Performance Analysis Of Manufacturing Systems Research Articles

Modeling and Performance Analysis of Manufacturing Systems in Footwear Industry

This study deals with modeling and performance analysis of footwear manufacturing using arena simulation modeling software. It was investigated that modeling and simulation is a potential tool for modeling and analysis of manufacturing assembly lines like footwear manufacturing because it allows the researcher to experiment with different variables and controls the manufacturing process without affecting the real production system. In this study Arena simulation software is employed to model and measure performance of existing manufacturing systems of footwear. A footwear assembly plant producing a moccasin model shoe in Ethiopia with a total number of 19 major parts to be assembled on two consecutive assembly lines (stitching and lasting) were selected for the model. Furthermore, 39 and 37 activities were identified for stitching and lasting production line respectively. For each activity, 15 numbers of observations have taken using stopwatch. All the collected data are statistically analyzed using arena input analyzer for statistical significance and determination of expressions to be used in simulation modeling. A standard validated simulation model was developed and run for 41 replications. The result shows that the stitching assembly line is operating with a line balance efficiency of 58.7% and lasting assembly line 67.6%. In the course of action, about four major problems were identified and solved with five proposed scenarios of which the best scenario results in improvement of assembly line balance efficiency of 93.5 and 86.3% for stitching and lasting respectively. This Arena Simulation Model has considered the production resources like machineries, employees and processing time; activity precedence relationships; and production methods in developing and testing scenarios. It can be applied to other complex manufacturing industries wishing to analyze and improve the performance of the production systems.Keywords: Modeling Simulation Performance Analysis Footwear Manufacturing

Performance analysis of manufacturing systems composed of modular machines using the universal generating function

The modularity and reconfigurability of the building blocks of modern manufacturing systems have to be considered when evaluating their performance. This paper proposes a model for evaluating system availability and expected production rates for manufacturing systems that are composed of unreliable modular machines with multiple functionally parallel production units. These units are treated as independent modules, where the breakdown/stoppage of one unit does not necessitate the failure/stoppage of the whole machine and its production. The considered systems are multi-state manufacturing systems (MSMS) that can handle multiple parts simultaneously, and their structure is that of nonbuffered flow lines allowing paralleling of identical multi-state modular machines (MSMM) in each production stage. In spite of the inherent computational complexity of the proposed analysis, due to the large number of system states, it was made possible by the use of the universal generating function (UGF) technique, which proved efficient for large MSMS. The proposed model was applied to a number of case studies for demonstration and verification. The case studies were based on a family of engine front covers. The results show that machines with a larger number of modules, usually thought of as having lower availability, provided higher overall system availability in the case of machines with multiple spindles. Based on the new analysis and results, it is recommended that system designers favorably consider machines with multiple spindles rather than increasing the number of machines in parallel. These results provide an important support for the use of modular/reconfigurable equipment compared with traditional equipment, in spite of the higher cost.