Made available in DSpace on 2016-06-02T19:53:32Z (GMT). No. of bitstreams: 1 PEREZ_MARTINEZ_Karim_2013.pdf: 1435441 bytes, checksum: dc4551ff55ece881790f51193596d2bd (MD5) Previous issue date: 2013-09-27 / Financiadora de Estudos e Projetos / This research deals with the production planning and scheduling problem in the molded pulp packing industry, studying particularly a plant of molded pulp packages for eggs. The production process can be subdivided into two processes: molding process and printing process. The main challenge for production planning activities is on the molding process, where products are produced through tooling that have several molds. These tooling are called "Molding Patterns" or " Conformation Patterns". Each one of the molding patterns can contain one, two, until three kind of molds, allowing to produce several products simultaneously. Producing several products at the time can generate large inventory for low demand products and also null inventory for high demand products. Thus, different inventory levels are defined for each product based on their demand behavior, in order to control inventory quantities. In this way, decisions related to the production planning and scheduling in this production process involve deciding which molding patterns should used, how much time they should be used, and how they should be sequenced. All these should be make taking into account a parallel machine system and sequenced-dependent setups time and costs, in order to minimize inventory and setups costs, as well as penalties associated to inventory out of the specified inventory levels of each product. To represent this problem we proposed two formulations: the first one based on the Capacitated Lot Sizing and Scheduling Problem (CLSP), and the second one based on the General Lot Sizing and Scheduling Problem (GLSP). The results from the models were compared in a set of real word instances of a plant, in order to check the adequacy to represent the decisions involved in the studied production process, as well as the main differences between their production plans and performance of the models. The proposed formulations were also adapted for a particular instance, in order to compare their productions plans against the production plan implement by the studied plant. Results show that the proposed models represent rightly decisions involved in the production planning and scheduling in the molded pulp. Furthermore, the solutions obtained by the proposed models represent production plans with costs significantly lower than the schedule implemented by a real plant in this kind of industry. / Este trabalho aborda o problema de planejamento e programação da produção na indústria de embalagens em polpa moldada, considerando particularmente uma fábrica de embalagens para acondicionamento de ovos. O processo de produção pode ser subdividido em dois processos: processo de moldagem e processo de estampagem. O principal desafio para as atividades de planejamento encontra-se no processo de moldagem, em que a obtenção dos produtos depende da utilização de diferentes ferramentais, formados por um conjunto de moldes. Estes ferramentais são chamados de padrões de conformação ou padrões de moldagem , e podem conter um, dois ou até três tipos de moldes, permitindo a produção simultânea de produtos diferentes. Esta produção simultânea de itens pode gerar grandes níveis de estoque de produtos de baixa demanda e estoques nulos para produtos de alta demanda, desta forma, são definidos diferentes níveis de estoque para cada produto com base no comportamento da sua demanda. As decisões envolvidas no planejamento e programação da produção neste tipo de processo envolve a escolha dos padrões de moldagem a serem utilizados, o tempo de produção de cada padrão, e a sequência em que estes devem ser programados, considerando um sistema de linhas paralelas idênticas e tempos e custos de preparação dependentes da sequência. Estas decisões devem ser definidas de modo a minimizar os custos de estocagem, preparação, e penalidades associadas ao desvio do volume do estoque em relação aos níveis estabelecidos para cada produto. Para representar o problema são propostas dois tipos de formulações: a primeira baseada no Problema de Dimensionamento de Lotes Capacitado (CLSP), e a segunda baseada no Problema de Dimensionamento e Sequenciamento de Lotes Geral (GLSP). Os resultados da resolução dos modelos são comparados com base em exemplares reais da fábrica em estudo, a fim de verificar sua adequação para representar as decisões envolvidas no sistema de produção, as principais diferenças nos planos de produção gerados, e o desempenho destes modelos. Os resultados obtidos demonstram que os modelos propostos representam adequadamente as decisões no sistema de produção estudado, e geram planos de produção significativamente melhores que os planos praticados pela fábrica.

<p>  </p> <p>Available literature indicated that construction projects have been experiencing significant time overruns from their planned duration. In many cases, the primary reasons for project delays were ineffective planning and scheduling methods, poor communication and collaboration between the key stakeholders, and the construction operations and task requirements have been overlooked.</p> <p>Construction project planning and scheduling are extensively studied topics, and several techniques have been developed to solve construction project scheduling problems. Traditional production planning and scheduling techniques are based on the push planning strategy, such as linear and network scheduling techniques. In the traditional method, the project scheduler calculates activity durations and then sequences them to determine when to complete the work. These techniques and planning methods have been criticized for lacking collaboration between project workers and realistic integration of the project time, location, and other essential resources to create a reliable work schedule. Furthermore, the inability to account for site operations, tasks, and workflow leads to waste and delay. </p> <p>Consequently, Ballard and Howell (1990) proposed the last planner system, and then Ballard et al. (2000) further developed the method. In the last planner system, all key stakeholders and the project management team actively communicate and coordinate to accomplish the project’s planned milestones. The last planner system and pull planning scheduling objective is improving workflow and increasing plan reliability. However, the pull planning scheduling method has some limitations. For instance, this method cannot be used to determine the available work capacity in each working space and show how much work can be completed at a given time. In addition, the pull planning and LPS system are highly descriptive and experienced-based, relying on the decision and experiences of the site supervisors. </p> <p>Available literature concerning construction project delay also indicated that ineffective planning and scheduling, slow decision-making, and poor communication and coordination had been the top critical causes of construction project delay.</p> <p>Therefore, this research was conducted to minimize construction project time and cost overrun due to poor scheduling and production planning. The study has been conducted in two main parts. In the first part of this study, critical causes of project delay have been analyzed, and the contribution of poor planning and scheduling to construction project delays in different environments has been assessed. The relative importance index and Spearman’s coefficient techniques have been utilized to analyze the collected data.  The second section of this research work was conducted to investigate the construction scheduling reliability and production efficiency and developed the enhanced production planning and scheduling method to improve schedule reliability and production plan efficiency.  The reason for developing the enhanced production planning and scheduling method was to find the best work option to optimize work duration and efficiently plan required resources per category of the identified activities. In addition, this study has automated the scheduling input data capturing from the project BIM model by utilizing the developed visual program.</p> <p>The study finding in the first section indicated that the top ten critical causes of identified causes of project delay in specified environments were significantly different. However, Ineffective project planning and scheduling had been among the most critical causes in all three conditions. Ineffective planning and scheduling were ranked number one in developed environment conditions, second in developing countries, and fifth in high-risk environments.</p> <p>Study results in the second section have shown that the case study's executed schedule had experienced significant changes in the planned dates of individual tasks, project milestones, and resource allocation. The project schedule critical path and critical activities were changed repeatedly after each update, and the project structure work was delayed for 30 days from its initial plan, as illustrated in figures 33 to 35. Subsequently, the enhanced planning methodology has been applied in the selected case study to validate the developed method and evaluate the result of the case study. The case study implemented work plan has been compared with the enhanced planning-based developed schedule. The total duration of the enhanced planning-based method has been calculated to be 240 work days, which shows 30 days less time from implemented case study plan and 50 days from the project base plan in the construction document, as illustrated in figures 39 to 41. </p> <p>Furthermore, the production schedule sensitivity analysis has shown that the production schedule and the case study base plan tasks duration have not been significantly different since both schedules were created based on the similar size of the work crew, but in terms of the number of the planned task, the production schedule had been created based on the most suitable work option. Another advantage of the production schedule is that it is more reliable because the schedule is created for a shorter duration, not long before the project work starts, and it is created after multiple collaborations and assessment steps. In addition, the developed program in this study using Revit dynamo automated the extraction of input data from the BIM model to create the project schedule. </p> <p>In conclusion, based on the case study results, the enhanced production planning methodology and developed metrics and indices can be applied to various building construction projects to find the most suitable work option and create a reliable and resource-efficient work schedule. </p>