A Simulation-Based System for Calculating Optimal Numbers of Forklift Drivers in Industrial Plants

Abstract

This article describes an optimization method for the material handling system of forklifts using queueing theory and simulation. The objective is to reduce several types of wastes such as waiting time, capacity costs, delayed job orders, and transportation costs. A certain IT infrastructure is assumed, such as monitors for forklift drivers to check on the current job orders at different work stations.
Mathematical equations are used to find initial upper and lower limits for the needed capacity levels over the day. Subsequently, a simulation for different levels of capacity within the range of theoretical results is performed in order to find the exact man hour needed for different jobs sequencing strategies. On the basis of the statistical software R, a tool is devised to provide companies with the results
for the different parameters they determine. These results show the effects of using batching, considering limitation of line-side space, and the empty drives reduction strategy on performance measures. The strategy of reducing empty drives by identifying the nearest workstation needing a job order was found to be not efficient since it increases the needed capacity. This is due to the fact that the variability of waiting time and hence the late orders percentage are increased.