Job sequencing & wip level determination in a cyclic conwip flowshop with blocking

Raju, B.N. and Siddiqui, M.A. (2017) Job sequencing & wip level determination in a cyclic conwip flowshop with blocking. International Journal of Mechanical Engineering and Technology, 8 (9). pp. 274-280. ISSN 9766340

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CONWIP (Constant Work in process) is the material within the system undergoing transformation into a final product, and cycle time is the average amount of time required for raw material to be converted into a final product. Insufficient throughput leads to unmet demand. Excessive WIP requires tying up excessive capital. Excessive cycle time leads to the loss of customer orders. In short, if any of these parameters are not managed properly, then the manufacturing industry loses money. These parameters are influenced by process variability, process time, process reliability, system bottlenecks, and the production control system used. Manufacturing industries are required to focus and manage their system's throughput, WIP, and cycle time. Here, throughput is the number of final products produced per unit time by the system. Managing the bottlenecks effectively and efficiently yields higher system throughput. Many production control systems have been proposed to improve throughput in the past. Among them following are constraints used by the manufacturing industries are the Materials Requirement Planning (MRP), Just-in-Time (JIT), Kanban (developed by Toyota Japan), Constant Work in Process (CONWIP), and Drum Buffer-Rope (DBR) systems. In this process an analysis made of bottlenecks and their impact on throughput, work-in-process (WIP), and cycle time in manufacturing systems where three parallel production lines feed components into an assembly line is carried out. The goal of these works is to determine optimal settings of control parameters within the production control systems, and selecting the appropriate production control systems for different manufacturing environments. Among the manufacturing control systems push and pull systems are important systems which tell material is released into the production facility depending upon demand forecast. And the material is released into the system only when it is needed, these control system are also called JIT systems. CONWIP come under the JIT systems. The basic findings of the production line analysis is that under any pure production control system increasing the number of bottlenecks generally increases WIP, and cycle time, and decreases throughput. According to Utilizing Little's law given constant WIP and increased cycle time results in deceased throughput, and given constant throughput and increased cycle time results in increased WIP. Through the analysis performed shows the flow lines are constant by managing the assembly system with a push system; nonbottleneck flow lines with a pull system, the WIP of the system can be reduced. If the bottleneck station does not shift between flow lines, management of all feeder lines with CONWIP systems can result in higher system throughput and reduced system WIP.

Item Type: Article
Uncontrolled Keywords: Cyclic CONWIP; JIT; Job; MRP; WIP level
Subjects: T Technology > T Technology (General)
Divisions: Faculties > Faculty of Engineering and Technology > Zakir Husain College of Engineering & Technology > Department of Mechanical Engineering
Depositing User: AMU Library
Date Deposited: 07 Feb 2018 04:36
Last Modified: 07 Feb 2018 04:56

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