Os modelos de programação e controle Constant Work-In-Process (CONWIP) e Drum-Buffer-Rope (DBR) são mecanismos bastante conhecidos na literatura de Planejamento e Controle da Produção, especialmente, pela robustez e bom desempenho. Esses modelos já foram comparados, sobretudo, em ambientes do tipo flow shop. Há muitos trabalhos que apontam o DBR como superior, outros que sugerem equivalência entre ambos e, em menor proporção, casos onde o CONWIP foi melhor. Contudo, estudos comparativos em ambientes mais complexos, como sistemas com montagem, ainda são escassos na literatura. Diante do exposto, a presente tese visa comparar o CONWIP e o DBR em um ambiente de montagem (assembly flow shop) contra pedido. Para tanto, foram desenvolvidos dois modelos de simulação por eventos discretos e um experimento hierárquico-cruzado, com os seguintes fatores: modelo de programação e controle, posição do gargalo, severidade do gargalo e limite de buffer. Os mecanismos foram avaliados quanto aos indicadores tempo médio de fluxo, lead time médio, utilização do gargalo, percentual de ordens atrasadas e atraso médio. Os resultados demonstraram que, para o ambiente em análise, os modelos se mostraram estatisticamente semelhantes, havendo diferenças significativas apenas para a variável tempo médio de fluxo, o que ratifica e estende conclusões de estudos anteriores. Há evidências de que o CONWIP realiza um controle mais efetivo do estoque em processo e não é significativamente afetado pelas diferentes posições do gargalo. Para o CONWIP, os melhores resultados foram identificados quando a restrição estava no início do sistema, enquanto que para o DBR os melhores resultados foram quando o gargalo estava na última estação da linha de fabricação (operação anterior a montagem). / The Constant Work-In-Process (CONWIP) and Drum-Buffer-Rope (DBR) scheduling and control models are well known mechanisms in the Production Planning and Control literature, especially for robustness and good performance. These models have already been compared, especially, to flow shop environments. There are many papers that point to DBR as superior, others that suggest equivalence between both and, less often, cases were CONWIP was better. However, comparative studies in more complex environments, such as assembly systems, are still rare in the literature. Therefore, this thesis aims to compare CONWIP and DBR in a make-to-order assembly flow shop environment. For that, two models of discrete event simulation and a crossed and nested experiment were developed, with the following factors: scheduling and control model, bottleneck position, bottleneck severity and buffer limit. The mechanisms were evaluated with respect to the indicators mean flow time, mean lead time, bottleneck utilization, percentage tardy and mean tardiness. The results showed that, for the environment under analysis, the models were statistically similar, with significant differences only for the variable mean flow time, which ratifies and extends the conclusions from previous studies. There is evidence that CONWIP performs more effective control of order release and is not significantly affected by the different bottleneck positions. For the CONWIP, the best results were identified when the constraint was at the beginning of the system, while for the DBR the best results were when the bottleneck was at the last station of the manufacturing line (before assembly operation).

With the success of Revenue Management (RM) techniques over the past three decades in various segments of the service industry, many manufacturing firms have started exploring innovative RM technologies to improve their profits. This dissertation studies RM for make-to-order (MTO) and make-to-stock (MTS) systems. We start with a problem faced by a MTO firm that has the ability to reject or accept the order and set prices and lead-times to influence demands. The firm is confronted with the problem to decide, which orders to accept or reject and trade-off the price, lead-time and potential for increased demand against capacity constraints, in order to maximize the total profits in a finite planning horizon with deterministic demands. We develop a mathematical model for this problem. Through numerical analysis, we present insights regarding the benefits of price customization and lead-time flexibilities in various demand scenarios. However, the demands of MTO firms are always hard to be predicted in most situations. We further study the above problem under the stochastic demands, with the objective to maximize the long-run average profit. We model the problem as a Semi-Markov Decision Problem (SMDP) and develop a reinforcement learning (RL) algorithm-Q-learning algorithm (QLA), in which a decision agent is assigned to the machine and improves the accuracy of its action-selection decisions via a “learning" process. Numerical experiment shows the superior performance of the QLA. Finally, we consider a problem in a MTS production system consists of a single machine in which the demands and the processing times for N types of products are random. The problem is to decide when, what, and how much to produce so that the long-run average profit. We develop a mathematical model and propose two RL algorithms for real-time decision-making. Specifically, one is a Q-learning algorithm for Semi-Markov decision process (QLS) and another is a Q-learning algorithm with a learning-improvement heuristic (QLIH) to further improve the performance of QLS. We compare the performance of QLS and QLIH with a benchmarking Brownian policy and the first-come-first-serve policy. The numerical results show that QLIH outperforms QLS and both benchmarking policies.

Postponement is widely recognised as an approach that can lead to superior supply chains, and its application is widely observed as a growing trend in manufacturing. Form postponement (FPp) involves the delay of final manufacturing until a customer order is received and is commonly regarded as an approach to mass customisation. However, while much is written in the literature on the benefits and strategic impact of FPp, little is still known about its application. Thus this research project aims to address how FPp is applied in terms of the operational implications within the manufacturing facility. Here the ‘postponed’ manufacturing processes are performed in the factory where the preceding processes are carried out. An in-depth case study research design was developed and involved case studies at three manufacturing facilities, which provided diverse contexts in which to study FPp applications. Each case study incorporated multiple units of analysis which were based around product groups subject to different inventory management policies – FPp, make to order (MTO) and make to stock (MTS). The same research design was used in each study and involved both qualitative and quantitative evidence. Qualitative evidence was gathered via structured interviews and included the operational changes required to apply FPp in a previously MTO and MTS environment. Eleven quantitative variables, providing a broad based measurement instrument, were compared across the three units of analysis to test the hypotheses. This combination of qualitative and quantitative evidence in the case studies helped to triangulate the research findings. Comparison between the three case studies provided further conclusions regarding operational implications that were context specific and those which were not. The research concludes that the manufacturing planning system presents a major obstacle to the application of FPp in a MTO and MTS environment. In spite of this, and even when the FPp application is flawed, the benefits of FPp still justify its application. The research also contributes two frameworks: one which determines when FPp is a viable alternative to MTO or MTS; and another that illustrates the major operational implications of applying FPp to a product exhibiting component swapping modularity.

The goal of the thesis is to point out usability budgets for the management of a specific company and also reviews existing usage all the tools of managerial accounting to support management. Thesis analyzes utilization budgets and other tools of managerial accounting as an information medium for control of production to order on the premises of a particular company. The theoretical part gives basic matte, which reveals the specificities of made-to-order production and its management techniques, requiring appropriate linked information support. The practical part analyzes the kind of production, the organizational arrangements and the appropriateness of the use of existing instruments of managerial accounting, in specific company. Thesis suggests the possibility of introducing new tools in company or editing existing instruments for improving their benefits.

No description available.

Empresas de manufatura contratada terão sucesso se conseguirem definir sua estratégia por meio do desenvolvimento de competências operacionais alinhadas aos requisitos do mercado, direcionando decisões e ações que as impulsionem a obterem um melhor desempenho. As incertezas, tanto de produtos como de volumes que serão demandados, envolvidas no relacionamento com as empresas-cliente reduzem a oportunidade de um planejamento antecipado da produção, requerendo, então, uma política de atendimento da demanda do tipo make-to-order (MTO). O grande desafio enfrentado pelas empresas que operam no ambiente MTO é atender à demanda do cliente de forma rápida e confiável, ou seja, respeitando-se os prazos e as quantidades requeridos. O objetivo geral deste trabalho foi analisar como práticas do sistema Lean Manufacturing (LM) poderiam ser efetivamente implementadas em conjunto a um sistema de planejamento e controle da produção (PCP) apropriado, visando ao desenvolvimento de competências operacionais alinhadas à política MTO. Os objetivos específicos do estudo concentraram-se em identificar na literatura as principais competências operacionais requeridas no ambiente MTO, discutir o processo de implementação de práticas do sistema LM e comparar, conceitualmente, sistemas de PCP. A empresa de manufatura contratada escolhida para este estudo representava um caso puro da utilização da política MTO, dada a natureza de seu relacionamento com os clientes. A aplicação da metodologia pesquisa-ação permitiu que o estudo fosse conduzido de forma participativa e com uma abordagem de solução de problemas, além de fornecer um roteiro de referência, relacionando as etapas da pesquisa aos conceitos abordados na literatura. Como resultado, verificou-se que a adoção de práticas do sistema LM auxilia de forma significativa no desenvolvimento de competências operacionais em empresas que operam em ambientes MTO. No entanto, é necessário que estas práticas estejam associadas a um sistema de PCP apropriado - Workload Control (WLC) - para que se obtenham os resultados esperados. / Contract manufacturing companies will succeed if they can define their strategy through the development of operational competencies aligned to market requirements, directing decisions and actions that lead them to have a better performance. The relationship with the hiring firm involves multiple products and demand uncertainty, reducing the opportunities for advanced planning, requiring a make-to-order (MTO) demand management policy. The main challenge faced by companies operating in an MTO environment is to achieve high delivery reliability in terms of order quantities and delivery schedules. The general objective of this study was to analyze how Lean Manufacturing (LM) practices could be effectively implemented together with an appropriate production planning and control system (PPC), aiming to develop operational competences aligned to the MTO policy. The specific objectives of this study include identifying in the literature the main operational competencies required to operate on a MTO basis, discussing the LM implementation process and comparing conceptually PPC systems. The contract manufacturing company chosen for this study operated according to a MTO policy due to the nature of its relationship with the customers. The application of the action research methodology allowed conducting the study in a participative manner, using a problem solving approach and providing a reference guide relating the action research steps to concepts discussed in the literature review. As a result, it was found that the adoption of LM practices contributes substantially to the development of operational competences in companies operating in an MTO environment. However, it is necessary that these practices are associated with an appropriated PPC - Workload Control - to obtain the expected results.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-04-23T19:33:59Z No. of bitstreams: 1 Ariel Peixoto Possebon.pdf: 3073454 bytes, checksum: 3123d6ee99ea9509d9a3ef1e02464701 (MD5) / Made available in DSpace on 2015-04-23T19:33:59Z (GMT). No. of bitstreams: 1 Ariel Peixoto Possebon.pdf: 3073454 bytes, checksum: 3123d6ee99ea9509d9a3ef1e02464701 (MD5) Previous issue date: 2013-01-31 / Nenhuma / O Planejamento, Programação e Controle da Produção e dos Materiais é um importante processo do fluxo de informação que visa o desdobramento do Planejamento Estratégico para os níveis operacionais da empresa. Tais atividades, planejamento e programação, são atividades analíticas que envolvem a tomada de decisões que impactam na operação dos sistemas de produção. Para tomar estas decisões de forma correta, estes processos precisam da robustez necessária para auxiliar tais decisões. Na contrapartida, os sistemas de produção são diferentes aumentando ou diminuindo sua complexidade e consequentemente a forma como a empresa toma suas decisões. Neste contexto, este estudo pretende evidenciar quais são as diferenças existentes sob o prisma do PPCPM para dois tipos de sistemas de produção, os sistemas que atendem à demanda baseado em uma produção Make-To-Order (MTO), e os sistemas baseado em uma produção Make-To-Stock (MTS). Para tanto, a pesquisa foi realizada utilizando um Estudo de Caso múltiplo, considerando o PPCPM como sua unidade de análise. A partir desta análise, obteve-se como resultados desta pesquisa, as principais diferenças entre os processos de PPCPM para estes dois tipos de sistemas de produção com base nos casos estudados. / The Production Planning and Production Scheduling processes are important flow of information aimed at the deployment of the Strategic Planning for the operational levels of the company. Such activities, planning and scheduling, are analytical activities that involve making decisions that affect the operation of production systems. To make these decisions so correct, these processes require robustness needed to support these decisions. In contrast, the different production systems are increasing or decreasing its complexity and consequently how the company makes its decisions. In this context, this study aims to highlight what are the differences through the prism of PPCPM for two types of production systems, systems that meet the demand based on a production Make-To-Order (MTO), and systems based on a production Make-To-Stock (MTS). Therefore, the survey was conducted using a multiple case study, considering the PPCPM as unit of analysis. From this analysis, it was obtained as result of this research, the main differences between the PPCPM processes for these two types of production systems based on case studies.

In the make-to-order (MTO) industry, offering competitive due dates and on-time delivery for customer orders is important to the survival of MTO companies. Workload control is a production planning and control approach designed to meet the need of the MTO companies. In this dissertation, a multi-agent workload control methodology that simultaneously deals with due date setting, job release and scheduling is proposed to discourage job early or tardy completions. The earliness and tardiness objectives are consistent with the just-in-time production philosophy which has attracted significant attention in both industry and academic community. This methodology consists of the order entry agent, job release agent, job routing and sequencing agent, and information feedback agent. Two new due date setting rules are developed to establish job due dates based on two existing rules. A feedback mechanism to dynamically adjust due date setting is introduced. Both new rules are nonparametric and easy to be implemented in practice. A job release mechanism is applied to reduce job flowtimes (up to 20.3%) and work-in-process inventory (up to 33.1%), without worsening earliness and tardiness, and lead time performances. Flexible job shop scheduling problems are an important extension of the classical job shop scheduling problems and present additional complexity. A multi-agent scheduling method with job earliness and tardiness objectives in a flexible job shop environment is proposed. A new job routing and sequencing mechanism is developed. In this mechanism, different criteria for two kinds of jobs are proposed to route these jobs. Two sequencing algorithms based on existing methods are developed to deal with these two kinds of jobs. The proposed methodology is implemented in a flexible job shop environment. The computational results indicate that the proposed methodology is extremely fast. In particular, it takes less than 1.5 minutes of simulation time on a 1.6GHz PC to find a complete schedule with over 2000 jobs on 10 machines. Such computational efficiency makes the proposed method applicable in real time. Therefore, the proposed workload control methodology is very effective for the production planning and control in MTO companies.

Nowadays, many companies attempt to adapt their production planning and strategy to make order fulfillment more flexible. In manufacturing, the capacity and capability constraints are key factors which need efficient production planning for controlling service level and minimizing inventory cost. This thesis focuses on looking for the economic and efficient strategies for Capability to Promise or CTP handling. This strategy is proposed to work for Low Volume/High Mixed product manufacturing. Moreover, SAP is used as Enterprise Resource Planning (ERP) system for steering the CTP handling strategies in order to increase automated order handling regarding cost efficiency. The results of this research are both concepts and implementations on how to set CTP handling by using SAP, regarding the demand uncertainty environment in Make to Order (MTO) fulfillment.

The difficulties in responding to variation in product order mixes and load levels effectively in make to order are known. Most of the existing approaches consider releasing jobs to the shop (input control), changing capacity levels (output control) in a controlled way, order acceptance with different definitions of work load and due date assignment. Controlling the processes, routing options and the order accepting capacity with various tool combinations that will decrease tool loading are not considered properly. However the manufacturing flexibility provided by the computer numerically controlled (CNC) machines, provides both part variety and due date achievement given a reasonable extra capacity. Positive effects of flexibility on the due date achievement of the make to order is shown with a variety of experimental and field studies leaving little doubt. However taking flexibility only as a strategic issue and not considering it as a means of planning and management in either the short term or medium term decisions have been commonplace practice. In this study, benefits of providing three kinds of flexibility, considering order pool and acceptance probability of the new arrivals in a periodic setting, is the focal issue. If the required flexible environment is provided, the necessity to make a detailed job loading, route planning and scheduling will be reduced to a low level and a high shop congestion and due date achievement will be realized simultaneously. A typical realistic shop with a scaled part mix is assumed in the flexibility management modeling and simulation experiments are conducted applying periodical flexibility planning approach. These experiments briefly support the ideas that worth of anticipation is more than plain expectations and flexibility improves robustness.