Timothy Matis, Ivan Guardiola, Iris Rivero
Texas Tech University
This project develops a dispatching rule that balanced the considerations of job priority as set dynamically by management with minimizing weighted tardiness, examines the flow and inventory levels of incoming materials, revises policies for response for resolving issues with incoming inventory and production rework, and develops a materials database to avoid the purchasing of redundant inventory
Pantex currently uses a due-date based push scheduling system. This system does not make adjustments for the level of the current work in progress, nor does it schedule parts within each workstation. As a result, the generated schedule is likely to be infeasible or not optimal in minimizing production measures related to latency, throughput, and work in progress. The use of heuristic methods, e.g. shifting bottleneck heuristic, edge finder, etc., have been proven to generate near optimal schedules for job shop environments in a computationally efficient manner. An improvement in productivity measures of the machine shop will be realized through the integration of such methods into current practice.
As a result of this research, a dispatching rule called the Relative Index Operator (RIO rule) was developed. This dispatching rule was subsequently used by Pantex to be the engine for the iTools software that they created to manage tooling production. Several reports that documented their inventory practices were develop upon which changes to their practices were made. A MSAccess database system with VBA macros was developed to describe the association between inventory and aid in avoiding redundant purchases and decreasing lead time due to purchasing unnecessary materials.