Africa Journal of Business Management Vol. 4(17), pp. 3697-3707, 4 December, 2010 Available online at http://www.academicjournals.org/AJBM ISSN 1993-8233 ©2010 Academic Journals Full Length Research Paper Component and process commonalities in production system under various uncertain factors M. A. Wazed 1,2 *, S. Ahmed 1 and Y. Nukman 1 1 Department of Engineering Design and Manufacture, University of Malaya (UM) 50603 Kuala Lumpur, Malaysia. 2 Department of Mechanical Engineering, Chittagong University of Engineering and Technology (CUET), Chittagong 4349, Bangladesh. Accepted 19 May, 2010 In this paper, the authors studied the effects of process and component/part commonality and uncertain factors (viz. lead time, machine breakdown etc.) on deliverable parameters of a multi product, multi-period and multistage dependent demand manufacturing environment. The throughput of finished products and average production time of the system are examined for various experimental scenarios on the basis of existing manufacturing setup of a company consisting of multiple end products. Simulation package, namely WITNESS is used to simulate/analyze the situations of the production lines. Simulation models are developed, verified and validated with the historical data from the company. It is found that inclusion of common components in manufacturing system is always beneficial over the non-commonality environment, especially i) in uncertain situations, ii) for long procurement lead time of components and iii) when the number of parts increase in the system. Impacts of machine breakdown on system outcomes are higher than that of the lead time variation. The combination of uncertain factors has more impact on outcomes (throughput and average production time) compared to the individual factor. Commonality has a better control over the machine breakdown than lead time uncertainty. Component commonality is more effective for a production environment under uncertain situations than the process commonality. Key words: Commonality, simulation, witness. INTRODUCTION Component commonality refers to a manufacturing environment where two or more products use the same components in their assembly. Commonality is an integral element of the increasingly popular assemble-to- order strategy that inventories certain critical components –typically, with long lead time and expensive - in a generic form (Mirchandani and Mishra, 2002). Commona- lity is an approach in manufacturing, production and inventory management system where different components replace by common component(s) or same components are used for multiple products. It simplifies the management and control of resources and eases the analysis. Commonality helps to improve the existing product *Corresponding author. E-mail: awazed@gmail.com. /process or to develop a new product/process at an optimize costs. The authors would like to humbly refer the readers to Wazed et al. (2010a) for the big picture of the commonality and for its state-of-the-art. Multi-stage production planning is a system which transforms or transfers inventories through a set of connected stages to produce finished goods. This system may contain stages which represent the delivery or transformation of raw materials, the transfer of work-in- process between production facilities, the assembly of component parts, or the distribution of finished goods. The fundamental challenge of multi-stage production is the propagation and accumulation of uncertainties, which influences the conformity of the outputs (Du and Chen, 2000). Machine breakdown means the failure or stoppage of machine(s) for unknown reason(s) and a representation of