Reduction of production disturbances of a shoemaking industry through a discrete event simulation approach

This study presents a reduction of production disturbances of a shoemaking industry through discrete event simulation approach. The study is conducted at Peacock Shoe factory found in Addis Ababa, Ethiopia.  This factory faces line balancing problem that becomes production disturbance for its assembly lines. Detail time study is carried out for the selected shoe model using stopwatch. Assembly process chart is used to understand the chronological sequence of assembly operations. Arena input analyzer is used to fit the input data, and K-S test is conducted to validate the goodness of fit. Hence, a simulation model for existing stitching, and lasting and finishing assembly lines are developed after taking basic simulation assumptions. The model is verified by checking a coding error of SIMAN language through try and error and validated by comparing its output with real system. Production disturbance (bottleneck) assembly line and operations are identified based on parameters such as average waiting time, WIP, production rate, capacity utilization and total flow time. To alleviate line balancing problem, five scenarios are proposed, and the detail what if the analysis is done using Arena simulation software. Scenario five is selected to reduce the level of production disturbances of the stitching assembly line. This scenario reduces the average waiting time and WIP from 2118.28 to 417.05 sec. and 252 to 85 respectively. Scenario one is selected to reduce the level of production disturbances of existing lasting and finishing assembly line. This scenario reduces the average waiting time and WIP from 2026.91 to 641.26 sec. and 169 to 65 respectively.