Common AMHS myths [automated material handling systems]

The goal of an automation system is to enable predictable flow of work in progress (WIP) using the smallest buffering practical, as a way of minimizing inventory (and thus cycle time per Little's Law [Wallace J. Hopp et al., 2000]) while maintaining a defined (measurable) and acceptable amount of risk to production throughput (capital return). Often, the automated material handling system (AHMS) is evaluated on transport metrics like point-to-point delivery times and cost per storage shelf. However, from a capital-intensive factory's point of view, more critical metrics involve process tool utilization and overall throughput. By looking at the problem from the process tool's point-of-view, one can avoid certain common "myths" about the AMHS that might lead to additional costs without benefit to the factory's productivity.