مدیریت تولید و عملیات (Apr 2018)
Muti-Objective Optimization and Simulation Model To Design The Withdrawal Kanban Systems
Abstract
The withdrawal Kanban system, by capability of data transferring in supply chain reduces different types of the waists such as inventories level and unnecessary movements. To achieve the aims of lean production, the parameters of the Kanban system such as the number of Kanban should be determined properly. The number of Kanban problem is a multi-objective problem which should met the aims of producers and suppliers simultaneously. In this paper, the objectives and constraints of withdrawal Kanban problem has been determined based on a case study in automobile supply chain. A mathematical integer multi-objective model with non-linear objects has been developed. Two sets of solutions are generated by the optimization model. A simulation model is developed to check the possibility and validity of solutions. The simulation studies show that one of the solutions can reduce up to 46 percent the inventory costs while increase 11 percent transportation costs compared to the current state. Introduction: Kanban as a scheduling system is an effective tool in lean manufacturing and pull production systems Kanban which helps to determine and order the quantity of allowed production and the amount of Semi-manufactured product allowed movement between workstations or supply chain components. By controlling the inventories at any point in the production and supply chain, Kanban could improve the efficiency. There are two types of Kanban: production Kanban and withdrawal Kanban. The production Kanban determines what to produce, when to produce it, and how much to produce in the workstations of manufacturing systems. While, the withdrawal Kanban determines the transfer time of different parts between various stations of the production line, or between the supply chain components. To be effective, the Kanban systems should be designed for a production system. The number of Kanban in cycle, the volume of each Kanban and the ordering point are the designing elements of Kanban. In this paper, designing the withdrawal Kanban including determining the optimal number of Kanban in cycle in supply chains is examined. Designing the withdrawal Kanban system in a supply chains affects the performance and satisfaction of supply chain components. The main contributions of this paper are: (1) Analysis of withdrawal Kanban in supply chains to identify the effects of the Kanban parameters on components of supply chain. (2) Developing a multi-objective optimization model to determine the optimal number of withdrawal Kanban by considering the objectives and constraints of the main manufacturer and supplies in the supply chain. (3) A discrete-event simulation model is constructed to compare the results of optimization model and other solutions in terms of performance indexes. Materials and Methods: A non-linear multi-objective mathematical model with four objectives is developed to determine the optimal number of withdrawal Kanban and type of vehicles which transport the Kanbans between supplies and manufacturer. The inventory, transportation, capital costs are the objective functions of the mathematical optimization model. The constraints such as vehicle capacities are considered in the mathematical model. The L-P metric method is used to convert the multi-objective model to single-objective mathematical model. The proposed model is used to design the withdrawal Kanban system in the production of an automobile component in Iran-Khodro. To evaluate the results of mathematical model and other models, a simulation model is developed. The case study are simulated with different scenarios based on the results of the proposed model, existing conditions, and other solutions. Finally, the results of simulation studies are compared Results and Discussion: The simulation studies show the solutions which obtained the proposed model compared to the current state, which can reduce up to 28 and 46 percent the capital and inventory costs, respectively. While the transportation costs will increase 11 percent. Conclusion: The Kanban system increase the efficiency of production system, if the Kanban system design properly. The design parameters of withdrawal Kanban system affect the performance and costs in a supply chain. By minimizing the capital, transportation and inventory costs in main manufacturer and suppliers of a supply chain, the optimal number of withdrawal Kanban in cycle is determined. The simulation model is proposed to evaluate the results of optimization model and measure the performance indexes of Kanban system before implementation. References Abdul Rahman, N. A., Sharif S. M. & Mashitah M. E. (2013). “Lean Manufacturing Case Study with Kanban System Implementation”. Procedia Economics and Finance, 7, 174 – 180. Azadeh, A., Layegh, J. & Pourankooh, P. (2010a). “Optimal Model for Supply Chain Controlled by kanban under JIT Philosophy by Integration of computer Simulation and Genetic Algorithm”. Basic and Applied Sciences, 4(3), 370-378. Belisario, L. S. & Pierreval, H. (2015). “Using genetic programming and simulation to learn how to dynamically adapt the number of cards in reactive pull systems”, Expert Systems with Applications, 42 (6), 3129-3141
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