Performance Assessment of Assigned Tool Management Philosophy with Black and Colored Petri Net
Zuhaib Ali Khan, Muhammad Zeeshan Zahir*, Shaukat Ali Shah, Arsalan Muhammad Ahmad, Naveed Ullah, Ashfaq Khan
Department of Mechanical Engineering, University of Engineering and Technology, Peshawar, Peshawar 25120, Pakistan.
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The implementation of a flexible manufacturing system (FMS) in the industries is a difficult task due to the underutilization of the resources. To fully utilize FMS resources; planning and analysis are required before implementing it. The most critical component is the tool which contributes to a significant amount in the overall cost of production. Little research is done in implementing tool management philosophies in Flexible Manufacturing. Tool inventory accounts for 25% of FMS’s operating expenses, lowering the tool inventory lowers the operating expenses dramatically. In this paper assigned tool management philosophy is integrated using the black and colored Petri Net (PN) technique, intending to reduce the number of tools required for the assigned plan. A generic Petri Net model is proposed for the assigned tool philosophy. The structural design of the model is derived from the process plan. Integrated Net Analyzer (INA) is used to find the total number of elementary circuits according to the process plan and optimization of the model is done with the help of LINGO software. An Excel sheet is developed to find all the performance parameters of the proposed model. In this research it is assumed that the routing and the process plan will not vary; furthermore, there is no blocking of parts during the operation and the raw materials are in excess. The black and colored PN models were compared for assigned tool philosophy and it was observed that the number of tools required was 62 and 47 for black and colored PN model respectively, further the colored PN significantly reduced the total number of invariants from 99 to 16 while keeping work in progress (WIP) same. By reducing the total number of invariants colored PN reduced the complexity of the flexible manufacturing system.