118. Considering the Effects of Pre-Set Service Level and Actual Service Level in a Safety-Stock Based SPIRP
1Gent University, Belgium; 2Department of Industrial Systems Engineering and Product Design, and Flanders Make,
To deal with uncertain demand rates in stochastic periodic inventory routing problem (SPIRP), supply chain planners foresee an extra stock amount, known as “safety stock” at the retailers. This safety stock prevents stock-out and gives the supply chain planner the possibility to offer a level of service assurance to serve the retailers. The pre-set service level for the retailers guarantees the reliability of having the demand rates satisfied at a certain rate during the planning horizon. To prove the guaranteed service level at the retailers, the actual service level is measured in a simulation experiment with multiple scenarios. The problem is that the difference between the actual and pre-set service level does not behave linearly for the different scenarios. In addition, this non-linearity changes with the length of the planning horizon. In this paper, we evaluate the behavior of the actual service level compared to the pre-set service level. Also the effects on short/long term planning horizon is measured and analyzed. A case study of a distribution center is considered to show how to optimize the inventory level and routing system with different planning horizon and pre-set service level. We simulate the optimized solutions to evaluate the service level behavior.
41. Evaluation of the effect of product demand uncertainty on manufacturing system selection
ECU Westeran Australia University, Australia
Market competition is leading manufacturers to utilise advanced manufacturing systems. This paper focuses on a relatively new manufacturing system which provides a flexible and modular platform for drilling-related operations within automotive component industries. The use of these systems which include modular machine tools is widespread; however, manufacturers wishing to choose this technology, frequently face selecting the most appropriate and productive manufacturing system versus different available alternatives. Besides, due to the fact that today manufacturers face uncertainty of product demand, this process becomes more difficult as a lot of factors are influenced by demand variation simultaneously. Accordingly, a reliable decision should be made before making an investment on the production method. The aim of this research is analysing the sensitivity of demand uncertainty on the economic performance of modular drilling machine tool versus other alternatives and is evaluating the uncertainty’s impacts on the decision making process. To do so, a model is suggested which helps in machine tool evaluation for producing a given part to select the most productive machine tool. In this model, the demand is assumed to be independent and uncertain. Accordingly, the parameters which are influenced by demand are identified and the contribution of demand uncertainty in these parameters are investigated. Three automotive parts of varying complexity are used to examine the proposed approach and the results are discussed. The results show that considering demand uncertainty in the manufacturing system selection problem provides critical information and leads users to make logical and reliable decisions.
345. Efficient machine layout design method with a fuzzy set theory within a bay in a TFT-LCD plant
Chaoyang University of Technology, Taiwan
Building a thin-film transistor liquid-crystal display (TFT-LCD) plant is a huge investment, as a result TFT-LCD designers have been looking to a good layout design to increase their production efficiency. A multiple-zone in-line stocker is the plant’s intra-bay automated material handling system (AMHS). Due to the unique multiple-zone characteristic, the machine layout in a TFT-LCD bay is different from that in a semiconductor bay. The machine layout design within a TFT-LCD bay is required to solve not only the machine grouping problem, but also the zone formation problem. Furthermore, except for precisely quantitative criteria, vague information provided by the human natural language is a part of inputs to the machine layout design. A method capable of taking designers’ linguistic variables, like low, medium, and high, into consideration in producing a machine layout of a TFT-LCD bay is becoming more important. In this paper, we propose an efficient machine layout design method with a fuzzy set theory within a bay in a TFT-LCD plant. An intelligent hybrid heuristic algorithm with a mixed integer linear programming (MILP) model is developed. The objective aimed to achieve is to maximize in-sequence movements and minimize backtracking movements, the total flow distance, and the total backtracking flow distance. An example is given to illustrate the proposed layout procedure. It is our hope that the proposed approaches from this study benefits TFT-LCD designers to deal with both quantitative and linguistic variables for their machine layout problems.
314. Evaluation of interoperability between automation systems using multi-criteria methods
1Pontifical Catholic University of Parana (PUCPR), Brazil; 2Dominus – Automação, Sistemas e Acionamentos, Avenida Manoel Ribas, 8.120 Curitiba, Paraná, Brazil; 3Department of Mechanical Engineering (DEMEC), Federal University of Paraná (UFPR), Rua Coronel Francisco Heráclito dos Santos, 230 Curitiba, Paraná, Brazil; 4Department of Electro-tecnology (DAEL), Federal University of Technology – Paraná (UTFPR), Avenida Sete de Setembro, 3033 Curitiba, Paraná, Brazil
The business model of many companies is based on the customization of the products in the portfolio. The request for proposal and quotation moves from the product technical requirements and starts a negotiation phase ending with the offer generation. Usually, a simplified but complete design process is needed involving time-consuming activities and technical expertise. It has been observed that many companies just base the process on poor empirical models working by analogy on the basis of the expertise of senior designers and searching for similar past solutions. Then, product BOM is adapted and costs are updated accordingly.
In addition, design considerations and choices should not be limited to manufacturing cost evaluations. Environmental concerns pushes toward the early analysis of the lifecycle cost of a product, including the use and end-of-life phase. Indeed, the investment costs for tooling, accessory plants, and assets in general, needs to be included in the analysis as well as the technological background of the producer and the available IT infrastructure.
On the basis of such considerations, a research program has been started aiming at conceiving a tool to support stakeholders in the process of the early estimation in the view of the entire life-cycle of the new product. The paper investigates the requirements of such a tool on the basis of the literature background and the industrial needs. A structure of the system is depicted along with the main functionalities that should be provided.
One of the main issue regards the data exchange between the tool and other company software (e.g. CAD, ERP, PLM, KBE). Integration is needed in order to avoid information redundancy, while functionalities overlap between different systems is to be avoided. On the contrary, original functionalities are highlighted.
The framework has been proposed to a panel of partner companies that have shown interest for the system. Functionalities and benefits of the tool have been analyzed toward each company context.
The paper reports the output of the interviews with the stakeholders. The expectations of the companies have been analyzed and synthetized in a list of requirements which have been sorted and prioritized. Directions for the design and implementation of the system are finally proposed at the end of the paper.