Examining the use of dedicated and general purpose pallets in a dedicated flexible manufacturing system

Abstract

This research describes one example of how the failure to understand the relationships between the flexibility associated with all resources within an FMS can be critical to overall performance. The need for such understanding is clearly spelled out by Jaikumar (1986). This research illustrates that even in situations where the demands placed upon the system are very well defined, tooling resources, such as pallets, may constrain overall system flexibility and subsequent system performance. In this paper, we simulate the operational performance of an existing FMS designed to manufacture a relatively small set of agricultural equipment components (only eight part types) over a known planning horizon using general purpose pallets and dedicated pallets. The simulation model is run under experimental conditions that include levels of: demand mix variability, number of each type pallet available to the system, and incremental loading time and scrap rate when general purpose pallets are used. In most cases, the results indicate a significant increase in system performance when using general purpose pallets. In general, while system performance decreases as the level of demand mix variability increases, relatively higher throughput is obtained using general purpose pallets except where the assumed incremental loading times and scrap rates associated with assembling the pallets are highest. System performance also improves as additional pallets are made available. In addition, overall system investment is impacted as fewer general purpose pallets are required to achieve a given level of performance compared to the use or dedicated pallets. As the overall system investment and scheduling restrictions associated with dedicated pallets would be expected to increase with the number of part types made in the system, the results found in this analysis for a dedicated FMS producing a small number of parts on a regular basis form a relative ‘lower bound’ on the scheduling and investment benefits of using general purpose pallets.