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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.
1

Résolution de problèmes d'ordonnancement survenant dans l'industrie capillaire. / Solutions for scheduling problems arising in capillary industry

Belaïd, Rabah 07 December 2011 (has links)
Les travaux présentés dans cette thèse abordent la minimisation de coûts de production dans uneindustrie de produits douches et capillaires. Dans cette industrie, le processus de production inclus deuxétapes successives : la fabrication des lots de produit cosmétique et le stockage intermédiaire de ces derniers.Les coûts de production sont essentiellement liés aux opérations de lavage des ressources de fabrication etde stockage intermédiaire. Ces opérations de lavage doivent être effectuées lors de la succession des lots vuleur différentes caractéristiques physiques (couleur, viscosité,...) et chimiques (contenus chimiques,...).Ce problème est décomposé en deux sous-problèmes. Le premier consiste en l'optimisation du stockageintermédiaire. Le site dispose de plusieurs cuves de stockage, de différentes capacités, disposées en parallèle.Le rôle de ces cuves de stockage est de contenir temporairement les lots. Résoudre ce problème équivautà calculer les affectations des lots sur les cuves ainsi que leur date de début de transfert. L'objectif est deminimiser le nombre d'opérations de lavages des cuves de stockage.Le second sous-problème consiste à optimiser la fabrication des lots. Le site comprend plusieurs sallesde fabrication disposées en parallèle. Chaque salle de fabrication est constituée par plusieurs machinesorganisées en Flowshop Hybride. Pour résoudre ce problème, il faut calculer une affectation des lots sur lessalles de fabrication et les ordonnancer sur les machines de celles-ci. L'objectif est de minimiser le nombred'opérations de lavage induites par la succession des lots sur les machines.Nous proposons de résoudre le sous-problème d'optimisation du stockage intermédiaire en premier lieu,pour ensuite résoudre le sous-problème d'optimisation de la fabrication. Nous proposons et expérimentonsplusieurs méthodes heuristiques (gloutons, colonies de fourmis, méthodes arborescentes tronquées, méthodes dédiées) pour la résolution de chaque sous-problème. Les meilleures méthodes de résolution sontdestinées à être intégrées dans un logiciel de planification de la production quotidienne. / The work presented in this thesis addresses the minimization of production costs in an industry ofshowers and hair products. In this industry, the production process consists in two successive steps : themaking of cosmetic products and the intermediate storage of these latter. Production costs are mainlyrelated to cleaning operations of the making and the storage resources. These cleaning operations must beperformed in the sequence of two different batches of cosmetic product because of their different physical(color, viscosity, ...) and chemical (chemical contents,..) characteristics.This problem is decomposed into two sub-problems. The first one is the optimization of intermediatestorage. The shop is made up of parallel storage tanks of various capacities. These storage tanks haveto temporarily store the batches. Solving this problem is equivalent to calculating the assignment of thebatches on the storage tanks and their starting date of transfer. The objective is to minimize the numberof cleaning operations of the storage tanks.The second sub-problem is the optimization of the making process of the batches. The shop gathersseveral making units arranged in parallel. Each making unit consists in multiple mixing machines organizedin hybrid flowshop. To solve this problem, we have to calculate an assignment of the batches on the makingunits and their schedule on the mixing machines. The objective is to minimize the number of cleaningoperations.We propose to solve the sub-problem of optimization of the intermediate storage first, and then solvethe sub-problem of the optimization of the making process. We propose and experiment several heuristics(greedy, ant colonies, truncated tree methods, dedicated methods) for solving each sub-problem. The bestsolution methods are designed to be integrated into a software production planning.
2

Kartläggning av kapacitetsutnyttjandet och ställtider på Stålöv AB : Survey of the use of capacity and set up times at Stålöv AB

Nilsson, Marie, Hagström, Pernilla January 2006 (has links)
The aim of this report is to analyse the use of the capacity at the CNC (computer numerical control) cutters and show how the level of set up time for these cutters at Stålöv AB. This assignment is concrete whereas there are no subjective questions to this matter and there are only cold figures presented. Production economy is getting more important as the competition hardens and there are several different ways to increase productivity and efficiency in a company. In order to increase productivity and efficiency work studies are used to, through an analysis, find developments in methods that result in improved work methods and to establish the time that are used. Increased production of different parts and customer driven production in combination with increased demands on rationalisation of capital have led to an enlarged interest for shorter set up times in the production. To point out the use of capacity and the set up time of the cutters at Stålöv AB we used frequency studies. Frequency studies are work measure methods based on random observations on predetermined events to calculate the relative occurrence of these events. The purpose is to present the objective cold figures that show the use of capacity for all machines and totally. The compilation of the seven CNC cutters shows that the use of capacity reaches 33 %. The lack of machine operators is the single largest reason, 45 % of the total use of capacity. The set up time reaches 6 % totally of the 36 hours of observation of the machines. The study of the separate CNC cutters shows that the result follows the result of the compilation of all machines; the main reason why the use of capacity is low depends on the lack of machine operators. This means that if the demand increases there will not be enough operators to meet this demand. If using SMED, the set up time percentage share of the total use of capacity are too large, but the production of prototypes that supplies great value to the company may justify the set up times. By using Total Productive Maintenance (TPM), based on the elimination of breakdowns and defective products, the stability in production and the use of capacity may increase.
3

Kartläggning av kapacitetsutnyttjandet och ställtider på Stålöv AB : Survey of the use of capacity and set up times at Stålöv AB

Nilsson, Marie, Hagström, Pernilla January 2006 (has links)
<p>The aim of this report is to analyse the use of the capacity at the CNC (computer numerical control) cutters and show how the level of set up time for these cutters at Stålöv AB. This assignment is concrete whereas there are no subjective questions to this matter and there are only cold figures presented.</p><p>Production economy is getting more important as the competition hardens and there are several different ways to increase productivity and efficiency in a company. In order to increase productivity and efficiency work studies are used to, through an analysis, find developments in methods that result in improved work methods and to establish the time that are used. Increased production of different parts and customer driven production in combination with increased demands on rationalisation of capital have led to an enlarged interest for shorter set up times in the production.</p><p>To point out the use of capacity and the set up time of the cutters at Stålöv AB we used frequency studies. Frequency studies are work measure methods based on random observations on predetermined events to calculate the relative occurrence of these events. The purpose is to present the objective cold figures that show the use of capacity for all machines and totally.</p><p>The compilation of the seven CNC cutters shows that the use of capacity reaches 33 %. The lack of machine operators is the single largest reason, 45 % of the total use of capacity. The set up time reaches 6 % totally of the 36 hours of observation of the machines.</p><p>The study of the separate CNC cutters shows that the result follows the result of the compilation of all machines; the main reason why the use of capacity is low depends on the lack of machine operators. This means that if the demand increases there will not be enough operators to meet this demand.</p><p>If using SMED, the set up time percentage share of the total use of capacity are too large, but the production of prototypes that supplies great value to the company may justify the set up times.</p><p>By using Total Productive Maintenance (TPM), based on the elimination of breakdowns and defective products, the stability in production and the use of capacity may increase.</p>

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