t'lA Back-of-the-Envelope Miniload Throughput Bounds and Approximations

We derive simple formulas bounding and approximating the throughput of an end-of-aisle miniload system with exponentially distributed pick times and either uniform or turnover-based storage. For typical configurations, the worst case relative error for the bounds is less than 4%. We use our bounds to show that , for all practical purposes, regardless of the configuration, the picker utilization determines the s/r machine utilization, and vice-versa. Thus, a system designer cannot hope to independently achieve separate goals for the utilization rates.