proper ergonomic and technical considerations. In this thesis work, the safety problems, economic issues and environmental effects associated with roll containers being used in VGR-WESTMA organization are reviewed in order to come up with alternative solutions to the current way of using old roll containers in their supply chain. The analysis of the problem resulted in ergonomic, safety and technical recommendation on using roll containers within their associated supply chain. The appropriate technical design of roll containers that fits the organization facilities are introduced with the aim of streamlining the supply chain flow within the organization. However, cost is considered as a limiting factor for this organization. Hence, proper ergonomic awareness and use of appropriate accessories to the roll containers are considered as a contemporary alternative solution to replacing roll containers being used in this supply chain.
34

Concurrent design of facility layout and flow-based department formation

Chae, Junjae 17 February 2005 (has links)
The design of facility layout takes into account a number of issues including the formation of departments, the layout of these, the determination of the material handling methods to be used, etc. To achieve an efficient layout, these issues should be examined simultaneously. However, in practice, these problems are generally formulated and solved sequentially due to the complicated nature of the integrated problem. Specifically, there is close interaction between the formation of departments and layout of these departments. These problems are treated as separate problems that are solved sequentially. This procedure is mainly due to the complexity of each problem and the interrelationships between them. In this research, we take a first step toward integrating the flow-based department formation and departmental layout into comprehensive mathematical models and develop appropriate solution procedures. It is expected that these mathematical models and the solution procedures developed will generate more efficient manufacturing system designs, insights into the nature of the concurrent facility layout problem, and new research directions.
35

Internal material handling at Volvo Construction Equipment Braås

Saleh, Fatima, Bartsch, Susann, Steen, Jessica January 2008 (has links)
Background: Material handling is a large part of a company´s internal work and represents between 15 % and 70 % of the total cost of a manufactured product. By improving the internal handling of material, more efficient distribution and manufacturing flows are possible. The material handling process is an input to the production and assembly process that has to be defined and mapped so that it can be improved. The material handling process studied at Volvo CE Braås includes goods receiving, storage, packaging as well as the order/delivery process to assembly, and will finish with the material transport to the assembly line. Research questions: How can the material handling process, from goods receiving to assembly line, at Volvo CE in Braås be described by using VSM? What kinds of waste can be identified? By proposing a future-state map, how can the identified problems and waste be reduced or eliminated? Methodology: This thesis is a descriptive case study and was conducted with a deductive approach. Data was collected by our own observations, personal interviews, statistics, benchmarking and questionnaire. The scientific credibility of this thesis was secured by for example using many sources, avoidance of assumptions, studying a common process and following standardized steps of the VSM tool. Conclusions: The material handling process was described in the separated areas of goods receiving, storage and assembly line. Visualization was given in a current-state map. Five different kinds of waste were identified. Finally, suggestions of improvements were presented along with a future-state map. Suggestions on future research: A more detailed VSM including information flow and lead times could be studied. Scenario simulations of critical areas within the material handling process could be preformed. Furthermore, an ABC classification of articles and storage locations can be done to optimize storage.
36

Analytical Approach to Estimating AMHS Performance in 300mm Fabs

Nazzal, Dima 07 July 2006 (has links)
This thesis proposes a computationally effective analytical approach to automated material handling system (AMHS) performance modeling for a simple closed loop AMHS, such as is typical in supporting a 300mm wafer fab bay. Discrete-event simulation can produce accurate assessments of the production performance, including the contribution by the AMHS. However, the corresponding simulation models are both expensive and time-consuming to construct, and require long execution times to produce statistically valid estimates. These attributes render simulation ineffective as a decision support tool in the early phase of system design, where requirements and configurations are likely to change often. We propose an alternative model that estimates the AMHS performance considering the possibility of vehicle-blocking. A probabilistic model is developed, based on a detailed description of AMHS operations, and the system is analyzed as an extended Markov chain. The model tracks the operations of all the vehicles on the closed-loop considering the possibility of vehicle-blocking. The resulting large-scale model provided reasonably accurate performance estimates; however, it presented some computational challenges. These computational challenges motivated the development of a second model that also analyzes the system as an extended Markov chain but with a much reduced state space because the model tracks the movement of a single vehicle in the system with additional assumptions on vehicle-blocking. Neither model is a conventional Markov Chain because they combine the conventional Markov Chain analysis of the AMHS operations with additional constraints on AMHS stability and vehicle-blocking that are necessary to provide a unique solution to the steady-state behavior of the AMHS. Based on the throughput capacity model, an approach is developed to approximate the expected response time of the AMHS to move requests. The expected response times are important to measure the performance of the AMHS and for estimating the required queue capacity at each pick-up station. The derivation is not straightforward and especially complicated for multi-vehicle systems. The approximation relies on the assumption that the response time is a function of the distribution of the vehicles along the tracks and the expected length of the path from every possible location to the move request location.
37

Concurrent design of facility layout and flow-based department formation

Chae, Junjae 17 February 2005 (has links)
The design of facility layout takes into account a number of issues including the formation of departments, the layout of these, the determination of the material handling methods to be used, etc. To achieve an e&#64259;cient layout, these issues should be examined simultaneously. However, in practice, these problems are generally formulated and solved sequentially due to the complicated nature of the integrated problem. Speci&#64257;cally, there is close interaction between the formation of departments and layout of these departments. These problems are treated as separate problems that are solved sequentially. This procedure is mainly due to the complexity of each problem and the interrelationships between them. In this research, we take a &#64257;rst step toward integrating the &#64258;ow-based department formation and departmental layout into comprehensive mathematical models and develop appropriate solution procedures. It is expected that these mathematical models and the solution procedures developed will generate more e&#64259;cient manufacturing system designs, insights into the nature of the concurrent facility layout problem, and new research directions.
38

Analytical models to evaluate system performance measures for vehicle based material-handling systems under various dispatching policies

Lee, Moonsu 29 August 2005 (has links)
Queueing network-based approximation models were developed to evaluate the performance of fixed-route material-handling systems supporting a multiple workcenter manufacturing facility. In this research, we develop analytical models for fixed-route material-handling systems from two different perspectives: the workcenters?? point of view and the transporters?? point of view. The state-dependent nature of the transportation time is considered here for more accurate analytical approximation models for material-handling systems. Also, an analytical methodology is developed for analytical descriptions of the impact of several different vehicledispatching policies for material-handling systems. Two different types of vehicledispatching policies are considered. Those are workcenter-initiated vehicle dispatching rules and vehicle-initiated vehicle dispatching rules. For the workcenterinitiated vehicle dispatching rule, the Closest Transporter Allocation Rule (CTAR) was used to assign empty transporters to jobs needing to be moved between various workcenters. On the other hand, four different vehicle-initiated vehicle dispatching rules, Shortest Distance Dispatching Rule (SDR), Time Limit/Shortest DistanceDispatching Rule (TL/SDR), First-Come First-Serve Dispatching Rule (FCFSR), Longest Distance Dispatching Rule (LDR), are used to select job requests from workcenters when a transporter is available. From the models with a queue space limit of one at each workcenter and one transporter, two different types of extensions are considered. First, the queue space limit at each workcenter is increased from one to two while the number of transporters remains at one. Second, the number of transporters in the system is also increased from one to two while maintaining the queue space limit of one at each workcenter. Finally, using a simulation approach, we modified the Nearest Neighbor (NN) heuristic dispatching procedure for multi-load transporters proposed by Tanchoco and Co (1994) and tested for a fixed-route material-handling system. The effects of our modified NN and the original NN transporter dispatching procedures on the system performance measures, such as WIP or Cycle Time were investigated and we demonstrated that the modified NN heuristic dispatching procedure performs better than the original NN procedure in terms of these system performance measures.
39

Internal material handling at Volvo Construction Equipment Braås

Saleh, Fatima, Bartsch, Susann, Steen, Jessica January 2008 (has links)
<p>Background: Material handling is a large part of a company´s internal work and represents between 15 % and 70 % of the total cost of a manufactured product. By improving the internal handling of material, more efficient distribution and manufacturing flows are possible. The material handling process is an input to the production and assembly process that has to be defined and mapped so that it can be improved. The material handling process studied at Volvo CE Braås includes goods receiving, storage, packaging as well as the order/delivery process to assembly, and will finish with the material transport to the assembly line.</p><p>Research questions: How can the material handling process, from goods receiving to assembly line, at Volvo CE in Braås be described by using VSM? What kinds of waste can be identified? By proposing a future-state map, how can the identified problems and waste be reduced or eliminated?</p><p>Methodology: This thesis is a descriptive case study and was conducted with a deductive approach. Data was collected by our own observations, personal interviews, statistics, benchmarking and questionnaire. The scientific credibility of this thesis was secured by for example using many sources, avoidance of assumptions, studying a common process and following standardized steps of the VSM tool.</p><p>Conclusions: The material handling process was described in the separated areas of goods receiving, storage and assembly line. Visualization was given in a current-state map. Five different kinds of waste were identified. Finally, suggestions of improvements were presented along with a future-state map.</p><p>Suggestions on future research: A more detailed VSM including information flow and lead times could be studied. Scenario simulations of critical areas within the material handling process could be preformed. Furthermore, an ABC classification of articles and storage locations can be done to optimize storage.</p>
40

Scheduling of Generalized Cambridge Rings

Bauer, Daniel Howard 14 October 2009 (has links)
A Generalized Cambridge Ring is a queueing system that can be used as an approximate model of some material handling systems used in modern factories. It consists of one or more vehicles that carry cargo from origins to destinations around a loop, with queues forming when cargo temporarily exceeds the capacity of the system. For some Generalized Cambridge Rings that satisfy the usual traffic conditions for stability, it is demonstrated that some nonidling scheduling polices are unstable. A good scheduling policy will increase the efficiency of these systems by reducing waiting times and by therefore also reducing work in process (WIP). Simple heuristic policies are developed which provide substantial improvements over the commonly used first-in-first-out (FIFO) policy. Variances are incorporated into previously developed fluid models that used only means to produce a more accurate partially discrete fluid mean-variance model, which is used to further reduce waiting times. Optimal policies are obtained for some simple special cases, and simulations are used to compare policies in more general cases. The methods developed may be applicable to other queueing systems. / text

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