Designing Dispatching Rules for an Interbay AMHS in Facilities with Multiple Levels
Posted by Dr. Jesus Jimenez
October 25, 2017
Some chip manufacturers are running out of manufacturing footprint within their fabs since they are experiencing an increase in capacity. These manufacturers are expanding their fabs by building additional production floors or by connecting two or more contiguous fabs.
In this project, the research team developed and evaluated dispatching rules to achieve the lowest delivery time in a multi-floor facility layout. A simulation model was built to test a generic AMHS configuration featuring two lifters, 8 stockers in the first production floor and 6 stockers in the second production floor. The dispatching rules under analysis included the shortest distance rule, the minimum number in queue rule, and the hybrid rule.
The simulation results showed that the "minimum number in queue" rule resulted in the lowest delivery time. This result was critical for expansion projects seeking to connect one or more buildings/production floors with a limited number of transferring resources (i.e. lifters, elevators, conveyors, etc.). Our results also indicated that multi-floor fabs should have access to as many transfer points as possible in order to mitigate the risk of constraining the system.