Since the production is aimed at fulfilling specific needs of demanding customers and not at filling warehouses, the production volume should reflect the volume of orders. In times of fight for the client every order ...
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Since the production is aimed at fulfilling specific needs of demanding customers and not at filling warehouses, the production volume should reflect the volume of orders. In times of fight for the client every order has to be performed on time. What is more, in times of fight for shortening the delivery cycle, meeting safe deadlines, that is distant in time, is not enough. Companies are forced to meet short deadlines with keeping the product price competitiveness condition. It is hardly possible without a proper, APS (Advanced Planning System) class, advanced planning support system. Currently, advanced planning systems are coming into use, however their cost exceeds the possibilities of small and medium enterprises and algorithms used often require great customization to industries' needs and conditions of unit and small-batch production. The paper has been drawn on the basis of research on overloads of moving bottlenecks in conditions of unit and small batch production in real conditions having a big number of resources and tasks. The methods used so far are not capable of finding the global optimum of such big data ranges. The author took on building a heuristic algorithm which could find solution good enough and based on TOC (Theory of Constraints) assumptions and verification of assumptions using tests in real production systems.
This work presents the development and implementation of. a production scheduling system for an electrical appliance manufacturer. based on recent advances in optimisation-basedscheduling approaches, two different so...
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This work presents the development and implementation of. a production scheduling system for an electrical appliance manufacturer. based on recent advances in optimisation-basedscheduling approaches, two different software architectures based on two different scheduling formulations, namely the RTN and the STN, are proposed to integrate information available in the different production units and stages with formal algorithmic tools. optimization results indicate that significant economic benefits can be achieved (e.g. minimization of total operating costs) while ensuring full customer satisfaction as opposed to normal practices followed in the company relying on human expertise. The work indicates that it is possible to solve real-life manufacturing problems using optimization-based approaches but the integration of information in a timely fashion seems to be a major factor in successfully implementing the system and fully realizing its benefits.. (c) 2005 Elsevier Ltd. All rights reserved.
scheduling is a key factor for manufacturing productivity. Effective scheduling can improve on-time delivery of products, reduce inventory, cut lead times, and improve the utilization of bottleneck resources. This stu...
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scheduling is a key factor for manufacturing productivity. Effective scheduling can improve on-time delivery of products, reduce inventory, cut lead times, and improve the utilization of bottleneck resources. This study was motivated by the design and implementation of a scheduling system for the manufacturing of Toshiba's gas insulated switchgears. The manufacturing is characterized by significant machine setup times, strict local buffer capacities, the option of choosing a few alternative processing routes, and long horizon as compared to the time resolution required. This problem has been recognized to be extremely difficult because of the combinatorial nature of integer optimization and the large size of the real problem. Our goal is thus to obtain near-optimal schedules with quantifiable quality in a computationally efficient manner. To achieve this goal, a novel integer optimization formulation with a separable structure is developed, and a solution methodology based on a combined Lagrangian relaxation, dynamic programming, and heuristics is developed. The method has been implemented using the object-oriented programming language C++, and numerical testing shows that the method generates high-quality schedules in a timely fashion to achieve on-time delivery of products and low inventory. Through explicit consideration of setups, tanks with the same processing requirements tend to be processed together to avoid excessive setups. The integrated treatment of machines and buffers facilitates the smooth flow of parts through the system. The embedded routing selection mechanism also balances the load among candidate routes. Finally, the newly developed "time step reduction technique" implicitly establishes two time scales to reduce computational requirements without much loss of modeling accuracy and scheduling performance, thereby enabling the resolution of long horizon problems with controllable computational requirements.
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