The number of pickers and SKU arrangement on a unidirectional picking line

A picking line is often the single largest expense in a DC (Distribution Centre). In the case of the Pep Durban DC, the picking line is also a significant bottleneck neck in overall efficiency and inventory flow. The number of pickers in a picking line and the initial SKU (Stock Keeping Unit) arrangements are two known factors that affect the picking line efficiency. The main objective of this study was to model the picking line with an agent based simulation that describes individual behaviour of picker, and furthermore, through the simulation, provide analysis on the stated efficiency factors. The simulation, through verification and validation, was shown to model the real-world picking line to a satisfactory degree. Thorough analysis of simulation runs revealed that the density of a picking line, which refers to the average distance between SKU picks, was shown to be a factor in choosing a good number of pickers for a picking line. A look-up table is presented to provide decision support for the choice of a good number of pickers for a specific picking line. The initial SKU arrangement on a picking line is shown to be a factor that can affect the level of congestion and the total completion time. The GRP (Greedy ranking and partitioning) SKU arrangement technique from literature and the historical SKU arrangements used by the Pep Durban DC were compared against the CDH (classroom discipline algorithm) SKU arrangement technique proposed in this study. The CDH was shown to provide a more even spread of SKUs that are picked most frequently, thus decreasing congestion and total completion time.